Sample records for anion gap metabolic

  1. Evaluation of urine acidification by urine anion gap and urine osmolal gap in chronic metabolic acidosis

    Microsoft Academic Search

    Gheun-Ho Kim; Jin Suk Han; Yon Su Kim; Kwon Wook Joo; Suhnggwon Kim; Jung Sang Lee

    1996-01-01

    To investigate the clinical significance of urine anion gap and urine osmolal gap as indirect markers of urine acidification in chronic metabolic acidosis, we evaluated urine ammonium (NH4+), net acid excretion (NAE), urine anion gap (Na+ + K+ ? Cl?), and urine osmolal gap (urine osmolality ? [2(Na+ + K+) + urea]) in 24 patients with chronic renal failure (CRF),

  2. Diagnostic Challenge in a Patient with Severe Anion Gap Metabolic Acidosis

    PubMed Central

    Tan, Eugene M.; Kalimullah, Ejaaz; Sohail, M. Rizwan; Ramar, Kannan

    2015-01-01

    The approach to the patient with acute renal failure and elevated anion and osmolal gap is difficult. Differential diagnoses include toxic alcohol ingestion, diabetic or starvation ketoacidosis, or 5-oxoproline acidosis. We present a 76-year-old female with type 2 diabetes mellitus, who was found at home in a confused state. Laboratory analysis revealed serum pH 6.84, bicarbonate 5.8?mmol/L, pCO2 29?mmHg, anion gap 22.2?mmol/L, osmolal gap 17.4?mOsm/kg, elevated beta-hydroxybutyrate (4.2?mmol/L), random blood sugar 213?mg/dL, creatinine 2.1?mg/dL, and potassium 7.5?mmol/L with no electrocardiogram (EKG) changes. Fomepizole and hemodialysis were initiated for presumed ethylene glycol or methanol ingestion. Drug screens returned negative for ethylene glycol, alcohols, and acetaminophen, but there were elevated urine levels of acetone (11?mg/dL). The acetaminophen level was negative, and 5-oxoproline was not analyzed. After 5 days in the intensive care unit (ICU), her mental status improved with supportive care. She was discharged to a nursing facility. Though a diagnosis was not established, our patient's presentation was likely due to starvation ketosis combined with chronic acetaminophen ingestion. Acetone ingestion is less likely. Overall, our case illustrates the importance of systematically approaching an elevated osmolal and anion gap metabolic acidosis.

  3. Successfully Treated Calcific Uremic Arteriolopathy: Two Cases of a High Anion Gap Metabolic Acidosis with Intravenous Sodium Thiosulfate

    PubMed Central

    Rein, Joshua L.; Miyata, Kana N.; Dadzie, Kobena A.; Gruber, Steven J.; Sulica, Roxana; Winchester, James F.

    2014-01-01

    Calcific uremic arteriolopathy (CUA) is a rare and potentially fatal disorder of calcification involving subcutaneous small vessels and fat in patients with renal insufficiency. We describe the successful use of intravenous sodium thiosulfate (STS) for the treatment of CUA in two patients. The first case was complicated by the development of a severe anion gap metabolic acidosis, which was accompanied by a seizure. Both patients had complete wound healing within five months. Although STS should be considered in the treatment of CUA, little is known about pharmacokinetics and additional studies are required to determine dosing strategies to minimize severe potential side effects. PMID:25506005

  4. Is Serum Lactate Necessary in Patients with Normal Anion Gap and Serum Bicarbonate?

    PubMed Central

    Aronovich, Daniel; Trotter, Maykel; Rivera, Cynthia; Dalley, Michael; Farcy, David; Betancourt, Michel; Howard, Lydia; Licciardi, Sharon; Cubeddu, Luigi; Goldszer, Robert

    2015-01-01

    Introduction There has been an increase in patients having serum lactate drawn in emergency situations. The objective of this study was to determine whether or not it was necessary to obtain a lactate level in patients with a normal serum bicarbonate level and anion gap. Methods This is a retrospective chart review evaluation of 304 patients who had serum lactate and electrolytes measured in an emergency setting in one academic medical center. Results In 66 patients who had elevated serum lactate (>2.2mmol/L), 45 (68%) patients had normal serum bicarbonate (SB) (greater than 21 mmol/L). Normal anion gap (AG) (normal range <16 mEq/l) was found in 51 of the 66 patients (77%). Conclusion We found that among patients with elevated serum lactate, 77% had a normal anion gap and 68% had normal serum bicarbonate. We conclude serum lactate should be drawn based on clinical suspicion of anaerobic tissue metabolism independent of serum bicarbonate or anion gap values. PMID:25987907

  5. Near-fatal persistent anion- and osmolal-gap acidosis due to massive gamma-butyrolactone/ethanol intoxication.

    PubMed

    Heytens, Luc; Neels, Hugo; Van Regenmortel, Niels; van den Brink, Wim; Henckes, Manu; Schouwers, Sofie; Dockx, Greet; Crunelle, Cleo L

    2015-03-01

    We report a case of an ethanol and massive gamma-butyrolactone (GBL) intoxication, the precursor of the recreational drug gamma-hydroxybutyric acid (GHB), resulting in life-threatening metabolic acidosis (pH 6.5) with a highly increased anion- and osmolal gap. Rapid analysis using gas chromatography revealed a GHB plasma concentration of 4400?mg/L, far above the upper limit concentration of 1000?mg/L found in adult fatalities attributed to GBL. Full recovery was established following supportive treatment including haemodialysis. This is the first report of a combined ethanol/GBL intoxication as a cause of high serum anion- and osmolal-gap metabolic acidosis. PMID:25205856

  6. Facile doping of anionic narrow-band-gap conjugated polyelectrolytes during dialysis.

    PubMed

    Mai, Cheng-Kang; Zhou, Huiqiong; Zhang, Yuan; Henson, Zachary B; Nguyen, Thuc-Quyen; Heeger, Alan J; Bazan, Guillermo C

    2013-12-01

    PCPDTBTSO3 K, an anionic, narrow-band-gap conjugated polyelectrolyte, was found to be doped after dialysis. The proposed doping mechanism involves protonation of the polymer backbone, followed by electron transfer from a neutral chain, to generate radical cations, which are stabilized by the pendant sulfonate anions. Formation of polarons is supported by spectroscopy and electrical-conductivity measurements. PMID:24281883

  7. The Anion Gap and Routine Serum Protein Measurements in Monoclonal Gammopathies

    PubMed Central

    Joseph, Rosy E.; Gaughan, William J.; McBride, Laura; Bilotti, Elizabeth; McNeill, Ann; Schmidt, Linda; Schillen, Danielle; Siegel, David S.

    2011-01-01

    Summary Background and objectives An abnormal anion gap and an increased total protein and globulin are clues to the diagnosis of monoclonal gammopathy. We explored the utility of these markers in IgG, IgA, IgM, and free light chain monoclonal gammopathies. Design, Setting, Participants, & Measurements The anion gap, Na+ – (Cl– + HCO3–), corrected for hypoalbuminemia, was calculated in patients with monoclonal gammopathies. Exclusion criteria were serum calcium >10.5 mg/dl and/or creatinine >2 mg/dl. Results Among 287 patients, 242 remained after applying exclusion criteria (109 IgG, 64 IgA, 21 IgM, and 48 light chain); 36% of 242 patients required correction for hypoalbuminemia. The anion gap was decreased (<10) in 22% of IgG and increased (>15) in 31% of IgA monoclonal gammopathies. IgM did not affect the gap. In light chain gammopathies, the anion gap showed no consistent trend (15% increased, 17% decreased). Mean clonal IgG, IgA, and IgM concentrations were 10-fold higher than mean clonal free light chain concentrations in the respective monoclonal gammopathies (P < 0.001). These paraprotein level disparities were reflected in significantly increased mean serum total protein and globulin concentrations in IgG, IgA, and IgM versus free light chain monoclonal gammopathies, where mean total protein and globulin levels were within normal limits (P < 0.001). Conclusions The anion gap was significantly altered in IgG and IgA monoclonal gammopathies, but it was not a sensitive tool for suspecting the diagnosis. In light chain monoclonal gammopathies, the anion gap, total protein, and globulin did not provide reliable diagnostic clues. PMID:22157711

  8. A retrospective analysis of glycol and toxic alcohol ingestion: utility of anion and osmolal gaps

    PubMed Central

    2012-01-01

    Background Patients ingesting ethylene glycol, isopropanol, methanol, and propylene glycol ('toxic alcohols') often present with non-specific signs and symptoms. Definitive diagnosis of toxic alcohols has traditionally been by gas chromatography (GC), a technique not commonly performed on-site in hospital clinical laboratories. The objectives of this retrospective study were: 1) to assess the diagnostic accuracy of the osmolal gap in screening for toxic alcohol ingestion and 2) to determine the common reasons other than toxic alcohol ingestion for elevated osmolal gaps. Methods Electronic medical records from an academic tertiary care medical center were searched to identify all patients in the time period from January 1, 1996 to September 1, 2010 who had serum/plasma ethanol, glucose, sodium, blood urea nitrogen, and osmolality measured simultaneously, and also all patients who had GC analysis for toxic alcohols. Detailed chart review was performed on all patients with osmolal gap of 9 or greater. Results In the study period, 20,669 patients had determination of serum/plasma ethanol and osmolal gap upon presentation to the hospitals. There were 341 patients with an osmolal gap greater than 14 (including correction for estimated contribution of ethanol) on initial presentation to the medical center. Seventy-seven patients tested positive by GC for one or more toxic alcohols; all had elevated anion gap or osmolal gap or both. Other than toxic alcohols, the most common causes for an elevated osmolal gap were recent heavy ethanol consumption with suspected alcoholic ketoacidosis, renal failure, shock, and recent administration of mannitol. Only 9 patients with osmolal gap greater than 50 and no patients with osmolal gap greater than 100 were found to be negative for toxic alcohols. Conclusions Our study concurs with other investigations that show that osmolal gap can be a useful diagnostic test in conjunction with clinical history and physical examination. PMID:22240170

  9. Anionic metabolic profiling of urine from antibiotic-treated rats by capillary electrophoresis-mass spectrometry.

    PubMed

    Kok, Miranda G M; Ruijken, Marco M A; Swann, Jonathan R; Wilson, Ian D; Somsen, Govert W; de Jong, Gerhardus J

    2013-03-01

    A recently developed capillary electrophoresis (CE)-negative-ionisation mass spectrometry (MS) method was used to profile anionic metabolites in a microbial-host co-metabolism study. Urine samples from rats receiving antibiotics (penicillin G and streptomycin sulfate) for 0, 4, or 8 days were analysed. A quality control sample was measured repeatedly to monitor the performance of the applied CE-MS method. After peak alignment, relative standard deviations (RSDs) for migration time of five representative compounds were below 0.4 %, whereas RSDs for peak area were 7.9-13.5 %. Using univariate and principal component analysis of obtained urinary metabolic profiles, groups of rats receiving different antibiotic treatment could be distinguished based on 17 discriminatory compounds, of which 15 were downregulated and 2 were upregulated upon treatment. Eleven compounds remained down- or upregulated after discontinuation of the antibiotics administration, whereas a recovery effect was observed for others. Based on accurate mass, nine compounds were putatively identified; these included the microbial-mammalian co-metabolites hippuric acid and indoxyl sulfate. Some discriminatory compounds were also observed by other analytical techniques, but CE-MS uniquely revealed ten metabolites modulated by antibiotic exposure, including aconitic acid and an oxocholic acid. This clearly demonstrates the added value of CE-MS for nontargeted profiling of small anionic metabolites in biological samples. PMID:23314487

  10. Survival of hydrogen anions near atomically flat metal surfaces: Band gap confinement and image state recapture effects

    NASA Astrophysics Data System (ADS)

    Schmitz, Andrew; Shaw, John; Chakraborty, Himadri; Thumm, Uwe

    2010-03-01

    Resonant charge transfer (RCT) between ions and surfaces is a key intermediate step in surface-chemical processes as well as in micro- and nano-fabrications on the surface. The RCT process in the collision of hydrogen anions with metal surfaces is described within a wave packet propagation methodology using Crank-Nicholson algorithm [1]. The ion-survival probability is found to strongly enhance at two different ion velocities perpendicular to the surface. The low velocity enhancement is induced from a dynamical confinement of the ion level inside the band gap, while the high velocity enhancement emerges owing to the recapture from transiently populated image states [2]. These structures are found to be somewhat sensitive to the ion's distance of closest approach to the surface and the choice of inter-atomic potentials between the ion and the surface atoms. [1] Chakraborty et al., Phys. Rev. A 70, 052903 (2004); [2] Schmitz et al., Phys. Rev. A (submitted).

  11. Highly Polarizable Triiodide Anions (I3(-)) as Cross-Linkers for Coordination Polymers: Closing the Semiconductive Band Gap.

    PubMed

    He, Jun; Cao, Peng; Wu, Chao; Huang, Jiahong; Huang, Jian; He, Yonghe; Yu, Lin; Zeller, Matthias; Hunter, Allen D; Xu, Zhengtao

    2015-07-01

    From a hydrothermal reaction using CuI, KI, and 3,3'5,5'-tetramethyl-4,4'-bipyrazole (TMBP), the triiodide anion I3(-) has been integrated into the water-stable 2D coordination polymer Cu(TMBP)I3 (1). In contrast with other metal triiodide complexes, 1 features remarkably small distortions in the bond distances associated with the I3(-) units (i.e., the Cu-I and I-I bonds), which effectively link up the copper(I) centers into infinite CuI3 chains. The electronic band gaps and electrical conductivity data are also found to be consistent with the I3(-) ion acting as an effective linker across the copper(I) centers. PMID:26098817

  12. Effect of the Independent Acid Base Variables on Anion Gap Variation in Cardiac Surgical Patients: A Stewart-Figge Approach

    PubMed Central

    Keklikoglou, Ilias; Papoti, Sofia; Diminikos, George; Diplaris, Konstantinos

    2014-01-01

    Purpose. To determine the effect of each of independent acid base variables on the anion gap (AG) value in cardiac surgical patients. Methods. This retrospective study involved 128 cardiac surgical patients admitted for postoperative care. The variation of AG (AGvar) between the day of admission and the first postoperative day was correlated via a multiple linear regression model with the respective variations of the independent acid base variables, that is, apparent strong ion difference (SIDa), strong ion gap (SIG), carbon dioxide (PCO2), and albumin and phosphate concentrations. Results. The variations of all the above variables contributed significantly to the prediction of AGvar (adjusted R2 = 0.9999, F = 201890.24, and P < 0.001). According to the standardized coefficients (?),??SIGvar (? = 0.948, P < 0.001), [Albumin]var (? = 0.260, P < 0.001), and [Phosphate]var (? = 0.191, P < 0.001) were the major determinants of AGvar with lesser contributions from SIDa,?var (? = 0.071, P < 0.001) and PCO2,?var (? = ?0.067, P < 0.001). Conclusions. All the independent acid base variables contribute to the prediction of the AG value. However, albumin and phosphate and SIG variations seem to be the most important predictors, while AG appears to be rather stable with changes in PCO2 and SIDa. PMID:24688446

  13. Likelihood-Based Gene Annotations for Gap Filling and Quality Assessment in Genome-Scale Metabolic Models

    PubMed Central

    Benedict, Matthew N.; Mundy, Michael B.; Henry, Christopher S.; Chia, Nicholas; Price, Nathan D.

    2014-01-01

    Genome-scale metabolic models provide a powerful means to harness information from genomes to deepen biological insights. With exponentially increasing sequencing capacity, there is an enormous need for automated reconstruction techniques that can provide more accurate models in a short time frame. Current methods for automated metabolic network reconstruction rely on gene and reaction annotations to build draft metabolic networks and algorithms to fill gaps in these networks. However, automated reconstruction is hampered by database inconsistencies, incorrect annotations, and gap filling largely without considering genomic information. Here we develop an approach for applying genomic information to predict alternative functions for genes and estimate their likelihoods from sequence homology. We show that computed likelihood values were significantly higher for annotations found in manually curated metabolic networks than those that were not. We then apply these alternative functional predictions to estimate reaction likelihoods, which are used in a new gap filling approach called likelihood-based gap filling to predict more genomically consistent solutions. To validate the likelihood-based gap filling approach, we applied it to models where essential pathways were removed, finding that likelihood-based gap filling identified more biologically relevant solutions than parsimony-based gap filling approaches. We also demonstrate that models gap filled using likelihood-based gap filling provide greater coverage and genomic consistency with metabolic gene functions compared to parsimony-based approaches. Interestingly, despite these findings, we found that likelihoods did not significantly affect consistency of gap filled models with Biolog and knockout lethality data. This indicates that the phenotype data alone cannot necessarily be used to discriminate between alternative solutions for gap filling and therefore, that the use of other information is necessary to obtain a more accurate network. All described workflows are implemented as part of the DOE Systems Biology Knowledgebase (KBase) and are publicly available via API or command-line web interface. PMID:25329157

  14. Hydrophilic interaction chromatography-mass spectrometry for anionic metabolic profiling of urine from antibiotic-treated rats.

    PubMed

    Kok, Miranda G M; Swann, Jonathan R; Wilson, Ian D; Somsen, Govert W; de Jong, Gerhardus J

    2014-04-01

    Hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) was used for anionic metabolic profiling of urine from antibiotic-treated rats to study microbial-host co-metabolism. Rats were treated with the antibiotics penicillin G and streptomycin sulfate for four or eight days and compared to a control group. Urine samples were collected at day zero, four and eight, and analyzed by HILIC-MS. Multivariate data analysis was applied to the urinary metabolic profiles to identify biochemical variation between the treatment groups. Principal component analysis found a clear distinction between those animals receiving antibiotics and the control animals, with twenty-nine discriminatory compounds of which twenty were down-regulated and nine up-regulated upon treatment. In the treatment group receiving antibiotics for four days, a recovery effect was observed for seven compounds after cessation of antibiotic administration. Thirteen discriminatory compounds could be putatively identified based on their accurate mass, including aconitic acid, benzenediol sulfate, ferulic acid sulfate, hippuric acid, indoxyl sulfate, penicillin G, phenol and vanillin 4-sulfate. The rat urine samples had previously been analyzed by capillary electrophoresis (CE) with MS detection and proton nuclear magnetic resonance ((1)H NMR) spectroscopy. Using CE-MS and (1)H NMR spectroscopy seventeen and twenty-five discriminatory compounds were found, respectively. Both hippuric acid and indoxyl sulfate were detected across all three platforms. Additionally, eight compounds were observed with both HILIC-MS and CE-MS. Overall, HILIC-MS appears to be highly complementary to CE-MS and (1)H NMR spectroscopy, identifying additional compounds that discriminate the urine samples from antibiotic-treated and control rats. PMID:24503197

  15. Bridging the gap between gene expression and metabolic phenotype via kinetic models

    PubMed Central

    2013-01-01

    Background Despite the close association between gene expression and metabolism, experimental evidence shows that gene expression levels alone cannot predict metabolic phenotypes, indicating a knowledge gap in our understanding of how these processes are connected. Here, we present a method that integrates transcriptome, fluxome, and metabolome data using kinetic models to create a mechanistic link between gene expression and metabolism. Results We developed a modeling framework to construct kinetic models that connect the transcriptional and metabolic responses of a cell to exogenous perturbations. The framework allowed us to avoid extensive experimental characterization, literature mining, and optimization problems by estimating most model parameters directly from fluxome and transcriptome data. We applied the framework to investigate how gene expression changes led to observed phenotypic alterations of Saccharomyces cerevisiae treated with weak organic acids (i.e., acetate, benzoate, propionate, or sorbate) and the histidine synthesis inhibitor 3-aminotriazole under steady-state conditions. We found that the transcriptional response led to alterations in yeast metabolism that mimicked measured metabolic fluxes and concentration changes. Further analyses generated mechanistic insights of how S. cerevisiae responds to these stresses. In particular, these results suggest that S. cerevisiae uses different regulation strategies for responding to these insults: regulation of two reactions accounted for most of the tolerance to the four weak organic acids, whereas the response to 3-aminotriazole was distributed among multiple reactions. Moreover, we observed that the magnitude of the gene expression changes was not directly correlated with their effect on the ability of S. cerevisiae to grow under these treatments. In addition, we identified another potential mechanism of action of 3-aminotriazole associated with the depletion of tetrahydrofolate. Conclusions Our simulation results show that the modeling framework provided an accurate mechanistic link between gene expression and cellular metabolism. The proposed method allowed us to integrate transcriptome, fluxome, and metabolome data to determine and interpret important features of the physiological response of yeast to stresses. Importantly, given its flexibility and robustness, our approach can be applied to investigate the transcriptional-metabolic response in other cellular systems of medical and industrial relevance. PMID:23875723

  16. Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells

    PubMed Central

    Wang, Yizhou; Blatt, Michael R.

    2011-01-01

    Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (malate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (ICl) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect ICl, but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of ICl by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with ICl through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes. PMID:21745184

  17. METABOLIC RESPONSES OF TRANSITION HOLSTEIN COWS FED ANIONIC SALTS AND SUPPLEMENTED AT CALVING WITH CALCIUM AND ENERGY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), and glucose in transition cows fed anionic salts prepartum and provided with calcium and energy supplements at calving. The study was conducted on a Fl...

  18. Monovalent Cation Permeation through the Connexin40 Gap Junction Channel: Cs, Rb, K, Na, Li, TEA, TMA, TBA, and Effects of Anions Br, Cl, F, Acetate, Aspartate, Glutamate, and NO3

    Microsoft Academic Search

    Dolores A. Beblo; Richard D. Veenstra

    1997-01-01

    The unitary conductances and permeability sequences of the rat connexin40 (rCx40) gap junction channel s to seven monovalent cations and anions were studied in rCx40-transfected neuroblastoma 2A (N2A) cell pairs using the dual whole cell recording technique. Chloride salt cation substitutions (115 mM principal salt) re- sulted in the following junctional maximal single channel current-voltage relationship slope conductances ( g

  19. AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability

    PubMed Central

    Yang, Yoon Mee; Han, Chang Yeob; Kim, Yoon Jun; Kim, Sang Geon

    2010-01-01

    The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function. PMID:20698033

  20. Metabolism

    MedlinePLUS

    ... For Kids For Parents MORE ON THIS TOPIC Metabolic Syndrome Blood Test: Basic Metabolic Panel (BMP) Your Child's ... System Thyroid Disorders Diabetes Center Movie: Endocrine System Metabolic Syndrome Blood Test: Basic Metabolic Panel Blood Test: Comprehensive ...

  1. Dysfunction of Organic Anion Transporting Polypeptide 1a1 Alters Intestinal Bacteria and Bile Acid Metabolism in Mice

    PubMed Central

    Zhang, Youcai; Limaye, Pallavi B.; Lehman-McKeeman, Lois D.; Klaassen, Curtis D.

    2012-01-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in liver and is able to transport bile acids (BAs) in vitro. Male Oatp1a1-null mice have increased concentrations of taurodeoxycholic acid (TDCA), a secondary BA generated by intestinal bacteria, in both serum and livers. Therefore, in the present study, BA concentrations and intestinal bacteria in wild-type (WT) and Oatp1a1-null mice were quantified to investigate whether the increase of secondary BAs in Oatp1a1-null mice is due to alterations in intestinal bacteria. The data demonstrate that Oatp1a1-null mice : (1) have similar bile flow and BA concentrations in bile as WT mice; (2) have a markedly different BA composition in the intestinal contents, with a decrease in conjugated BAs and an increase in unconjugated BAs; (3) have BAs in the feces that are more deconjugated, desulfated, 7-dehydroxylated, 3-epimerized, and oxidized, but less 7-epimerized; (4) have 10-fold more bacteria in the small intestine, and 2-fold more bacteria in the large intestine which is majorly due to a 200% increase in Bacteroides and a 30% reduction in Firmicutes; and (5) have a different urinary excretion of bacteria-related metabolites than WT mice. In conclusion, the present study for the first time established that lack of a liver transporter (Oatp1a1) markedly alters the intestinal environment in mice, namely the bacteria composition. PMID:22496825

  2. Molecular anions.

    PubMed

    Simons, Jack

    2008-07-24

    The experimental and theoretical study of molecular anions has undergone explosive growth over the past 40 years. Advances in techniques used to generate anions in appreciable numbers as well as new ion-storage, ion-optics, and laser spectroscopic tools have been key on the experimental front. Theoretical developments on the electronic structure and molecular dynamics fronts now allow one to achieve higher accuracy and to study electronically metastable states, thus bringing theory in close collaboration with experiment in this field. In this article, many of the experimental and theoretical challenges specific to studying molecular anions are discussed. Results from many research groups on several classes of molecular anions are overviewed, and both literature citations and active (in online html and pdf versions) links to numerous contributing scientists' Web sites are provided. Specific focus is made on the following families of anions: dipole-bound, zwitterion-bound, double-Rydberg, multiply charged, metastable, cluster-based, and biological anions. In discussing each kind of anion, emphasis is placed on the structural, energetic, spectroscopic, and chemical-reactivity characteristics that make these anions novel, interesting, and important. PMID:18630888

  3. Metabolism

    MedlinePLUS

    ... Some metabolic diseases and conditions include: Hyperthyroidism (pronounced: hi-per-THIGH-roy-dih-zum). Hyperthyroidism is caused ... or through surgery or radiation treatments. Hypothyroidism (pronounced: hi-po-THIGH-roy-dih-zum) . Hypothyroidism is caused ...

  4. Acute kidney injury, hyperosmolality and metabolic acidosis associated with lorazepam

    Microsoft Academic Search

    Irfan Yusufzai; Anna Sullivan; Charles Graeber; Tausif Zar

    2007-01-01

    Background A 54-year-old male with a history of multiple admissions for alcohol intoxication was admitted to hospital with right flank pain. He received a high-dose lorazepam infusion for alcohol withdrawal during hospitalization and developed severe hyperosmolality, high anion gap metabolic acidosis, and acute kidney injury on his eighth day of hospitalization.Investigations Serum chemistries, arterial blood gas analysis, and measurement of

  5. Gap Between Evidence and Patient Access: Policy Implications for Bariatric and Metabolic Surgery in the Treatment of Obesity and its Complications.

    PubMed

    Chawla, Amarpreet S; Hsiao, Chia-Wen; Romney, Martha C; Cohen, Ricardo; Rubino, Francesco; Schauer, Philip; Cremieux, Pierre

    2015-07-01

    Despite consistently supportive evidence of clinical effectiveness and economic advantages compared with currently available non-surgical obesity treatments, patient access to bariatric and metabolic surgery (BMS) is impeded. To address this gap and better understand the relationship between value and access, the objectives of this study were twofold: (i) identify the multidimensional barriers to adoption of BMS created by clinical guidelines, public policies, and health technology assessments; and, most importantly, (ii) develop recommendations for stakeholders to improve patient access to BMS. Updated public policies focused on treatment and clinical guidelines that reflect the demonstrated advantages of BMS, patient education on safety and effectiveness, updated reimbursement policies, and additional data on long-term BMS effectiveness are needed to improve patient access. PMID:26063335

  6. SLC17: A functionally diverse family of organic anion transporters

    PubMed Central

    Reimer, Richard J.

    2012-01-01

    Molecular studies have determined that the SLC17 transporters, a family of nine proteins initially implicated in phosphate transport, mediate the transport of organic anions. While their role in phosphate transport remains uncertain, it is now clear that the transport of organic anions facilitated by this family of proteins is involved in diverse processes ranging from the vesicular storage of the neurotransmitters, to urate metabolism, to the degradation and metabolism of glycoproteins. PMID:23506876

  7. Quantum Chemical Approach to Estimating the Thermodynamics of Metabolic Reactions

    NASA Astrophysics Data System (ADS)

    Jinich, Adrian; Rappoport, Dmitrij; Dunn, Ian; Sanchez-Lengeling, Benjamin; Olivares-Amaya, Roberto; Noor, Elad; Even, Arren Bar; Aspuru-Guzik, Alán

    2014-11-01

    Thermodynamics plays an increasingly important role in modeling and engineering metabolism. We present the first nonempirical computational method for estimating standard Gibbs reaction energies of metabolic reactions based on quantum chemistry, which can help fill in the gaps in the existing thermodynamic data. When applied to a test set of reactions from core metabolism, the quantum chemical approach is comparable in accuracy to group contribution methods for isomerization and group transfer reactions and for reactions not including multiply charged anions. The errors in standard Gibbs reaction energy estimates are correlated with the charges of the participating molecules. The quantum chemical approach is amenable to systematic improvements and holds potential for providing thermodynamic data for all of metabolism.

  8. Anions in Cometary Comae

    NASA Technical Reports Server (NTRS)

    Charnley, Steven B.

    2011-01-01

    The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of IP/Halley. The anions 0-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not yet been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydro dynamical model of Rodgers & Charnley (2002), we investigate the role of large carbon-chain anions in cometary coma chemistry. We calculate the effects of these anions on coma thermodynamics, charge balance and examine their impact on molecule formation.

  9. A Case of Chronic Ethylene Glycol Intoxication Presenting without Classic Metabolic Derangements

    PubMed Central

    Toth-Manikowski, Stephanie M.; Menn-Josephy, Hanni

    2014-01-01

    Acute ethylene glycol ingestion classically presents with high anion gap acidosis, elevated osmolar gap, altered mental status, and acute renal failure. However, chronic ingestion of ethylene glycol is a challenging diagnosis that can present as acute kidney injury with subtle physical findings and without the classic metabolic derangements. We present a case of chronic ethylene glycol ingestion in a patient who presented with acute kidney injury and repeated denials of an exposure history. Kidney biopsy was critical to the elucidation of the cause of his worsening renal function. PMID:25215251

  10. REVIEW ARTICLE Molecular Anions

    E-print Network

    Simons, Jack

    REVIEW ARTICLE Molecular Anions Jack Simons Chemistry Department, Henry Eyring Center in close collaboration with experiment in this field. In this article, many of the experimental that make these anions novel, interesting, and important. Opening Remarks This article offers many links

  11. Chemiluminescence and superoxide anion production by leukocytes from chronic hemodialysis patients

    Microsoft Academic Search

    Elizabeth E Ritchey; John D Wallin; Sudhir V Shah

    1981-01-01

    Chemiluminescence and superoxide anion production by leukocytes from chronic hemodialysis patients. During phagocytosis or in response to a soluble stimulus, polymorphonuclear leukocytes (PMN) undergo a burst of oxidative metabolism involved intimately in antimicrobial activity. Superoxide anion produced during the burst is bactericidal either directly or as an intermediate metabolite. In addition, stimulated PMN's emit light or chemiluminescence (CL). CL is

  12. Citrate metabolism in blood transfusions and its relationship due to metabolic alkalosis and respiratory acidosis

    PubMed Central

    Li, Kai; Xu, Yuan

    2015-01-01

    Metabolic alkalosis commonly results from excessive hydrochloric acid (HCl), potassium (K+) and water (H2O) loss from the stomach or through the urine. The plasma anion gap increases in non-hypoproteinemic metabolic alkalosis due to an increased negative charge equivalent on albumin and the free ionized calcium (Ca++) content of plasma decreases. The mean citrate load in all patients was 8740±7027 mg from 6937±6603 mL of transfused blood products. The citrate load was significantly higher in patients with alkalosis (9164±4870 vs. 7809±3967, P < 0.05). The estimated mean total citrate administered via blood and blood products was calculated as 43.2±34.19 mg/kilogram/day. In non-massive and frequent blood transfusions, the elevated carbon dioxide output has been shown to occur. Due to citrate metabolism causes intracellular acidosis. As a result of intracellular acidosis compensation, decompensated metabolic alkalosis + respiratory acidosis and electrolyte imbalance may develop, blood transfusions may result in certain complications.

  13. Anion selective membrane

    Microsoft Academic Search

    S. S. Alexander; R. R. Geoffroy; R. B. Hodgdon

    1975-01-01

    Experimental anion permselective membranes were prepared and tested for their suitability as cell separators in a chemical redox power storage system being developed at NASA-Lewis Research Center. The goals of long-term (1000 hr) oxidative and thermal stability at 80 C in FeCl3 and CrCl3 electrolytes were met by most of the weak base and strong base amino exchange groups considered

  14. Anion permselective membrane

    NASA Technical Reports Server (NTRS)

    Hodgdon, R. B.; Waite, W. A.; Alexander, S. S.

    1984-01-01

    Two polymer ion exchange membranes were synthesized to fulfill the needs of both electrical resistivity and anolyte/catholyte separation for utility load leveling utilizing the DOE/NASA mixed electrolyte REDOX battery. Both membranes were shown to meet mixed electrolyte utility load leveling criteria. Several modifications of an anion exchange membrane failed to meet utility load leveling REDOX battery criteria using the unmixed electrolyte REDOX cell.

  15. An unrecognised case of metabolic acidosis following neobladder augmentation cystoplasty

    PubMed Central

    Eldred-Evans, David; Khan, Fahd; Abbaraju, Jay; Sriprasad, Seshadri

    2015-01-01

    Introduction We present a case where there was a delay in the diagnosis of severe metabolic acidosis in a patient with an orthotopic neobladder. There are a growing number of patients with orthotopic neobladders and a wider range of clinicians are encountering these patients. A delay in the diagnosis can lead to significant morbidity but if identified early it can be easily treated. Presentation of case A 59-year old patient with a recent neobladder augmentation cystoplasty was admitted under the medical team with a metabolic acidosis which was incorrectly presumed to be secondary to urosepsis. His condition rapidly deteriorated until a surgical review identified hyperchloremic metabolic acidosis secondary to neobladder augmentation. The patient required admission to the intensive care unit where he was treated with intravenous alkalising therapy which produced rapid metabolic improvement. Following a full recovery, he underwent neo-bladder excision and ileal conduit formation. Discussion Hyperchloraemic metabolic acidosis develops due to the bowel segment absorbing urinary constituents including ammonium, hydrogen ions and chloride in exchange for sodium and bicarbonate. It can be diagnosed by careful interpretation of the arterial blood gas and calculation of the anion gap. This hyperchloraemic metabolic acidosis can be corrected with alkalizing agents combined with catheterisation. Conclusion Hyperchloremic metabolic acidosis is a well-established complication of urinary diversion. Patient with orthotopic neobladder with high residual urine and large capacity are at even higher risk of metabolic acidosis. This information should be clearly documented in the post-operative discharge documentation to ensure early recognition by non-specialists. PMID:25979515

  16. Anion permselective membrane

    NASA Technical Reports Server (NTRS)

    Hodgdon, R. B.; Waite, W. A.

    1980-01-01

    The efforts on the synthesis of polymer anion redox membranes were mainly concentrated in two areas, membrane development and membrane fabrication. Membrane development covered the preparation and evaluation of experimental membranes systems with improved resistance stability and/or lower permeability. Membrane fabrication covered the laboratory scale production of prime candidate membranes in quantities of up to two hundred and sizes up to 18 inches x 18 inches (46 cm x 46 cm). These small (10 in x 11 in) and medium sized membranes were mainly for assembly into multicell units. Improvements in processing procedures and techniques for preparing such membrane sets lifted yields to over 90 percent.

  17. Anion/anion exchange in human neutrophils

    PubMed Central

    1986-01-01

    Of the total one-way chloride fluxes (approximately 1.4 meq/liter cell water X min) in steady state human polymorphonuclear leukocytes bathed in 148 mM Cl media, approximately 70% behaves as self-exchange mediated by a nonselective anion carrier that is not inhibited by stilbene disulfonates. Five properties of this carrier-mediated exchange were investigated: substrate saturation is seen with respect to 36Cl influx as a function of the external Cl concentration [for normal-Cl cells, the apparent Km(Cl) is approximately 22 mM when Cl replaces para-amino- hippurate (PAH) and approximately 5 mM when Cl replaces glucuronate], and with respect to 36Cl efflux as a function of the concentration of internal Cl replacing PAH [apparent Km(Cl) congruent to 35 mM for cells bathed in 148 mM Cl]; there is trans stimulation of 36Cl influx by internal Cl (replacing PAH) with an apparent Km(Cl) congruent to 35 mM, and of 36Cl efflux by external Cl with an apparent Km(Cl) congruent to 22 mM (Cl replacing PAH) or approximately 5 mM (Cl replacing glucuronate); there is substrate competition between Cl and PAH, but the carrier appears devoid of affinity for glucuronate; influxes and effluxes mediated by the carrier are subject to competitive inhibition by extracellular alpha-cyano-4-hydroxycinnamate (CHC), with an apparent Ki congruent to 9 mM in Cl medium or approximately 1 mM in PAH medium (transport of the inhibitor itself is very slow); and internal Cl and external Cl or PAH undergo 1:1 countertransport, which is CHC sensitive. A simple equilibrium-competition model is proposed that accounts for all the extracellular ligand interactions presented for normal-Cl cells. Least-squares values of the carrier's true Michaelis constants for extracellular Cl, PAH, and CHC are 5.03 +/- 0.83, 50.3 +/- 14.9, and 0.29 +/- 0.09 mM, respectively. PMID:3746251

  18. Anion permselective membrane

    NASA Technical Reports Server (NTRS)

    Hodgdon, R. B.; Waite, W. A.

    1982-01-01

    The synthesis and fabrication of polymeric anion permselective membranes for redox systems are discussed. Variations of the prime candidate anion membrane formulation to achieve better resistance and/or lower permeability were explored. Processing parameters were evaluated to lower cost and fabricate larger sizes. The processing techniques to produce more membranes per batch were successfully integrated with the fabrication of larger membranes. Membranes of about 107 cm x 51 cm were made in excellent yield. Several measurements were made on the larger sample membranes. Among the data developed were water transport and transference numbers for these prime candidate membranes at 20 C. Other work done on this system included characterization of a number of specimens of candidate membranes which had been returned after service lives of up to sixteen months. Work with new polymer constituents, with new N.P.'s, catalysts and backing fabrics is discussed. Some work was also done to evaluate other proportions of the ingredients of the prime candidate system. The adoption of a flow selectivity test at elevated temperature was explored.

  19. Cation disorder and anion displacement in DIIXVI - AIBIIIXVI2 semiconductors

    NASA Astrophysics Data System (ADS)

    Schorr, S.; Wagner, G.; Tovar, M.; Sheptyakov, D.

    2006-09-01

    The composition dependent structural phase transitions (tetragonal-cubic) in (ZnX)2x(CuBX2)1-x alloys (B = Ga, In; X = S, Se, Te) were studied by neutron and X-ray powder diffraction as well as TEM. The transitions are due to the interplay of disorder within the cation substructure and the displacement of the anions. It goes along with a phase separation by cation ordering, i. e. there is a miscibility gap (2-phase field), where tetragonal domains and a cubic matrix coexist. Within a homologous series its extension and the particular composition of end members of this 2-phase field depend on the size of the anion. However, for the same anion its width is determined by the BIII cation. For the tetragonal single phase a non-random Zn distribution on the cation sites of the chalcopyrite-type structure was revealed, indicating the tendency of disorder in the cation substructure.

  20. Kinetics of Anionic Surfactant Anoxic Degradation 

    E-print Network

    Camacho, Julianna G.

    2010-07-14

    commonly present in personal cleansing products and detergents; anionic, nonionic, and amphoteric. The surfactant used in this study is an anionic surfactant. Anionic synthetic detergents may be classified into sulfates and sulfonates (Figure 1). R...

  1. Kinetics of Anionic Surfactant Anoxic Degradation

    E-print Network

    Camacho, Julianna G.

    2010-07-14

    commonly present in personal cleansing products and detergents; anionic, nonionic, and amphoteric. The surfactant used in this study is an anionic surfactant. Anionic synthetic detergents may be classified into sulfates and sulfonates (Figure 1). R...

  2. Anion permselective membrane

    NASA Technical Reports Server (NTRS)

    Alexander, S.; Hodgdon, R. B.

    1977-01-01

    The objective of NAS 3-20108 was the development and evaluation of improved anion selective membranes useful as efficient separators in a redox power storage cell system being constructed. The program was divided into three parts, (a) optimization of the selected candidate membrane systems, (b) investigation of alternative membrane/polymer systems, and (c) characterization of candidate membranes. The major synthesis effort was aimed at improving and optimizing as far as possible each candidate system with respect to three critical membrane properties essential for good redox cell performance. Substantial improvements were made in 5 candidate membrane systems. The critical synthesis variables of cross-link density, monomer ratio, and solvent composition were examined over a wide range. In addition, eight alternative polymer systems were investigated, two of which attained candidate status. Three other alternatives showed potential but required further research and development. Each candidate system was optimized for selectivity.

  3. Gap Winds

    NSDL National Science Digital Library

    2014-09-14

    This module provides a basic understanding of why gap winds occur, their typical structures, and how gap wind strength and extent are controlled by larger-scale, or synoptic, conditions. You will learn about a number of important gap flows in coastal regions around the world, with special attention given to comprehensively documented gap wind cases in the Strait of Juan de Fuca and the Columbia River Gorge. Basic techniques for evaluating and predicting gap flows are presented. The module reviews the capabilities and limitations of the current generation of mesoscale models in producing realistic gap winds. By the end of this module, you should have sufficient background to diagnose and forecast gap flows around the world, and to use this knowledge to understand their implications for operational decisions. Other features in this module include a concise summary for quick reference and a final exam to test your knowledge. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.

  4. Gap Junctions

    PubMed Central

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2013-01-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

  5. A rare metabolic complication of acute lymphoblastic leukemia in childhood: lactic acidosis.

    PubMed

    Gökçe, Müge; Unal, Sule; Gül?en, Hayriye; Ba?aran, Ozge; Cetin, Mualla; Gümrük, Fatma; Be?ba?, Nesrin; Gürgey, Aytemiz

    2012-01-01

    A 13-year-old boy presented with nausea, fatigue, weight loss, and bone pain for two months. Complete blood count and serum renal and liver function tests were all normal. Blood gas analysis revealed severe metabolic acidosis with high anion gap. Lactate level was 61.2 mmol/L. Abdominal ultrasonography yielded bilateral nephromegaly and hepatomegaly with increased echogenicity. Peripheral blood smear revealed 2% blasts. Bone marrow aspiration showed 'Common ALL Antigen'-negative acute lymphoblastic leukemia by flow cytometric analysis. Metabolic acidosis dissolved as soon as chemotherapy was begun. Lactic acidosis at the presentation of acute lymphoblastic leukemia--especially with low tumor burden--is a very rare and almost always fatal complication. Our patient is still alive and in remission, which is a point of interest in this child. PMID:22397045

  6. The CN7(-) anion.

    PubMed

    Klapötke, Thomas M; Stierstorfer, Jörg

    2009-01-28

    Several salts containing the CN7(-) anion were prepared by deprotonation of 5-azido-1H-tetrazole (1). The highly explosive compounds hydrazinium (2), ammonium (3), aminoguanidinium (4), guanidinium (5), lithium (6), sodium (7), potassium (8), cesium (9), and calcium (10) azidotetrazolate were characterized by low temperature single X-ray diffraction. Other analytic methods, such as IR and Raman spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, and differential scanning calorimetry were performed when possible since some of the metal salts explode spontaneously. 2 contains the highest nitrogen content (87.48%) of all known tetrazole salts. The impact, friction, and electrical spark sensitivity of 2, 3, 4, and 5 were measured, resulting in values which belong to primary explosives. In addition, the heats of formation of 2, 3, and 4 were calculated using the CBS-4M level of quantum mechanical theory. These, in turn, were used to estimate detonation pressure p(C-J) and velocity D(det) as well as the specific impulse I(sp). PMID:19115947

  7. Metabolic Syndrome

    MedlinePLUS

    ... applies to a condition known as metabolic syndrome. Metabolic Syndrome Is an Early Warning Sign Metabolic syndrome isn' ... 2 diabetes down the road. What Exactly Is Metabolic Syndrome? Metabolic syndrome is a collection of problems that ...

  8. Hydrogen in anion vacancies of semiconductors

    SciTech Connect

    Du, Mao-Hua [ORNL; Singh, David J [ORNL

    2009-01-01

    Density functional calculations show that, depending on the anion size, hydrogen in anion vacancies of various II-VI semiconductors can be either two-fold or four-fold coordinated, and has either amphoteric or shallow donor character. In general, the multi-coordination of hydrogen in an anion vacancy is the indication of an anionic H, H { ion, in the relatively ionic environment. In more covalent semiconductors, H would form a single cation-H bond in the anion vacancy.

  9. Anion exchange polymer electrolytes

    DOEpatents

    Kim, Yu Seung; Kim, Dae Sik; Lee, Kwan-Soo

    2013-07-23

    Solid anion exchange polymer electrolytes and compositions comprising chemical compounds comprising a polymeric core, a spacer A, and a guanidine base, wherein said chemical compound is uniformly dispersed in a suitable solvent and has the structure: ##STR00001## wherein: i) A is a spacer having the structure O, S, SO.sub.2, --NH--, --N(CH.sub.2).sub.n, wherein n=1-10, --(CH.sub.2).sub.n--CH.sub.3--, wherein n=1-10, SO.sub.2-Ph, CO-Ph, ##STR00002## wherein R.sub.5, R.sub.6, R.sub.7 and R.sub.8 each are independently --H, --NH.sub.2, F, Cl, Br, CN, or a C.sub.1-C.sub.6 alkyl group, or any combination of thereof; ii) R.sub.9, R.sub.10, R.sub.11, R.sub.12, or R.sub.13 each independently are --H, --CH.sub.3, --NH.sub.2, --NO, --CH.sub.nCH.sub.3 where n=1-6, HC.dbd.O--, NH.sub.2C.dbd.O--, --CH.sub.nCOOH where n=1-6, --(CH.sub.2).sub.n--C(NH.sub.2)--COOH where n=1-6, --CH--(COOH)--CH.sub.2--COOH, --CH.sub.2--CH(O--CH.sub.2CH.sub.3).sub.2, --(C.dbd.S)--NH.sub.2, --(C.dbd.NH)--N--(CH.sub.2).sub.nCH.sub.3, where n=0-6, --NH--(C.dbd.S)--SH, --CH.sub.2--(C.dbd.O)--O--C(CH.sub.3).sub.3, --O--(CH.sub.2).sub.n--CH--(NH.sub.2)--COOH, where n=1-6, --(CH.sub.2).sub.n--CH.dbd.CH wherein n=1-6, --(CH.sub.2).sub.n--CH--CN wherein n=1-6, an aromatic group such as a phenyl, benzyl, phenoxy, methylbenzyl, nitrogen-substituted benzyl or phenyl groups, a halide, or halide-substituted methyl groups; and iii) wherein the composition is suitable for use in a membrane electrode assembly.

  10. ATP release via anion channels.

    PubMed

    Sabirov, Ravshan Z; Okada, Yasunobu

    2005-12-01

    ATP serves not only as an energy source for all cell types but as an 'extracellular messenger' for autocrine and paracrine signalling. It is released from the cell via several different purinergic signal efflux pathways. ATP and its Mg(2+) and/or H(+) salts exist in anionic forms at physiological pH and may exit cells via some anion channel if the pore physically permits this. In this review we survey experimental data providing evidence for and against the release of ATP through anion channels. CFTR has long been considered a probable pathway for ATP release in airway epithelium and other types of cells expressing this protein, although non-CFTR ATP currents have also been observed. Volume-sensitive outwardly rectifying (VSOR) chloride channels are found in virtually all cell types and can physically accommodate or even permeate ATP(4-) in certain experimental conditions. However, pharmacological studies are controversial and argue against the actual involvement of the VSOR channel in significant release of ATP. A large-conductance anion channel whose open probability exhibits a bell-shaped voltage dependence is also ubiquitously expressed and represents a putative pathway for ATP release. This channel, called a maxi-anion channel, has a wide nanoscopic pore suitable for nucleotide transport and possesses an ATP-binding site in the middle of the pore lumen to facilitate the passage of the nucleotide. The maxi-anion channel conducts ATP and displays a pharmacological profile similar to that of ATP release in response to osmotic, ischemic, hypoxic and salt stresses. The relation of some other channels and transporters to the regulated release of ATP is also discussed. PMID:18404516

  11. Metabolic Syndrome

    MedlinePLUS

    ... page from the NHLBI on Twitter. What Is Metabolic Syndrome? Metabolic (met-ah-BOL-ik) syndrome is the ... three metabolic risk factors to be diagnosed with metabolic syndrome. A large waistline. This also is called abdominal ...

  12. Anions 2007 Azolide Ion Chemistry

    E-print Network

    Simons, Jack

    coupling raises complex issues (ignored here today) #12;Azolides and related anions - Pyrazole (vibronic coupling) N-methyl pyrazole (deprotonation site ID) N-methyl imidazole (selective reactions) Vinyl rxnHo - 35.4 kcal mol-1 (exp -36.7 ± 0.4) - 5.8 kcal mol-1 + 9.9 kcal mol-1 + 6.6 kcal mol-1 pyrazole

  13. Anion binding in biological systems

    NASA Astrophysics Data System (ADS)

    Feiters, Martin C.; Meyer-Klaucke, Wolfram; Kostenko, Alexander V.; Soldatov, Alexander V.; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Küpper, Frithjof C.; Hollenstein, Kaspar; Locher, Kaspar P.; Bevers, Loes E.; Hagedoorn, Peter-Leon; Hagen, Wilfred R.

    2009-11-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L3 (2p3/2) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  14. Plasmalemmal VDAC controversies and maxi-anion channel puzzle.

    PubMed

    Sabirov, Ravshan Z; Merzlyak, Petr G

    2012-06-01

    The maxi-anion channel has been observed in many cell types from the very beginning of the patch-clamp era. The channel is highly conductive for chloride and thus can modulate the resting membrane potential and play a role in fluid secretion/absorption and cell volume regulation. A wide nanoscopic pore of the maxi-anion channel permits passage of excitatory amino acids and nucleotides. The channel-mediated release of these signaling molecules is associated with kidney tubuloglomerular feedback, cardiac ischemia/hypoxia, as well as brain ischemia/hypoxia and excitotoxic neurodegeneration. Despite the ubiquitous expression and physiological/pathophysiological significance, the molecular identity of the maxi-anion channel is still obscure. VDAC is primarily a mitochondrial protein; however several groups detected it on the cellular surface. VDAC in lipid bilayers reproduced the most important biophysical properties of the maxi-anion channel, such as a wide nano-sized pore, closure in response to moderately high voltages, ATP-block and ATP-permeability. However, these similarities turned out to be superficial, and the hypothesis of plasmalemmal VDAC as the maxi-anion channel did not withstand the test by genetic manipulations of VDAC protein expression. VDAC on the cellular surface could also function as a ferricyanide reductase or a receptor for plasminogen kringle 5 and for neuroactive steroids. These ideas, as well as the very presence of VDAC on plasmalemma, remain to be scrutinized by genetic manipulations of the VDAC protein expression. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism. PMID:21986486

  15. DETECTION OF PERCHLORATE ANION ON FUNCTIONALIZED SILVER COLLOIDS USING SURFACE-ENHANCED RAMAN SCATTERING

    Microsoft Academic Search

    JACQUELINE TIO; WEI WANG

    Perchlorate anion interferes with the uptake of iodide by the human thyroid gland and consequently disrupts the regulation of metabolism. Chronic exposure to high levels of perchlorate may lead to the formation of thyroid gland tumors. Although the Environmental Protection Agency (EPA) has not set a maximum contaminant level (MCL) for perchlorate, a draft drinking water range of 4-18 ppb

  16. Polymerization of anionic wormlike micelles.

    PubMed

    Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

    2006-01-31

    Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles. PMID:16430253

  17. Laser Cooling of Molecular Anions

    NASA Astrophysics Data System (ADS)

    Yzombard, Pauline; Hamamda, Mehdi; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-05-01

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarize the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C2 - , the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photodetachment process is present, as well as Doppler laser cooling of trapped C2 - , are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources, and antimatter physics.

  18. Laser Cooling of Molecular Anions.

    PubMed

    Yzombard, Pauline; Hamamda, Mehdi; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-05-29

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarize the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C_{2}^{-}, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photodetachment process is present, as well as Doppler laser cooling of trapped C_{2}^{-}, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources, and antimatter physics. PMID:26066432

  19. Laser Cooling of Molecular Anions

    E-print Network

    Yzombard, Pauline; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-01-01

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics.

  20. Multiply Charged Metal Cluster Anions

    SciTech Connect

    Yannouleas, Constantine; Landman, Uzi; Herlert, Alexander; Schweikhard, Lutz

    2001-04-02

    Formation and stability patterns of silver dianionic and gold trianionic clusters are investigated with Penning-trap experiments and a shell-correction method including shape deformations. The theoretical predictions pertaining to the appearance sizes and electronic shell effects are in remarkable agreement with the experiments. Decay of the multiply anionic clusters occurs predominantly by electron tunneling through a Coulomb barrier rather than via fission, leading to appearance sizes unrelated to those of multiply cationic clusters.

  1. Aza compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.Q.; McBreen, J.

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li{sup +} ion in alkali metal batteries. 3 figs.

  2. Aza compounds as anion receptors

    SciTech Connect

    Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Qing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li.sup.+ ion in alkali metal batteries.

  3. Systematizing the Generation of Missing Metabolic Knowledge

    PubMed Central

    Orth, Jeffrey D.; Palsson, Bernhard Ø.

    2011-01-01

    Genome-scale metabolic network reconstructions are built from all of the known metabolic reactions and genes in a target organism. However, since our knowledge of any organism is incomplete, these network reconstructions contain gaps. Reactions may be missing, resulting in dead-ends in pathways, while unknown gene products may catalyze known reactions. New computational methods that analyze data, such as growth phenotypes or gene essentiality, in the context of genome-scale metabolic networks, have been developed to predict these missing reactions or genes likely to fill these knowledge gaps. A growing number of experimental studies are appearing that address these computational predictions, leading to discovery of new metabolic capabilities in the target organism. Gap-filling methods can thus be used to improve metabolic network models while simultaneously leading to discovery of new metabolic gene functions. PMID:20589842

  4. computational group theory with GAP 1 GAP in Sage

    E-print Network

    Verschelde, Jan

    computational group theory with GAP 1 GAP in Sage the GAP system combinatorics and list 2013 1 / 44 #12;computational group theory with GAP 1 GAP in Sage the GAP system combinatorics and list explicitly in Sage via 1 the class Gap, do help(gap); or 2 opening a Terminal Session with GAP, type gap

  5. Analysis of anions in beer using ion chromatography.

    PubMed

    Bruce, Jonathan

    2002-01-01

    The majority of anions found in beer are a consequence of impurities derived from the water used during the brewing process. The process of beer manufacture consists of malting, brewing and fermentation followed by maturation before filtration and finally storage. Strict quality control is required because the presence of certain anions outside strictly defined tolerance limits can affect the flavour characteristics of the finished product. The anions present were quantified using the technique of ion chromatography with the Metrohm modular system following sample preparation. The analysis produced a result of the order 200 mg l(-1) for chloride, phosphate and sulphate and around 20 mg l(-1) for nitrate. If the chloride level exceeds 250 mg l(-1), then the sweetness of the beer is enhanced, but yeast flocculation can be hindered. An excess of sulphate can give a sharp, dry edge to hopped beers and excessive amounts of nitrate have been found to harm the yeast metabolism after conversion to the nitrite form. As water is a primary ingredient within beer, its quality and type is a fundamental factor in establishing many of the distinctive regional beers that can be found in the United Kingdom and is thus monitored carefully. PMID:18924733

  6. Metabolic neuropathies

    MedlinePLUS

    Neuropathy - metabolic ... can be caused by many different things. Metabolic neuropathy may be caused by: A problem with the ... one of the most common causes of metabolic neuropathies. People who are at the highest risk of ...

  7. Metabolic Fluxes and Metabolic Engineering

    Microsoft Academic Search

    Gregory Stephanopoulos

    1999-01-01

    Metabolic engineering is the directed improvement of cellular properties through the modification of specific biochemical reactions or the introduction of new ones, with the use of recombinant DNA technology. As such, metabolic engineering emphasizes metabolic pathway integration and relies on metabolic fluxes as determinants of cell physiology and measures of metabolic control. The combination of analytical methods to quantify fluxes

  8. Molecular Orbital Studies of Hydrogen Chemisorption at Anion Vacancy Sites of LiF Surfaces

    NASA Astrophysics Data System (ADS)

    Matsumura, Keiko

    1983-06-01

    The possibility of hydrogen chemisorption onto anion vacancies on the (001) surface, < 110> edge and < 111> corner of LiF cluster is investigated with MBP CNDO MO. The clusters with an anion vacancy capture an electron to be localized at the vacancy and a singly occupied level (SOMO) of F-center character appears in the band gap. An approaching hydrogen atom can be bound tightly as sn H- substitute at each charged vacant site. The strong binding is caused by the overlap between H 1s orbital ?s(H) and SOMO and adsorption energy depends on the number of cations nearest to the vacancy.

  9. Organic anion transporter (Slc22a) family members as mediators of toxicity

    SciTech Connect

    Sweet, Douglas H. [Department of Pharmaceutical Sciences, Medical University of South Carolina, 280 Calhoun Street (Room QE218), PO Box 250140, Charleston, SC 29425 (United States)]. E-mail: sweetd@musc.edu

    2005-05-01

    Exposure of the body to toxic organic anions is unavoidable and occurs from both intentional and unintentional sources. Many hormones, neurotransmitters, and waste products of cellular metabolism, or their metabolites, are organic anions. The same is true for a wide variety of medications, herbicides, pesticides, plant and animal toxins, and industrial chemicals and solvents. Rapid and efficient elimination of these substances is often the body's best defense for limiting both systemic exposure and the duration of their pharmacological or toxicological effects. For organic anions, active transepithelial transport across the renal proximal tubule followed by elimination via the urine is a major pathway in this detoxification process. Accordingly, a large number of organic anion transport proteins belonging to several different gene families have been identified and found to be expressed in the proximal nephron. The function of these transporters, in combination with the high volume of renal blood flow, predisposes the kidney to increased toxic susceptibility. Understanding how the kidney mediates the transport of organic anions is integral to achieving desired therapeutic outcomes in response to drug interactions and chemical exposures, to understanding the progression of some disease states, and to predicting the influence of genetic variation upon these processes. This review will focus on the organic anion transporter (OAT) family and discuss the known members, their mechanisms of action, subcellular localization, and current evidence implicating their function as a determinant of the toxicity of certain endogenous and xenobiotic agents.

  10. Is 9-acridinamine anion a dispersion-bound anion? Piotr Skurski

    E-print Network

    Simons, Jack

    Is 9-acridinamine anion a dispersion-bound anion? Piotr Skurski Henry Eyring Center for Theoretical of Chemistry, University of Gdan´sk, ul. Sobieskiego 18, 80-952 Gdan´sk, Poland Jack Simonsa) Henry Eyring

  11. Adsorption affinity of anions on metal oxyhydroxides

    NASA Astrophysics Data System (ADS)

    Pechenyuk, S. I.; Semushina, Yu. P.; Kuz'mich, L. F.

    2013-03-01

    The dependences of anion (phosphate, carbonate, sulfate, chromate, oxalate, tartrate, and citrate) adsorption affinity anions from geometric characteristics, acid-base properties, and complex forming ability are generalized. It is shown that adsorption depends on the nature of both the anions and the ionic medium and adsorbent. It is established that anions are generally grouped into the following series of adsorption affinity reduction: PO{4/3-}, CO{3/2-} > C2O{4/2-}, C(OH)(CH2)2(COO){3/3-}, (CHOH)2(COO){2/2-} > CrO{4/2-} ? SO{4/2-}.

  12. Cd(II)-coordination framework: synthesis, anion-induced structural transformation, anion-responsive luminescence, and anion separation.

    PubMed

    Hou, Shan; Liu, Qi-Kui; Ma, Jian-Ping; Dong, Yu-Bin

    2013-03-18

    A series of Cd(II) coordination frameworks that are constructed from a new oxadiazole-bridged ligand 3,5-bis(3-pyridyl-3-(3'-methylphenyl)-1,3,4-oxadiazole (L) and CdX2 (X = NO3(-), Cl(-), Br(-), I(-), N3(-), and SCN(-)) were synthesized. The NO3(-) anion of the solid CdL2(NO3)2·2THF (1) is able to be quantitatively exchanged with Cl(-), Br(-), I(-), SCN(-), and N3(-) in the solid state. For Cl(-) and Br(-), the anion exchange resulted in a anion-induced structural transformation to form the structures of 2 and 3, respectively. In addition, the Cd(II) structure herein exhibits the anion-responsive photoluminescence, which could be a useful method to monitor the anion-exchange process. Notably, compound 1 can recognize and completely separate SCN(-)/N3(-) with similar geometry. PMID:23461490

  13. Effect of eluent composition on retention behavior of anions in ion chromatography on anion-exchangers modified with heparin

    Microsoft Academic Search

    Safni; Toyohide Takeuchi; Tomoo Miwa; Yoshimi Hashimoto; Hiroyuki Moriyama

    1999-01-01

    Effects of eluent composition on retention behavior of inorganic anions have been investigated in ion chromatography using anion-exchangers modified with heparin. Both cation and anion of the eluent affected the retention of analyte anions and unusual retention behavior was observed on the modified stationary phase. The retention time of anions decreased with decreasing eluent concentration when sodium sulfate, magnesium sulfate

  14. Covalent Polymers Containing Discrete Heterocyclic Anion Receptors.

    PubMed

    Rambo, Brett M; Silver, Eric S; Bielawski, Christopher W; Sessler, Jonathan L

    2010-01-01

    This chapter covers recent advances in the development of polymeric materials containing discrete heterocyclic anion receptors, and focuses on advances in anion binding and chemosensor chemistry. The development of polymers specific for anionic species is a relatively new and flourishing area of materials chemistry. The incorporation of heterocyclic receptors capable of complexing anions through non-covalent interactions (e.g., hydrogen bonding and electrostatic interactions) provides a route to not only sensitive but also selective polymer materials. Furthermore, these systems have been utilized in the development of polymers capable of extracting anionic species from aqueous environments. These latter materials may lead to advances in water purification and treatment of diseases resulting from surplus ions. PMID:20871791

  15. Covalent Polymers Containing Discrete Heterocyclic Anion Receptors

    PubMed Central

    Rambo, Brett M.; Silver, Eric S.; Bielawski, Christopher W.; Sessler, Jonathan L.

    2010-01-01

    This chapter covers recent advances in the development of polymeric materials containing discrete heterocyclic anion receptors, and focuses on advances in anion binding and chemosensor chemistry. The development of polymers specific for anionic species is a relatively new and flourishing area of materials chemistry. The incorporation of heterocyclic receptors capable of complexing anions through non-covalent interactions (e.g., hydrogen bonding and electrostatic interactions) provides a route to not only sensitive but also selective polymer materials. Furthermore, these systems have been utilized in the development of polymers capable of extracting anionic species from aqueous environments. These latter materials may lead to advances in water purification and treatment of diseases resulting from surplus ions. PMID:20871791

  16. Maxi-anion channel and pannexin 1 hemichannel constitute separate pathways for swelling-induced ATP release in murine L929 fibrosarcoma cells.

    PubMed

    Islam, Md Rafiqul; Uramoto, Hiromi; Okada, Toshiaki; Sabirov, Ravshan Z; Okada, Yasunobu

    2012-11-01

    The maxi-anion channel plays a classically recognized role in controlling the membrane potential through the chloride conductance. It also has novel functions as a regulated pathway for the release of the anionic signaling molecules ATP and excitatory amino acids from cells subjected to osmotic perturbation, ischemia, or hypoxia. Because hemichannels formed by pannexins and connexins have been reported to mediate ATP release from a number of cell types, these hemichannels may represent the molecular correlate of the maxi-anion channel. Here, we found that L929 fibrosarcoma cells express functional maxi-anion channels which mediate a major portion of swelling-induced ATP release, and that ATP released via maxi-anion channels facilitates the regulatory volume decrease after osmotic swelling. Also, it was found that the cells express the mRNA for pannexin 1, pannexin 2, and connexin 43. Hypotonicity-induced ATP release was partially suppressed not only by known blockers of the maxi-anion channel but also by several blockers of pannexins including the pannexin 1-specific blocking peptide (10)Panx1 and small interfering (si)RNA against pannexin 1 but not pannexin 2. The inhibitory effects of maxi-anion channel blockers and pannexin 1 antagonists were additive. In contrast, maxi-anion channel activity was not affected by pannexin 1 antagonists and siRNAs against pannexins 1 and 2. Although a connexin 43-specific blocking peptide, Gap27, slightly suppressed hypotonicity-induced ATP release, maxi-anion channel activity was not affected by Gap27 or connexin 43-specific siRNA. Thus, it is concluded that the maxi-anion channel is a molecular entity distinct from pannexin 1, pannexin 2, and connexin 43, and that the maxi-anion channel and the hemichannels constitute separate pathways for swelling-induced ATP release in L929 cells. PMID:22785119

  17. Sulfate Is Both a Substrate and an Activator of the Voltage-Dependent Anion Channel of Arabidopsis Hypocotyl Cells1

    PubMed Central

    Frachisse, Jean-Marie; Thomine, Sébastien; Colcombet, Jean; Guern, Jean; Barbier-Brygoo, Hélène

    1999-01-01

    On the basis of the anion content of in vitro-cultured Arabidopsis plantlets, we explored the selectivity of the voltage-dependent anion channel of the plasma membrane of hypocotyl cells. In the whole-cell configuration, substitution of cytosolic Cl? by different anions led to the following sequence of relative permeabilities: NO3? (2.6) ? SO42? (2.0) > Cl? (1.0) > HCO3? (0.8) ? malate2? (0.03). Large whole-cell currents were measured for NO3? and SO42?, about five to six times higher than the equivalent Cl? currents. Since SO42? is usually considered to be a weakly permeant or non-permeant ion, the components of the large whole-cell current were explored in more detail. Aside from its permeation through the channel with a unitary conductance, about two-thirds that of Cl?, SO42? had a regulatory effect on channel activity by preventing the run-down of the anion current both in the whole-cell and the outside-out configuration, increasing markedly the whole-cell current. The fact that the voltage-dependent plasma membrane anion channel of hypocotyl cells can mediate large NO3? and SO42? currents and is regulated by nucleotides favors the idea that this anion channel can contribute to the cellular homeostasis of important metabolized anions. PMID:10482681

  18. Characterization of Antisense Transformed Plants Deficient in the Tobacco Anionic Peroxidase.

    PubMed Central

    Lagrimini, L. M.; Gingas, V.; Finger, F.; Rothstein, S.; Liu, TTY.

    1997-01-01

    On the basis of the biological compounds that they metabolize, plant peroxidases have long been implicated in plant growth, cell wall biogenesis, lignification, and host defenses. Transgenic tobacco (Nicotiana tabacum L.) plants that underexpress anionic peroxidase were generated using antisense RNA. The antisense RNA was found to be specific for the anionic isoenzyme and highly effective, reducing endogenous transcript levels and total peroxidase activity by as much as 1600-fold. Antisense-transformed plants appeared normal at initial observation; however, growth studies showed that plants with reduced peroxidase activity grow taller and flower sooner than control plants. In contrast, previously transformed plants overproducing anionic peroxidase were shorter and flowered later than controls. Axillary buds were more developed in antisense-transformed plants and less developed in plants overproducing this enzyme. It was found that the lignin content in leaf, stem, and root was unchanged in antisense-transformed plants, which does not support a role for anionic peroxidase in the lignification of secondary xylem vessels. However, studies of wounded tissue show some reduction in wound-induced deposition of lignin-like polymers. The data support a possible role for tobacco anionic peroxidase in host defenses but not without a reduction in growth potential. PMID:12223765

  19. Metabolic syndrome

    MedlinePLUS

    Metabolic syndrome is a name for a group of risk factors that occur together and increase the chance ... Metabolic syndrome is becoming very common in the United States. Doctors are not sure whether the syndrome is ...

  20. Metabolic Syndrome

    MedlinePLUS

    Metabolic syndrome is a group of conditions that put you at risk for heart disease and diabetes. These ... doctors agree on the definition or cause of metabolic syndrome. The cause might be insulin resistance. Insulin is ...

  1. Supramolecular electron transfer by anion binding.

    PubMed

    Fukuzumi, Shunichi; Ohkubo, Kei; D'Souza, Francis; Sessler, Jonathan L

    2012-10-11

    Anion binding has emerged as an attractive strategy to construct supramolecular electron donor-acceptor complexes. In recent years, the level of sophistication in the design of these systems has advanced to the point where it is possible to create ensembles that mimic key aspects of the photoinduced electron-transfer events operative in the photosynthetic reaction centre. Although anion binding is a reversible process, kinetic studies on anion binding and dissociation processes, as well as photoinduced electron-transfer and back electron-transfer reactions in supramolecular electron donor-acceptor complexes formed by anion binding, have revealed that photoinduced electron transfer and back electron transfer occur at time scales much faster than those associated with anion binding and dissociation. This difference in rates ensures that the linkage between electron donor and acceptor moieties is maintained over the course of most forward and back electron-transfer processes. A particular example of this principle is illustrated by electron-transfer ensembles based on tetrathiafulvalene calix[4]pyrroles (TTF-C4Ps). In these ensembles, the TTF-C4Ps act as donors, transferring electrons to various electron acceptors after anion binding. Competition with non-redox active substrates is also observed. Anion binding to the pyrrole amine groups of an oxoporphyrinogen unit within various supramolecular complexes formed with fullerenes also results in acceleration of the photoinduced electron-transfer process but deceleration of the back electron transfer; again, this is ascribed to favourable structural and electronic changes. Anion binding also plays a role in stabilizing supramolecular complexes between sulphonated tetraphenylporphyrin anions ([MTPPS](4-): M = H(2) and Zn) and a lithium ion encapsulated C(60) (Li(+)@C(60)); the resulting ensemble produces long-lived charge-separated states upon photoexcitation of the porphyrins. PMID:22766725

  2. Ketoprofen as a photoinitiator for anionic polymerization.

    PubMed

    Wang, Yu-Hsuan; Wan, Peter

    2015-06-01

    A new photoinitiating system for anionic polymerization of acrylates based on the efficient photodecarboxylation of Ketoprofen () and the related derivatives and that generate the corresponding carbanion intermediates is presented. Carbanion intermediates are confirmed by deuterium incorporation in the trapped Michael adducts and by spectroscopic detection using laser flash photolysis (LFP). This novel anionic initiating system features excitation in the near UV and visible regions, potential characteristics of photocontrolled living polymerization, and metal-free photoinitiators generated from photoexcitation, different from typical anionic polymerization where the polymerizations are initiated by heat and strong base containing alkali metals. PMID:25917384

  3. Metabolic Syndrome

    MedlinePLUS

    ... you know? One in five Americans has the metabolic syndrome. WhO is At risk fOr the metAbOlic syndrOme? The syndrome runs in families and is more ... High blood pressure Most people who have the metabolic syndrome feel healthy and may not have any signs ...

  4. Kinetics and mechanism of exogenous anion exchange in FeFbpA-NTA: significance of periplasmic anion lability and anion binding activity of ferric binding protein A.

    PubMed

    Heymann, Jared J; Gabricevi?, Mario; Mietzner, Timothy A; Crumbliss, Alvin L

    2010-02-01

    The bacterial transferrin ferric binding protein A (FbpA) requires an exogenous anion to facilitate iron sequestration, and subsequently to shuttle the metal across the periplasm to the cytoplasmic membrane. In the diverse conditions of the periplasm, numerous anions are known to be present. Prior in vitro experiments have demonstrated the ability of multiple anions to fulfill the synergistic iron-binding requirement, and the identity of the bound anion has been shown to modulate important physicochemical properties of iron-bound FbpA (FeFbpA). Here we address the kinetics and mechanism of anion exchange for the FeFbpA-nitrilotriacetate (NTA) assembly with several biologically relevant anions (citrate, oxalate, phosphate, and pyrophosphate), with nonphysiologic NTA serving as a representative synergistic anion/chelator. The kinetic data are consistent with an anion-exchange process that occurs in multiple steps, dependent on the identity of both the entering anion and the leaving anion. The exchange mechanism may proceed either as a direct substitution or through an intermediate FeFbpA-X* assembly based on anion (X) identity. Our kinetic results further develop an understanding of exogenous anion lability in the periplasm, as well as address the final step of the iron-free FbpA (apo-FbpA)/Fe(3+) sequestration mechanism. Our results highlight the kinetic significance of the FbpA anion binding site, demonstrating a correlation between apo-FbpA/anion affinity and the FeFbpA rate of anion exchange, further supporting the requirement of an exogenous anion to complete tight sequestration of iron by FbpA, and developing a mechanism for anion exchange within FeFbpA that is dependent on the identity of both the entering anion and the leaving anion. PMID:19813031

  5. Determination of Anion Ordering in Mixed Apatites via Multinuclear Solid-State NMR & X-ray Crystallography

    NASA Astrophysics Data System (ADS)

    Vaughn, J. S.; Phillips, B. L.; Hughes, J. M.; Nekvasil, H.; Ustunisik, G. K.; Lindsley, D. H.; Coraor, A. E.; McCubbin, F. M.; Woerner, W. R.

    2013-12-01

    Subtle changes in crystallographic anion position in apatite sensu latu Ca5(PO4)3(F,OH,Cl) are known to affect greatly its macroscopic physical properties, such as acid resistivity and hardness. While the anion positions in endmember compositions are well described, there exist substantial gaps in our understanding of anion ordering in mixed binary and ternary compositions because of potential steric anion interactions and symmetry changes. X-ray diffraction analysis of these binary/ternary mixtures is well-suited to address the atomic positions and average occupancies of these anion sites for well-ordered systems. Multinuclear solid-state NMR methods complement XRD structure studies if there exist column ordering reversals or disorder in the atomic positions of the anions, as NMR is sensitive to the atomic arrangement within short distances of the nucleus (<4Å). Using these analytical techniques the anion ordering along the F-Cl solid-solution join is reported, and features an off-mirror fluorine site at (0,0,0.167). The migration of fluorine away from its end-member site within the {00l} mirror plane and subsequent migration of chlorine in the opposing direction results in acceptable F-Cl distances in the anion column. Exceptionally low H content in the anion channel was afforded via high-temperature (1200°C) solid-state reaction under vacuum. The speciation of H was determined by 1H{31P} REDOR experiments, from which the REDOR difference spectrum features a single resonance at ?H = 1.6 ppm which can be assigned to OH groups. The abundance of OH was confirmed by comparison of single-pulse (SP) 31P and cross-polarization 31P{1H} NMR (CP) spectral intensities to those of a crystalline synthetic hydroxylapatite, and showed that only 0.4 mol% of the 31P in the composition occurs in hydroxylapatite-like configurations.

  6. Processing gapped verbs.

    PubMed

    Kaan, Edith; Overfelt, Carlie; Tromp, Do; Wijnen, Frank

    2013-08-01

    The time course was investigated of the processing of "missing" verbs in gapping constructions, such as John ate the hamburger, and Bill __ the hotdog. Native speakers of Dutch silently read Dutch sentences with and without gapping while their EEG was recorded. A left anterior negativity (LAN) was found at the first possible position at which the gapped verb could be detected, at least, for in participants who performed poorly in an end-of-sentence acceptability judgment task. This suggests that some readers do not anticipate the gapped verb, but infer the gapped verb in a bottom-up fashion, resulting in a LAN. Second, a P600 effect was observed for gapping versus no-gapping conditions, the early part of which was unaffected by plausibility. This suggests that the semantic and syntactic integration of a gapped verb is a relatively late process, and involves mechanisms similar to integrating a wh-phrase object with its verb. PMID:22538968

  7. NATIONAL GAP ANALYSIS PROGRAM

    EPA Science Inventory

    GAP Analysis is a rapid conservation evaluation method for assessing the current status of biodiversity at large spatial scales. GAP Analysis provides a systematic approach for evaluating the protection afforded biodiversity in given areas. It uses Geographic Information System (...

  8. Effect of alkyl groups in anionic surfactants on solution properties of anionic-nonionic surfactant system

    Microsoft Academic Search

    Eid M. S. Azzam

    2001-01-01

    The effect of different alkyl chains of anionic surfactants on properties of binary anionic-nonionic mixed surfactant systems\\u000a was studied. These systems included ocytldodecyl-, and cetylsulfoacetates mixed with isooctyl phenol nonyl ethoxylate. The\\u000a critical micelle concentration of mixed surfactants shifted to lower values compared to those of the single anionic surfactants.\\u000a Effectiveness values increased with decreases in the mole fraction of

  9. Thiosquaramides: pH switchable anion transporters†

    PubMed Central

    Busschaert, Nathalie; Elmes, Robert B. P.; Czech, Dawid D.; Wu, Xin; Kirby, Isabelle L.; Peck, Evan M.; Hendzel, Kevin D.; Shaw, Scott K.; Chan, Bun; Smith, Bradley D.; Jolliffe, Katrina A.; Gale, Philip A.

    2015-01-01

    The transport of anions across cellular membranes is an important biological function governed by specialised proteins. In recent years, many small molecules have emerged that mimick the anion transport behaviour of these proteins, but only a few of these synthetic molecules also display the gating/switching behaviour seen in biological systems. A small series of thiosquaramides was synthesised and their pH-dependent chloride binding and anion transport behaviour was investigated using 1H NMR titrations, single crystal X-ray diffraction and a variety of vesicle-based techniques. Spectrophotometric titrations and DFT calculations revealed that the thiosquaramides are significantly more acidic than their oxosquaramide analogues, with pKa values between 4.0 and 9.0. This led to the observation that at pH 7.2 the anion transport ability of the thiosquaramides is fully switched OFF due to deprotonation of the receptor, but is completely switched ON at lower pH.

  10. Anaerobic Metabolism 1 ANAEROBIC METABOLISM

    E-print Network

    Prestwich, Ken

    to aerobic metabolsm. This said, it is not uncommon to hear microbiologists talk about anaerobic respiration it for respiration. However, in many animals anaerobic metabolism may occur even when there are large amounts of O2Anaerobic Metabolism 1 ANAEROBIC METABOLISM 1 Introduction About the Next Three Sets of Class Notes

  11. Electron collisions with diatomic anions

    SciTech Connect

    Pedersen, H.B.; Jensen, M.J.; Kella, D.; Safvan, C.P.; Vejby-Christensen, L.; Andersen, L.H. [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)] [Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Djuric, N. [JILA, University of Colorado and National Institute of Standards and Technology, Boulder, Colorado 80309-0440 (United States)] [JILA, University of Colorado and National Institute of Standards and Technology, Boulder, Colorado 80309-0440 (United States); Schmidt, H.T. [Department of Physics, Atomic Physics, Stockholm University, S-10405 Stockholm (Sweden)] [Department of Physics, Atomic Physics, Stockholm University, S-10405 Stockholm (Sweden)

    1999-10-01

    Electron collisions with negative ions (B{sub 2}{minus}, C{sub 2}{minus}, O{sub 2}{minus}, BN{sup {minus}}, and OH) have been performed in a merged- beams experiment at the heavy-ion storage ring ASTRID (Aarhus Storage Ring, Denmark). Absolute cross sections for detachment (e{sup {minus}}+AB{sup {minus}}{r_arrow}AB{sup 0}+2e{sup {minus}}) and detachment plus dissociation (e{sup {minus}}+AB{sup {minus}}{r_arrow}A{sup 0}+B{sup 0}+2e{sup {minus}}) are reported for energies below 40 eV. For the homonuclear ions, X{sub 2}{sup {minus}} (X=B,&hthinsp;C,&hthinsp;O), cross sections are also presented for dissociative reactions leading to an X{sup {minus}} particle in the final state. The detachment process is dominant for all investigated systems. The detachment cross section is characterized by an effective threshold larger than the electron binding energy. The shapes of the detachment cross sections are similar for the studied anions pointing to a common nonresonant mechanism for detachment. Also, the cross section for detachment plus dissociation and pure dissociation show regularities pointing to a general nonresonant mechanism. Structures are observed in the detachment cross section of C{sub 2}{sup {minus}} and BN{sup {minus}} and in the dissociation cross section of B{sub 2}{minus} and C{sub 2}{minus}. The structures are attributed to short-lived dianions (resonances) formed during the collision process. The results are supported by {ital ab initio} calculations, and it is inferred that electronic excitations are important in the resonant reactions. {copyright} {ital 1999} {ital The American Physical Society}

  12. Development of an In Silico Metabolic Simulator and Searchable Metabolism Database for Chemical Risk Assessments

    EPA Science Inventory

    The US EPA is faced with long lists of chemicals that need to be assessed for hazard, and a gap in evaluating chemical risk is accounting for metabolic activation resulting in increased toxicity. The goals of this project are to develop a capability to predict metabolic maps of x...

  13. Effect of dietary potassium and anionic salts on acid-base and mineral status in periparturient cows.

    PubMed

    Rérat, M; Schlegel, P

    2014-06-01

    Dry cow diets based on grassland forage from intensive production contain high amounts of K and could be responsible for a reduced ability to maintain Ca homoeostasis. The aim of this study was to determine whether a moderate anionic salt supplementation to a forage-based pre-calving diet with varying native K content affects the mineral and acid-base status in transition cows. Twenty-four dry and pregnant Holstein cows, without antecedent episodes of clinical hypocalcemia, were assigned to two diets during the last 4 weeks before estimated calving date. Twelve cows were fed a hay-based diet low in K (18 g K/kg DM), and 12, a hay-based diet high in K (35 g K/kg DM). Within each diet, six cows received anionic salts during the last 2 weeks before the estimated calving day. After calving, all cows received the high K diet ad libitum. Blood samples were taken daily from day 11 pre-partum to day 5 post-partum. Urine samples were taken on days 7 and 2 pre-partum and on day 2 post-partum. The anionic salt did not alter feed intake during the pre-partum period. Serum Ca was not influenced by the dietary treatments. Feeding pre-partum diets with low K concentrations induced a reduced metabolic alkalotic charge, as indicated by reduced pre-partum urinary base-acid quotient. Transition cows fed the low K diet including anionic salts induced a mild metabolic acidosis before calving, as indicated by higher urinary Ca, lower urinary pH and net acid-base excretion. Although serum Ca during the post-partum period was not affected by dietary treatment, feeding a low K diet moderately supplemented with anionic salts to reach a dietary cation-anion difference close to zero permitted to obtain a metabolic response in periparturient cows without altering the dry matter intake. PMID:23796109

  14. Metabolic syndrome.

    PubMed

    Cho, L W

    2011-11-01

    Metabolic syndrome is a clustering of different risk factors that collectively increases the risk of developing cardiovascular disease and type 2 diabetes mellitus. The syndrome itself is associated with various metabolic abnormalities, including insulin resistance, non-alcoholic fatty liver disease, obstructive sleep apnoea, male hypogonadism and polycystic ovary syndrome. This review aims to discuss recent developments related to the syndrome, including the associated metabolic complications and goals for therapeutic strategies. PMID:22173246

  15. Metabolic myopathies

    NASA Technical Reports Server (NTRS)

    Martin, A.; Haller, R. G.; Barohn, R.; Blomqvist, C. G. (Principal Investigator)

    1994-01-01

    Metabolic myopathies are disorders of muscle energy production that result in skeletal muscle dysfunction. Cardiac and systemic metabolic dysfunction may coexist. Symptoms are often intermittent and provoked by exercise or changes in supply of lipid and carbohydrate fuels. Specific disorders of lipid and carbohydrate metabolism in muscle are reviewed. Evaluation often requires provocative exercise testing. These tests may include ischemic forearm exercise, aerobic cycle exercise, and 31P magnetic resonance spectroscopy with exercise.

  16. Studies of anions sorption on natural zeolites.

    PubMed

    Barczyk, K; Mozgawa, W; Król, M

    2014-12-10

    This work presents results of FT-IR spectroscopic studies of anions-chromate, phosphate and arsenate - sorbed from aqueous solutions (different concentrations of anions) on zeolites. The sorption has been conducted on natural zeolites from different structural groups, i.e. chabazite, mordenite, ferrierite and clinoptilolite. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA(+)) and organo-zeolites were obtained. External cation exchange capacities (ECEC) of organo-zeolites were measured. Their values are 17mmol/100g for chabazite, 4mmol/100g for mordenite and ferrierite and 10mmol/100g for clinoptilolite. The used initial inputs of HDTMA correspond to 100% and 200% ECEC of the minerals. Organo-modificated sorbents were subsequently used for immobilization of mentioned anions. It was proven that aforementioned anions' sorption causes changes in IR spectra of the HDTMA-zeolites. These alterations are dependent on the kind of anions that were sorbed. In all cases, variations are due to bands corresponding to the characteristic Si-O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolites). Alkylammonium surfactant vibrations have also been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed. The amounts of sorbed CrO4(2-), AsO4(3-) and PO4(3-) ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of anions were determined by spectrophotometric method. PMID:25002191

  17. Prediction of selectivity coefficients of univalent anions for anion-selective electrode using support vector machine

    Microsoft Academic Search

    Mohammad Hossein Fatemi; Sajjad Gharaghani; Samahe Mohammadkhani; Zeinab Rezaie

    2008-01-01

    As a new method, support vector machine (SVM) was applied for the prediction of selectivity coefficients of anion-selective electrode for some univalent anions. In this way a quantitative structure–property relationship model was constructed based on calculated molecular descriptors. In the first step more than 1000 molecular descriptors were calculated. Then the stepwise multiple linear regression method was used to select

  18. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    SciTech Connect

    Bowman-James, K.; Wilson, G.; Moyer, B. A.

    2004-12-11

    This project involves the design and synthesis of receptors for oxoanions of environmental importance, including emphasis on high level and low activity waste. Target anions have included primarily oxoanions and a study of the basic concepts behind selective binding of target anions. A primary target has been sulfate because of its deleterious influence on the vitrification of tank wastes

  19. Cytotoxic mechanisms of hydrosulfide anion and cyanide anion in primary rat hepatocyte cultures.

    PubMed

    Thompson, Rodney W; Valentine, Holly L; Valentine, William M

    2003-06-30

    Hydrogen sulfide and hydrogen cyanide are known to compromise mitochondrial respiration through inhibition of cytochrome c oxidase and this is generally considered to be their primary mechanism of toxicity. Experimental studies and the efficiency of current treatment protocols suggest that H(2)S may exert adverse physiological effects through additional mechanisms. To evaluate the role of alternative mechanisms in H(2)S toxicity, the relative contributions of electron transport inhibition, uncoupling of mitochondrial respiration, and opening of the mitochondrial permeability transition pore (MPTP) to hydrosulfide and cyanide anion cytotoxicity in primary hepatocyte cultures were examined. Supplementation of hepatocytes with the glycolytic substrate, fructose, rescued hepatocytes from cyanide anion induced toxicity, whereas fructose supplementation increased hydrosulfide anion toxicity suggesting that hydrosulfide anion may compromise glycolysis in hepatocytes. Although inhibitors of the MPTP opening were protective for hydrosulfide anion, they had no effect on cyanide anion toxicity, consistent with an involvement of the permeability transition pore in hydrosulfide anion toxicity but not cyanide anion toxicity. Exposure of isolated rat liver mitochondria to hydrosulfide did not result in large amplitude swelling suggesting that if H(2)S induces the permeability transition it does so indirectly through a mechanism requiring other cellular components. Hydrosulfide anion did not appear to be an uncoupler of mitochondrial respiration in hepatocytes based upon the inability of oligomycin and fructose to protect hepatocytes from hydrosulfide anion toxicity. These findings support mechanisms additional to inhibition of cytochrome c oxidase in hydrogen sulfide toxicity. Further investigations are required to assess the role of the permeability transition in H(2)S toxicity, determine whether similar affects occur in other cell types or in vivo and evaluate whether this may provide a basis for the design of more effective therapeutic measures for hydrogen sulfide intoxication. PMID:12767687

  20. Electron impact induced anion production in acetylene.

    PubMed

    Szyma?ska, Ewelina; ?adež, Iztok; Krishnakumar, E; Mason, Nigel J

    2014-02-28

    A detailed experimental investigation of electron induced anion production in acetylene, C2H2, in the energy range between 1 and 90 eV is presented. The anions are formed by two processes in this energy range: dissociative electron attachment (DEA) and dipolar dissociation (DD). DEA in C2H2 is found to lead to the formation of H(-) and C2(-)/C2H(-) through excitation of resonances in the electron energy range 1-15 eV. These anionic fragments are formed with super thermal kinetic energy and reveal no anisotropy in the angular distributions. DD in C2H2 leads to the formation of H(-), C(-)/CH(-) and C2(-)/C2H(-) with threshold energies of 15.7, 20.0 and 16.5 eV respectively. The measured anion yields have been used to calculate anion production rates for H(-), C(-)/CH(-) and C2(-)/C2H(-) in Titan's ionosphere. PMID:24343432

  1. Bimolecular Nucleophilic Substitution of an Anion by an Anion. A Theoretical Study of Phenylboronic Acids as a Source of Phenyl Anions.

    E-print Network

    Glaser, Rainer

    Acids as a Source of Phenyl Anions. Nathan Knotts and Rainer Glaser* Department of Chemistry, University of Missouri­Columbia, Columbia, MO 65211 Phenylboronic acid, 1, is a source of reactive phenyl anions - and phenyl anion in two steps as outlined in the Scheme. B OH OH OH B OH OH OH B OH OH OH OH +B OH OHHO OH 1

  2. Metabolic and immune responses in Pacific whiteleg shrimp Litopenaeus vannamei exposed to a repeated handling stress

    Microsoft Academic Search

    Laurence Mercier; Elena Palacios; Ángel I. Campa-Córdova; Dariel Tovar-Ramírez; Roberto Hernández-Herrera; Ilie S. Racotta

    2006-01-01

    Juvenile Pacific whiteleg shrimp reared in either outdoor concrete tanks or indoor plastic tanks were exposed to a repeated stress induced by daily handling for 4 weeks. Metabolic responses (glucose, lactate, total protein, cholesterol, triglyceride, total lipid, hemocyanin, and carotenoid content) and immune responses (total hemocyte count, superoxide anion production, and superoxide dismutase activity) were compared with unstressed shrimp. Metabolic responses

  3. GapZappers

    NSDL National Science Digital Library

    Colleen King

    2013-01-01

    In this online Flash activity students use their knowledge of addition of fractions and equivalent forms to navigate 15 levels of play. Each level progresses in difficulty and includes gaps measured in meters that students must fill in using fractional pieces to enable the lizard to move on in the field of play. Once the gap is filled, check the gap and the lizard will move on showing the fractional equation that solved the problem.

  4. Metabolic engineering

    Microsoft Academic Search

    J. Nielsen

    2001-01-01

    Metabolic engineering has developed as a very powerful approach to optimising industrial fermentation processes through the introduction of directed genetic changes using recombinant DNA technology. Successful metabolic engineering starts with a careful analysis of cellular function; based on the results of this analysis, an improved strain is designed and subsequently constructed by genetic engineering. In recent years some very powerful

  5. An anionic surfactant for EOR applications

    NASA Astrophysics Data System (ADS)

    Sagir, Muhammad; Tan, Isa M.; Mushtaq, Muhammad

    2014-10-01

    This work is to investigate the new anionic surfactants for the Enhanced Oil Recovery (EOR) application. Sulfonated anionic surfactant was produced by attaching SO3 to an ethoxylated alcohol to increase the performance of the surfactant. Methallyl chloride and ethoxylated alcohol was reacted followed by the reaction with sodium bisulfite to produce anionic sulfonated surfactant in 80.3 % yield. The sulfonation reaction parameters such as reactants mole ratio, reaction temperature and catalyst amount were optimized. The generation and stability of foam from the synthesized surfactant is also tested and results are reported. The synthesized novel surfactant was further investigated for the effect on the CO2 mobility in porous media and the findings are presented here. This in house developed surfactant has a great potential for CO2- EOR applications.

  6. Photoelectron Spectroscopy and Theoretical Studies of Anion-pi Interactions: Binding Strength and Anion Specificity

    SciTech Connect

    Zhang, Jian; Zhou, Bin; Sun, Zhenrong; Wang, Xue B.

    2015-01-01

    Proposed in theory and confirmed to exist, anion?? interactions have been recognized as new and important non-covalent binding forces. Despite extensive theoretical studies, numerous crystal structural identifications, and a plethora of solution phase investigations, intrinsic anion???interaction strengths that are free from complications of condensed phases’ environments, have not been directly measured in the gas phase. Herein we present a joint photoelectron spectroscopic and theoretical study on this subject, in which tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic was used as a charge-neutral molecular host to probe its interactions with a series of anions with distinctly different shapes and charge states (spherical halides Cl?, Br?, I?, linear thiocyanate SCN?, trigonal planar nitrate NO3?, pyramidic iodate IO3?, and tetrahedral sulfate SO42?). The binding energies of the resultant gaseous 1:1 complexes (1•Cl?, 1•Br?, 1•I?, 1•SCN?, 1•NO3?, 1•IO3? and 1•SO42?) were directly measured experimentally, exhibiting substantial non-covalent interactions with pronounced anion specific effects. The binding strengths of Cl?, NO3?, IO3? with 1 are found to be strongest among all singly charged anions, amounting to ca. 30 kcal/mol, but only about 40% of that between 1 and SO42?. Quantum chemical calculations reveal that all anions reside in the center of the cavity of 1 with anion???binding motif in the complexes’ optimized structures, where 1 is seen to be able to self-regulate its cavity structure to accommodate anions of different geometries and three-dimensional shapes. Electron density surface and natural bond orbital charge distribution analysis further support anion???binding formation. The calculated??binding energies of the anions and 1 nicely reproduce the experimentally estimated electron binding energy increase. This work illustrates that size-selective photoelectron spectroscopy combined with theoretical calculations represent a powerful technique to probe intrinsic anion???interactions and has potential to provide quantitative guest-host molecular binding strengths and unravel fundamental insights in specific anion recognitions.

  7. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  8. Senseless Extravagance, Shocking Gaps

    ERIC Educational Resources Information Center

    Weissbourd, Richard; Dodge, Trevor

    2012-01-01

    Although most people in the United States believe, at least theoretically, in educational equality, fewer and fewer appear to care about the resource gaps between affluent and poor schools, says Weissbourd. He illustrates these gaps with vivid descriptions of what he calls an "opulence arms race" among affluent independent schools, but points out…

  9. The complexity gap

    Microsoft Academic Search

    L. B. S. Raccoon

    1995-01-01

    The Complexity Gap defines a new way to think about software development. We have all heard that developers need to be more productive and to work harder. But what does this mean exactly? The Complexity Gap defines a structure in which to explore concepts of process and productivity and to show how these concepts relate to conventional software development issues

  10. Gap year volunteer tourism

    Microsoft Academic Search

    Stephen Wearing; John Neil

    The valorisation of cross-cultural understanding and promotion of an ethic of global citizenship are at the forefront of the recent development and proliferation of international ‘gap year’ travel programs and policies. Governments and industry alike promote gap year travel uncritically as a guaranteed pathway to the development of inclusive ideologies associated with global citizenship. In this paper we examine how

  11. Anion permselective membrane. [For redox fuel cells

    Microsoft Academic Search

    S. S. Alexander; R. B. Hodgdon

    1978-01-01

    Experimental anion permeselective membranes were improved and characterized for use as separators in a chemical redox, power storage cell being developed at the NASA Lewis Research Center. The goal of minimal Fe\\/sup +3\\/ ion transfer was achieved for each candidate membrane system. Minimal membrane resistivity was demonstrated by reduction of film thickness using synthetic backing materials but usefulness of thin

  12. Intercrystalline anion exchange, sorption, and base catalysis

    SciTech Connect

    Marcelin, G.

    1990-01-01

    Double-metal layered hydroxides are compounds similar in structure to the mineral hydrotalcite. They consist of brucite layers {l brace}Mg(OH){sub 2}{r brace} in which a portion of the divalent magnesium has been substituted by a trivalent cation in an octahedral coordination state, such as aluminum. Such substitution results in a mixed-metal hydroxide layer bearing a net positive charge which is balanced by the presence of anions in the interlayer. These materials can be conceptualized as being the anionic analogs of cationic clays (such as montmorillonite). It should be feasible to prepare double metal layered hydroxides with strong basic anions in the interlayer (anions such as OH{sup {minus}}, O{sup 2{minus}}, or NH{sub 2}{sup {minus}}) in order to carry out catalytic processes useful in coal liquefaction. This report outlines work performed dealing with various aspects of HT-like compounds. The synthesis and sorptive properties of double-metal layered hydroxides have been examined, as were the acid-base properties of these layered materials and on the use of the layered materials as precursors of solid bases, and the role of the nature of the cations and the layer composition on the acid-base properties of the resulting mixed-oxide. The decomposition of 2-propanol was used as a model reaction since the products depend on the acid-base character of the catalyst. 24 refs., 12 figs., 3 tabs.

  13. Superporous agarose anion exchangers for plasmid isolation

    Microsoft Academic Search

    Peter Tiainen; Per-Erik Gustavsson; Anders Ljunglöf; Per-Olof Larsson

    2007-01-01

    Superporous agarose beads have wide, connecting flow pores allowing large molecules such as plasmids to be transported into the interior of the beads by convective flow. The pore walls provide additional surface for plasmid binding thus increasing the binding capacity of the adsorbent. Novel superporous agarose anion exchangers have been prepared, differing with respect to bead diameter, superpore diameter and

  14. Anion-conducting polymer, composition, and membrane

    DOEpatents

    Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

    2011-11-22

    Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

  15. Anion-Conducting Polymer, Composition, and Membrane

    DOEpatents

    Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

    2008-10-21

    Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

  16. Anion-conducting polymer, composition, and membrane

    DOEpatents

    Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

    2010-12-07

    Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

  17. Anion-conducting polymer, composition, and membrane

    DOEpatents

    Pivovar, Bryan S. (Los Alamos, NM); Thorn, David L. (Los Alamos, NM)

    2009-09-01

    Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

  18. Anionic Homopolymers Efficiently Target Zerovalent Iron Particles to

    E-print Network

    of microscale carbonyl iron powder suspensions modified with anionic homopolymers was studied in waterAnionic Homopolymers Efficiently Target Zerovalent Iron Particles to Hydrophobic Contaminants (DNAPL) contaminants. By comparing iron particle transport in uncontaminated columns with those

  19. Synthesis and study of frustrated oxide and mixed anion materials 

    E-print Network

    Clark, Lucy

    2013-11-28

    Mixed anion systems, such as oxynitrides and oxyfluorides, are an emerging class of interesting materials. The lower stability of mixed anion systems in comparison to oxide materials has had the consequence that this ...

  20. Temperature Dependence of the Mitochondrial Inner Membrane Anion Channel

    E-print Network

    Abraham, Nader G.

    in the efflux of the superoxide anion from mitochondria during ischemic preconditioning, and O of the potassium ionophore valinomycin to mitochon- dria suspended in potassium salts of the test anion (1

  1. Bipyrrole-strapped calix[4]pyrroles: strong anion receptors that extract the sulfate anion.

    PubMed

    Kim, Sung Kuk; Lee, Juhoon; Williams, Neil J; Lynch, Vincent M; Hay, Benjamin P; Moyer, Bruce A; Sessler, Jonathan L

    2014-10-22

    Cage-type calix[4]pyrroles 2 and 3 bearing two additional pyrrole groups on the strap have been synthesized. Compared with the parent calix[4]pyrrole (1), they were found to exhibit remarkably enhanced affinities for anions, including the sulfate anion (TBA(+) salts), in organic media (CD2Cl2). This increase is ascribed to participation of the bipyrrole units in anion binding. Receptors 2 and 3 extract the hydrophilic sulfate anion (as the methyltrialkyl(C(8-10))ammonium (A336(+)) salt) from aqueous media into a chloroform phase with significantly improved efficiency (>10-fold relative to calix[4]pyrrole 1). These two receptors also solubilize into chloroform the otherwise insoluble sulfate salt, (TMA)2SO4 (tetramethylammonium sulfate). PMID:25254498

  2. SUPRAMOLECULAR CHEMISTRY OF SELECTIVE ANION RECOGNITION FOR ANIONS OF ENVIRONMENTAL RELEVANCE

    EPA Science Inventory

    The supramolecular chemistry of selective anion recognition by synthetic polyammonium macrocycles will be explored in a comprehensive, long term program designed to provide new solutions to problems critical to the environmental initiative of DOE. Highly shape- and charge selecti...

  3. Bipyrrole-Strapped Calix[4]pyrroles: Strong Anion Receptors That Extract the Sulfate Anion

    SciTech Connect

    Kim, Sung Kuk [University of Texas at Austin; Lee, Juhoon [University of Texas at Austin; Williams, Neil J [ORNL; Lynch, Vincent M. [University of Texas at Austin; Hay, Benjamin [ORNL; Moyer, Bruce A [ORNL; Sessler, Jonathan L. [University of Texas

    2014-01-01

    Cage-type calix[4]pyrroles 2 and 3 bearing two additional pyrrole groups on the strap have been synthesized. Compared with the parent calix[4]pyrrole (1), they were found to exhibit remarkably enhanced affinities for anions, including the sulfate anion (TBA+ salts), in organic media (CD2Cl2). This increase is ascribed to participation of the bipyrrole units in anion binding. Receptors 2 and 3 extract the hydrophilic sulfate anion (as the methyltrialkyl(C8-10)ammonium (A336+) salt)) from aqueous media into a chloroform phase with significantly improved efficiency (>10-fold relative to calix[4]pyrrole 1). These two receptors also solubilize into chloroform the otherwise insoluble sulfate salt, (TMA)2SO4 (tetramethylammonium sulfate).

  4. Anionic polysulfone ionomers and membranes containing fluorenyl groups for anionic fuel cells

    Microsoft Academic Search

    Junfeng Zhou; Murat Unlu; Jose A. Vega; Paul A. Kohl

    2009-01-01

    Poly(arylene ether sulfone) ionomers containing fluorenyl groups and functionalized with benzyltrimethylammonium groups were synthesized through polycondensation, chloromethylation, and amination reactions. The resulting polymers were characterized by 1H NMR, FT-IR and TGA. Polymer membranes were solvent cast from DMF on Teflon plates to form clear, flexible anion exchange membranes (AEMs). Carbonate anions had conductivities in the AEMs up to 63.12mScm?1 at

  5. Ab initio theoretical study of dipole-bound anions of molecular complexes: Water tetramer anions

    Microsoft Academic Search

    Dayle M. A. Smith; Johan Smets; Yasser Elkadi; Ludwik Adamowicz

    1998-01-01

    We present results of ab initio calculations of the (H2O)4\\/(H2O)4- system. The main conclusions of this work are as follows: The calculated results predict that water tetramer anions are metastable systems in agreement with weak spectral manifestation of these systems in gas-phase experiments of Bowen and co-workers; the excess electrons in all four structural isomers of water tetramer anions found

  6. COMMUNICATIONS Anion photoelectron spectroscopy of iodine-carbon dioxide clusters

    Microsoft Academic Search

    Don W. Arnold; Stephen E. Bradforth; Eun Ha Kim; Daniel M. Neumark

    2003-01-01

    Anion photoelectron spectroscopy has proved to be a powerful method for the study of molecular clusters be- cause it combines mass-selectivity and reasonable spectral resolution. Anion photoelectron spectra have been re- ported for elemental and molecular clusters of the type Ai, in which the additional electron is delocalized over the entire anion cluster,'-6 and for mixed clusters of the type

  7. Hydrocarbon Anions in Interstellar Clouds and Circumstellar Envelopes

    Microsoft Academic Search

    T. J. Millar; C. Walsh; M. A. Cordiner; R. Ní Chuimín; Eric Herbst

    2007-01-01

    The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion\\/neutral abundance ratio can be quite large, on the order of at least a few percent, once the neutral has more than five carbon atoms. Detailed

  8. Process for solvent extraction of vanadate and molybdate anions

    SciTech Connect

    Nevitt, T.D.

    1984-08-28

    A process for recovery of vanadium and molybdenum from a feed material containing compounds of these metals by reacting at an effective pH an aqueous solution of vanadate and molybdate anions with a quaternary ammonium surfactant dissolved in an organic solvent which is immiscible with water and separating a vanadate anion rich phase from a molybdate anion rich phase.

  9. Evaluation of cation-anion interaction strength in ionic liquids.

    PubMed

    Fernandes, Ana M; Rocha, Marisa A A; Freire, Mara G; Marrucho, Isabel M; Coutinho, João A P; Santos, Luís M N B F

    2011-04-14

    Electrospray ionization mass spectrometry with variable collision induced dissociation of the isolated [(cation)(2)anion](+) and/or [(anion)(2)cation](-) ions of imidazolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ionic liquids (ILs) combined with a large set of anions, such as chloride, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, and bis[(trifluoromethyl)sulfonyl]imide, was used to carry out a systematic and comprehensive study on the ionic liquids relative interaction energies. The results are interpreted in terms of main influences derived from the structural characteristics of both anion and cation. On the basis of quantum chemical calculations, the effect of the anion upon the dissociation energies of the ionic liquid pair, and isolated [(cation)(2)anion](+) and/or [(anion)(2)cation](-) aggregates, were estimated and are in good agreement with the experimental data. Both experimental and computational results indicate an energetic differentiation between the cation and the anion to the ionic pair. Moreover, it was found that the quantum chemical calculations can describe the trend obtained for the electrostatic cation-anion attraction potential. The impact of the cation-anion interaction strengths in the surface tension of ionic liquids is further discussed. The surface tensions dependence on the cation alkyl chain length, and on the anion nature, follows an analogous pattern to that of the relative cation-anion interaction energies determined by mass spectrometry. PMID:21425809

  10. Anion conductance of the human red cell is carried by a maxi-anion channel.

    PubMed

    Glogowska, Edyta; Dyrda, Agnieszka; Cueff, Anne; Bouyer, Guillaume; Egée, Stéphane; Bennekou, Poul; Thomas, Serge L Y

    2010-04-15

    Historically, the anion transport through the human red cell membrane has been perceived to be mediated by Band 3, in the two-component concept with the large electroneutral anion exchange accompanied by the conductance proper, which dominated the total membrane conductance. The status of anion channels proper has never been clarified, and the informations obtained by different groups of electrophysiologists are rather badly matched. This study, using the cell-attached configuration of the patch-clamp technique, rationalizes and explains earlier confusing results by demonstrating that the diversity of anionic channel activities recorded in human erythrocytes corresponds to different kinetic modalities of a unique type of maxi-anion channel with multiple conductance levels and probably multiple gating properties and pharmacology, depending on conditions. It demonstrates the role of activator played by serum in the recruitment of multiple new conductance levels showing very complex kinetics and gating properties upon serum addition. These channels, which seem to be dormant under normal physiological conditions, are potentially activable and could confer a far higher anion conductance to the red cell than the ground leak mediated by Band 3. PMID:20226698

  11. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    SciTech Connect

    Jonathan L. Sessler

    2007-09-21

    The major thrust of this project, led by the University of Kansas (Prof. Kristin Bowman-James), entails an exploration of the basic determinants of anion recognition and their application to the design, synthesis, and testing of novel sulfate extractants. A key scientific inspiration for the work comes from the need, codified in simple-to-appreciate terms by the Oak Ridge National Laboratory component of the team (viz. Dr. Bruce Moyer), for chemical entities that can help in the extractive removal of species that have low solubilities in borosilicate glass. Among such species, sulfate anion, has been identified as particularly insidious. Its presence interferes with the vitrification process, thus rendering the remediation of tank waste from, e.g., the Hanford site far more difficult and expensive. The availability of effective extractants, that would allow for the separation of separating sulfate from the major competing anions in the waste, especially nitrate, could allow for pre-vitrification removal of sulfate via liquid-liquid extraction. The efforts at The University of Texas, the subject of this report, have thus concentrated on the development of new sulfate receptors. These systems are designed to increase our basic understanding of anion recognition events and set the stage for the development of viable sulfate anion extractants. In conjunction with the Oak Ridge National Laboratory (ORNL) members of the research team, several of these new receptors were studied as putative extractants, with two of the systems being shown to act as promising synergists for anion exchange.

  12. Bridging The Inferential Gap

    PubMed Central

    Stewart, Walter F.; Shah, Nirav R.; Selna, Mark J.; Paulus, Ronald A.; Walker, James M.

    2009-01-01

    Most clinical decisions involve bridging the inferential gap: Clinicians are required to “fill in” where they lack knowledge or where no knowledge yet exists. In this context we consider how the inferential gap is a product, in part, of how knowledge is created, the limits to gaining access to such knowledge, and the variable ways in which knowledge is translated into decisions. We consider how electronic health records (EHRs) will help narrow this gap by accelerating the creation of evidence relevant to everyday practice needs and facilitating real-time use of knowledge in practice. PMID:17259202

  13. ldentification of High-Affinity Slow Anion Channel Blockers and Evidence for Stomatal Regulation by Slow Anion

    Microsoft Academic Search

    Julian I. Schroeder; Christian Schmidt; Jennifer Sheaffer

    Slow anion channels in the plasma membrane of guard cells have been suggested to constitute an important control mechanism for long-term ion efflux, which produces stomatal closing. ldentification of pharmacological blockers of these slow anion channels is instrumental for understanding plant anion channel function and structure. Patch clamp studies were performed on guard cell protoplasts to identify specific extracellular inhibitors

  14. SOUTHWEST REGIONAL GAP LAND COVER

    EPA Science Inventory

    The Gap Analysis Program is a national inter-agency program that maps the distribution of plant communities and selected animal species and compares these distributions with land stewardship to identify gaps in biodiversity protection. GAP uses remote satellite imag...

  15. Rab GEFs and GAPs

    PubMed Central

    Barr, Francis; Lambright, David G.

    2010-01-01

    Rabs are GTP-binding proteins with conserved functions in membrane trafficking. They are regulated by a diverse group of structurally unrelated GDP-GTP exchange factors (GEFs), and a family of GTP-hydrolysis activating proteins (GAPs) containing the conserved TBC domain. Recent structural and cell biological studies shed new light on the mechanisms of Rab GEF and GAP action, and the cellular trafficking pathways they act in. PMID:20466531

  16. Atomic-scale structure and band-gap bowing in Cu(In,Ga)Se2

    NASA Astrophysics Data System (ADS)

    Schnohr, C. S.; Kämmer, H.; Stephan, C.; Schorr, S.; Steinbach, T.; Rensberg, J.

    2012-06-01

    Mixed systems such as the Cu(In,Ga)Se2 chalcopyrite semiconductor consist of different local atomic arrangements, that is, of different combinations of first-nearest-neighbor cations surrounding the Se anions. The anion position of Cu-III-VI2 compounds is predicted to strongly influence the material band gap. We therefore used extended x-ray absorption fine structure spectroscopy to study the atomic-scale structure of Cu(In,Ga)Se2 as a function of composition. Based on these results, the anion position was modeled for all first-nearest-neighbor configurations using a valence force-field approach. We show that the atomic-scale structure strongly depends on the kind of first-nearest-neighbor atoms. Structural relaxation of the anion occurs with respect to both (i) Cu and group III atoms and (ii) In and Ga atoms. In both cases, the average anion displacement exhibits a nonlinear behavior with changing composition and thus results in two separate but significant contributions to the band gap bowing observed in Cu(In,Ga)Se2.

  17. Giant and composition-dependent optical band gap bowing in dilute GaSb1-xNx alloys

    NASA Astrophysics Data System (ADS)

    Belabbes, A.; Ferhat, M.; Zaoui, A.

    2006-04-01

    Ab initio pseudopotential plane wave calculations and large 64-atom relaxed supercells are used to investigate the structural and electronic properties of GaNxSb1-x dilute alloys. While the band gaps of conventional III-V semiconductors have a simple and weak dependence on composition, this work illustrate a violation of this expected behavior. We show that the band gap decreases rapidly with increasing compositions of N and that GaNxSb1-x show an abnormal giant gap reduction. As a consequence, the optical band gap bowing is found to be giant and composition dependent as found for other mixed anion III-V-N systems.

  18. The organic anion transporter (OAT) family: a systems biology perspective.

    PubMed

    Nigam, Sanjay K; Bush, Kevin T; Martovetsky, Gleb; Ahn, Sun-Young; Liu, Henry C; Richard, Erin; Bhatnagar, Vibha; Wu, Wei

    2015-01-01

    The organic anion transporter (OAT) subfamily, which constitutes roughly half of the SLC22 (solute carrier 22) transporter family, has received a great deal of attention because of its role in handling of common drugs (antibiotics, antivirals, diuretics, nonsteroidal anti-inflammatory drugs), toxins (mercury, aristolochic acid), and nutrients (vitamins, flavonoids). Oats are expressed in many tissues, including kidney, liver, choroid plexus, olfactory mucosa, brain, retina, and placenta. Recent metabolomics and microarray data from Oat1 [Slc22a6, originally identified as NKT (novel kidney transporter)] and Oat3 (Slc22a8) knockouts, as well as systems biology studies, indicate that this pathway plays a central role in the metabolism and handling of gut microbiome metabolites as well as putative uremic toxins of kidney disease. Nuclear receptors and other transcription factors, such as Hnf4? and Hnf1?, appear to regulate the expression of certain Oats in conjunction with phase I and phase II drug metabolizing enzymes. Some Oats have a strong selectivity for particular signaling molecules, including cyclic nucleotides, conjugated sex steroids, odorants, uric acid, and prostaglandins and/or their metabolites. According to the "Remote Sensing and Signaling Hypothesis," which is elaborated in detail here, Oats may function in remote interorgan communication by regulating levels of signaling molecules and key metabolites in tissues and body fluids. Oats may also play a major role in interorganismal communication (via movement of small molecules across the intestine, placental barrier, into breast milk, and volatile odorants into the urine). The role of various Oat isoforms in systems physiology appears quite complex, and their ramifications are discussed in the context of remote sensing and signaling. PMID:25540139

  19. There Are GAPS and There Are GAPS

    NSDL National Science Digital Library

    Ravi Iyengar (Mount Sinai School of Medicine; Department of Pharmacology)

    1997-01-03

    Access to the article is free, however registration and sign-in are required. Guanine nucleotide-binding proteins (G proteins) transduce a very large number of cellular regulatory signals. Several recent papers have shown that the larger heterotrimeric G proteins are regulated by a class of molecules known as the RGS proteins (regulators of G protein-signaling family) that are analogous to the GAPs (GTPase activating proteins), which regulate small monomeric G proteins. Iyengar summarizes this evidence and discusses the mechanism of action of the RGS proteins.

  20. Do coinage metal anions interact with substituted benzene derivatives?

    PubMed

    Aliakbar Tehrani, Zahra; Jamshidi, Zahra; Farhangian, Hossein

    2013-11-01

    The nature of the anion-? interaction has been investigated by carrying out ab initio calculations of the complexes of coinage metal anions (Au(-), Ag(-), and Cu(-)) with different kinds of ?-systems. The binding energies indicate that gold anion has the highest and copper anion has the lowest affinity for interactions with ?-systems. Different aspects of the anion-? interaction in these systems have been investigated, including charge-transfer effects (using the Merz-Kollman method), "atoms-in-molecules" (AIM) topological parameters, and interaction energies (using energy decomposition analysis, EDA). Our results indicated that, for most M(-)···? interactions, the electrostatic term provides the dominant contribution, whereas polarization, charge transfer, and dispersion effects contribute less than 25 % of the interaction. We believe that the present results should lead to a greater understanding of the basis for anion-? interactions of coinage metal anions. PMID:23989771

  1. Specific anion effects in Artemia salina.

    PubMed

    Lo Nostro, Pierandrea; Ninham, Barry W; Carretti, Emiliano; Dei, Luigi; Baglioni, Piero

    2015-09-01

    The specific anion effect on the vitality of Artemia salina was investigated by measuring the Lethal Time LT50 of the crustaceans in the presence of different sodium salts solutions at room temperature and at the same ionic strength as natural seawater. Fluoride, thiocyanate and perchlorate are the most toxic agents, while chloride, bromide and sulfate are well tolerated. The rates of oxygen consumption of brine shrimps were recorded in mixed NaCl+NaF or NaCl+NaSCN solutions as a function of time. The results are discussed in terms of the Hofmeister series, and suggest that, besides the biochemical processes that involve F(-), SCN(-) and ClO4(-), the different physico-chemical properties of the strong kosmotropic and chaotropic anions may contribute in determining their strong toxicity for A. salina. PMID:25978674

  2. Transition metal complexes with (NO) 3 ? anions

    Microsoft Academic Search

    Itai Panas; Anders Snis; Filip Acke; Tobias Johnson

    1999-01-01

    Density functional theory calculations are performed to determine structures, stabilities, and characteristic vibrational frequencies for metal complexes with nitric oxide trimer ligands. The study emphasizes the possible crucial importance of the 3.0 eV first ionization energy of the (NO)3? anion. Metal complexes with the composition M[(NO)3]2 are considered, where M is Mg, Ni, Cu, and Zn. Properties of the Cu(NO)3

  3. Donnan Membrane Technique (DMT) for Anion Measurement

    Microsoft Academic Search

    M. F. Alonso Vega; L. P. Weng; E. J. M. Temminghoff; Riemsdijk van W. H

    2010-01-01

    Donnan membrane technique (DMT) is developed and tested for determination of free anion concentrations. Time needed to reach the Donnan membrane equilibrium depends on type of ions and the background. The Donnan membrane equilibrium is reached in 1 day for Cl?, 1?2 days for NO3?, 1?4 days for SO42? and SeO42?, and 1?14 days for H2PO4? in a background of

  4. Deuterium anions in inertial electrostatic confinement devices

    Microsoft Academic Search

    D. R. Boris; E. Alderson; G. Becerra; D. C. Donovan; B. Egle; G. A. Emmert; L. Garrison; G. L. Kulcinski; J. F. Santarius; C. Schuff; S. J. Zenobia

    2009-01-01

    A magnetic deflection-energy analyzer and Faraday trap diagnostic have been used to make measurements of divergent deuterium anion flow in the inertial electrostatic confinement experiment at the University of Wisconsin-Madison (UW-IEC) [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, I. E. Radel, and A.

  5. Aza crown ether compounds as anion receptors

    SciTech Connect

    Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

    1998-08-04

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI.sup.+ ion in alkali metal batteries.

  6. Aza crown ether compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.O.; McBreen, J.

    1998-08-04

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI{sup +} ion in alkali metal batteries. 3 figs.

  7. Safe 5-nitrotetrazolate anion transfer reagents.

    PubMed

    Klapötke, Thomas M; Sabaté, Carles Miró

    2009-03-14

    Silver 5-nitrotetrazolate (1) and copper(ii) 5-nitrotetrazolate 5-nitrotetrazole dihydrate (2) are useful reagents for the synthesis of 5-nitrotetrazole (NT) salts. Both compounds were synthesized and characterized by vibrational spectroscopy (IR and Raman) and differential scanning calorimetry (DSC). In addition, their sensitivity towards friction, shock and electrostatic discharge was tested by standard BAM methods. The extremely high sensitivity of both materials makes the transfer of the NT(-) anion using and hazardous and not suitable for up-scaling. In order to diminish the hazards involved with the transfer of the energetic anion and to render the synthesis of NT salts suitable for an industrial scale the two compounds were stabilized by coordination with a chelating ligand and silver(ethylendiamine) 5-nitrotetrazolate and bis(ethylendiamine)copper(ii) 5-nitrotetrazolate were synthesized in high yields. Both the stabilized NT(-) anion transfer reagents were characterized by analytical and spectroscopic methods. In addition, the crystal structure of the ethylendiamine copper complex was determined: orthorombic, Pbca; a = 7.5200(1), b = 14.0124(2), c = 14.7740(2) A; V = 1556.78(4) A(3). Furthermore, we synthesized triaminocopper(ii) 5-nitrotetrazolate, which has potential as a more environmentally-friendly primary explosive. Lastly, the synthetic potential of the ethylediamine adducts and to form energetic salts of NT was investigated. PMID:19240919

  8. Electronically excited states of PANH anions.

    PubMed

    Theis, Mallory L; Candian, Alessandra; Tielens, Alexander G G M; Lee, Timothy J; Fortenberry, Ryan C

    2015-05-27

    The singly deprotonated anion derivatives of nitrogenated polycyclic aromatic hydrocarbons (PANHs) are investigated for their electronically excited state properties. These include single deprotonation of the two unique arrangements of quinoline producing fourteen different isomers. This same procedure is also undertaken for single deprotonation of the three nitrogenation isomers of acridine and the three of pyrenidine. It is shown quantum chemically that the quinoline-class of PANH anion derivatives can only produce a candidate dipole-bound excited state each, a state defined as the interaction of an extra electron with the dipole moment of the corresponding neutral. However, the acridine- and pyrenidine-classes possess valence excited states as well as the possible dipole-bound excited states where the latter is only possible if the dipole moment is sufficiently large to retain the extra electron; the valence excitation is independent of the radical dipolar strength. As a result, the theoretical vertically computed electronic spectra of deprotonated PANH anion derivatives is fairly rich in the 1.5 eV to 2.5 eV range significantly opening the possibilities for these molecules to be applied to longer wavelength studies of visible and near-IR spectroscopy. Lastly, the study of these systems is also enhanced by the inclusion of informed orbital arrangements in a simply constructed basis set that is shown to be more complete and efficient than standard atom-centered functions. PMID:25975430

  9. Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies

    PubMed Central

    Chomicz, Lidia; Rak, Janusz; Paneth, Piotr; Sevilla, Michael; Ko, Yeon Jae; Wang, Haopeng; Bowen, Kit H.

    2011-01-01

    We report the photoelectron spectrum of anionic N-acetylproline, (N-AcPro)?, measured with 3.49 eV photons. This spectrum, which consists of a band centered at an electron binding energy of 1.4 eV and a higher energy spectral tail, confirms that N-acetylproline forms a valence anion in the gas phase. The neutrals and anions of N-AcPro were also studied computationally at the B3LYP/6-31++G(d,p) level. Based on the calculations, we conclude that the photoelectron spectrum is due to anions which originated from proton transfer induced by electron attachment to the ?* orbital localized at the acetyl group of N-AcPro. We also characterized the energetics of reaction paths leading to pyrrolidine ring opening in the anionic N-AcPro. These data suggest that electron induced decomposition of peptides/proteins comprising proline strongly depends on the presence of proton donors in the close vicinity to the proline residue. PMID:21950856

  10. Membrane process for separating contaminant anions from aqueous solutions of valuable metal anions

    SciTech Connect

    Hepworth, M.T.; Laferty, J.M.

    1980-11-18

    An aqueous solution of at least one valuable oxyanion containing molybdenum, tungsten, vanadium, or uranium is refined to lower the content of contaminant anions such as PO/sub 4//sup -3/, SO/sub 4//sup -2/, NO/sub 3//sup -/, Cl/sup -/, ClO/sub 3//sup -/, and ClO/sub 4//sup -/, by subjecting the solution to electrolysis at a ph of from 0.5 to 4.0 between a cation-permselective membrane and an anion-permselective membrane having tertiary amine or quaternary ammonium anion exchange groups, to cause contaminant anions to pass from the solution into the anolyte. Ammonium molybdates, tungstates, vanadates, and uranates are formed from the thus-refined solution by subjecting it to a second stage of electrolysis at a ph of at least 7 between a cation-permselective membrane and an anion-permselective membrane to cause valuable oxyanions to pass from the solution into an anolyte which comprises an aqueous solution of ammonia and to form the desired ammonium compound.

  11. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    SciTech Connect

    Bowman-James, Kristin; Wilson, George S.

    2003-06-01

    The original funded project (1996) had as its major goal the design and synthesis of polyammonium macrocyclic receptors for oxoanions of environmental importance, particularly those found in high level waste tanks. Nitrate was a major ion of focus. The project evolved over the last six years to target important and timely problems of critical interest to the EMSP mission. Emphasis was shifted from polyammonium receptors to lipophilic amide-based receptors more amenable for both separations and sensing applications in the last renewal, and significant effort was directed toward selective recognition of sulfate because of its detrimental role in the vitrification process. The last three years have been focused on the basic chemical aspects of anion receptor design of functional pH independent systems, with the ultimate goal of targeting the selective binding of sulfate, as well as design of separations strategies for selective and efficient removal of targeted anions. Key findings during these years include: (1) among the first synthetic sulfate-selective anion-binding agents; (2) simple, structure-based methods for modifying the intrinsic anion selectivity of a given class of anion receptors; and (3) two new classes of macrocyclic ligands, mixed amide/quaternary amine, thioamide-based macrocycles and cryptands.

  12. The benzene radical anion: A computationally demanding prototype for aromatic anions

    NASA Astrophysics Data System (ADS)

    Bazante, Alexandre P.; Davidson, E. R.; Bartlett, Rodney J.

    2015-05-01

    The benzene radical anion is studied with ab initio coupled-cluster theory in large basis sets. Unlike the usual assumption, we find that, at the level of theory investigated, the minimum energy geometry is non-planar with tetrahedral distortion at two opposite carbon atoms. The anion is well known for its instability to auto-ionization which poses computational challenges to determine its properties. Despite the importance of the benzene radical anion, the considerable attention it has received in the literature so far has failed to address the details of its structure and shape-resonance character at a high level of theory. Here, we examine the dynamic Jahn-Teller effect and its impact on the anion potential energy surface. We find that a minimum energy geometry of C2 symmetry is located below one D2h stationary point on a C2h pseudo-rotation surface. The applicability of standard wave function methods to an unbound anion is assessed with the stabilization method. The isotropic hyperfine splitting constants (Aiso) are computed and compared to data obtained from experimental electron spin resonance experiments. Satisfactory agreement with experiment is obtained with coupled-cluster theory and large basis sets such as cc-pCVQZ.

  13. The benzene radical anion: A computationally demanding prototype for aromatic anions.

    PubMed

    Bazante, Alexandre P; Davidson, E R; Bartlett, Rodney J

    2015-05-28

    The benzene radical anion is studied with ab initio coupled-cluster theory in large basis sets. Unlike the usual assumption, we find that, at the level of theory investigated, the minimum energy geometry is non-planar with tetrahedral distortion at two opposite carbon atoms. The anion is well known for its instability to auto-ionization which poses computational challenges to determine its properties. Despite the importance of the benzene radical anion, the considerable attention it has received in the literature so far has failed to address the details of its structure and shape-resonance character at a high level of theory. Here, we examine the dynamic Jahn-Teller effect and its impact on the anion potential energy surface. We find that a minimum energy geometry of C2 symmetry is located below one D2h stationary point on a C2h pseudo-rotation surface. The applicability of standard wave function methods to an unbound anion is assessed with the stabilization method. The isotropic hyperfine splitting constants (Aiso) are computed and compared to data obtained from experimental electron spin resonance experiments. Satisfactory agreement with experiment is obtained with coupled-cluster theory and large basis sets such as cc-pCVQZ. PMID:26026444

  14. Evidence for anionic cation transport of lithium, sodium and potassium across the human erythrocyte membrane induced by divalent anions.

    PubMed Central

    Becker, B F; Duhm, J

    1978-01-01

    1. The passive net transport of Li+ and Na+ across the human red cell membrane was accelerated by the divalent anions carbonate, sulphite, oxalate, phosphite and malonate. Phthalate, maleate, sulphate and succinate were found additionally to stimulate downhill transport of K+. Marked differences in anion efficacy and selectivity were observed. 2. The effects of these 'carbonate type' anions were reversible and fully blocked by SITS, dipyridamole and other inhibitors of anion transfer. 3. Cation transport acceleration induced by the monovalent anions salicylate, benzoate, thiocyanate and 2,4-dinitrophenol were inhibited by dipyridamole, but not affected by SITS. A great number of mono- and polyvalent anions were without detectable influence on Li+ transport. 4. Li+ net uptake induced by oxalate exhibited a pH dependence similar to that reported for halide self exchange. 5. Transport acceleration by carbonate type anions displayed a linear, 1:1 dependence on the concentrations of both the anion and the cation and was symmetric with respect to the two sides of the membrane. 6. It is concluded that the divalent carbonate type anions form singly charged, negative 1:1 ion pairs with the respective alkali metal cations, the ion pairs traversing the red cell membrane via the anion exchange pathway. This concept of anionic formation of some of the ion pairs considered. The relative efficacies and cation selectivities of polyvalent anions can largely be explained on the basis of electrostatic interactions governing ion pair formation. However, the chelating properties, structural flexibility, polarizability of the anions and the accessibility of the ion pairs to the anion exchange pathway need also be considered. 7. An exchange of NaCO-3 ion pairs for internal HCO-3 or Cl- is discussed as a possible mode of cellular pH regulation. PMID:31458

  15. Band gap reduction in GaNSb alloys due to the anion mismatch

    Microsoft Academic Search

    T. D. Veal; L. F. J. Piper; S. Jollands; B. R. Bennett; P. H. Jefferson; P. A. Thomas; C. F. McConville; B. N. Murdin; L. Buckle; G. W. Smith; T. Ashley

    2005-01-01

    The structural and optoelectronic properties in GaNxSb1-x alloys (0<=x<0.02) grown by molecular-beam epitaxy on both GaSb substrates and AlSb buffer layers on GaAs substrates are investigated. High-resolution x-ray diffraction (XRD) and reciprocal space mapping indicate that the GaNxSb1-x epilayers are of high crystalline quality and the alloy composition is found to be independent of substrate, for identical growth conditions. The

  16. Estrogen and cyclic amp action, and the involvement of the cytoskeleton on gap junction formation in rat myometrium 

    E-print Network

    Gaddy, Dana

    1985-01-01

    specialization known as the gap junction ( 12-14). There is an excellent correlation between the presence of gap junctions and physiological properties of cells including metabolic and electrotonic coupling ( 14). Without physiological measurements... in hypophysectomized rat myometrium. The role of cAI'iP in myometrial gap junction formation appears to be different than that reported for all other cell types. Disruption of microtubu les and microfi laments increased estradiol benzoate (E2B)-induced gap junction...

  17. Parma consensus statement on metabolic disruptors.

    PubMed

    Heindel, Jerrold J; Vom Saal, Frederick S; Blumberg, Bruce; Bovolin, Patrizia; Calamandrei, Gemma; Ceresini, Graziano; Cohn, Barbara A; Fabbri, Elena; Gioiosa, Laura; Kassotis, Christopher; Legler, Juliette; La Merrill, Michele; Rizzir, Laura; Machtinger, Ronit; Mantovani, Alberto; Mendez, Michelle A; Montanini, Luisa; Molteni, Laura; Nagel, Susan C; Parmigiani, Stefano; Panzica, Giancarlo; Paterlini, Silvia; Pomatto, Valentina; Ruzzin, Jérôme; Sartor, Giorgio; Schug, Thaddeus T; Street, Maria E; Suvorov, Alexander; Volpi, Riccardo; Zoeller, R Thomas; Palanza, Paola

    2015-01-01

    A multidisciplinary group of experts gathered in Parma Italy for a workshop hosted by the University of Parma, May 16-18, 2014 to address concerns about the potential relationship between environmental metabolic disrupting chemicals, obesity and related metabolic disorders. The objectives of the workshop were to: 1. Review findings related to the role of environmental chemicals, referred to as "metabolic disruptors", in obesity and metabolic syndrome with special attention to recent discoveries from animal model and epidemiology studies; 2. Identify conclusions that could be drawn with confidence from existing animal and human data; 3. Develop predictions based on current data; and 4. Identify critical knowledge gaps and areas of uncertainty. The consensus statements are intended to aid in expanding understanding of the role of metabolic disruptors in the obesity and metabolic disease epidemics, to move the field forward by assessing the current state of the science and to identify research needs on the role of environmental chemical exposures in these diseases. We propose broadening the definition of obesogens to that of metabolic disruptors, to encompass chemicals that play a role in altered susceptibility to obesity, diabetes and related metabolic disorders including metabolic syndrome. PMID:26092037

  18. Metabolic Syndrome (For Parents)

    MedlinePLUS

    ... this is a condition called metabolic syndrome . About Metabolic Syndrome Not to be confused with metabolic disease (which ... chemicals in the body fail to interact properly), metabolic syndrome describes a cluster of risk factors that put ...

  19. Expanded Porphyrin-Anion Supramolecular Assemblies: Environmentally Responsive Sensors for Organic Solvents and Anions.

    PubMed

    Zhang, Zhan; Kim, Dong Sub; Lin, Chung-Yon; Zhang, Huacheng; Lammer, Aaron D; Lynch, Vincent M; Popov, Ilya; Miljani?, Ognjen Š; Anslyn, Eric V; Sessler, Jonathan L

    2015-06-24

    Porphyrins have been used frequently to construct supramolecular assemblies. In contrast, noncovalent ensembles derived from expanded porphyrins, larger congeners of naturally occurring tetrapyrrole macrocycles, are all but unknown. Here we report a series of expanded porphyrin-anion supramolecular assemblies. These systems display unique environmentally responsive behavior. Addition of polar organic solvents or common anions to the ensembles leads to either a visible color change, a change in the fluorescence emission features, or differences in solubility. The actual response, which could be followed easily by the naked eye, was found to depend on the specifics of the assembly, as well as the choice of analyte. Using the ensembles of this study, it proved possible to differentiate between common solvents, such as diethyl ether, THF, ethyl acetate, acetone, alcohol, acetonitrile, DMF, and DMSO, identify complex solvent systems, as well as distinguish between the fluoride, chloride, bromide, nitrate, and sulfate anions. PMID:25965790

  20. Skills Gaps in Australian Firms

    ERIC Educational Resources Information Center

    Lindorff, Margaret

    2011-01-01

    This paper reports the results of a survey of more than 2000 managers examining perceptions of skills gaps in a range of Australian firms. It finds that three quarters report a skills gap, and almost one third report skills gaps across the whole organisation. Firm size and industry differences exist in perceptions of the effect of the skills gap…

  1. GAP PROGRAM SIX YEAR REVIEW

    E-print Network

    Ronquist, Fredrik

    GAP PROGRAM SIX YEAR REVIEW Background for $250,000 request for FY 2011-12 budget year 10/1/2013 1 to take 10-15 years. #12;GAP HISTORY ­ 6 years in · 11 Competitions (69 proposals). 6 years · 37 Projects down by GAP committee #12;Learning As We Go · Members of GAP Committee Assigned as Year Long Mentor

  2. Tunable photonic band gap fiber

    Microsoft Academic Search

    R. T. Bise; R. S. Windeler; K. S. Kranz; C. Kerbage; B. J. Eggleton; D. J. Trevor

    2002-01-01

    The ability to change the photonic band gap structure continuously and reversibly by modifying the index thermally allows the band gap features to be sensitively tuned, allowing for a thorough investigation of the various band gap guiding properties. Furthermore, it may be possible to use this type of band gap fiber as a tunable filter. Investigations of the dispersion properties

  3. [Gap junctions and secretion].

    PubMed

    Haefliger, Jacques-Antoine; Allagnat, Florent; Krattinger, Nathalie; Martin, David; Waeber, Gérard; Nicod, Pascal; Meda, Paolo

    2005-04-27

    The emergence of multicellular organisms has necessitated the development of mechanisms for interactions between adjacent and distant cells. A consistent feature of this network is the expression of gap junction channels between the secretory cells of all glands so far investigated in vertebrates. Here, we reviewed the distribution of the gap junctions proteins, named connexins, in a few mammalian glands, and discussed the recent evidence pointing to the participation of these proteins in the functioning of endocrine and exocrine cells. Specifically, available data indicate the importance of gap junctions for the proper control of glucose-induced insulin secretion. Understanding the functions of beta-cell connexins are crucial for the engineering of surrogate cells, which is necessary for implementation of a replacement cell therapy in diabetic patients. PMID:15943000

  4. Uncertainties in Gapped Graphene

    E-print Network

    Eylee Jung; Kwang S. Kim; DaeKil Park

    2012-03-20

    Motivated by graphene-based quantum computer we examine the time-dependence of the position-momentum and position-velocity uncertainties in the monolayer gapped graphene. The effect of the energy gap to the uncertainties is shown to appear via the Compton-like wavelength $\\lambda_c$. The uncertainties in the graphene are mainly contributed by two phenomena, spreading and zitterbewegung. While the former determines the uncertainties in the long-range of time, the latter gives the highly oscillation to the uncertainties in the short-range of time. The uncertainties in the graphene are compared with the corresponding values for the usual free Hamiltonian $\\hat{H}_{free} = (p_1^2 + p_2^2) / 2 M$. It is shown that the uncertainties can be under control within the quantum mechanical law if one can choose the gap parameter $\\lambda_c$ freely.

  5. Precision gap particle separator

    DOEpatents

    Benett, William J.; Miles, Robin; Jones, II., Leslie M.; Stockton, Cheryl

    2004-06-08

    A system for separating particles entrained in a fluid includes a base with a first channel and a second channel. A precision gap connects the first channel and the second channel. The precision gap is of a size that allows small particles to pass from the first channel into the second channel and prevents large particles from the first channel into the second channel. A cover is positioned over the base unit, the first channel, the precision gap, and the second channel. An port directs the fluid containing the entrained particles into the first channel. An output port directs the large particles out of the first channel. A port connected to the second channel directs the small particles out of the second channel.

  6. "Target-Site" Drug Metabolism and Transport.

    PubMed

    Foti, Robert S; Tyndale, Rachel F; Garcia, Kristine L P; Sweet, Douglas H; Nagar, Swati; Sharan, Satish; Rock, Dan A

    2015-08-01

    The recent symposium on "Target-Site" Drug Metabolism and Transport that was sponsored by the American Society for Pharmacology and Experimental Therapeutics at the 2014 Experimental Biology meeting in San Diego is summarized in this report. Emerging evidence has demonstrated that drug-metabolizing enzyme and transporter activity at the site of therapeutic action can affect the efficacy, safety, and metabolic properties of a given drug, with potential outcomes including altered dosing regimens, stricter exclusion criteria, or even the failure of a new chemical entity in clinical trials. Drug metabolism within the brain, for example, can contribute to metabolic activation of therapeutic drugs such as codeine as well as the elimination of potential neurotoxins in the brain. Similarly, the activity of oxidative and conjugative drug-metabolizing enzymes in the lung can have an effect on the efficacy of compounds such as resveratrol. In addition to metabolism, the active transport of compounds into or away from the site of action can also influence the outcome of a given therapeutic regimen or disease progression. For example, organic anion transporter 3 is involved in the initiation of pancreatic ?-cell dysfunction and may have a role in how uremic toxins enter pancreatic ?-cells and ultimately contribute to the pathogenesis of gestational diabetes. Finally, it is likely that a combination of target-specific metabolism and cellular internalization may have a significant role in determining the pharmacokinetics and efficacy of antibody-drug conjugates, a finding which has resulted in the development of a host of new analytical methods that are now used for characterizing the metabolism and disposition of antibody-drug conjugates. Taken together, the research summarized herein can provide for an increased understanding of potential barriers to drug efficacy and allow for a more rational approach for developing safe and effective therapeutics. PMID:25986849

  7. [Gap functions and diseases].

    PubMed

    Allagnat, Florent; Krattinger, Nathalie; Nicod, Pascal; Meda, Paolo; Haefliger, Jacques-Antoine

    2005-04-27

    Gap junctions are highly conserved structures that provide cells with a direct pathway for sharing ions, nutrients and other intracellular messengers, thus participating to the homeostasis of various tissues. Research on transgenic mice has revealed a major involvement of gap junctions proteins (connexins) in several cellular functions. At the same time, an increasing number of mutations of connexin genes has been linked to several hereditary diseases, including peripheral neuropathies, skin diseases, genetic deafness, cataracts and some forms of epilepsy. This review summarizes the state of knowledge about the implication of connexins in human pathologies. PMID:15942999

  8. Closing the Health Gap

    NSDL National Science Digital Library

    2001-01-01

    The US Department of Health and Human Services (HHS) and ABC Radio Networks are working together to help African-Americans gain access to the best possible information regarding health issues. HHS reports that life expectancies for African-Americans lag five years behind expectancies for White Americans. The new Website Closing the Health Gap has links to information on health conditions such as diabetes and cancer as well as consumer health resources that relate to African-Americans' particular needs. Each page offers links, publications, and any news related to the subject, all in an effort to close "the health gap."

  9. Anion recognition: synthetic receptors for anions and their application in sensors.

    PubMed

    Snowden, T S; Anslyn, E V

    1999-12-01

    Important contributions to the field of anion sensing include electrochemical lipophilic uranyl salophene receptors incorporated into membranes that act as fluoride-selective potentiometric microsensors. A promising optical-based sensor, selective for cyclic AMP, involves a preorganized, molecularly imprinted polymer employing an intrinsic fluorophore. Competition methods using ensembles of recognition units and external indicators have been used to sense citrate in highly competitive media and micromolar concentrations of inositol(tris)phosphate in water. In addition, DNA dendrimers immobilized on a quartz-crystal microbalance acted as an elegant biosensor for Cryptosporidium DNA. These designs display the varied methods of anion detection currently being pursued. PMID:10651521

  10. Overcoming the Income Gap. The Achievement Gap: Overcoming the Income Gap. Info Brief. Number 47

    ERIC Educational Resources Information Center

    Nelson, Anne

    2006-01-01

    One of the most complex aspects of the achievement gap--one that, by and large, is out of the direct control of educational leaders--is the income gap. Broadly defined, the income gap is the standard of living difference between rich and poor, but in the education system, the gap permeates deeply into many dimensions of a student's progression…

  11. GAP TESTS; COMPARISON BETWEEN UN GAP TEST AND CARD GAP TEST

    E-print Network

    Paris-Sud XI, Université de

    98-36 GAP TESTS; COMPARISON BETWEEN UN GAP TEST AND CARD GAP TEST by R. BRANKA and C. MICHOT, FRANCE (tel.: 33 3 44 55 65 19, fax: 33 3 44 55 65 10) ABSTRACT: UN gap test, type 1(a) or 2(a), is the recommended test in the acceptance procedure for transport of explosives in class 1. Up to the revision

  12. Forest Spatial Dynamics with Gap Expansion: Total Gap Area and Gap Size Distribution

    Microsoft Academic Search

    Takuya Kubo; Yoh Iwasa; Naoki Furumoto

    1996-01-01

    Recent studies on forest dynamics in diverse forested ecosystems suggest that forest stands are disturbed more frequently if they are next to existing gaps, and that gaps once formed tend to expand their area in subsequent years. We examine total gap area and the size distribution of gaps at equilibrium in a lattice-structured forest model. Each site undergoes transition between

  13. STEMMING the Gap

    ERIC Educational Resources Information Center

    Kahler, Jim; Valentine, Nancy

    2011-01-01

    America has a gap when it comes to youth pursuing science and technology careers. In an effort to improve the knowledge and application of science, technology, engineering, and math (STEM), after-school programs can work in conjunction with formal in-school curriculum to improve science education. One organization that actively addresses this…

  14. Crossing the Gap

    ERIC Educational Resources Information Center

    Lockette, Tim

    2009-01-01

    In a nation where education is funded largely by local property taxes, schools in wealthy communities have plenty of funds to spend on programs that get their kids ready for college. Schools in poor communities scrimp and save to get the job done--or hope that funding from the state will help fill in the gap. This article describes how students…

  15. Confronting the Autonomy Gap

    ERIC Educational Resources Information Center

    Adamowski, Steven; Petrilli, Michael J.

    2007-01-01

    "The Autonomy Gap," a recent study by the American Institute for Research and the Thomas B. Fordham Institute, found that many public elementary school principals feel constrained by a bureaucracy that impedes their ability to raise student achievement. Unfortunately, those principals are still held accountable for their school's results--even…

  16. Graphene: Mind the gap

    Microsoft Academic Search

    Kostya Novoselov

    2007-01-01

    Research now shows that interaction with silicon carbide substrate leads to the opening of a semiconductor gap in epitaxial graphene. This is an important first step towards bandgap engineering in this two-dimensional crystal, and its incorporation in electronic devices.

  17. Sodium Bicarbonate Therapy in Patients with Metabolic Acidosis

    PubMed Central

    Adeva-Andany, María M.; Fernández-Fernández, Carlos; Mouriño-Bayolo, David; Castro-Quintela, Elvira; Domínguez-Montero, Alberto

    2014-01-01

    Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated. PMID:25405229

  18. Squarylium-based chromogenic anion sensors.

    PubMed

    Lee, Eun-Mi; Gwon, Seon-Yeong; Son, Young-A; Kim, Sung-Hoon

    2012-09-01

    A squarylium (SQ) dye was synthesized by the reaction between squaric acid and 2,3,3-trimethylindolenine and its anion sensing properties were investigated using absorption and emission spectroscopy. This chemosensor exhibited high selectivity for CN(-) as compared with F(-), CH(3)CO(2)(-), Br(-), H(2)PO(4)(-), Cl(-), and NO(3)(-) in acetonitrile, which was attributed to the formation of a 1:1 squarylium:CN(-) coordination complex, the formation of which was supported by the calculated geometry of the complex. PMID:22613120

  19. Design of inorganic compounds with tetrahedral anions

    NASA Astrophysics Data System (ADS)

    Lazoryak, B. I.

    1996-04-01

    The review deals with aspects of the modelling of the compositions and properties of inorganic compounds with tetrahedral anions on the basis of crystal-chemical information. One of the possible algorithms employing crystal-chemical data for the modelling of the compositions, structures, and properties of new compounds is proposed on the basis of the structures of six structural types (glaserite, ?-K2SO4, bredigite, palmierite, NASICON, and whitlockite). The likely usefulness of such data for the solution of various problems in materials science is demonstrated. The bibliography includes 208 references.

  20. Metabolic Downregulation

    PubMed Central

    Yenari, Midori; Kitagawa, Kazuo; Lyden, Patrick; Perez-Pinzon, Miguel

    2008-01-01

    Background and Purpose The search for effective neuroprotectants remains frustrating, particularly with regard to specific pharmaceuticals. However, laboratory studies have consistently shown remarkable neuroprotection with 2 nonpharmacological strategies—therapeutic hypothermia and ischemic preconditioning. Recent studies have shown that the mechanism of protection underlying both of these treatments is correlated to downregulation of cellular and tissue metabolism. Thus, understanding the mechanisms underlying such robust protective effects could lead to appropriate translation at the clinical level. In fact, hypothermia is already being used at many centers to improve neurological outcome from cardiac arrest. Methods A systematic review of both topics is presented in terms of underlying pathophysiological mechanisms and application at the clinical level. Results Although the mechanisms of protection for both therapeutic strategies are multifold, both share features of downregulating metabolism. Both therapeutic strategies are robust neuroprotectants, but translating them to the clinical arena is challenging, though not impossible, and clinical studies have shown or suggest benefits of both treatments. Conclusions The strategy of metabolic downregulation should be further explored to identify effective neuroprotectants that can be easily applied clinically. PMID:18658035

  1. Hydrocarbon anions in interstellar clouds and circumstellar envelopes

    Microsoft Academic Search

    T. J. Millar; C. Walsh; M. A. Cordiner; R. Ní Chuimín; Eric Herbst

    2007-01-01

    The recent detection of the hydrocarbon anion C6H- in the interstellar medium\\u000ahas led us to investigate the synthesis of hydrocarbon anions in a variety of\\u000ainterstellar and circumstellar environments. We find that the anion\\/neutral\\u000aabundance ratio can be quite large, on the order of at least a few percent,\\u000aonce the neutral has more than five carbon atoms. Detailed

  2. PROGRESS REPORT. SUPRAMOLECULAR CHEMISTRY OF SELECTIVE ANION RECOGNITION FOR ANIONS OF ENVIRONMENTAL RELEVANCE

    EPA Science Inventory

    This project involves the design and synthesis of receptors for oxoanions of environmental importance and specifically those found in high level waste tanks. Polyammonium macrocycles as receptors and nitrate as anion were the focus of the first phase of this project. A second pha...

  3. Charge regulation enables anionic hydroxypropyl guar-borate adsorption onto anionic and cationic polystyrene latex.

    PubMed

    Zhang, Liang; Pelton, Robert; Ketelson, Howard; Meadows, David

    2011-01-15

    Reported are adsorption isotherms for guar and hydroxypropyl guar (HPG), with and without the presence of borate ions, onto surfactant free anionic polystyrene latex. Guar and HPG formed adsorbed monolayers on the hydrophobic latex. The presence of borate ions converted the nonionic guar and HPG into an anionic polyelectrolyte. However, there was no measurable influence of bound borate ions on the adsorption of guar or HPG onto anionic, hydrophobic latex. To underscore the unusual behavior of HPG-borate, a sample of HPG was oxidized to introduce carboxyl groups, and the adsorption of the carboxylated HPG onto anionic polystyrene was measured. Unlike HPG-borate, oxidized HPG did not adsorb onto negative polystyrene latex at neutral pH because of electrostatic repulsion. To explain the adsorption of negative HPG-borate onto negative latex, we proposed that as HPG-borate segments approach the latex surface, the negative electrostatic potential near the latex surface induces the detachment of the labile borate groups from HPG. PMID:21030034

  4. Aluminum Zintl anion moieties within sodium aluminum clusters

    SciTech Connect

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Bowen, Kit H., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schnöckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany)] [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States)] [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States); Lee, Mal-Soon; Jena, P. [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kandalam, Anil K., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383 (United States); Kiran, Boggavarapu, E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)] [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)

    2014-02-07

    Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium–aluminum cluster anions, Na{sub m}Al{sub n}{sup ?}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.

  5. Purification Or Organic Acids Using Anion Exchange Chromatography.

    DOEpatents

    Ponnampalam; Elankovan (Okemos, MI)

    2001-09-04

    Disclosed is a cost-effective method for purifying and acidifying carboxylic acids, including organic acids and amino acids. The method involves removing impurities by allowing the anionic form of the carboxylic acid to bind to an anion exchange column and washing the column. The carboxylic anion is displaced as carboxylic acid by washing the resin with a strong inorganic anion. This method is effective in removing organic carboxylic acids and amino acids from a variety of industrial sources, including fermentation broths, hydrolysates, and waste streams.

  6. Infrared photodissociation spectroscopy of mononuclear iron carbonyl anions.

    PubMed

    Wang, Guanjun; Chi, Chaoxian; Cui, Jieming; Xing, Xiaopeng; Zhou, Mingfei

    2012-03-15

    The infrared photodissociation spectroscopy of mass-selected mononuclear iron carbonyl anions Fe(CO)(n)(-) (n = 2-8) were studied in the carbonyl stretching frequency region. The FeCO(-) anion does not fragment when excited with infrared light. Only a single IR active band was observed for the Fe(CO)(2)(-) and Fe(CO)(3)(-) anions, consistent with theoretical predictions that these complexes have linear D(?h) and planar D(3h) symmetry, respectively. The Fe(CO)(4)(-) anion is the most intense peak in the mass spectra and was characterized to have a completed coordination sphere with high stability. Anion clusters larger than n = 4 were determined to involve a Fe(CO)(4)(-) core anion that is progressively solvated by external CO molecules. Three CO stretching vibrational fundamentals were observed for the Fe(CO)(4)(-) core anion, indicating that the Fe(CO)(4)(-) anion has a C(3v) structure. All the carbonyl stretching frequencies of the Fe(CO)(n)(-) anion complexes are red-shifted with respect to those of the corresponding neutrals. PMID:22360767

  7. Bis(imidazolium)-calix[4]arene receptors for anion binding.

    PubMed

    Dinarès, Immaculada; Garcia de Miguel, Cristina; Mesquida, Neus; Alcalde, Ermitas

    2009-01-01

    Efficient access to the bis(imidazolyl)calixarene 2 and dicationic bis(imidazolium) salts 1a,b x 2X directly bonded to the upper rim of calixarene structure has been reported. Anion binding properties of the new receptors were studied by 1H NMR spectroscopic methods. Bis(N-butylimidazolium) dication 1a exhibited the best recognition properties toward carboxylate anions with a 1:1 receptor-anion binding stoichiometry, whereas the presence of a bulky group such as isopropyl (1b) increased the difficulty of both imidazolium moieties to be able to support the association with the same single anion. PMID:19053578

  8. Monitoring trace anion contamination in disk drive components.

    PubMed

    Kaiser, Edward; Rohrer, Jeff; Campbell, Faye

    2003-05-16

    Ion chromatography was used to determine trace anionic contamination on the surface of hard disk drive components. These contaminants can have a detrimental effect on device reliability and yield. Disk drive components were soaked in deionized water and these extracts were analyzed for anions. The anions fluoride, acetate, formate, acrylate, methacrylate, chloride, nitrite, bromide, nitrate, benzoate, sulfate, oxalate, phthalate and phosphate were separated on a high-performance anion-exchange column and determined at concentrations less than 1 microg/l with suppressed conductivity detection. The extract solutions were analyzed either by injecting 1 ml or by preconcentrating 5 ml. We evaluated the performance of both methods. PMID:12830900

  9. Closing gaps: linking elements that control stomatal movement.

    PubMed

    Kollist, Hannes; Nuhkat, Maris; Roelfsema, M Rob G

    2014-07-01

    Stomata are an attractive experimental system in plant biology, because the responses of guard cells to environmental signals can be directly linked to changes in the aperture of stomatal pores. In this review, the mechanics of stomatal movement are discussed in relation to ion transport in guard cells. Emphasis is placed on the ion pumps, transporters, and channels in the plasma membrane, as well as in the vacuolar membrane. The biophysical properties of transport proteins for H(+), K(+), Ca(2+), and anions are discussed and related to their function in guard cells during stomatal movements. Guard cell signaling pathways for ABA, CO2, ozone, microbe-associated molecular patterns (MAMPs) and blue light are presented. Special attention is given to the regulation of the slow anion channel (SLAC) and SLAC homolog (SLAH)-type anion channels by the ABA signalosome. Over the last decade, several knowledge gaps in the regulation of ion transport in guard cells have been closed. The current state of knowledge is an excellent starting point for tackling important open questions concerning stress tolerance in plants. PMID:24800691

  10. Gapped Domain Walls, Gapped Boundaries, and Topological Degeneracy

    E-print Network

    Lan, Tian

    Gapped domain walls, as topological line defects between (2+1)D topologically ordered states, are examined. We provide simple criteria to determine the existence of gapped domain walls, which apply to both Abelian and ...

  11. Mixed micelles of some anionic-anionic, cationic-cationic, and ionic-nonionic surfactants in aqueous media

    Microsoft Academic Search

    Sambhav Vora; Alex George; Hemangi Desai; Pratap Bahadur

    1999-01-01

    Critical micelle concentrations (CMC) were obtained from tensiometric studies on several binary surfactant mixtures (anionic-anionic,\\u000a cationic-cationic, anionic-nonionic, and cationic-nonionic) in water at different mole fractions (0–1). The composition of\\u000a mixed micelles and the interaction parameter ?, evaluated from the CMC data for different systems using Rubingh's theory,\\u000a are discussed. Marked interaction is observed for ionic-nonionic systems, whereas it is weak

  12. An intracellular anion channel critical for pigmentation

    PubMed Central

    Bellono, Nicholas W; Escobar, Iliana E; Lefkovith, Ariel J; Marks, Michael S; Oancea, Elena

    2014-01-01

    Intracellular ion channels are essential regulators of organellar and cellular function, yet the molecular identity and physiological role of many of these channels remains elusive. In particular, no ion channel has been characterized in melanosomes, organelles that produce and store the major mammalian pigment melanin. Defects in melanosome function cause albinism, characterized by vision and pigmentation deficits, impaired retinal development, and increased susceptibility to skin and eye cancers. The most common form of albinism is caused by mutations in oculocutaneous albinism II (OCA2), a melanosome-specific transmembrane protein with unknown function. Here we used direct patch-clamp of skin and eye melanosomes to identify a novel chloride-selective anion conductance mediated by OCA2 and required for melanin production. Expression of OCA2 increases organelle pH, suggesting that the chloride channel might regulate melanin synthesis by modulating melanosome pH. Thus, a melanosomal anion channel that requires OCA2 is essential for skin and eye pigmentation. DOI: http://dx.doi.org/10.7554/eLife.04543.001 PMID:25513726

  13. Deuterium anions in inertial electrostatic confinement devices.

    PubMed

    Boris, D R; Alderson, E; Becerra, G; Donovan, D C; Egle, B; Emmert, G A; Garrison, L; Kulcinski, G L; Santarius, J F; Schuff, C; Zenobia, S J

    2009-09-01

    A magnetic deflection-energy analyzer and Faraday trap diagnostic have been used to make measurements of divergent deuterium anion flow in the inertial electrostatic confinement experiment at the University of Wisconsin-Madison (UW-IEC) [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, I. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)], a device to confine high-energy light ions in a spherically symmetric electrostatic potential well. Deuterium anion current densities as high as 8.5 microA/cm2 have been measured at the wall of the UW-IEC device, 40 cm from the surface of the device cathode with a detector assembly of admittance area 0.7 cm2. Energy spectra obtained using a magnetic deflection-energy analyzer diagnostic indicate the presence of D2(-), and D- ions produced through thermal electron attachment near the device cathode, as well as D- ions produced via charge-transfer processes between the anode and cathode of the device. PMID:19905231

  14. Photonic band gap materials

    NASA Astrophysics Data System (ADS)

    Cassagne, D.

    Photonic band gap materials Photonic band gap materials are periodic dielectric structures that control the propagation of electromagnetic waves. We describe the plane wave method, which allows to calculate the band structures of photonic crystals. By symmetry analysis and a perturbative approach, we predict the appearance of the low energy photonic band gaps of hexagonal structures. We propose new two-dimensional structures called graphite and boron nitride. Using a transfer matrix method, we calculate the transmission of the graphite structure and we show the crucial role of the coupling with external modes. We study the appearance of allowed modes in the photonic band gap by the introduction of localized defects in the periodicity. Finally, we discuss the properties of opals formed by self-organized silica microspheres, which are very promising for the fabrication of three-dimensional photonic crystals. Les matériaux à bandes interdites photoniques sont des structures diélectriques périodiques qui contrôlent la propagation des ondes électromagnétiques. Nous décrivons la méthode des ondes planes qui permet de calculer les structures de bandes des cristaux photoniques. Par une analyse de la symétrie et une approche perturbative, nous précisons les conditions d'existence des bandes interdites de basse énergie. Nous proposons de nouvelles structures bidimensionnelles appelées graphite et nitrure de bore. Grâce à une méthode de matrices de transfert, nous calculons la transmission de la structure graphite et nous mettons en évidence le rôle fondamental du couplage avec les modes extérieurs. Nous étudions l'apparition de modes permis dans la bande interdite grâce à l'introduction de défauts dans la périodicité. Enfin, nous discutons les propriétés des opales constituées de micro-billes de silice auto-organisées, qui sont très prometteuses pour la fabrication de cristaux photoniques tridimensionnels.

  15. Air-gap heterostructures

    SciTech Connect

    Heyn, Ch.; Schmidt, M.; Schwaiger, S.; Stemmann, A.; Mendach, S.; Hansen, W. [Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Jungiusstrasse 11, D-20355 Hamburg (Germany)

    2011-01-17

    We demonstrate the fabrication of thin GaAs layers which quasi hover above the underlying GaAs substrate. The hovering layers have a perfect epitaxial relationship to the substrate crystal lattice and are connected to the substrate surface only by lattice matched nanopillars of low density. These air-gap heterostructures are created by combining in situ molecular beam epitaxy compatible self-assembled droplet-etching and ex situ selective wet-chemical etching.

  16. Gender gaps within management.

    PubMed

    Ronk, L L

    1993-05-01

    Traditional roles need not become self-fulfilling prophecies if managers can bridge the gender gap. Feminine, as well as masculine, characteristics can be incorporated into managerial styles to enhance effective leadership. Autonomy, decision-making and assertiveness are as important as nurturing and caring. What are little girls made of? Little girls are made of sugar and spice and everything nice. What are little boys made of? Little boys are made of rats and snails and puppy dog tails. PMID:8265083

  17. Extended negative dietary cation-anion difference feeding does not negatively affect postpartum performance of multiparous dairy cows.

    PubMed

    Weich, W; Block, E; Litherland, N B

    2013-09-01

    Low postpartum blood calcium remains one of the largest constraints to postpartum feed intake, milk yield, and energy balance in transitioning dairy cows. Supplemental dietary anions decrease the dietary cation-anion difference (DCAD) and reduce the risk for postpartum hypocalcemia. Prepartum management strategies aiming to minimize social stress and diet changes have resulted in a need to explore the effects of extended exposure to a negative DCAD (>21 d) diet. Holstein and Holstein-cross dairy cows (n=60) were assigned to 1 of 3 treatments 42 d before expected calving to evaluate effects of supplying anions for 21 or 42 d during the dry period on energy status, postpartum production, and Ca homeostasis. Treatments included (1) a control diet (CON; DCAD=12 mEq/100 g of DM), (2) a 21-d negative DCAD diet (21-ND; DCAD=12 and -16 mEq/100 g of DM), and (3) a 42-d negative DCAD diet (42-ND; DCAD=-16 mEq/100 g of DM). Cows fed CON were fed positive DCAD prepartum for 42 d. Cows fed 21-ND received the positive DCAD (12 mEq/100 g of DM) diet for the first 21 d of the dry period and the anionic diet (-16 mEq/100 g of DM) from d 22 until calving. Cows fed 42-ND received the anionic diet for the entire dry period. Control and anionic diets were formulated by using 2 isonitrogenous protein mixes: (1) 97.5% soybean meal and (2) 52.8% BioChlor (Church & Dwight Co. Inc.), 45.8% soybean meal. Supplementing anions induced a mild metabolic acidosis, reducing urine pH for 21-ND and 42-ND compared with CON. Prepartum DMI was not different among treatments. Postpartum DMI was higher for 21-ND compared with CON (20.8 vs. 18.1±1.1 kg/d), and 42-ND had similar DMI compared with 21-ND. During the first 56 d of lactation 21-ND had greater average milk production compared with CON (44.8 vs. 39.2±2.1 kg/d). Average milk production by 42-ND was similar to 21-ND. Postpartum total blood Ca concentration was greater for 42-ND. Cows fed anionic diets prepartum tended to have lower lipid accumulation in the liver after calving compared with CON. These data suggest low-DCAD diets fed for 21 or 42 d during the dry period can have positive effects on postpartum DMI, Ca homeostasis, and milk production. PMID:23831094

  18. Why Metabolic Syndrome Matters

    MedlinePLUS

    Why Metabolic Syndrome Matters Updated:Jul 24,2014 Metabolic syndrome may be diagnosed when a patient has a cluster of ... Diabetes High Blood Pressure My Life Check Heart360® Metabolic Syndrome • Home • About Metabolic Syndrome • Why Metabolic Syndrome Matters • ...

  19. [Hyperthermia and metabolic acidosis during subtotal thyroidectomy for a patient with Basedow's disease].

    PubMed

    Mizuno, Ju; Yonenaga, Kazumichi; Mimura, Yoshikazu; Arita, Hideko; Hanaoka, Kazuo

    2008-07-01

    A 32-year-old man underwent subtotal thyroidectomy for Basedow's disease under general anesthesia. Preoperatively, the free thyroxine (fT4) and free triiodothyronine (fT3) levels were suppressed and thyroid stimulating hormone level was elevated with administration of iodine and propylthiouracil. Heart rate was 52 beats x min(-1) in sinus rhythm. General anesthesia was induced with fentanyl, propofol and vecuronium, and maintained with nitrous oxide, oxygen and sevoflurane. Systolic blood pressure was controlled within 100 and 130 mmHg. Rectal temperature was 36.5 degrees C after anesthesia induction, gradually rising at a range of 0.4 and 0.7 degrees C per hour, up to 38.6 degrees C four hours after the operation. Arterial blood gas showed bicarbonate 17.1 mEq x l(-1) and base excess -8.1 mmol x l(-1). The metabolic acidosis with normal anion gap lasted during and after the operation. We cooled his body with cold acetyl linger fluid and cooling mattress, and administered sodium bicarbonate. Heart rate increased to 96 beats x min(-1) before the end of operation. Subtotal thyroidectomy was finished in 5 hours 16 minutes. The amount of blood loss was 950 ml. Postoperatively, the serum fT4 and fT3 were suppressed. The serum creatine kinase and lactate dehydrogenase levels increased slightly. He did not show muscle rigidity and neurological disorders. We suspect that he has developed thyroid storm-like symptoms such as hyperthermia and tachycardia induced by subtotal thyroidectomy. Metabolic acidosis might be the result of distal tubular acidosis, which rarely accompanies Basedow's disease. Arterial blood gas analysis and urinalysis should be performed, preoperatively. PMID:18649649

  20. Electroactive Materials for Anion Separation - Technetium from Nitrate

    Microsoft Academic Search

    Johanes H. Sukamto; William H. Smyrl; James McBreen; Timothy L. Hubler; Michael A. Lilga

    2000-01-01

    Many contaminants of interest to the U.S. Department of Energy (DOE) exist as anions. These include the high priority pollutants chromate, pertechnetate, and nitrate ions. In addition, there are also industrial and urban applications where the separation of anionic species from aqueous streams is critical. Examples include industrial water recycle and waste water treatment (e.g., chloride ion removal for the

  1. An anion sensor based on an organic field effect transistor.

    PubMed

    Minami, Tsuyoshi; Minamiki, Tsukuru; Tokito, Shizuo

    2015-05-26

    We propose an organic field effect transistor (OFET)-based sensor design as a new and innovative platform for anion detection. OFETs could be fabricated on low-cost plastic film substrates using printing technologies, suggesting that OFETs can potentially be applied to practical supramolecular anion sensor devices in the near future. PMID:25966040

  2. Angiotensin II induces superoxide anion production by mesangial cells

    Microsoft Academic Search

    Edgar A Jaimes; Josep Maria Galceran; Leopoldo Raij

    1998-01-01

    Angiotensin II induces superoxide anion production by mesangial cells.BackgroundThe recognized role of angiotensin II (Ang II) in the pathogenesis of the progression of renal disease cannot be solely attributed to Ang II's hemodynamic effects. Indeed, growth stimulating signals driven by Ang II promote mesangial cell (MC) hypertrophy and extracellular matrix production, prominent features of progressive glomerular injury. Superoxide anion (O2?)

  3. 8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE ...

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

    8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE PROCESS. THE ANION EXCHANGE PROCESS PURIFIED AND CONCENTRATED PLUTONIUM-BEARING NITRIC ACID SOLUTIONS TO MAKE THEM ACCEPTABLE AS FEED FOR CONVERSION TO METAL. (6/20/60) - Rocky Flats Plant, Plutonium Recovery & Fabrication Facility, North-central section of plant, Golden, Jefferson County, CO

  4. Organic anions and the diarrhea of inflammatory bowel disease

    Microsoft Academic Search

    P. Vernia; A. Gnaedinger; W. Hauck; R. I. Breuer

    1988-01-01

    To determine if organic anions contribute to the diarrhea of inflammatory bowel disease, we measured osmolality, electrolytes, short-chain fatty acids, lactic acid, and some Krebs cycle anions in 24-hr fecal collections from 18 patients with chronic ulcerative colitis, 20 with Crohn's disease of the colon, and 16 normals. Mean lactic acid concentration was significantly elevated in ulcerative and Crohn's colitis,

  5. Superoxide Anion Radical Production in the Tardigrade Paramacrobiotus richtersi, the First Electron Paramagnetic Resonance Spin-Trapping Study.

    PubMed

    Savic, Aleksandar G; Guidetti, Roberto; Turi, Ana; Pavicevic, Aleksandra; Giovannini, Ilaria; Rebecchi, Lorena; Mojovic, Milos

    2015-01-01

    Anhydrobiosis is an adaptive strategy that allows withstanding almost complete body water loss. It has been developed independently by many organisms belonging to different evolutionary lines, including tardigrades. The loss of water during anhydrobiotic processes leads to oxidative stress. To date, the metabolism of free radicals in tardigrades remained unclear. We present a method for in vivo monitoring of free radical production in tardigrades, based on electron paramagnetic resonance and spin-trap DEPMPO, which provides simultaneous identification of various spin adducts (i.e., different types of free radicals). The spin trap can be easily absorbed in animals, and tardigrades stay alive during the measurements and during 24-h monitoring after the treatment. The results show that hydrated specimens of the tardigrade Paramacrobiotus richtersi produce the pure superoxide anion radical ((•)O2(-)). This is an unexpected result, as all previously examined animals and plants produce both superoxide anion radical and hydroxyl radical ((•)OH) or exclusively hydroxyl radical. PMID:26052642

  6. Poly(phenylene)-based anion exchange membrane

    DOEpatents

    Hibbs, Michael (Albuquerque, NM); Cornelius, Christopher J. (Albuquerque, NM); Fujimoto, Cy H. (Albuquerque, NM)

    2011-02-15

    A poly(phenylene) compound of copolymers that can be prepared with either random or multiblock structures where a first polymer has a repeat unit with a structure of four sequentially connected phenyl rings with a total of 2 pendant phenyl groups and 4 pendant tolyl groups and the second polymer has a repeat unit with a structure of four sequentially connected phenyl rings with a total of 6 pendant phenyl groups. The second polymer has chemical groups attached to some of the pendant phenyl groups selected from CH.sub.3, CH.sub.2Br, and CH.sub.2N(CH.sub.3).sub.3Br groups. When at least one group is CH.sub.2N(CH.sub.3).sub.3Br, the material functions as an anion exchange membrane.

  7. Simulations of zwitterionic and anionic phospholipid monolayers.

    PubMed Central

    Kaznessis, Yiannis N; Kim, Sangtae; Larson, Ronald G

    2002-01-01

    Results of atomistic molecular dynamics simulations of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol monolayers at the air/water interface are presented. Dipalmitoylphosphatidylcholine is zwitterionic and dipalmitoylphosphatidylglycerol is anionic at physiological pH. NaCl and CaCl2 water subphases are simulated. The simulations are carried out at different surface densities, and a simulation cell geometry is chosen that greatly facilitates the investigation of phospholipid monolayer properties. Ensemble average monolayer properties calculated from simulation are in agreement with experimental measurements. The dependence of the properties of the monolayers on the surface density, the type of the headgroup, and the ionic environment are explained in terms of atomistically detailed pair distribution functions and electron density profiles, demonstrating the strength of simulations in investigating complex, multicomponent systems of biological importance. PMID:11916834

  8. Living anionic polymerization using a microfluidic reactor.

    PubMed

    Iida, Kazunori; Chastek, Thomas Q; Beers, Kathryn L; Cavicchi, Kevin A; Chun, Jaehun; Fasolka, Michael J

    2009-01-21

    Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 degrees C) and high monomer concentration (42%, by volume). The reactions were safely maintained at a controlled temperature at all points in the reactor. Conducting these reactions in a batch reactor results in uncontrolled heat generation with potentially dangerous rises in pressure. Moreover, the microfluidic nature of these devices allows for flexible 2D designing of the flow channel. Four flow designs were examined (straight, periodically pinched, obtuse zigzag, and acute zigzag channels). The ability to use the channel pattern to increase the level of mixing throughout the reactor was evaluated. When moderately high molecular mass polymers with increased viscosity were made, the patterned channels produced polymers with narrower PDI, indicating that passive mixing arising from the channel design is improving the reaction conditions. PMID:19107294

  9. Living anionic polymerization using a microfluidic reactor

    SciTech Connect

    Iida, Kazunori; Chastek, Thomas Q.; Beers, Kathryn L.; Cavicchi, Kevin A.; Chun, Jaehun; Fasolka, Michael J.

    2009-02-01

    Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 °C) and high monomer concentration (42%, by volume). The reactions were safely maintained at a controlled temperature at all points in the reactor. Conducting these reactions in a batch reactor results in uncontrolled heat generation with potentially dangerous rises in pressure. Moreover, the microfluidic nature of these devices allows for flexible 2D designing of the flow channel. Four flow designs were examined (straight, periodically pinched, obtuse zigzag, and acute zigzag channels). The ability to use the channel pattern to increase the level of mixing throughout the reactor was evaluated. When moderately high molecular mass polymers with increased viscosity were made, the patterned channels produced polymers with narrower PDI, indicating that passive mixing arising from the channel design is improving the reaction conditions.

  10. Bimetallic anionic formyl complexes: synthesis and properties

    SciTech Connect

    Tam, W.; Marsi, M.; Gladysz, J.A.

    1983-05-11

    Three bimetallic anionic complexes, (2) lithium + dimanganese nonacarbonyl formyl/sup -/, (3) lithium + rhenium manganese nonacarbonyl formyl/sup -/, and (4) lithium + cisdirhenium nonacarbonyl formyl, are prepared by the reaction of lithium triethylboron hydride with the corresponding neutral metal carbonyl dimers, dimanganese decacarbonyl and manganese rhenium decarbonyl. 2 has a half-life of ca 8 min at room temperature, 4 is stable for days and is easily isolated as a tetrahydrofuran solvate. When 2 - 4 are treated with electrophiles such as benzaldehyde, iron pentacarbonyl, n-octyl iodide, hydride transfer occurs to produce benzyl alcohol, lithium + iron tetracarbonyl formyl/sup -/ complex, and octane, respectively. 3 is the weakest hydride donor. Reaction of 4 with methyl iodide produces ca 52% methane. The only identifiable product from the pyrolysis of 4 is dirhenium decacarbonyl; photolysis of 4 produces lithium + dirhenium nonacarbonyl hydride. 1 figure.

  11. The first anionic defensin from amphibians.

    PubMed

    Wei, Lin; Che, Helong; Han, Yi; Lv, Jing; Mu, Lixian; Lv, Lechun; Wu, Jing; Yang, Hailong

    2015-07-01

    A variety of antimicrobial peptides against infection have been identified from the skin of amphibians. However, knowledge on amphibian defensins is very limited. A novel anionic defensin designated PopuDef was purified from the skin of tree frog Polypedates puerensis, and the cDNA encoding PopuDef precursor was cloned from the skin cDNA library. The amino acid sequence of PopuDef (net charge: -2, pI: 4.75) shared the highest identity of 57 % (25/44) with the salamander defensin CFBD-1 (net charge: 0, pI: 6.14) from urodela amphibians. PopuDef showed moderate antimicrobial activities against P. aeruginosa and S. aureus (MICs are 19.41 and 17.25 ?M, respectively), and relatively weak activities against E. coli and B. subtilis (MICs are 38.82 and 43.14 ?M, respectively). Tissue distribution analysis indicated that relatively high expression level of PopuDef mRNA was observed in immune-related tissues including skin, gut, lung and spleen. Furthermore, the expression level of PopuDef was significantly upregulated in these tissues after tree frogs were infected with different bacteria strains mentioned above. Interestingly, the induction of PopuDef challenged with E. coli or B. subtilis, which was less sensitive to PopuDef, was much higher than that did with P. aeruginosa or S. aureus. These findings highlight the key role of PopuDef in innate immunity against infection. To our knowledge, PopuDef is the first anionic defensin characterized from amphibians. PMID:25792112

  12. Ab initio theoretical study of dipole-bound anions of molecular complexes: Water pentamer anions

    Microsoft Academic Search

    Dayle M. A. Smith; Johan Smets; Ludwik Adamowicz

    1999-01-01

    Results of ab initio calculations of the (H2O)5\\/(H2O)5- systems are presented. The main conclusions of the study are as follows: Based on the calculations we predict that water pentamer anions are metastable systems in agreement with their weak spectral manifestation in the gas-phase experiments of Bowen and co-workers; the excess electrons in all five structural isomers of the water pentamer

  13. Basic metabolic panel

    MedlinePLUS

    The basic metabolic panel is a group of blood tests that provides information about your body's metabolism . ... SMAC7; Sequential multi-channel analysis with computer-7; SMA7; Metabolic panel 7; CHEM-7

  14. Designation and Exploration of Halide-Anion Recognition Based on Cooperative Noncovalent Interactions Including Hydrogen Bonds and Anion-?.

    PubMed

    Liu, Yan-Zhi; Yuan, Kun; Lv, Ling-Ling; Zhu, Yuan-Cheng; Yuan, Zhao

    2015-06-01

    A novel urea-based anion receptor with an electron-deficient aromatic structural unit, N-p-nitrophenyl-N-(4-vinyl-2-five-fluoro-benzoic acid benzyl ester)-phenyl-urea (FUR), was designed to probe the potential for halide-anion recognition through the cooperation of two distinct noncovalent interactions including hydrogen bonds and anion-? in this work. The nature of the recognition interactions between halide-anion and the designed receptor was theoretically investigated at the molecular level. The geometric features of the hydrogen bond and anion-? of the FUR@X(-) (X = F, Cl, Br, and I) systems were thoroughly investigated. The binding energies and thermodynamic information on the halide-anion recognitions show that the presently designed FUR might selectively recognize anion F(-) based on the cooperation of the N-H···F(-) hydrogen bond and anion-? interactions both in vacuum and in solvents. IR and UV-visible spectra of free FUR and FUR@F(-) have been simulated and discussed qualitatively, which may be helpful for further experimental investigations in the future. Additionally, the electronic properties and behaviors of the FUR@X(-) systems were discussed according to the calculations on the natural bond orbital (NBO) data, molecular electrostatic potential (MEP), and weak interaction regions. PMID:25928400

  15. Mind the gap

    E-print Network

    M. S. Bhagwat; A. Krassnigg; P. Maris; C. D. Roberts

    2006-12-06

    In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

  16. Mind the gap.

    SciTech Connect

    Bhagwat, M. S.; Krassnigg, A.; Maris, P.; Roberts, C. D.; Physics; Univ. Graz; Univ. of Pittsburgh

    2007-03-01

    In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

  17. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    SciTech Connect

    Moyer, Bruce a.; Bostick, Debra A.; Fowler, Christopher J.; Kang, Hyun-Ah; Ruas, Alexandre; Delmau, Laetitia H.; Haverlock, Tamara J.; Llinares, Jose M.; Hossain, Alamgir; Kang, S. O.; Bowman-James, Kristin; Shriver, James A.; Marquez, Manuel; Sessler, Jonathan L.

    2005-09-22

    The major thrust of this project led by the University of Kansas (Prof. Kristin Bowman-Jones) entails the exploration of the principles of recognition and separation of sulfate by the design, synthesis, and testing of novel sulfate extractants. A key science need for the cleanup of tank wastes at Hanford has been identified in developing methods to separate those bulk waste components that have low solubilities in borosilicate glass. Sulfate has been identified as a particularly difficult and expensive problem in that its concentration in the waste is relatively high, its solubility in glass is especially low, and it interferes with the performance of both vitrification equipment and the glass waste form. The new extractants will be synthesized by the University of Kansas and the University of Texas, Austin. Oak Ridge National Laboratory (ORNL) is subjecting the new extractants to experiments that will determine their properties and effectiveness in separating sulfate from the major competing anions in the waste, especially nitrate. Such experiments will entail primarily liquid-liquid extraction. Current efforts focus on exciting new systems in which the anion receptors act as synergists for anion exchange.

  18. Gapped domain walls, gapped boundaries, and topological degeneracy.

    PubMed

    Lan, Tian; Wang, Juven C; Wen, Xiao-Gang

    2015-02-20

    Gapped domain walls, as topological line defects between (2+1)D topologically ordered states, are examined. We provide simple criteria to determine the existence of gapped domain walls, which apply to both Abelian and non-Abelian topological orders. Our criteria also determine which (2+1)D topological orders must have gapless edge modes, namely, which (1+1)D global gravitational anomalies ensure gaplessness. Furthermore, we introduce a new mathematical object, the tunneling matrix W, whose entries are the fusion-space dimensions W(ia), to label different types of gapped domain walls. By studying many examples, we find evidence that the tunneling matrices are powerful quantities to classify different types of gapped domain walls. Since a gapped boundary is a gapped domain wall between a bulk topological order and the vacuum, regarded as the trivial topological order, our theory of gapped domain walls inclusively contains the theory of gapped boundaries. In addition, we derive a topological ground state degeneracy formula, applied to arbitrary orientable spatial 2-manifolds with gapped domain walls, including closed 2-manifolds and open 2-manifolds with gapped boundaries. PMID:25763965

  19. Equine digital veins are more sensitive to superoxide anions than digital arteries.

    PubMed

    Lapo, Rock Allister; Gogny, Marc; Chatagnon, Gérard; Lalanne, Valérie; Harfoush, Khaled; Assane, Moussa; Desfontis, Jean-Claude; Mallem, Mohamed Yassine

    2014-10-01

    This work was designed to investigate (i) the effect of superoxide dismutase (SOD) inhibition on endothelial function and (ii) the free radical-induced endothelial dysfunction in equine digital veins (EDVs) and equine digital arteries (EDAs) isolated from healthy horses. EDV and EDA rings were suspended in a 5 ml organ bath containing Krebs solution. After a 60 min equilibration period, EDV and EDA rings were contracted with phenylephrine. Then, cumulative concentration-response curves (CCRCs) to acetylcholine were performed. In both EDVs and EDAs, acetylcholine (1 nM to 10 µM) produced concentration-dependent relaxation. We investigated the influence of SOD inhibition by diethyldithiocarbamate (DETC; 100 µM), a CuZnSOD inhibitor, on EDAs and EDVs relaxant responses to acetylcholine. Acetylcholine -mediated relaxation was impaired by DETC only in EDVs. SOD activity assayed by a xanthine-xanthine oxidase method was higher in EDAs compared with EDVs (P<0.05). CCRCs to acetylcholine established in the presence of pyrogallol (30 µM) or homocysteine (20 µM), two superoxide anions generating systems showed that in both EDVs and EDAs, the acetylcholine-mediated relaxation was significantly impaired by pyrogallol and homocysteine. This impairment was more pronounced in EDVs than in EDAs. Moreover, the pyrogallol-induced impairment of acetylcholine-mediated relaxation was potentiated by DETC to a greater extent in EDVs. We concluded that due to the lower activity of SOD, EDVs are more sensitive to superoxide anions than EDAs. So, any alteration of superoxide anions metabolism is likely to have a more important impact on venous rather than arterial relaxation. PMID:25014758

  20. Survey of organic acid eluents for anion chromatography

    SciTech Connect

    Book, D.E.

    1981-10-01

    Of all the potential eluents surveyed (including aromatic, sulfonic, phosphonic, among other acids), only the carboxylic acids and the nitrophenols are recommended as eluents for anion chromatography. The concentration of the eluent should be in the range 5 x 10/sup -5/ to 1 x 10/sup -3/ M. The eluent should have the same charge as inorganic anions, a higher charge than organic acid samples. Choice of eluents for separation of halides, chloride and sulfate, multivalent inorganic anions, small alkyl acids, and aromatic acids is discussed. (DLC)

  1. A note on gaps

    E-print Network

    Hisanobu Shinya

    2011-09-11

    Let $p_{k}$ denote the $k$-th prime and $d(p_{k}) = p_{k} - p_{k - 1}$, the difference between consecutive primes. We denote by $N_{\\epsilon}(x)$ the number of primes $\\leq x$ which satisfy the inequality $d(p_{k}) \\leq (\\log p_{k})^{2 + \\epsilon}$, where $\\epsilon > 0$ is arbitrary and fixed, and by $\\pi(x)$ the number of primes less than or equal to $x$. In this paper, we first prove a theorem that $\\lim_{x \\to \\infty} N_{\\epsilon}(x)/\\pi(x) = 1$. A corollary to the proof of the theorem concerning gaps between consecutive squarefree numbers is stated.

  2. Zintl-phase compounds with SnSb4 tetrahedral anions: Electronic structure and thermoelectric properties

    SciTech Connect

    Zhang, Lijun; Du, Mao-Hua; Singh, David J.

    2010-01-01

    We report the investigation of Zintl-phase Na(K){sub 8}SnSb{sub 4} and related compounds that contain SnSb{sub 4} tetrahedral anions using first principles electronic structure, Boltzmann transport, and density functional phonon calculations. We find that these compounds are narrow-gap semiconductors and there is a combination of heavy and light bands at valence band edge, which may lead to a combination of high thermopower and reasonable conductivity. High values of the thermopower are found for p-type doping within the Boltzmann transport theory. Furthermore, these materials are expected to have low thermal conductivity due to their structures that consist of a network of weakly coupled SnSb{sub 4} clusters, which leads to low phonon frequencies. In particular, we find low-frequency optical phonons that should effectively scatter the heat-carrying acoustic phonons. These results are discussed in terms of the structure, which consists of anionic clusters. Based on the results, it is suggested that such compounds may represent a useful paradigm for finding new thermoelectric materials.

  3. The C3N- anion: first detection of its electronic luminescence in rare gas solids.

    PubMed

    Turowski, Micha?; Gronowski, Marcin; Boyé-Péronne, Séverine; Douin, Stéphane; Monéron, Laurence; Crépin, Claudine; Ko?os, Robert

    2008-04-28

    The 193 nm laser irradiation of cyanoacetylene (HCCCN) that was isolated in rare gas solids led to a long-lived luminescence (origin at 3.58 eV), which was assigned to the a (3)Sigma(+)-X (1)Sigma(+) system of cyanoacetylide (CCCN(-)). The identification, which involved (15)N and (2)H isotopic substitution studies, is based on vibronic spacings in the phosphorescence spectrum (compared to previous infrared absorption measurements and to theoretical results regarding CCCN(-) vibrational frequencies), as well as on a BD(T)/cc-pVTZ prediction for the singlet-triplet energy gap in this anion (3.61 eV). The same emission was also generated from KrHC(3)N mixtures subjected to a glow electric discharge immediately before the solidification (cold-window-radial-discharge technique). PMID:18447436

  4. Optimization based automated curation of metabolic reconstructions

    Microsoft Academic Search

    Vinay Satish Kumar; Madhukar S. Dasika; Costas D. Maranas

    2007-01-01

    BACKGROUND: Currently, there exists tens of different microbial and eukaryotic metabolic reconstructions (e.g., Escherichia coli, Saccharomyces cerevisiae, Bacillus subtilis) with many more under development. All of these reconstructions are inherently incomplete with some functionalities missing due to the lack of experimental and\\/or homology information. A key challenge in the automated generation of genome-scale reconstructions is the elucidation of these gaps

  5. The HMG-CoA reductase inhibitor pravastatin stimulates insulin secretion through organic anion transporter polypeptides.

    PubMed

    Abe, Michiaki; Toyohara, Takafumi; Ishii, Akiko; Suzuki, Takehiro; Noguchi, Naoya; Akiyama, Yasutoshi; Shiwaku, Hiromi O; Nakagomi-Hagihara, Rie; Zheng, Guodong; Shibata, Eisuke; Souma, Tomokazu; Shindo, Tomohiko; Shima, Hirohito; Takeuchi, Yoichi; Mishima, Eikan; Tanemoto, Masayuki; Terasaki, Tetsuya; Onogawa, Tohru; Unno, Michiaki; Ito, Sadayoshi; Takasawa, Shin; Abe, Takaaki

    2010-01-01

    The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor pravastatin has been reported to have a beneficial effect on reducing the new onset of diabetes as well as lowering plasma lipids. Because pravastatin is a water-soluble organic anion, it cannot easily penetrate the lipid bilayer of the cell membrane. As the precise mechanisms of the effect of pravastatin on glucose metabolism and diabetes have not been clarified, we examined the roles of the organic anion transporter family on pravastatin-treated islet and adipocyte functions. Rat oatp1/slco1a1, oatp2/slco1a4 and oatp3/slco1a5 were expressed in the pancreas, and rat oatp3/slco1a5 was also detected in rat insulinoma cell line INS-1e. Pravastatin was transported not only by oatp1/slco1a1 and oatp2/slco1a4, but also by rat oatp3/slco1a5. Pravastatin uptake into INS-1e cells was detected and this transport was inhibited by sulfobromophthalein and rifampicin, both of which are known to inhibit oatp family-mediated uptake. In addition, pravastatin enhanced the glucose-stimulated insulin secretion from INS-1e cells. When fat-loaded db/db mice were treated with pravastatin, glucose intolerance and insulin resistance were prevented. In addition, insulin secretion from isolated islets was enhanced by pravastatin. These data suggest that pravastatin has pleiotropic effects on islets through membrane transport under high fat/glucose conditions. PMID:20610886

  6. Renal transport of organic anions and cations.

    PubMed

    Pelis, Ryan M; Wright, Stephen H

    2011-10-01

    Organic anions and cations (OAs and OCs, respectively) comprise an extraordinarily diverse array of compounds of physiological, pharmacological, and toxicological importance. The kidney, primarily the renal proximal tubule, plays a critical role in regulating the plasma concentrations of these organic electrolytes and in clearing the body of potentially toxic xenobiotics agents, a process that involves active, transepithelial secretion. This transepithelial transport involves separate entry and exit steps at the basolateral and luminal aspects of renal tubular cells. Basolateral and luminal OA and OC transport reflects the concerted activity of a suite of separate proteins arranged in parallel in each pole of proximal tubule cells. The cloning of multiple members of several distinct transport families, the subsequent characterization of their activity, and their subcellular localization within distinct regions of the kidney, now allows the development of models describing the molecular basis of the renal secretion of OAs and OCs. New information on naturally occurring genetic variation of many of these processes provides insight into the basis of observed variability of drug efficacy and unwanted drug-drug interactions in human populations. The present review examines recent work on these issues. PMID:23733689

  7. Domain walls in gapped graphene

    E-print Network

    G. W. Semenoff; V. Semenoff; Fei Zhou

    2008-05-31

    The electronic properties of a particular class of domain walls in gapped graphene are investigated. We show that they can support mid-gap states which are localized in the vicinity of the domain wall and propagate along its length. With a finite density of domain walls, these states can alter the electronic properties of gapped graphene significantly. If the mid-gap band is partially filled,the domain wall can behave like a one-dimensional metal embedded in a semi-conductor, and could potentially be used as a single-channel quantum wire.

  8. Domain walls in gapped graphene

    E-print Network

    Semenoff, G W; Zhou, Fei

    2015-01-01

    The electronic properties of a particular class of domain walls in gapped graphene are investigated. We show that they can support mid-gap states which are localized in the vicinity of the domain wall and propagate along its length. With a finite density of domain walls, these states can alter the electronic properties of gapped graphene significantly. If the mid-gap band is partially filled,the domain wall can behave like a one-dimensional metal embedded in a semi-conductor, and could potentially be used as a single-channel quantum wire.

  9. Gap and stripline combined monitor

    DOEpatents

    Yin, Yan (Palo Alto, CA)

    1986-01-01

    A combined gap and stripline monitor device (10) for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchotron radiation facility. The monitor has first and second beam pipe portions (11a, 11b) with an axial gap (12) therebetween. An outer pipe (14) cooperates with the first beam pipe portion (11a) to form a gap enclosure, while inner strips (23a-d) cooperate with the first beam pipe portion (11a) to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

  10. Gap and stripline combined monitor

    DOEpatents

    Yin, Y.

    1986-08-19

    A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility is disclosed. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length. 4 figs.

  11. Electronic characterization of defects in narrow gap semiconductors

    NASA Technical Reports Server (NTRS)

    Patterson, James D.

    1994-01-01

    We use a Green's function technique to calculate the position of deep defects in narrow gap semiconductors. We consider substitutional (including antisite), vacancy, and interstitial (self and foreign) deep defects. We also use perturbation theory to look at the effect of nonparabolic bands on shallow defect energies and find nonparabolicity can increase the binding by 10 percent or so. We consider mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS). For substitutional and interstitial defects we look at the situation with and without relaxation. For substitutional impurities in MCT, MZT, and MZS, we consider x (the concentration of Cd or Zn) in the range 0.1 less than x less than 0.3 and also consider appropriate x so E(sub g) = 0.1 eV for each of the three compounds. We consider several cation site s-like deep levels and anion site p-like levels. For E(sub g) = 0.1 eV, we also consider the effects of relaxation. Similar comments apply to the interstitial deep levels whereas no relaxation is considered for the ideal vacancy model. Relaxation effects can be greater for the interstitial than the substitutional cases. Specific results are given in figures and tables and comparison to experiment is made in a limited number of cases. We find, for example, that I, Se, S, Rn, and N are possible cation site, s-like deep levels in MCT and Zn and Mg are for anion site, p-like levels (both levels for substitutional cases). The corresponding cation and anion site levels for interstitial deep defects are (Au, Ag, Hg, Cd, Cu, Zn) and (N, Ar, O, F). For the substitutional cases we have some examples of relaxation moving the levels into the band gap, whereas for the interstitial case we have examples where relaxation moves it out of the band gap. Future work involves calculating the effects of charge state interaction and seeing the effect of relaxation on vacancy levels.

  12. An Unstable Anion Stabilized in a Molecular Trap Piotr Skurski

    E-print Network

    Simons, Jack

    An Unstable Anion Stabilized in a Molecular Trap Piotr Skurski Henry Eyring Center for Theoretical of Chemistry, UniVeristy of Gdan~sk, 80-952 Gdan~sk, Poland Jack Simons* Henry Eyring Center for Theoretical

  13. Hydrocarbon Anions in Interstellar Clouds and Circumstellar Envelopes

    NASA Astrophysics Data System (ADS)

    Millar, T. J.; Walsh, C.; Cordiner, M. A.; Ní Chuimín, R.; Herbst, Eric

    2007-06-01

    The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion/neutral abundance ratio can be quite large, on the order of at least a few percent, once the neutral has more than five carbon atoms. Detailed modeling shows that the column densities of C6H- observed in IRC +10 216 and TMC-1 can be reproduced. Our calculations also predict that other hydrocarbon anions, such as C4H- and C8H-, are viable candidates for detection in IRC +10 216, TMC-1, and photon-dominated regions such as the Horsehead Nebula.

  14. Hydrocarbon anions in interstellar clouds and circumstellar envelopes

    E-print Network

    T. J. Millar; C. Walsh; M. A. Cordiner; R. Ní Chuimín; Eric Herbst

    2007-05-07

    The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion/neutral abundance ratio can be quite large, on the order of at least a few percent, once the neutral has more than five carbon atoms. Detailed modeling shows that the column densities of C6H- observed in IRC+10216 and TMC-1 can be reproduced. Our calculations also predict that other hydrocarbon anions, such as C4H- and C8H-, are viable candidates for detection in IRC+10216, TMC-1 and photon-dominated regions such as the Horsehead Nebula.

  15. DETERMINATION OF TRACE ANIONS IN WATER BY MULTIDIMENSIONAL ION CHROMATOGRAPHY

    EPA Science Inventory

    Selenate, selenite, and arsenate ions were separated from the major anions chloride, nitrate, and sulfate in drinking water, surface water, and groundwater sources by collecting a selected portion of the ion chromatogram, after suppression, on a concentrator column and reinjectin...

  16. Cationic Main Group Compounds as Water Compatible Small Anion Receptors 

    E-print Network

    Leamer, Lauren Anne

    2013-05-06

    anion. A significant amount of research has been conducted on triarylboranes containing cationic moieties such as ammonium, phosphonium, and sulfonium groups. This thesis will describe additional examples of such species, including a series of ammonium...

  17. Factors affecting selectivity of inorganic anions in capillary electrophoresis.

    PubMed

    Lucy, C A

    1999-07-30

    Capillary zone electrophoretic separations of inorganic anions are largely governed by the intrinsic (infinite dilution) mobility of the anion. This in turn is a function of the hydrodynamic friction caused by the size of the ion and the dielectric friction caused by the charge density of the anion re-orienting the surrounding solvent. The influence of these factors on the mobility of anions is examined in both water and nonaqueous solvents. The influence of other experimental parameters, such as ionic strength, ion association, electroosmotic flow modifier concentration, and the addition of complexing agents such as polymeric cations, cyclodextrins, crown ethers and cryptands are also reviewed. From this discussion, some rules of thumb as to when different approaches will be most effective are drawn. PMID:10457494

  18. The taming of CN7(-): the azidotetrazolate 2-oxide anion.

    PubMed

    Klapötke, Thomas M; Piercey, Davin G; Stierstorfer, Jörg

    2011-11-11

    The highly sensitive 5-azidotetrazolate anion was oxidized to its corresponding N-oxide by aqueous oxidation in a buffered oxone solution to the azidotetrazolate 2-oxide anion. After acidic extraction and neutralization with ammonia, the ammonium salt was isolated. Several energetic salts of this novel anion were prepared from the ammonium salt, and in all cases were found to be of lower sensitivity than the corresponding 5-azidotetrazolate salt while still being highly sensitive towards mechanical stimuli. Explosive performances (detonation velocity, detonation pressure) of applicable salts were also found to be higher than the non-N-oxide variants. Preparation of the free acid 2-hydroxy-5-azidotetrazole was achieved by protonation of the anion and identified by NMR spectroscopy, whereas the majority of the azidotetrazolate 2-oxide salts have unequivocal crystallographic proof. PMID:21971954

  19. Effects of anions on thermally induced whey protein isolate gels

    Microsoft Academic Search

    Eilene L. Bowland; E. Allen Foegeding

    1995-01-01

    Fundamental fracture, water-holding and microstructural properties of thermally induced whey protein isolate gels containing one of two divalent, stabilizing anions (sulfate and phosphate) or one monovalent, chaotropic anion (thiocyanate) were investigated. All of the salts produced similar overall trends in stress and strain; however, transition points were salt specific. At ionic strengths 0.09 ? ? ? 0.50, Na2SO4 and NaSCN

  20. Molecular anion chemistry in interstellar and circumstellar environments

    Microsoft Academic Search

    M. A. Cordiner; T. J. Millar; E. Herbst; R. Ni Chuimin; C. Walsh

    2007-01-01

    The recent detection of C4H-, C6H- and C8H- in TMC-1 and IRC+10216 led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion\\/neutral abundance ratio can be quite large, on the order of at least a few percent, once the neutral has more than five carbon atoms. Detailed modeling

  1. Interaction of Pd cluster anions (Pdn -, n < 11) with oxygen

    Microsoft Academic Search

    F. von Gynz-Rekowski; G. Ganteför; Y. D. Kim

    2007-01-01

    Interactions between oxygen and Pd cluster anions were studied using Time-of-Flight (ToF) mass spectrometry and Ultraviolet Photoelectron Spectroscopy (UPS). In contrast to the coinage metal clusters, no pronounced size selectivity towards chemisorption of oxygen molecules can be observed for the Pd cluster anions: regardless of the cluster size, no more than 2 oxygen molecules can be attached to a cluster.

  2. Self-assembly of silicotungstate anions on silver surfaces

    Microsoft Academic Search

    Maohui Ge; Bianxiao Zhong; Walter G. Klemperer; Andrew A. Gewirth

    1996-01-01

    We report here the self assembly of α-dodecatungstosilicate anions, α-SiWââOââ⁴⁻, on Ag(111) surfaces from acidic aqueous solution. The ability of α-SiWââOââ⁴⁻ to form self-assembled monolayers on Ag(111) offers great opportunity for generalization to other functionalized inorganic molecules on other surfaces. We find that the silicotungstate anions will also adhere to Cu surfaces, and we anticipate that they will bind to

  3. Boron compounds as anion binding agents for nonaqueous battery electrolytes

    DOEpatents

    Lee, Hung Sui (East Setauket, NY); Yang, Xia-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY); Xiang, Caili (Upton, NY)

    2000-02-08

    Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

  4. Radiation-grafted PVDF anion exchange membrane for salt splitting

    Microsoft Academic Search

    N. Tzanetakis; J. R. Varcoe; R. C. T. Slade; K. Scott

    2005-01-01

    Poly(vinylidenefluoride) (PVDF) was radiation grafted using vinylbenzyl chloride (VBC) followed by amination with trimethylamine to yield a VBC-grafted PVDF anion-exchange membrane. Evaluation of the electrochemical characteristics of the anionic membrane is obtained from the electrohydrolysis of sodium sulphate in a two-compartment electrolysis cell. The influence of different experimental conditions on the behaviour of the new material is described. The electrochemical

  5. Aerobic oxidation of indole-3-acetic acid catalysed by anionic and cationic peanut peroxidase

    Microsoft Academic Search

    Irina G Gazaryan; Tatyana A Chubar; Elena A Mareeva; L. Mark Lagrimini; Robert B Van Huystee; Roger N. F Thorneley

    1999-01-01

    The catalytic properties of anionic and cationic peanut peroxidases with regards to the oxidation of indole-3-acetic acid (IAA) by molecular oxygen at low pH have been studied. Transient kinetic studies demonstrate that only cationic peroxidases (peanut and horseradish) but not anionic peroxidases (such as anionic tobacco and anionic peanut peroxidases) form a stable compound III in the course of IAA

  6. Determination of anionic minerals in black and kombucha tea using ion chromatography

    Microsoft Academic Search

    Sangita D. Kumar; G. Narayan; S. Hassarajani

    2008-01-01

    A simple, rapid and accurate method for the determination of anionic minerals in tea brew has been developed. The quantitative determination of anions – fluoride, chloride, bromide, iodide, nitrate, phosphate and sulphate was accomplished by anion exchange chromatography with conductometric detection. A Metrosep Anion Dual 2 analytical column connected in series with a Metrosep RP guard column was used for

  7. Electronic materials with a wide band gap: recent developments.

    PubMed

    Klimm, Detlef

    2014-09-01

    The development of semiconductor electronics is reviewed briefly, beginning with the development of germanium devices (band gap E g = 0.66?eV) after World War II. A tendency towards alternative materials with wider band gaps quickly became apparent, starting with silicon (E g = 1.12?eV). This improved the signal-to-noise ratio for classical electronic applications. Both semiconductors have a tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or various anions and cations, other semiconductors with wider E g were obtained. These are transparent to visible light and belong to the group of wide band gap semiconductors. Nowadays, some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue regions. Oxide crystals, such as ZnO and ?-Ga2O3, offer similarly good electronic properties but still suffer from significant difficulties in obtaining stable and technologically adequate p-type conductivity. PMID:25295170

  8. Counterion-mediated pattern formation in membranes containing anionic lipids

    PubMed Central

    Slochower, David R.; Wang, Yu-Hsiu; Tourdot, Richard W.; Radhakrishnan, Ravi; Janmey, Paul A.

    2014-01-01

    Most lipid components of cell membranes are either neutral, like cholesterol, or zwitterionic, like phosphatidylcholine and sphingomyelin. Very few lipids, such as sphingosine, are cationic at physiological pH. These generally interact only transiently with the lipid bilayer, and their synthetic analogs are often designed to destabilize the membrane for drug or DNA delivery. However, anionic lipids are common in both eukaryotic and prokaryotic cell membranes. The net charge per anionic phospholipid ranges from ?1 for the most abundant anionic lipids such has phosphatidylserine, to near ?7 for phosphatidylinositol 3,4,5 trisphosphate, although the effective charge depends on many environmental factors. Anionic phospholipids and other negatively charged lipids such as lipopolysaccharides are not randomly distributed in the lipid bilayer, but are highly restricted to specific leaflets of the bilayer and to regions near transmembrane proteins or other organized structures within the plane of the membrane. This review highlights some recent evidence that counterions, in the form of monovalent or divalent metal ions, polyamines, or cationic protein domains, have a large influence of the lateral distribution of anionic lipids within the membrane, and that lateral demixing of anionic lipids has effects on membrane curvature and protein function that are important for biological control. PMID:24556233

  9. Thermodynamics of mixed anionic/nonionic surfactant adsorption on alumina.

    PubMed

    Lopata, Jeffrey J; Werts, Kendall M; Scamehorn, John F; Harwell, Jeffrey H; Grady, Brian P

    2010-02-15

    The adsorption of sodium dodecyl sulfate and a polyethoxylated nonylphenol, and well defined mixtures thereof, was measured on gamma-alumina. A pseudo-phase separation model to describe mixed anionic/nonionic admicelle (adsorbed surfactant aggregate) formation was developed, analogous to the pseudo-phase separation model frequently used to describe mixed micelle formation. In this model, regular solution theory was used to describe the anionic/nonionic surfactant interactions in the mixed admicelle and a patch-wise adsorption model was used to describe surfactant adsorption on a heterogeneous solid surface. The formation of mixed anionic/nonionic admicelles in the absence of micelles was accurately described by regular solution theory; mixed admicelle formation exhibited stronger negative deviations from ideality than mixed micelle formation. An adequate description of mixed anionic/nonionic admicelle formation in the presence of mixed micelles was obtained through a simultaneous solution of the pseudo-phase separation models for mixed admicelle and mixed micelle formation, and the appropriate mass balance equations. Anionic/nonionic mixed adsorption in the presence of mixed micelles was shown to correspond to an admicelle composition of approximately a 1:1 anionic/nonionic mole ratio throughout Regions II and III of the adsorption isotherm. PMID:19963226

  10. Grain boundary mobility in anion doped MgO

    NASA Technical Reports Server (NTRS)

    Kapadia, C. M.; Leipold, M. H.

    1973-01-01

    Certain anions OH(-), F(-) and Gl(-) are shown to enhance grain growth in MgO. The magnitude of their effect decreases in the order in which the anions are listed and depends on their location (solid-solution, second phase) in the MgO lattice. As most anions exhibit relatively high vapor pressures at sintering temperatures, they retard densification and invariably promote residual porosity. The role of anions on grain growth rates was studied in relation to their effect on pore mobility and pore removal; the atomic process controlling the actual rates was determined from observed kinetics in conjunction with the microstructural features. With respect to controlling mechanisms, the effects of all anions are not the same. OH(-) and F(-) control behavior through creation of a defect structure and a grain boundary liquid phase while Cl(-) promotes matter transport within pores by evaporation-condensation. Studies on an additional anion, S to the minus 2nd power gave results which were no different from undoped MgO, possibly because of evaporative losses during hot pressing. Hence, the effect of sulphur is negligible or undetermined.

  11. Metabolic fingerprinting of Arabidopsis thaliana accessions

    PubMed Central

    Sotelo-Silveira, Mariana; Chauvin, Anne-Laure; Marsch-Martínez, Nayelli; Winkler, Robert; de Folter, Stefan

    2015-01-01

    In the post-genomic era much effort has been put on the discovery of gene function using functional genomics. Despite the advances achieved by these technologies in the understanding of gene function at the genomic and proteomic level, there is still a big genotype-phenotype gap. Metabolic profiling has been used to analyze organisms that have already been characterized genetically. However, there is a small number of studies comparing the metabolic profile of different tissues of distinct accessions. Here, we report the detection of over 14,000 and 17,000 features in inflorescences and leaves, respectively, in two widely used Arabidopsis thaliana accessions. A predictive Random Forest Model was developed, which was able to reliably classify tissue type and accession of samples based on LC-MS profile. Thereby we demonstrate that the morphological differences among A. thaliana accessions are reflected also as distinct metabolic phenotypes within leaves and inflorescences. PMID:26074932

  12. Genome-scale models of bacterial metabolism: reconstruction and applications

    PubMed Central

    Durot, Maxime; Bourguignon, Pierre-Yves; Schachter, Vincent

    2009-01-01

    Genome-scale metabolic models bridge the gap between genome-derived biochemical information and metabolic phenotypes in a principled manner, providing a solid interpretative framework for experimental data related to metabolic states, and enabling simple in silico experiments with whole-cell metabolism. Models have been reconstructed for almost 20 bacterial species, so far mainly through expert curation efforts integrating information from the literature with genome annotation. A wide variety of computational methods exploiting metabolic models have been developed and applied to bacteria, yielding valuable insights into bacterial metabolism and evolution, and providing a sound basis for computer-assisted design in metabolic engineering. Recent advances in computational systems biology and high-throughput experimental technologies pave the way for the systematic reconstruction of metabolic models from genomes of new species, and a corresponding expansion of the scope of their applications. In this review, we provide an introduction to the key ideas of metabolic modeling, survey the methods, and resources that enable model reconstruction and refinement, and chart applications to the investigation of global properties of metabolic systems, the interpretation of experimental results, and the re-engineering of their biochemical capabilities. PMID:19067749

  13. ISABELLE cavity gap assemblies

    SciTech Connect

    Plotkin, M

    1981-01-01

    In a storage ring, where beam lifetime is measured in hours, it is necessary to keep the longitudinal impedance, as seen by the beam, very low, even into the gigahertz region. This is necessary to prevent the excitation of longitudinal instabilities. These impedances are due to the resistive wall effect and any deviation from a smooth vacuum chamber such as at pick-up electrodes, vacuum pump stations, rf cavities, etc. At low frequencies, up to 10 to 20 MHz, the low impedance requirement for the cavities can be satisfied by designing the driving power amplifiers with a very low output impedance. For ISABELLE a method has been designed for building a network into the cavity accelerating gaps which will satisfy the impedance criteria to at least 1300 MHz. The maximum allowable impedance at any frequency, f, is given in the form Z/n where n = f/f/sub rotation/. For the ISABELLE accelerating cavity, operating at 235.5 KHz, Z/n must be less than 10 ohms. For the stacking cavity, operating at 4.45 MHz, Z/n < 1 ohm.

  14. Gap solitons due to cascading

    NASA Astrophysics Data System (ADS)

    Kivshar, Yuri S.

    1995-02-01

    It is shown analytically that gap solitons can occur in materials with ?(2) susceptibility due to cascaded second-order nonlinearities. Families of bright and dard spatial gap solitons are described in the framework of asymptotic expansions that are valid, in particular, for nonzero phase mismatch between the first and second harmonics; effective coefficients of self- and cross-phase modulation are calculated.

  15. Energy gaps in ?-graphdiyne nanoribbons

    NASA Astrophysics Data System (ADS)

    Niu, X. N.; Yang, D. Z.; Si, M. S.; Xue, D. S.

    2014-04-01

    ?-graphdiyne is a novel predicted Dirac cone material, which is similar to graphene. But the absence of a band gap significantly limits its practical applications. In order to extend this limitation, an opening of energy gap is needed. To this end, we resort to the nanoribbon structure of ?-graphdiyne. This is a conventional proposal to open up the energy gaps in nanomaterials. The results show that both the armchair and the zigzag ?-graphdiyne nanoribbons do generate energy gaps, which are width-dependent. In addition, the underlying mechanism of this opening is explored. The former is ascribed to the combination of quantum confinement and edges' effect, while the latter arises from the edge magnetic ordering. These novel nanoribbons with opening energy gaps would be potentially used in electronic devices.

  16. Energy gaps in graphene nanoribbons.

    PubMed

    Son, Young-Woo; Cohen, Marvin L; Louie, Steven G

    2006-11-24

    Based on a first-principles approach, we present scaling rules for the band gaps of graphene nanoribbons (GNRs) as a function of their widths. The GNRs considered have either armchair or zigzag shaped edges on both sides with hydrogen passivation. Both varieties of ribbons are shown to have band gaps. This differs from the results of simple tight-binding calculations or solutions of the Dirac's equation based on them. Our ab initio calculations show that the origin of energy gaps for GNRs with armchair shaped edges arises from both quantum confinement and the crucial effect of the edges. For GNRs with zigzag shaped edges, gaps appear because of a staggered sublattice potential on the hexagonal lattice due to edge magnetization. The rich gap structure for ribbons with armchair shaped edges is further obtained analytically including edge effects. These results reproduce our ab initio calculation results very well. PMID:17155765

  17. Energy gaps in ?-graphdiyne nanoribbons

    SciTech Connect

    Niu, X. N.; Yang, D. Z.; Si, M. S., E-mail: sims@lzu.edu.cn; Xue, D. S., E-mail: xueds@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2014-04-14

    ?-graphdiyne is a novel predicted Dirac cone material, which is similar to graphene. But the absence of a band gap significantly limits its practical applications. In order to extend this limitation, an opening of energy gap is needed. To this end, we resort to the nanoribbon structure of ?-graphdiyne. This is a conventional proposal to open up the energy gaps in nanomaterials. The results show that both the armchair and the zigzag ?-graphdiyne nanoribbons do generate energy gaps, which are width-dependent. In addition, the underlying mechanism of this opening is explored. The former is ascribed to the combination of quantum confinement and edges' effect, while the latter arises from the edge magnetic ordering. These novel nanoribbons with opening energy gaps would be potentially used in electronic devices.

  18. In vivo tissue-wide synchronization of mitochondrial metabolic oscillations.

    PubMed

    Porat-Shliom, Natalie; Chen, Yun; Tora, Muhibullah; Shitara, Akiko; Masedunskas, Andrius; Weigert, Roberto

    2014-10-23

    Little is known about the spatiotemporal coordination of mitochondrial metabolism in multicellular organisms in situ. Using intravital microscopy in live animals, we report that mitochondrial metabolism undergoes rapid and periodic oscillations under basal conditions. Notably, mitochondria in vivo behave as a network of functionally coupled oscillators, which maintain a high level of coordination throughout the tissue via the activity of gap junctions. These findings reveal a unique aspect of the relationship between tissue architecture and self-organization of mitochondrial metabolism in vivo. PMID:25373899

  19. Extraordinary Changes in the Electronic Structure and Properties of CdS and ZnS by Anionic Substitution: Cosubstitution of P and Cl in Place of S.

    PubMed

    Kouser, Summayya; Lingampalli, S R; Chithaiah, P; Roy, Anand; Saha, Sujoy; Waghmare, Umesh V; Rao, C N R

    2015-07-01

    Unlike cation substitution, anion substitution in inorganic materials such as metal oxides and sulfides would be expected to bring about major changes in the electronic structure and properties. In order to explore this important aspect, we have carried out first-principles DFT calculations to determine the effects of substitution of P and Cl on the properties of CdS and ZnS in hexagonal and cubic structures and show that a sub-band of the trivalent phosphorus with strong bonding with the cation appears in the gap just above the valence band, causing a reduction in the gap and enhancement of dielectric properties. Experimentally, it has been possible to substitute P and Cl in hexagonal CdS and ZnS. The doping reduces the band gap significantly as predicted by theory. A similar decrease in the band gap is observed in N and F co-substituted in cubic ZnS. Such anionic substitution helps to improve hydrogen evolution from CdS semiconductor structures and may give rise to other applications as well. PMID:26031858

  20. Paying Attention to Dietary Cation-Anion Balance Can Mean More Milk and Fewer Metabolic Problems

    E-print Network

    Liskiewicz, Maciej

    +24 +35 +55 The animal response to the different DCAD diets was: DCAD +20 +35 +50 Sig. Dry matter intake, lb/day 36 38 34 NS Dry matter intake, % body weight 3.30 3.38 2.96 * Milk, lb/day 56 53 49 * 3.5% fat correct milk, lb/day 61 56 56 * Milk fat, % 4.1 4.0 4.3 NS Milk protein, % 2.9 3.0 2.9 NS NS

  1. Malate-induced feedback regulation of plasma membrane anion channels could provide a CO2 sensor to guard cells.

    PubMed

    Hedrich, R; Marten, I

    1993-03-01

    Plants have developed strategies to circumvent limitations in water supply through the adjustment of stomatal aperture in relation to the photosynthetic capacity (water-use efficiency). The CO2 sensor of guard cells, reporting on the metabolic status of the photosynthetic tissue, is, however, as yet unknown. We elucidated whether extracellular malate has the capability to serve as a signal metabolite in regulating the membrane properties of guard cells. Patch-clamp studies showed that slight variations in the external malate concentration induced major alterations in the voltage-dependent activity of the guard cell anion channel (GCAC1). Superfusion of guard cell protoplasts with malate solutions in the physiological range caused the voltage-gate to shift towards hyperpolarized potentials (Km(mal) = 0.4 mM elicits a 38 mV shift). The selectivity sequence of the anion channel NO3- (4.2) > or = I- (3.9) > Br- (1.9) > Cl- (1) > mal (0.1) indicates that malate is able to permeate GCAC1. The binding site for shifting the gate is, however, located on the extracellular face of the channel since cytoplasmic malate proved ineffective. Single-channel analysis indicates that extracellular malate affects the voltage-dependent mean open time rather than the unitary conductance of GCAC1. In contrast to malate the rise in the extracellular Cl- concentration increases the unit conductance of the anion efflux channel. We suggest that stomata sense changes in the intercellular CO2 concentration and thus the photosynthetic activity of the mesophyll via feedback regulation of anion efflux from guard cells through malate-sensitive GCAC1. PMID:7681395

  2. Malate-induced feedback regulation of plasma membrane anion channels could provide a CO2 sensor to guard cells.

    PubMed Central

    Hedrich, R; Marten, I

    1993-01-01

    Plants have developed strategies to circumvent limitations in water supply through the adjustment of stomatal aperture in relation to the photosynthetic capacity (water-use efficiency). The CO2 sensor of guard cells, reporting on the metabolic status of the photosynthetic tissue, is, however, as yet unknown. We elucidated whether extracellular malate has the capability to serve as a signal metabolite in regulating the membrane properties of guard cells. Patch-clamp studies showed that slight variations in the external malate concentration induced major alterations in the voltage-dependent activity of the guard cell anion channel (GCAC1). Superfusion of guard cell protoplasts with malate solutions in the physiological range caused the voltage-gate to shift towards hyperpolarized potentials (Km(mal) = 0.4 mM elicits a 38 mV shift). The selectivity sequence of the anion channel NO3- (4.2) > or = I- (3.9) > Br- (1.9) > Cl- (1) >> mal (0.1) indicates that malate is able to permeate GCAC1. The binding site for shifting the gate is, however, located on the extracellular face of the channel since cytoplasmic malate proved ineffective. Single-channel analysis indicates that extracellular malate affects the voltage-dependent mean open time rather than the unitary conductance of GCAC1. In contrast to malate the rise in the extracellular Cl- concentration increases the unit conductance of the anion efflux channel. We suggest that stomata sense changes in the intercellular CO2 concentration and thus the photosynthetic activity of the mesophyll via feedback regulation of anion efflux from guard cells through malate-sensitive GCAC1. PMID:7681395

  3. Mechanism of adsorption of hard and soft metal ions to Saccharomyces cerevisiae and influence of hard and soft anions.

    PubMed Central

    Avery, S V; Tobin, J M

    1993-01-01

    The applicability of the hard-and-soft principle of acids and bases in predicting metal adsorption characteristics in a biological context was investigated for metabolism-independent uptake of the metal ions Sr2+, Mn2+, Zn2+, Cu2+, Cd2+, and Tl+ by Saccharomyces cerevisiae. Metal adsorption increased with external metal concentration (5 to 50 microM), although some saturation of uptake of the harder ions examined, Sr2+, Mn2+, and Zn2+, was evident at the higher metal concentrations. Cation displacement experiments indicated that, with the exception of Tl+, relative covalent bonding (H+ displacement) of the metals was greater at low metal concentrations, while weaker electrostatic interactions (Mg2+ plus Ca2+ displacement) became increasingly important at higher concentrations. These results were correlated with curved Scatchard and reciprocal Langmuir plots of metal uptake data. Saturation of covalent binding sites was most marked for the hard metals, and consequently, although no relationship between metal hardness and ionic/covalent bonding ratios was evident at 10 microM metal, at 50 microM the ratio was generally higher for harder metals. Increasing inhibition of metal uptake at increasing external anion concentrations was partially attributed to the formation of metal-anion complexes. Inhibitory effects of the hard anion SO42(-) were most marked for uptake of the hard metals Sr2+ and Mn2+, whereas greater relative effects on adsorption of the softer cations Cu2+ and Cd2+ were correlated with complexation by the soft anion S2O32(-). Inhibition of uptake of the borderline metal Zn2+ by SO42(-) and that by S2O32(-) were approximately equal.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8215359

  4. Pneumatic gap sensor and method

    DOEpatents

    Bagdal, Karl T. (Middletown, OH); King, Edward L. (Trenton, OH); Follstaedt, Donald W. (Middletown, OH)

    1992-01-01

    An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment.

  5. Study of kinetic and fixed bed operation of removal of sulfate anions from an industrial wastewater by an anion exchange resin

    Microsoft Academic Search

    Reza Haghsheno; Ali Mohebbi; Hassan Hashemipour; Amir Sarrafi

    2009-01-01

    Sulfate anions represent very important wastewater pollutants, which appear in the effluents discharged from copper mines. In this study, for the first time, an attempt has been made on the removal of sulfate anions by an ion exchange resin. This work is focused on the removal of sulfate anions from the Sarcheshmeh copper complex (Kerman province, Southeast of Iran) wastewater

  6. Anion carrier in the human erythrocyte exists as a dimer

    SciTech Connect

    Cuppoletti, J.; Goldinger, J.; Kang, B.; Jo, I.; Berenski, C.; Jung, C.Y.

    1985-12-15

    The in situ state of assembly of the human erythrocyte anion carrier (band 3) has been investigated by applying target size analysis on the radiation-induced inactivation of anion flux and degradation of polypeptide band 3. Irradiation with a high energy electron beam resulted in inactivation of carrier-mediated anion flux in intact cells, in inside-out vesicles devoid of cytoskeletal and cytoplasmic proteins, and in inside-out vesicles whose band 3 protein has been partially proteolyzed, with little change in leak pathway. The inactivation showed a single exponential function of radiation dose from which the target size of the anion carrier was estimated to be 210,000, 220,000, and 98,000 daltons in intact cells, in the inside-out vesicles, and in the vesicles after a limited proteolysis, respectively. Irradiation also resulted in degradation of the band 3 of the inside-out vesicles, as detected on sodium dodecyl sulfate-gel electrophoresis, with a dose dependence characteristic of a target size of 220,000 daltons. It is suggested that the human erythrocyte anion carrier exists in situ as a dimer of band 3.

  7. Reversible Intercalation of Fluoride-Anion Receptor Complexes in Graphite

    NASA Technical Reports Server (NTRS)

    West, William C.; Whitacre, Jay F.; Leifer, Nicole; Greenbaum, Steve; Smart, Marshall; Bugga, Ratnakumar; Blanco, Mario; Narayanan, S. R.

    2007-01-01

    We have demonstrated a route to reversibly intercalate fluoride-anion receptor complexes in graphite via a nonaqueous electrochemical process. This approach may find application for a rechargeable lithium-fluoride dual-ion intercalating battery with high specific energy. The cell chemistry presented here uses graphite cathodes with LiF dissolved in a nonaqueous solvent through the aid of anion receptors. Cells have been demonstrated with reversible cathode specific capacity of approximately 80 mAh/g at discharge plateaus of upward of 4.8 V, with graphite staging of the intercalant observed via in situ synchrotron X-ray diffraction during charging. Electrochemical impedance spectroscopy and B-11 nuclear magnetic resonance studies suggest that cointercalation of the anion receptor with the fluoride occurs during charging, which likely limits the cathode specific capacity. The anion receptor type dictates the extent of graphite fluorination, and must be further optimized to realize high theoretical fluorination levels. To find these optimal anion receptors, we have designed an ab initio calculations-based scheme aimed at identifying receptors with favorable fluoride binding and release properties.

  8. Metabolic reprogramming and dysregulated metabolism: cause, consequence and/or enabler of environmental carcinogenesis?

    PubMed

    Brooks Robey, R; Weisz, Judith; Kuemmerle, Nancy; Salzberg, Anna C; Berg, Arthur; G Brown, Dustin; Kubik, Laura; Palorini, Roberta; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Colacci, Annamaria; Mondello, Chiara; Raju, Jayadev; Woodrick, Jordan; Scovassi, A Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Salem, Hosni K; Amedei, Amedeo; Hamid, Roslida A; Williams, Graeme P; Lowe, Leroy; Meyer, Joel; Martin, Francis L; Bisson, William H; Chiaradonna, Ferdinando; Ryan, Elizabeth P

    2015-06-01

    Environmental contributions to cancer development are widely accepted, but only a fraction of all pertinent exposures have probably been identified. Traditional toxicological approaches to the problem have largely focused on the effects of individual agents at singular endpoints. As such, they have incompletely addressed both the pro-carcinogenic contributions of environmentally relevant low-dose chemical mixtures and the fact that exposures can influence multiple cancer-associated endpoints over varying timescales. Of these endpoints, dysregulated metabolism is one of the most common and recognizable features of cancer, but its specific roles in exposure-associated cancer development remain poorly understood. Most studies have focused on discrete aspects of cancer metabolism and have incompletely considered both its dynamic integrated nature and the complex controlling influences of substrate availability, external trophic signals and environmental conditions. Emerging high throughput approaches to environmental risk assessment also do not directly address the metabolic causes or consequences of changes in gene expression. As such, there is a compelling need to establish common or complementary frameworks for further exploration that experimentally and conceptually consider the gestalt of cancer metabolism and its causal relationships to both carcinogenesis and the development of other cancer hallmarks. A literature review to identify environmentally relevant exposures unambiguously linked to both cancer development and dysregulated metabolism suggests major gaps in our understanding of exposure-associated carcinogenesis and metabolic reprogramming. Although limited evidence exists to support primary causal roles for metabolism in carcinogenesis, the universality of altered cancer metabolism underscores its fundamental biological importance, and multiple pleiomorphic, even dichotomous, roles for metabolism in promoting, antagonizing or otherwise enabling the development and selection of cancer are suggested. PMID:26106140

  9. Technology of fast spark gaps

    NASA Astrophysics Data System (ADS)

    Standler, Ronald B.

    1989-09-01

    To protect electronic systems from the effects of electromagnetic pulse (EMP) form nuclear weapons and high-power microwave (HPM) weapons, it is desirable to have fast responding protection components. The gas-filled spark gap appears to be an attractive protection component, except that it can be slow to conduct under certain conditions. This report reviews the literature and presents ideas for construction of a spark gap that will conduct in less than one nanosecond. The key concept to making a fast-responding spark gap is to produce a large number of free electrons quickly. Seven different mechanisms for production of free electrons are reviewed, and several that are relevant to miniature spark gaps for protective applications are discussed in detail. These mechanisms include: inclusion of radioactive materials, photoelectric effect, secondary electrode emission from the anode, and field emission from the cathode.

  10. Inflammation and metabolic disorders

    Microsoft Academic Search

    Gökhan S. Hotamisligil

    2006-01-01

    Metabolic and immune systems are among the most fundamental requirements for survival. Many metabolic and immune response pathways or nutrient- and pathogen-sensing systems have been evolutionarily conserved throughout species. As a result, immune response and metabolic regulation are highly integrated and the proper function of each is dependent on the other. This interface can be viewed as a central homeostatic

  11. Equine Metabolic Syndrome

    Microsoft Academic Search

    Nicholas Frank

    2009-01-01

    Equine metabolic syndrome (EMS) is important because of its association with laminitis. Obesity and insulin resistance are two important components of EMS, and the underlying cause of this syndrome is likely to be enhanced metabolic efficiency. Affected horses are often referred to as “easy keepers” because they require fewer calories to maintain body condition, and enhanced metabolic efficiency is an

  12. CYTOKININ METABOLISM AND ACTION

    Microsoft Academic Search

    David WS Mok; Machteld C Mok

    2001-01-01

    ? Abstract Cytokinins are structurally diverse and biologically versatile. The chem- istry and physiology of cytokinin have been studied extensively, but the regulation of cytokinin biosynthesis, metabolism, and signal transduction is still largely undefined. Recent advances in cloning metabolic genes and identifying putative receptors por- tend more rapid progress based on molecular techniques. This review centers on cytokinin metabolism with

  13. Trading indicators with information-gap uncertainty

    E-print Network

    Guttman, Tony

    1 Trading indicators with information-gap uncertainty Colin J. Thompson ARC Centre of Excellence. Practical implications ­ An additional technical trading tool for applying Information ­ Gap theory trading indicators, Information gaps, Uncertainty, Robustness, Financial modelling Paper type Research

  14. Eight electrode optical readout gap

    DOEpatents

    Boettcher, Gordon E. (Albuquerque, NM); Crain, Robert W. (Albuquerque, NM)

    1985-01-01

    A protective device for a plurality of electrical circuits includes a pluity of isolated electrodes forming a gap with a common electrode. An output signal, electrically isolated from the circuits being monitored, is obtained by a photosensor viewing the discharge gap through an optical window. Radioactive stabilization of discharge characteristics is provided for slowly changing voltages and carbon tipped dynamic starters provide desirable discharge characteristics for rapidly varying voltages. A hydrogen permeation barrier is provided on external surfaces of the device.

  15. Pneumatic gap sensor and method

    SciTech Connect

    Bagdal, K.T.; King, E.L.; Follstaedt, D.W.

    1992-03-03

    This patent describes in a casting system which including an apparatus for monitoring the gap between a casting nozzle and a casting surface of a substrate during casting of molten material, wherein the molten material is provided through a channel of the casting nozzle for casting onto the casting surface of the substrate for solidification. It comprises: a pneumatic gap mounted at least partially within a cavity in the casting nozzle adjacent the channel and having a sensor face located within the gap between the nozzle and the casting surface of the substrate, means for supply gas under predetermined pressure to the inlet orifice; and means for measuring the pressure of the gas within the sensor chamber during casting procedures, whereby relative changes in the gap can be determined by corresponding changes in the measured pressure. This patent also describes a method for monitoring the gap between a casting nozzle and a casting surface of a substrate for continuous casting of molten material. It comprises: providing a casting nozzle with a channel for directing the flow of molten material, locating the nozzle and the casting surface is proximity with one another and having a predetermined gap there-between, and dressing the sensor face to correspond in conformation to the casting surface and to adjust the predetermined distance as desired; providing a molten material to the nozzle for casting onto and casting surface; supplying gas at a predetermined pressure to the inlet orifice of the sensor during casting procedures.

  16. An ESR study of olefin iron carbonyl radical anions

    SciTech Connect

    Krusic, P.J. (E.I. du Pont de Nemours and Company, Wilmington, DE); Filippo, J.S. Jr.

    1982-05-05

    Recently we reported an electron spin resonance study of a series of iron carbonyl radical anions Fe/sub n/(CO)/sub m//sup -/.(n = 2-4), which are formed in the reduction of Fe/sub n/(CO)/sub 5/ by alkali metals as well as in the chemical one-electron oxidation of iron carbonylate dianions in tetrahydrofuran. Despite considerable effort, we failed to observe the ESR spectrum of the simplest member of this family, the 17-electron Fe(CO)/sub 4/-.radical anion, although many observations strongly implicated its involvement as a short-lived reaction intermediate. We now find that the closely related (..pi..-olefin)-Fe(CO)/sub 3/-.radical anions are sufficiently stable, for certain olefins, to be studied by electron spin resonance.

  17. Tunable Cytotoxicity of Rhodamine 6G via Anion Variations

    PubMed Central

    Magut, Paul K. S.; Das, Susmita; Fernand, Vivian E.; Losso, Jack; McDonough, Karen; Naylor, Brittni M.; Aggarwal, Sita; Warner, Isiah M.

    2014-01-01

    Chemotherapeutic agents with low toxicity to normal tissues are a major goal in cancer research. In this regard, the therapeutic activities of cationic dyes, such as rhodamine 6G, toward cancer cells have been studied for decades with observed toxicities toward normal and cancer cells. Herein, we report rhodamine 6G-based organic salts with varying counter-anions that are stable under physiological conditions, display excellent fluorescence photostability, and more importantly have tunable chemotherapeutic properties. Our in-vitro studies indicate that the hydrophobic compounds of this series allow production of nanoparticles which are non-toxic to normal cells and toxic to cancer cells. Furthermore, the anions, in combination with cations such as sodium, were observed to be non-toxic to both normal and cancer cells. To the best of our knowledge, this is the first demonstration that both the cation and anion play an extremely important and cooperative role in the antitumor properties of these compounds. PMID:24059469

  18. Effect of anions on the electrochemistry of zinc tetraphenylporphyrin

    SciTech Connect

    Seely, G.R.; Gust, D.; Moore, T.A.; Moore, A.L. (Arizona State Univ., Tempe, AZ (United States))

    1994-10-13

    Accurate measurements of porphyrin redox potentials are essential for the prediction and rationalization of the rates of electron transfer reactions involving these biologically important electron-donating and accepting chromophores. The present work describes a survey of redox potentials of zinc tetraphenylporphyrin obtained by cyclic voltammetry in dichloromethane, with tetrabutylammonium salts containing a variety of anions as electrolytes. Of the anions tested, hexafluorophosphate appears to have the least ability to ligate the metal, so that potentials measured in its presence as electrolyte should most closely approach those of the unligated porphyrin. With perchlorate electrolyte, the potential for one-electron oxidation is approximately 80 mV lower, enough to affect the interpretation of photochemical electron transfer rates. In general, anions bind much more strongly to the cation radical than to zinc tetraphenylporphyrin itself. The use of reference redox systems based on thymoquinone and ferrocene carboxylate enabled comparison of potentials measured with different electrolytes. 30 refs., 2 tabs.

  19. Molecular anion chemistry in interstellar and circumstellar environments

    NASA Astrophysics Data System (ADS)

    Cordiner, M. A.; Millar, T. J.; Herbst, E.; Chuimin, R. Ni; Walsh, C.

    2007-12-01

    The recent detection of C4H-, C6H- and C8H- in TMC-1 and IRC+10216 led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar environments. We find that the anion/neutral abundance ratio can be quite large, on the order of at least a few percent, once the neutral has more than five carbon atoms. Detailed modeling shows that the column densities of C6H- observed in IRC+10216 and TMC-1 can be reproduced. Our calculations also predict that hydrocarbon anions CnH- (for n = 4, 6, 8) are viable candidates for detection in photon-dominated regions such as the Horsehead Nebula and the Orion Bar.

  20. ABSOLUTE PHOTODETACHMENT CROSS-SECTION MEASUREMENTS FOR HYDROCARBON CHAIN ANIONS

    SciTech Connect

    Best, T.; Otto, R.; Wester, R. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Trippel, S.; Hlavenka, P.; Von Zastrow, A.; Eisenbach, S.; Jezouin, S. [Physikalisches Institut, Universitaet Freiburg, 79104 Freiburg (Germany); Vigren, E.; Hamberg, M.; Geppert, W. D., E-mail: roland.wester@uibk.ac.at [Molecular Physics Division, Stockholm University, Stockholm (Sweden)

    2011-12-01

    Absolute photodetachment cross sections have been measured for the hydrocarbon chain anions C{sub n}H{sup -}, n = 2, 4, and 6, which are relevant for an understanding of molecular clouds in the interstellar medium. Data have been obtained for different photon energies within approximately 1 eV of the detachment threshold. With our recently developed method we have achieved a precision of better than 25% on these absolute cross sections. The experiments have been carried out by means of photodetachment tomography of the mass-selected molecular anions in a multipole radio-frequency ion trap. The measured absolute cross sections are in accordance with the empirical scaling law of Millar et al. and have allowed us to determine its free parameters. These results are important for predicting the photostability and thus the abundance of carbon chain anions in planetary atmospheres, in circumstellar envelopes, and in photon-dominated regions of interstellar molecular clouds.

  1. Cell wall bound anionic peroxidases from asparagus byproducts.

    PubMed

    Jaramillo-Carmona, Sara; López, Sergio; Vazquez-Castilla, Sara; Jimenez-Araujo, Ana; Rodriguez-Arcos, Rocio; Guillen-Bejarano, Rafael

    2014-10-01

    Asparagus byproducts are a good source of cationic soluble peroxidases (CAP) useful for the bioremediation of phenol-contaminated wastewaters. In this study, cell wall bound peroxidases (POD) from the same byproducts have been purified and characterized. The covalent forms of POD represent >90% of the total cell wall bound POD. Isoelectric focusing showed that whereas the covalent fraction is constituted primarily by anionic isoenzymes, the ionic fraction is a mixture of anionic, neutral, and cationic isoenzymes. Covalently bound peroxidases were purified by means of ion exchange chromatography and affinity chromatography. In vitro detoxification studies showed that although CAP are more effective for the removal of 4-CP and 2,4-DCP, anionic asparagus peroxidase (AAP) is a better option for the removal of hydroxytyrosol (HT), the main phenol present in olive mill wastewaters. PMID:25195693

  2. Closing the Gap: Identification of Human 3-Ketosteroid Reductase, the Last Unknown Enzyme

    E-print Network

    Rogers, Simon

    Closing the Gap: Identification of Human 3- Ketosteroid Reductase, the Last Unknown Enzyme phosphate as cofactor. Expression of human and murine HSD17B7 in an Erg27p-deficient yeast strain cholesterol biosynthesis, thus completing the molecular cloning of all genes of this central metabolic pathway

  3. Photoelectron spectroscopy of boron aluminum hydride cluster anions

    SciTech Connect

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Gantefoer, Gerd; Bowen, Kit H., E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Li, Xiang [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States)] [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States); Kiran, Boggavarapu, E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States)] [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States); Kandalam, Anil K. [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)] [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)

    2014-04-28

    Boron aluminum hydride clusters are studied through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations. Boron aluminum hydride cluster anions, B{sub x}Al{sub y}H{sub z}{sup ?}, were generated in a pulsed arc cluster ionization source and identified by time-of-flight mass spectrometry. After mass selection, their photoelectron spectra were measured by a magnetic bottle-type electron energy analyzer. The resultant photoelectron spectra as well as calculations on a selected series of stoichiometries reveal significant geometrical changes upon substitution of aluminum atoms by boron atoms.

  4. Hydroxide Anion at the Air-Water Interface

    SciTech Connect

    Mundy, Christopher J.; Kuo, I-F W.; Tuckerman, Mark E.; Lee, Hee-Seung; Tobias, Douglas J.

    2009-10-19

    Here we use first-principles molecular dynamics simulations, in which the forces are obtained "on the fly" from electronic structure calculations based on density functional theory, to determine the intrinsic propensity of the hydroxide anion for the air-water interface. We find that the hydroxide anion is stabilized by about 0.5 kcal/mol at the air-water interface vs. in bulk water, and we predict, therefore, that the population of the ion is enhanced roughly twofold at the interface.

  5. Crystal structure, conformation, vibration and optical band gap analysis of bis[ rac-propranolol nitrate

    NASA Astrophysics Data System (ADS)

    Franklin, S.; Balasubramanian, T.; Nehru, K.; Kim, Youngmee

    2009-06-01

    The crystal structure of the title rac-propranolol salt, CHNO2+·NO3-, consists of two protonated propranolol residues and nitrate anions. Three virtually flat fragments, characteristics of most of the ?-adrenolytics with oxy-methylene bridge are present in both the cations (A and B). The plane of the propranolol chain is twisted with respect to the plane of the aromatic ring in both the cations. Present study investigates the conformation and hydrogen bonding interactions, which play an important role in biological functions. A gauche conformation is observed for the oxo-methylene bridge of cation A, while a trans conformation prevails in cation B. These conformations are found in majority of ?-blockers. Presence of twenty intermolecular hydrogen bonds mediating through the anions stabilizes the crystal packing. Vibration analysis and earlier theoretical predictions complement the structure analysed. From the UV-Vis spectral analysis for the crystal, the optical band gap is found to be Eg = 5.12 eV, where as the chloride salt has Eg = 3.81 eV. The increase in the band gap may be attributed by the increase in the number of intermolecular hydrogen bonds. Good optical transmittance in the entire visible region and the direct band gap property suggest that it is a suitable candidate for optical applications in UV region.

  6. Photoelectron Spectroscopy of Rare-Gas Solvated Nucleobase Anions

    NASA Astrophysics Data System (ADS)

    Buonaugurio, Angela M.; Chen, Jing; Bowen, Kit H.

    2012-06-01

    Gas-phase polar molecular anions [uracil (U^-), thymine (T^-), 1-3 dimethyluracil (DMU^-)] solvated by rare gas atoms were studied by means of negative ion photoelectron spectroscopy. The photoelectron spectrum (PES) of U^-, T^-, and DMU^- each exhibit a distinctive dipole-bound (DB) spectral signature. The spectra of U^-, U^- (Ar)_1,2 and U^- (Kr)_1 also only displayed the DB anion feature. Upon the solvation of more rare gas atoms, the spectra of U^- (Ar)_3, U^- (Kr)_2, and U^- (Xe)1-3 not only retained the DB signature but also exhibited the valence anion features. Moreover, the DB and the valence features shifted together to higher electron binding energies (EBEs) with increasing numbers of rare gas solvent atoms. Therefore, the co-existing DB and the valence anions appeared to be strongly coupled with each other, i.e. they effectively form a single state that is a superposition of both DB and valence anion states. For both U^- and T^- series, the ``onset size" of the Xe, Kr, and Ar solvents for the co-existing of the two anionic states was 1, 2, and 3 respectively. In addition, a minimum of 2 methane (CH_4) molecules or 1 ethane (C_2H_6) molecule were required to induce the coupling between the two states in the T^- series. Thus, the nucleobase anion interaction with non-polar solvent atoms tracks as the sum of the solvent polarizabilities. However for the DMU- series, the DB and the valence anions of DMU^-(Xe)_1, DMU^-(Kr)_2, and DMU^-(Ar)_3 were completely absent in both the mass spectra and the PES. Beyond these ``holes", their PES displayed the similar behaviors to the U^- and T^- series. Extrapolated EA values for these missing species were at or very close to zero, which may explain why they were not seen. However, why this was the case is not clear. With better Franck-Condon overlap between the origins of the NB^- (Rg)_n valence anion and the neutral NB(Rg)n than between those of the NB^- (H2O)n valence anion and the neutral NB(H2O)n, extrapolation of the valence electron affinities, measured from the NB(Rg)_n^- valence anions, should lead to significantly improved estimations of the valence electron affinity values of canonical, molecular nucleobases. EA_v(U) = 36 ±3 meV, EA_v(T) = 32 ± 7 meV, EA_v(1,3-DMU) = -34 ± 8 meV, and EA_v(A) = -80 meV, are our best recommended extrapolated EA_v values from our experiments. J. Chen, A. M. Buonaugurio and K. H. Bowen, TBA

  7. Aerobic and Anaerobic Metabolism Aerobic = oxidative metabolism

    E-print Network

    Jodice, Patrick

    and lizards · Anaerobic metabolism may supply 50-90% of energy during activity · As with many other processes flight is positively related to drag and velocity #12;Laysan Albatross Horned Puffin AspectRatio Red

  8. Schisandrin A and B induce organic anion transporting polypeptide 1B1 transporter activity.

    PubMed

    Guo, Cheng-Xian; Deng, Sheng; Yin, Ji-Ye; Liu, Zhao-Qian; Zhang, Wei; Zhou, Hong-Hao

    2015-01-01

    Organic anion transporting polypeptide 1B1 (OATP1B1) is the most important transporter in the organic anion transporting polypeptide family. OATP1B1 plays an important role in the hepatic uptake of many endogenous compounds and xenobiotics, including many clinical drugs. At present, the combinational usage of Chinese traditional herbal medicines and conventional chemical pharmaceuticals may affect the activity of enzymes and transporters activity and cause absorption of their substrates and metabolic changes. In this study, we aimed to investigate the effect of schisandrin A, schisandrin B and tanshinone IIA, which were extracted from medicinal plants, on OATP1B1 activity. HepG2 cells are used as in vitro models for OATP1B1 activity studies. A combination of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tertazolium bromide (MTT) assays, real-time RT-PCR, and transporter activity analysis were employed. We found that schisandrin A and B increased OATP1B1 mRNA levels by 1.81-fold (p < 0.01) and 1.87-fold (p < 0.01) at concentration of 10 ?M, respectively. Schisandrin A of 1 ?M and 10 ?M and schisandrin B of 10 ?M significantly increased the uptake of [3H] estrone-3-sulfate (p < 0.05 or p < 0.01). Tanshinone IIA had no effect on the mRNA expression and transport activity of OATP1B1 at nontoxic concentrations. Our study suggests that schisandrin A and B induced OATP1B1 expression and increased its transporter activity in HepG2 cells. PMID:25975095

  9. Hypotonicity induced K+ and anion conductive pathways activation in eel intestinal epithelium.

    PubMed

    Lionetto, M G; Giordano, M E; De Nuccio, F; Nicolardi, G; Hoffmann, E K; Schettino, T

    2005-02-01

    Control of cell volume is a fundamental and highly conserved physiological mechanism, essential for survival under varying environmental and metabolic conditions. Epithelia (such as intestine, renal tubule, gallbladder and gills) are tissues physiologically exposed to osmotic stress. Therefore, the activation of 'emergency' systems of rapid cell volume regulation is fundamental in their physiology. The aim of the present work was to study the physiological response to hypotonic stress in a salt-transporting epithelium, the intestine of the euryhaline teleost Anguilla anguilla. Eel intestinal epithelium, when symmetrically bathed with Ringer solution, develops a net Cl- current giving rise to a negative transepithelial potential at the basolateral side of the epithelium. The eel intestinal epithelium responded to a hypotonic challenge with a biphasic decrease in the transepithelial voltage (V(te)) and the short circuit current (I(sc)). This electrophysiological response correlated with a regulatory volume decrease (RVD) response, recorded by morphometrical measurement of the epithelium height. Changes in the transepithelial resistance were also observed following the hypotonicity exposure. The electrogenic V(te) and I(sc) responses to hypotonicity resulted from the activation of different K+ and anion conductive pathways on the apical and basolateral membranes of the epithelium: (a) iberiotoxin-sensitive K+ channels on the apical and basolateral membrane, (b) apamin-sensitive K+ channels mainly on the basolateral membrane, (c) DIDS-sensitive anion channels on the apical membrane. The functional integrity of the basal Cl- conductive pathway on the basolateral membrane is also required. The electrophysiological response to hypotonic stress was completely abolished by Ca2+ removal from the Ringer perfusing solution, but was not affected by depletion of intracellular Ca2+ stores by thapsigargin. PMID:15695766

  10. Field induced gap infrared detector

    NASA Technical Reports Server (NTRS)

    Elliott, C. Thomas (inventor)

    1990-01-01

    A tunable infrared detector which employs a vanishing band gap semimetal material provided with an induced band gap by a magnetic field to allow intrinsic semiconductor type infrared detection capabilities is disclosed. The semimetal material may thus operate as a semiconductor type detector with a wavelength sensitivity corresponding to the induced band gap in a preferred embodiment of a diode structure. Preferred semimetal materials include Hg(1-x)Cd(x)Te, x is less than 0.15, HgCdSe, BiSb, alpha-Sn, HgMgTe, HgMnTe, HgZnTe, HgMnSe, HgMgSe, and HgZnSe. The magnetic field induces a band gap in the semimetal material proportional to the strength of the magnetic field allowing tunable detection cutoff wavelengths. For an applied magnetic field from 5 to 10 tesla, the wavelength detection cutoff will be in the range of 20 to 50 micrometers for Hg(1-x)Cd(x)Te alloys with x about 0.15. A similar approach may also be employed to generate infrared energy in a desired band gap and then operating the structure in a light emitting diode or semiconductor laser type of configuration.

  11. Crop yield gaps in Cameroon.

    PubMed

    Yengoh, Genesis T; Ardö, Jonas

    2014-03-01

    Although food crop yields per hectare have generally been increasing in Cameroon since 1961, the food price crisis of 2008 and the ensuing social unrest and fatalities raised concerns about the country's ability to meet the food needs of its population. This study examines the country's potential for increasing crop yields and food production to meet this food security challenge. Fuzzy set theory is used to develop a biophysical spatial suitability model for different crops, which in turn is employed to ascertain whether crop production is carried out in biophysically suited areas. We use linear regression to examine the trend of yield development over the last half century. On the basis of yield data from experimental stations and farmers' fields we assess the yield gap for major food crops. We find that yields have generally been increasing over the last half century and that agricultural policies can have significant effects on them. To a large extent, food crops are cultivated in areas that are biophysically suited for their cultivation, meaning that the yield gap is not a problem of biophysical suitability. Notwithstanding, there are significantly large yield gaps between actual yields on farmers' farms and maximum attainable yields from research stations. We conclude that agronomy and policies are likely to be the reasons for these large yield gaps. A key challenge to be addressed in closing the yield gaps is that of replenishing and properly managing soil nutrients. PMID:23925855

  12. Alpha-aminoxy acids: new possibilities from foldamers to anion receptors and channels.

    PubMed

    Li, Xiang; Wu, Yun-Dong; Yang, Dan

    2008-10-01

    Naturally occurring peptides serve important functions as enzyme inhibitors, hormones, neurotransmitters, and immunomodulators in many physiological processes including metabolism, digestion, pain sensitivity, and the immune response. However, due to their conformational flexibility and poor bioavailability, such peptides are not generally viewed as useful therapeutic agents in clinical applications. In an effort to solve these problems, chemists have developed peptidomimetic foldamers, unnatural oligomeric molecules that fold into rigid and well-defined secondary structures mimicking the structures and biological functions of these natural peptides. We have designed peptidomimetic foldamers that give predictable, backbone-controlled secondary structures irrespective of the nature of the side chains. This Account presents our efforts to develop a novel class of peptidomimetic foldamers comprising alpha-aminoxy acids and explore their applications in the simulation of ion recognition and transport processes in living systems. Peptides constructed from alpha-aminoxy acids fold according to the following rules: (1) A strong intramolecular eight-membered-ring hydrogen bond forms between adjacent alpha-aminoxy acid residues (the alpha N-O turn). The chirality of the alpha-carbon, not the nature of the side chains, determines the conformation of this chiral N-O turn. (2) While homochiral oligomers of alpha-aminoxy acids form an extended helical structure (1.8 8 helix), heterochiral ones adopt a bent reverse turn structure. (3) In peptides of alternating alpha-amino acids and alpha-aminoxy acids, the seven-membered-ring intramolecular hydrogen bond, that is, the gamma-turn, is initiated by a succeeding alpha N-O turn. Thus, this type of peptide adopts a novel 7/8 helical structure. In investigating the potential applications of alpha-aminoxy acids, we have found that the amide NH units of alpha-aminoxy acids are more acidic than are regular amide NH groups, which makes them better hydrogen bond donors when interacting with anions. This property makes alpha-aminoxy acids ideal building blocks for the construction of anion receptors. Indeed, we have constructed both cyclic and acyclic anion receptors that have strong affinities and good (enantio-)selectivities toward chloride (Cl(-)) and chiral carboxylate ions. Taking advantage of these systems' preference for Cl(-) ions, we have also employed alpha-aminoxy acid units to construct a synthetic Cl(-) channel that can mediate the passage of Cl(-) ions across cell membranes. Continued studies of these peptidomimetic systems built from alpha-aminoxy acids should lead to a broad range of applications in chemistry, biology, medicine, and materials science. PMID:18785763

  13. Molecular Anions in Protostars, Prestellar Cores and Dark Clouds

    NASA Technical Reports Server (NTRS)

    Cordiner, Martin; Charnley, Steven; Buckle, Jane; Wash, Catherine; Millar, Tom

    2011-01-01

    From our recent survey work using the Green Bank Telescope, microwave emission lines from the hydrocarbon anion C6H(-) and its parent neutral C6H have been detected in six new sources. Using HC3N = 10(exp -9) emission maps, we targeted the most carbon-chain-rich sources for our anion survey, which included the low-mass Class 0 protostar L1251A-IRS3, the prestellar cores L1389-SMM1 and L1512, and the interstellar clouds Ll172A, TMC-1C and L1495B. Derived [C6H(-)]/[C6H] anion-to-neutral ratios are approximately 1-10. The greatest C6H(-) column densities are found in the quiescent clouds TMC-1C and L1495B, but the anion-to-neutral ratios are greatest in the prestellar cores and protostars. These results are interpreted in terms of the physical and chemical properties of the sources, and the implications for molecular cloud chemistry are discussed.

  14. Dietary Cation Anion Difference of Five Cool-Season Grasses

    Microsoft Academic Search

    Gaëtan F. Tremblay; Hélène Brassard; Gilles Bélanger; Philippe Seguin; Raynald Drapeau; Annie Brégard; Réal Michaud; Guy Allard

    2006-01-01

    Forage-based rations with a low dietary cation anion difference (DCAD) should be fed to dairy cows 2 to 4 wk prepartum to prevent hypocalcaemia or milk fever. We evaluated the DCAD of two to four cultivars of five grass species at three locations in Quebec, Canada. Orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), tall fescue (Festuca arundinacea Schreb.),

  15. Supporting Information for: Ammonium Bicarbonate Transport in Anion Exchange Membranes

    E-print Network

    S1 Supporting Information for: Ammonium Bicarbonate Transport in Anion Exchange Membranes was measured by first equilibrating the polymer film in the desired solution [e.g., DI water, 0.5 mol/L sodium chloride (NaCl), or 0.5 mol/L ammonium bicarbonate (AmB)]. Films were allowed to equilibrate

  16. Synthesis, characterization, anion complexation and electrochemistry of cationic Lewis acids 

    E-print Network

    Chiu, Ching-Wen

    2009-05-15

    .86 and -1.56 (vs. Fc/Fc+) corresponding to the formation of stable neutral and anionic derivatives. The one-electron reduction of [27]+ leads to the formation of a boron containing neutral radical featuring an unusual boron-carbon one-electron ? bond...

  17. Cation and anion transport through hydrophilic pores in lipid bilayers

    NASA Astrophysics Data System (ADS)

    Kandasamy, Senthil K.; Larson, Ronald G.

    2006-08-01

    To understand the origin of transmembrane potentials, formation of transient pores, and the movement of anions and cations across lipid membranes, we have performed systematic atomistic molecular dynamics simulations of palmitoyl-oleoyl-phosphatidylcholine (POPC) lipids. A double bilayer setup was employed and different transmembrane potentials were generated by varying the anion (Cl-) and cation (Na+) concentrations in the two water compartments. A transmembrane potential of ˜350mV was thereby generated per bilayer for a unit charge imbalance. For transmembrane potential differences of up to ˜1.4V, the bilayers were stable, over the time scale of the simulations (10-50ns). At larger imposed potential differences, one of the two bilayers breaks down through formation of a water pore, leading to both anion and cation translocations through the pore. The anions typically have a short residence time inside the pore, while the cations show a wider range of residence times depending on whether they bind to a lipid molecule or not. Over the time scale of the simulations, we do not observe the discharge of the entire potential difference, nor do we observe pore closing, although we observe that the size of the pore decreases as more ions translocate. We also observed a rare lipid flip-flop, in which a lipid molecule translocated from one bilayer leaflet to the opposite leaflet, assisted by the water pore.

  18. PHASE BEHAVIOR OF WATER/PERCHLOROETHYLENE/ANIONIC SURFACTANT SYSTEMS

    EPA Science Inventory

    Winsor Type I (o/w), Type II (w/o), and Type III (middle phase) microemulsions have been generated for water and perchloroethylene (PCE) in combination with anionic surfactants and the appropriate electrolyte concentration. The surfactant formulation was a combination of sodium d...

  19. Photostability enhancement of anionic natural dye by intercalation into hydrotalcite

    Microsoft Academic Search

    Yoshiumi Kohno; Koichi Totsuka; Shuji Ikoma; Keiko Yoda; Masashi Shibata; Ryoka Matsushima; Yasumasa Tomita; Yasuhisa Maeda; Kenkichiro Kobayashi

    2009-01-01

    The aim of this study is the improvement of the photostability of several natural anionic dyes, carmine (CM), carthamus yellow (CY), and annatto dye (ANA), by complexation with hydrotalcite. The composite of the dyes and hydrotalcite is prepared by the coprecipitation method. CM is successfully intercalated in the hydrotalcite layer when the amount of introduced CM is large. The photostability

  20. Anionic Salt Programs for Close-Up Dry Cows 

    E-print Network

    Stokes, Sandra R.

    1998-12-17

    Dairy farmers can improve long-term milk production by having a well-managed program for dry cows during the last 3 weeks before calving. This publication explains how an anionic salt program can help control subclinical hypocalcemia and "droopy cow...

  1. Efficiency of superoxide anions in the inactivation of selected dehydrogenases

    NASA Astrophysics Data System (ADS)

    Rodacka, Aleksandra; Serafin, Eligiusz; Puchala, Mieczyslaw

    2010-09-01

    The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as rad OH and ONOO -. In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH). We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion. Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.

  2. Absolute Photodetachment Cross-section Measurements for Hydrocarbon Chain Anions

    Microsoft Academic Search

    T. Best; R. Otto; S. Trippel; P. Hlavenka; A. von Zastrow; S. Eisenbach; S. Jézouin; R. Wester; E. Vigren; M. Hamberg; W. D. Geppert

    2011-01-01

    Absolute photodetachment cross sections have been measured for the hydrocarbon chain anions C n H--, n = 2, 4, and 6, which are relevant for an understanding of molecular clouds in the interstellar medium. Data have been obtained for different photon energies within approximately 1 eV of the detachment threshold. With our recently developed method we have achieved a precision

  3. Efficient NMR enantiodifferentiation of chiral quats with BINPHAT anion.

    PubMed

    Lacour, Jérôme; Vial, Laurent; Herse, Christelle

    2002-04-18

    Hexacoordinated phosphorus BINPHAT anion is an efficient NMR chiral shift agent for quaternary ammonium cations (quats) leading to large separations (DeltaDeltadelta up to 0.29 ppm) of the proton signals of the enantiomers. [reaction: see text] PMID:11950360

  4. Purification, characterization and catalytic activity of anionic zucchini peroxidase

    Microsoft Academic Search

    Luigi Casella; Michele Gullottit; Sonia Polit; Rosa Pia Ferrari; Enzo Laurenti; Augusto Marchesini

    1993-01-01

    The isolation and purification, by preparative electrofocusing, of the major anionic (ZPOA) and cationic (ZPOC) isoenzymes, collected from young zucchini squash, are reported. The Mr and sugar content are similar to those found previously for the major isoenzymes from the ripe fruits and in the range commonly observed for plant peroxidases. The amount of the two cationic enzymes was very

  5. Prescription Fire and Anion Retention in Tahoe Forest Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prescribed burning is a possible option to reduce fire potential in the Lake Tahoe Basin (California and Nevada). However, subsequent nutrient loading to the lake is a major concern. The effect of residual ash on anion leaching, primarily O-PO4 and SO42-, was studied in both the field and laboratory...

  6. Phytohormone control of the tobacco anionic peroxidase promoter

    Microsoft Academic Search

    Karen L. Klotz; L. Mark Lagrimini

    1996-01-01

    The tobacco anionic peroxidase gene encodes the predominant peroxidase isoenzyme in the aerial portions of tobacco. Three kb of the peroxidase promoter was joined to the coding region of theEscherichia coli ß-glucuronidase gene (GUS), and transiently expressed in tobacco mesophyll protoplasts in the presence or absence of plant growth regulators. Benzyladenine, ethylene, and gibberellic acid did not affect peroxidase gene

  7. A Reduced Polyoxomolybdenum Borophosphate Anion Related to the Wells-Dawson Clusters

    E-print Network

    A Reduced Polyoxomolybdenum Borophosphate Anion Related to the Wells-Dawson Clusters Eddy Dumas borophosphate anions that resemble the R-Wells- Dawson cluster. The polyoxometalates have already proven

  8. Synthesis, Characterization and Anion Binding Properties of Boron-based Lewis Acids 

    E-print Network

    Zhao, Hai Yan

    2012-07-16

    The recognition and capture of fluoride, cyanide and azide anions is attracting great deal of attention due to the negative effects of these anions on the environment and on human health. One of common methods used for ...

  9. Characterization of anion diffusion in polymer hydrogels used for wastewater remediation

    E-print Network

    Rubloff, Gary W.

    Characterization of anion diffusion in polymer hydrogels used for wastewater remediation Dimitri R pollutants, even at extremely low concentrations, from wastewater effluents are a major environmental need of reactive phosphorus, nitrogen, and sulfur anions from aquaculture production wastewater effluents

  10. Peripartal calcium homoeostasis of multiparous dairy cows fed rumen-protected rice bran or a lowered dietary cation/anion balance diet before calving.

    PubMed

    Martín-Tereso, J; ter Wijlen, H; van Laar, H; Verstegen, M W A

    2014-08-01

    Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close-up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen-protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen-protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen-protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post-calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen-protected rice bran may be a suitable feed to reduce hypocalcaemia post-partum and can be included in pre-calving compound feeds representing a palatable alternative to anionic salts. PMID:24138155

  11. Peripartal calcium homoeostasis of multiparous dairy cows fed rumen-protected rice bran or a lowered dietary cation/anion balance diet before calving

    PubMed Central

    Martín-Tereso, J; ter Wijlen, H; van Laar, H; Verstegen, M W A

    2014-01-01

    Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close-up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen-protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen-protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen-protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post-calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen-protected rice bran may be a suitable feed to reduce hypocalcaemia post-partum and can be included in pre-calving compound feeds representing a palatable alternative to anionic salts. PMID:24138155

  12. Tunneling magnetoresistance through a vacuum gap

    Microsoft Academic Search

    W. Wulfhekel; H. F. Ding; J. Kirschner

    2002-01-01

    We studied the tunneling magnetoresistance (TMR) effect through a vacuum barrier using spin-polarized scanning tunneling microscopy on Co(0001). By varying the gap width at a fixed bias voltage or by varying the bias voltage at a fixed gap width, the fundamental behaviour of the TMR across the vacuum gap was investigated. At large gap widths the TMR is constant with

  13. ABORT GAP CLEANING IN RHIC.

    SciTech Connect

    DREES,A.; AHRENS,L.; III FLILLER,R.; GASSNER,D.; MCINTYRE,G.T.; MICHNOFF,R.; TRBOJEVIC,D.

    2002-06-03

    During the RHIC Au-run in 2001 the 200 MHz storage cavity system was used for the first time. The rebucketing procedure caused significant beam debunching in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam could account for approximately 30%-40% of the total beam intensity. Some of it will be in the abort gap. In order to minimize the risk of magnet quenching due to uncontrolled beam losses at the time of a beam dump, a combination of a fast transverse kicker and copper collimators were used to clean the abort gap. This report gives an overview of the gap cleaning procedure and the achieved performance.

  14. Anion permeation in Ca(2+)-activated Cl(-) channels.

    PubMed

    Qu, Z; Hartzell, H C

    2000-12-01

    Ca(2+)-activated Cl channels (Cl(Ca)Cs) are an important class of anion channels that are opened by increases in cytosolic [Ca(2+)]. Here, we examine the mechanisms of anion permeation through Cl(Ca)Cs from Xenopus oocytes in excised inside-out and outside-out patches. Cl(Ca)Cs exhibited moderate selectivity for Cl over Na: P(Na)/P(Cl) = 0.1. The apparent affinity of Cl(Ca)Cs for Cl was low: K(d) = 73 mM. The channel had an estimated pore diameter >0.6 nm. The relative permeabilities measured under bi-ionic conditions by changes in E(rev) were as follows: C(CN)(3) > SCN > N(CN)(2) > ClO(4) > I > N(3) > Br > Cl > formate > HCO(3) > acetate = F > gluconate. The conductance sequence was as follows: N(3) > Br > Cl > N(CN)(2) > I > SCN > COOH > ClO(4) > acetate > HCO(3) = C(CN)(3) > gluconate. Permeant anions block in a voltage-dependent manner with the following affinities: C(CN)(3) > SCN = ClO(4) > N(CN)(2) > I > N(3) > Br > HCO(3) > Cl > gluconate > formate > acetate. Although these data suggest that anionic selectivity is determined by ionic hydration energy, other factors contribute, because the energy barrier for permeation is exponentially related to anion hydration energy. Cl(Ca)Cs exhibit weak anomalous mole fraction behavior, implying that the channel may be a multi-ion pore, but that ions interact weakly in the pore. The affinity of the channel for Ca(2+) depended on the permeant anion at low [Ca(2+)] (100-500 nM). Apparently, occupancy of the pore by a permeant anion increased the affinity of the channel for Ca(2+). The current was strongly dependent on pH. Increasing pH on the cytoplasmic side decreased the inward current, whereas increasing pH on the external side decreased the outward current. In both cases, the apparent pKa was voltage-dependent with apparent pKa at 0 mV = approximately 9.2. The channel may be blocked by OH(-) ions, or protons may titrate a site in the pore necessary for ion permeation. These data demonstrate that the permeation properties of Cl(Ca)Cs are different from those of CFTR or ClC-1, and provide insights into the nature of the Cl(Ca)C pore. PMID:11099350

  15. On the coexistence of localized and extended acceptor states in high gap semiconductors

    NASA Astrophysics Data System (ADS)

    Schirmer, O. F.

    2015-02-01

    Holes introduced into high gap materials by acceptor doping are often self-localized at anion sites as small polarons bound to the doping elements. The related lattice distortion lowers the hole energy; the hole levels thus tend to be deep. Electronic structure calculations of small polarons have identified, for some dopings, that such localized states can coexist with extended ones that result from the same doping. Using a scaling formalism, proposed by Emin and Holstein, it is shown that this appears to be a general phenomenon if the polaron-forming short-range hole–lattice coupling is taken into account.

  16. Adsorption of Anionic–Cationic Surfactant Mixtures on Metal oxide Surfaces

    Microsoft Academic Search

    A. Upadhyaya; E. J. Acosta; J. F. Scamehorn; D. A. Sabatini

    2007-01-01

    This research evaluates the adsorption of anionic and cationic surfactant mixtures on charged metal oxide surfaces (i.e.,\\u000a alumina and silica). For an anionic-rich surfactant mixture below the CMC, the adsorption of anionic surfactant was found\\u000a to substantially increase with the addition of low mole fractions of cationic surfactant. Two anionic surfactants (sodium\\u000a dodecyl sulfate and sodium dihexyl sulfosuccinate) and two

  17. Gap junctions in cardiovascular disease.

    PubMed

    Jongsma, H J; Wilders, R

    2000-06-23

    Connexins, the protein molecules forming gap junction channels, are reduced in number or redistributed from intercalated disks to lateral cell borders in a variety of cardiac diseases. This "gap junction remodeling" is considered to be arrhythmogenic. Using a simple model of human ventricular myocardium, we found that quantitative remodeling data extracted from the literature gave rise to only small to moderate changes in conduction velocity and the anisotropy ratio. Especially for longitudinal conduction, cytoplasmic resistivity (and thus cellular geometry) is much more important than commonly realized. None of the remodeling data gave rise to slow conduction on the order of a few centimeters per second. PMID:10864907

  18. Stacked insulator induction accelerator gaps

    SciTech Connect

    Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

    1997-05-01

    Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

  19. Activation of maxi-anion channel by protein tyrosine dephosphorylation.

    PubMed

    Toychiev, Abduqodir H; Sabirov, Ravshan Z; Takahashi, Nobuyaki; Ando-Akatsuka, Yuhko; Liu, Hongtao; Shintani, Takafumi; Noda, Masaharu; Okada, Yasunobu

    2009-10-01

    The maxi-anion channel with a large single-channel conductance of >300 pS, and unknown molecular identity, is functionally expressed in a large variety of cell types. The channel is activated by a number of experimental maneuvers such as exposing cells to hypotonic or ischemic stress. The most effective and consistent method of activating it is patch membrane excision. However, the activation mechanism of the maxi-anion channel remains poorly understood at present. In the present study, involvement of phosphorylation/dephosphorylation in excision-induced activation was examined. In mouse mammary fibroblastic C127 cells, activity of the channel was suppressed by intracellular application of Mg-ATP, but not Mg-5'-adenylylimidodiphosphate (AMP-PNP), in a concentration-dependent manner. When a cocktail of broad-spectrum tyrosine phosphatase inhibitors was applied, channel activation was completely abolished, whereas inhibitors of serine/threonine protein phosphatases had no effect. On the other hand, protein tyrosine kinase inhibitors brought the channel out of an inactivated state. In mouse adult skin fibroblasts (MAFs) in primary culture, similar maxi-anion channels were found to be activated on membrane excision, in a manner sensitive to tyrosine phosphatase inhibitors. In MAFs isolated from animals deficient in receptor protein tyrosine phosphatase (RPTP)zeta, activation of the maxi-anion channel was significantly slower and less prominent compared with that observed in wild-type MAFs; however, channel activation was restored by transfection of the RPTPzeta gene. Thus it is concluded that activation of the maxi-anion channel involves protein dephosphorylation mediated by protein tyrosine phosphatases that include RPTPzeta in mouse fibroblasts, but not in C127 cells. PMID:19657061

  20. Separation of anionic oligosaccharides by high-performance liquid chromatography

    SciTech Connect

    Green, E.D.; Baenziger, J.U.

    1986-10-01

    The authors have developed methods for rapid fractionation of anionic oligosaccharides containing sulfate and/or sialic acid moieties by high-performance liquid chromatography (HPLC). Ion-exchange HPLC on amine-bearing columns (Micropak AX-10 and AX-5) at pH 4.0 is utilized to separate anionic oligosaccharides bearing zero, one, two, three, or four charges, independent of the identity of the anionic moieties (sulfate and/or sialic acid). Ion-exchange HPLC at pH 1.7 allows separation of neutral, mono-, di-, and tetrasialylated, monosulfated, and disulfated oligosaccharides. Oligosaccharides containing three sialic acid residues and those bearing one each of sulfate and sialic acid, however, coelute at pH 1.7. Since the latter two oligosaccharide species separate at pH 4.0, analysis at pH 4.0 followed by analysis at pH 1.7 can be utilized to completely fractionate complex mixtures of sulfated and sialylated oligosaccharides. Ion-suppression amine adsorption HPLC has previously been shown to separate anionic oligosaccharides on the basis of net carbohydrate content (size). In this study they demonstrate the utility of ion-suppression amine adsorption HPLC for resolving sialylated oligosaccharide isomers which differ only in the linkages of sialic acid residues (..cap alpha..2,3 vs ..cap alpha..2,6) and/or location of ..cap alpha..2,3- and ..cap alpha..2,6-linked sialic acid moieties on the peripheral branches of oligosaccharides. These two methods can be used in tandem to separate oligosaccharides, both analytically and preparatively, based on their number, types, and linkages of anionic moieties.

  1. Metabolic profiling in nutrition and metabolic disorders.

    PubMed

    LeMieux, Monique; Al-Jawadi, Arwa; Wang, Shu; Moustaid-Moussa, Naima

    2013-01-01

    Nutrients exert potent effects on metabolism through a variety of regulatory mechanisms, resulting in local and systemic changes in metabolite levels. Numerous studies have focused on mechanisms by which nutrients and disease states regulate metabolism at the gene or protein levels using genomic and proteomic approaches, respectively. However, few studies have investigated nutritional regulation of the whole metabolome. Thus, metabolomic approaches have recently emerged to complement the genomics and proteomics research and to help identify biologically meaningful metabolites and metabolic networks that control cellular responses to genetic and environmental factors, including diet, and to identify metabolic diseases that are influenced by genetic and dietary factors. These large-scale studies expedite our ability to develop targeted treatments. The goal of this symposium was to provide a forum to introduce the metabolomics field to nutrition researchers. An overview of the state-of-the-art metabolomic technologies used was provided. The impact of some specific nutrients, disease states, or genetic variations and their interaction with the metabolome was discussed by the speakers. Our objectives were as follows: 1) to educate the audience about the use of metabolomics as an innovative tool for linking changes in cell metabolites and genetic variations to nutrient metabolism, energy balance, and the overlying effects on health and disease; 2) to understand the concept of metabolomics and describe the analytical tools and resources available in this area; 3) to introduce the potential application of metabolomics in the field of nutrition research; and 4) to provide specific nutrition-relevant metabolomics study examples in investigating regulation of the metabolic network or metabolic changes resulting from disease states by dietary factors. PMID:24038253

  2. The Metabolic Syndrome

    Microsoft Academic Search

    Aoife M. Brennan; Laura Sweeney; Christos S. Mantzoros

    The metabolic syndrome refers to the clustering of metabolic abnormalities more frequently than would be expected by chance\\u000a alone. These metabolic abnormalities are all risk factors for cardiovascular disease (CVD), and the epidemiological association\\u000a between these multiple risk factors points to the possibility of a unifying underlying pathophysiology. Obesity, in particular\\u000a visceral adiposity, insulin resistance, and some degree of abnormal

  3. Influences of anionic and cationic dopants on the morphology and optical properties of PbS nanostructures

    NASA Astrophysics Data System (ADS)

    Ramin, Yousefi; Mohsen, Cheragizade; Farid, Jamali-Sheini; R. Mahmoudian, M.; Abdolhossein, Saaédi; Nay, Ming Huang

    2014-10-01

    Selenium and zinc are used as anionic and cationic dopant elements to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a thermal evaporation method. Scanning electron microscopy (SEM) results show similar morphologies for the undoped and doped PbS nanostructures. X-ray diffraction (XRD) patterns of three sets of the nanostructures indicate that these nanostructures each have a PbS structure with a cubic phase. Evidence of dopant incorporation is demonstrated by X-ray photoelectron spectroscopy (XPS). Raman spectra of the synthesized samples confirm the XRD results and indicate five Raman active modes, which relate to the PbS cubic phase for all the nanostructures. Room temperature photoluminescence (PL) and UV—Vis spectrometers are used to study optical properties of the undoped and doped PbS nanostructures. Optical characterization shows that emission and absorption peaks are in the infrared (IR) region of the electromagnetic spectrum for all PbS nanostructures. In addition, the optical studies of the doped PbS nanostructures reveal that the band gap of the Se-doped PbS is smaller, and the band gap of the Zn-doped PbS is bigger than the band gap of the undoped PbS nanostructures.

  4. Regeneration of strong-base anion-exchange resins by sequential chemical displacement

    Microsoft Academic Search

    Gilbert M. Brown; Baohua Gu; Bruce A. Moyer; Peter V. Bonnesen

    2002-01-01

    A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed

  5. Vertical ionization potentials and CTTS energies for anions in water and acetonitrile

    Microsoft Academic Search

    Naoko Takahashi; Kanna Sakai; Hajime Tanida; Iwao Watanabe

    1995-01-01

    The photoelectron emission threshold energy values, Et, are collected for eleven anions in water and five anions in acetonitrite. The Et values are found to be linearly correlated with the charge-transfer-to-solvent (CTTS) energies, ECTTS. This correlation can be used to find CTTS bands for some of the anions for which it is difficult to distinguish the bands from the intramolecular

  6. An organic anion template: a 24-nucleus silver cluster encapsulating a squarate dimer.

    PubMed

    Liu, Kuan-Guan; Chen, Su-Kun; Lin, Yu-Mei; Wang, Quan-Ming

    2015-06-01

    The first silver cluster encapsulating an organic anion-squarate dianion-has been synthesized. Two C4O4(2-) anions arranged in a staggered sandwich type arrangement are confined in the Ag24 cage. The incorporation of squarate anions into the silver alkynyl system leads to the red shift of absorption of the cluster in comparison to silver squarate. PMID:25998911

  7. Photodetachment Imaging Study of the Vinoxide Anion M. Shane Bowen and Robert E. Continetti*

    E-print Network

    Continetti, Robert E.

    Photodetachment Imaging Study of the Vinoxide Anion M. Shane Bowen and Robert E. Continetti distributions produced by the 354.8-nm photodetachment of the vinoxide anion, H2CdCHO-, is reported-neutral system. 1. Introduction The vinoxide anion and the corresponding vinoxy radical are the simplest examples

  8. Interaction between cation and anion sublattices in molecular charge transfer salts: structural conditions for ferrimagnetism

    Microsoft Academic Search

    S. S. Turner; D. Le Pévelen; P. Day

    2003-01-01

    Many molecular charge transfer salts with organo-chalcogen donors and transition-metal complex anions have been synthesised in recent years in an effort to find lattices that combine conductivity with long range magnetic order, but in most cases interaction between the donor and anion sublattices is very weak. We have approached this issue by selecting anions that contain S or Se atoms

  9. From isolated 1H-pyrazole cryptand anion receptors to hybrid inorganic-organic 1D helical polymeric anion receptors.

    PubMed

    Pitarch-Jarque, Javier; Belda, Raquel; García-España, Laura; Llinares, José M; Pan, FangFang; Rissanen, Kari; Navarro, Pilar; García-España, Enrique

    2015-05-01

    We report a novel 1-D helical coordination polymer formed by protonated polyamine 1H-pyrazole cryptands interconnected by Cu(2+) metal ions that are able to encapsulate anionic species behaving as a multianion receptor. Switching from a monomeric receptor to a polymeric receptor is activated by metal ions and pH. PMID:25847794

  10. Anion- and Proton-Dependent Gating of ClC-4 Anion/Proton Transporter under Uncoupling Conditions

    PubMed Central

    Orhan, Gökce; Fahlke, Christoph; Alekov, Alexi K.

    2011-01-01

    ClC-4 is a secondary active transporter that exchanges Cl? ions and H+ with a 2:1 stoichiometry. In external SCN?, ClC-4 becomes uncoupled and transports anions with high unitary transport rate. Upon voltage steps, the number of active transporters varies in a time-dependent manner, resembling voltage-dependent gating of ion channels. We here investigated modification of the voltage dependence of uncoupled ClC-4 by protons and anions to quantify association of substrates with the transporter. External acidification shifts voltage dependence of ClC-4 transport to more positive potentials and leads to reduced transport currents. Internal pH changes had less pronounced effects. Uncoupled ClC-4 transport is facilitated by elevated external [SCN?] but impaired by internal Cl? and I?. Block by internal anions indicates the existence of an internal anion-binding site with high affinity that is not present in ClC channels. The voltage dependence of ClC-4 coupled transport is modulated by external protons and internal Cl? in a manner similar to what is observed under uncoupling conditions. Our data illustrate functional differences but also similarities between ClC channels and transporters. PMID:21354396

  11. Theoretical study of the geometric and electronic structure of neutral and anionic doped silver clusters, Ag 5X 0,? with X = Sc, Ti, V, Cr, Mn, Fe, Co, and Ni

    Microsoft Academic Search

    Xin-Juan Hou; Ewald Janssens; Peter Lievens; Minh Tho Nguyen

    2006-01-01

    Density functional theory (DFT) has been applied to investigate the low-lying electronic states of neutral and anionic transition metal doped silver clusters Ag5X0,? with X=Sc, Ti, V, Cr, Mn, Fe, Co, and Ni using the B3LYP functional with the Stuttgart SDD basis sets. The structural features, frontier orbital energy gaps (HOMO and LUMO), vertical detachment energies, and vertical and adiabatic

  12. [Metabolic functions and sport].

    PubMed

    Riviere, Daniel

    2004-01-01

    Current epidemiological studies emphasize the increased of metabolic diseases of the adults, such as obesity, type-2 diabetes and metabolic syndromes. Even more worrying is the rising prevalence of obesity in children. It is due more to sedentariness, caused more by inactivity (television, video, games, etc.) than by overeating. Many studies have shown that regular physical activities benefit various bodily functions including metabolism. After dealing with the major benefits of physical exercise on some adult metabolic disorders, we focus on the prime role played by physical activity in combating the public health problem of childhood obesity. PMID:15651421

  13. Mevalonate metabolism in cancer.

    PubMed

    Gruenbacher, Georg; Thurnher, Martin

    2015-01-28

    Cancer cells are characterized by sustained proliferative signaling, insensitivity to growth suppressors and resistance to apoptosis as well as by replicative immortality, the capacity to induce angiogenesis and to perform invasive growth. Additional hallmarks of cancer cells include the reprogramming of energy metabolism as well as the ability to evade immune surveillance. The current review focuses on the metabolic reprogramming of cancer cells and on the immune system's capacity to detect such changes in cancer cell metabolism. Specifically, we focus on mevalonate metabolism, which is a target for drug and immune based cancer treatment. PMID:24467965

  14. Evolution of Metabolism

    NASA Astrophysics Data System (ADS)

    Nealson, K. H.; Rye, R.

    2003-12-01

    This chapter is devoted to the discussion of the evolution of metabolism, with a particular focus towards redox metabolism and the utilization of redox energy by life. We will deal with various aspects of metabolism that involve direct interaction with, and the extraction of energy from, the environment (catabolic metabolism) and will talk briefly of the reactions that affect mineral formation and dissolution. However, we will de-emphasize the aspects related to the formation of complex molecules and organisms. To some, it will be refreshingly brief; to others, somewhat superficial. This is unavoidable, as our knowledge of the details of the evolution of metabolism is at best slim. However, by piecing together aspects of the properties and history of the Earth and coupling these with what we know of today's metabolism, it is possible to at least frame several different hypotheses that, with time, should be possible to test and modify so that the next writing of this chapter might contain some intellectual entrees and not just the appetizers. Any discussion of metabolic evolution must occur in concert with a consideration of the Earth - the understanding of the forces that drove the co-evolution of life and Earth can be achieved only by considering them together. This theme will pervade this chapter, and any real understanding of the evolution of metabolism must be inexorably coupled to, and consistent with, the geological record of the Earth.The first aspect of evolution concerns the metabolic participants as we know them now (i.e., a definition of metabolic diversity), and the second concerns the sequence of events that have led to this remarkable metabolic diversity. The first part is fairly straightforward: a discussion of the domains of life, and the metabolic achievements that are expressed in the various domains, and relating metabolism to biogeochemical processes whenever possible. The second part is much more problematic. While it is possible to make up nearly any story regarding the evolution of metabolism (and nearly all have been attempted!), the starting point of life is not known (great debates still rage as to the nature and origin of the first living systems), and it is not a trivial matter to specify the sequence and timing of metabolic innovations. As will be discussed below, genetic and genomic data have revealed that genetic exchange between organisms has been so pervasive that it has essentially uncoupled the evolution of taxonomic groups from the evolution of metabolic processes, thus, obscuring the evolutionary trail with blurred signals. Given these challenges, it may be prudent at this time to admit what we do not know, and lay out the challenges for the coming years.

  15. Eicosanoids in Metabolic Syndrome

    PubMed Central

    Hardwick, James P.; Eckman, Katie; Lee, Yoon Kwang; Abdelmegeed, Mohamed A.; Esterle, Andrew; Chilian, William M.; Chiang, John Y.; Song, Byoung-Joon

    2013-01-01

    Chronic persistent inflammation plays a significant role in disease pathology of cancer, cardiovascular disease, and metabolic syndrome (MetS). MetS is a constellation of diseases that include obesity, diabetes, hypertension, dyslipidemia, hypertriglyceridemia, and hypercholesterolemia. Nonalcoholic fatty liver disease (NAFLD) is associated with many of the MetS diseases. These metabolic derangements trigger a persistent inflammatory cascade, which includes production of lipid autacoids (eicosanoids) that recruit immune cells to the site of injury and subsequent expression of cytokines and chemokines that amplify the inflammatory response. In acute inflammation, the transcellular synthesis of antiinflammatory eicosanoids resolve inflammation, while persistent activation of the autacoid-cytokine-chemokine cascade in metabolic disease leads to chronic inflammation and accompanying tissue pathology. Many drugs targeting the eicosanoid pathways have been shown to be effective in the treatment of MetS, suggesting a common linkage between inflammation, MetS and drug metabolism.The cross-talk between inflammation and MetS seems apparent because of the growing evidence linking immune cell activation and metabolic disorders such as insulin resistance, dyslipidemia, and hypertriglyceridemia. Thus modulation of lipid metabolism through either dietary adjustment or selective drugs may become a new paradigm in the treatment of metabolic disorders. This review focuses on the mechanisms linking eicosanoid metabolism to persistent inflammation and altered lipid and carbohydrate metabolism in MetS. PMID:23433458

  16. [Porphyrin metabolism in women with metabolic syndrome].

    PubMed

    Krivosheev, A B; Kuimov, A D; Kondratova, M A; Tuguleva, T A

    2014-01-01

    A total of 47 women with metabolic syndrome (MS) were examined with the fractional determination of porphyrins in urine (uroporphyrin and coproporphyrin) and feces (coproporphyrin and protoporphyrin) as well as their precursors (5-aminolevulinic acid and porphobilinogen). Disorders of porphyrin metabolism were documented in 29 (61.7%) women All patients had elevated levels of porphyrin precursors. Five women exhibited qualitative changes in the form of abnormal ratios of different porphyrin fractions(coproporphyrin/uroporphyrin < 1--0.8 ± 0.1 vs normal ratio 3.6 ± 0.4). 21 patients suffered quantitative changes in porphyrin metabolism in the form of manifold increase of porphyrin levels in urine and/or feces and formation of biochemical syndromes of secondary coproporphyrinuiria, symptomatic rise in porphyrin content in feces, and chronic latent hepatic porfiria. Disorders of porphyrin metabolism were associated with insulin resistance. Changes of porphyrin metabolism in MS extend the spectrum of concomitant disturbances and can be regarded as an additional criterion. PMID:25980299

  17. Mass gap from pressure inequalities

    E-print Network

    Tamas S. Biro; Andras Laszlo; Peter Van

    2006-12-07

    We prove that a temperature independent mass distribution is identically zero below a mass threshold (mass gap) value, if the pressure satisfies certain inequalities. This supports the finding of a minimal mass in quark matter equation of state by numerical estimates and by substitution of analytic formulas. We present a few inequalities for the mass distribution based on the Markov inequality.

  18. Multiple input electrode gap controller

    DOEpatents

    Hysinger, C.L.; Beaman, J.J.; Melgaard, D.K.; Williamson, R.L.

    1999-07-27

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows. 17 figs.

  19. Multiple input electrode gap controller

    DOEpatents

    Hysinger, Christopher L. (Austin, TX); Beaman, Joseph J. (Austin, TX); Melgaard, David K. (Albuquerque, NE); Williamson, Rodney L. (Albuquerque, NE)

    1999-01-01

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows.

  20. GAP JUNCTION FUNCTION AND CANCER

    EPA Science Inventory

    Gap Junctions (GJs) provide cell-to-cell communication (GJIC) of essential metabolites and ions. Js allow tissues to average responses, clear waste products, and minimize the effects of xenobiotics by dilution and allowing steady-state catabolism. any chemicals can adversely affe...

  1. Electromagnetically induced photonic band gap

    Microsoft Academic Search

    Yuri V. Rostovtsev; Andrey B. Matsko; Marlan O. Scully

    1999-01-01

    A nonlinear propagation of electromagnetic waves has been investigated in a heterostructure formed by spatially modulated density of ladder-type (Xi) three-level atoms. The appearance of a forbidden band gap for an electromagnetic field induced by another electromagnetic field has been found. An alternative concept of an optical transistorlike device based on this effect has been proposed.

  2. Supramolecular chemistry of selective anion recognition for anions of environmental relevance. Progress report, October 1996--July 1997

    SciTech Connect

    Bowman-James, K.; Wilson, G.S.; Kuczera, K. [Univ. of Kansas, Lawrence, KS (US); Moyer, B. [Oak Ridge National Lab., TN (US)

    1997-01-01

    'This project has as its focus the design and synthesis of polyammonium macrocyclic receptors for oxoanions of environmental importance. The basic research aspects of this project involve synthesis (and the search for improved synthetic methods), solid state structure determination and thermodynamics studies (to ascertain structural criteria for and strength of anion binding), and molecular dynamics simulations (to assess solution characteristics of the interactions between anions and their receptors). Applications-oriented goals include the fabrication of more efficient anion-selective electrodes and the use of these compounds in liquid- liquid separations. The latter goal is the subcontract with Bruce Moyer at Oak Ridge National Laboratory. This first year the authors have focused on nitrates and phosphates. Considerable progress has been made in the basic areas of synthesis, solid state Structure, and molecular dynamics. Anion selective electrodes have also be made which show promising selectivities for oxoanions of interest. Below are described the major findings and significance in the categories of synthesis, structure and molecular dynamics, and electrode studies. Synthesis. The synthesis of polyaza macrocycles which are the focus of these studies is often tedious and time-consuming. A major breakthrough which the authors have made this year is to identify other polyaza macrocycles, which also bind the desired anions, but which are simpler to synthesize via a two step Schiff base/reduction process with high yields. This is truly significant since now the authors can obtain large quantities of the macrocycles and do multiple studies at once (crystallizations, thermodynamics, electrode, and eventually separations). Most of their studies to date have focused on monocyclic systems, but they are now beginning to examine bicyclic macrocycles, which can be synthesized by the same method starting with the tetraamine known as tren.'

  3. Photodestruction spectroscopy of carbon disulfide cluster anions (CS2)n-, n=1-4: Evidence for the dimer core structure and competitive reactions of the dimer anion

    Microsoft Academic Search

    Toshihiko Maeyama; Takanobu Oikawa; Tohru Tsumura; Naohiko Mikami

    1998-01-01

    Photodestruction spectra of carbon disulfide cluster anions, (CS2)n-, n=1-4, have been measured with a time-of-flight mass spectrometer coupled with an optical parametric oscillator. The spectra of all the cluster anions of n>=2 were found to exhibit a similar absorption band peaking at 1.6-1.8 eV, suggesting that a C2S4- core is involved in the cluster anions. Photon energy dependence of competition

  4. EFFECTS OF SELECTED ANTI-TUMOR-PROMOTING CHEMICALS ON METABOLIC COOPERATION BETWEEN CHINESE HAMSTER V79 CELLS

    EPA Science Inventory

    Many tumor-promoting chemicals inhibit gap junctional communication between cells. we investigated the possibility that antipromoting chemicals may act inversely and enhance gap junctional communication. he V79/metabolic cooperation assay is an in vitro test that measures pp junc...

  5. Attractor Metabolic Networks

    PubMed Central

    De la Fuente, Ildefonso M.; Cortes, Jesus M.; Pelta, David A.; Veguillas, Juan

    2013-01-01

    Background The experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a Systemic Metabolic Structure in the cell, characterized by a set of different enzymatic reactions always locked into active states (metabolic core) while the rest of the catalytic processes are only intermittently active. This global metabolic structure was verified for Escherichia coli, Helicobacter pylori and Saccharomyces cerevisiae, and it seems to be a common key feature to all cellular organisms. In concordance with these observations, the cell can be considered a complex metabolic network which mainly integrates a large ensemble of self-organized multienzymatic complexes interconnected by substrate fluxes and regulatory signals, where multiple autonomous oscillatory and quasi-stationary catalytic patterns simultaneously emerge. The network adjusts the internal metabolic activities to the external change by means of flux plasticity and structural plasticity. Methodology/Principal Findings In order to research the systemic mechanisms involved in the regulation of the cellular enzymatic activity we have studied different catalytic activities of a dissipative metabolic network under different external stimuli. The emergent biochemical data have been analysed using statistical mechanic tools, studying some macroscopic properties such as the global information and the energy of the system. We have also obtained an equivalent Hopfield network using a Boltzmann machine. Our main result shows that the dissipative metabolic network can behave as an attractor metabolic network. Conclusions/Significance We have found that the systemic enzymatic activities are governed by attractors with capacity to store functional metabolic patterns which can be correctly recovered from specific input stimuli. The network attractors regulate the catalytic patterns, modify the efficiency in the connection between the multienzymatic complexes, and stably retain these modifications. Here for the first time, we have introduced the general concept of attractor metabolic network, in which this dynamic behavior is observed. PMID:23554883

  6. Dual Role of the 1,2,3-Triazolium Ring as a Hydrogen-Bond Donor and Anion-? Receptor in Anion-Recognition Processes.

    PubMed

    Zapata, Fabiola; Gonzalez, Lidia; Caballero, Antonio; Alkorta, Ibón; Elguero, Jose; Molina, Pedro

    2015-06-26

    Several bis(triazolium)-based receptors have been synthesized as chemosensors for anion recognition. The central naphthalene core features two aryltriazolium side-arms. NMR experiments revealed differences between the binding modes of the two triazolium rings: one triazolium ring acts as a hydrogen-bond donor, the other as an anion-? receptor. Receptors 9(2+) ?2BF4 (-) (C6 H5 ), 11(2+) ?2BF4 (-) (4-NO2 ?C6 H4 ), and 13(2+) ?2BF(4-) (ferrocenyl) bind HP2 O7 (3-) anions in a mixed-binding mode that features a combination of hydrogen-bonding and anion-? interactions and results in strong binding. On the other hand, receptor 10(2+) ?2?BF4 (-) (4-CH3 O?C6 H4 ) only displays combined Csp2 ?H/anion-? interactions between the two arms of the receptors and the bound anion rather than triazolium (CH)(+) ???anion hydrogen bonding. All receptors undergo a downfield shift of the triazolium protons, as well as the inner naphthalene protons, in the presence of H2 PO4 (-) anions. That suggests that only hydrogen-bonding interactions exist between the binding site and the bound anion, and involve a combination of cationic (triazolium) and neutral (naphthalene) C?H donor interactions. Theoretical calculations relate the electronic structure of the substituent on the aromatic group with the interaction energies and provide a minimum-energy conformation for all the complexes that explains their measured properties. PMID:26031665

  7. Mutual influence between anion-? and pnicogen bond interactions: the enhancement of P?N and P?O interactions by an anion-? bond.

    PubMed

    Esrafili, Mehdi D; Mohammadian-Sabet, Fariba; Solimannejad, Mohammad

    2015-04-01

    In this work, the interplay between anion-? and pnicogen bond interactions is investigated by ab initio calculations. Cooperative effects are observed in the studied complexes in which anion-? and pnicogen bond interactions coexist. These effects are analyzed in detail in terms of the energetic, geometric, charge-transfer and electron density properties of the complexes. The cooperative energy ranges from -1.8 to -4.1kcalmol(-1). The effect of an anion-? bond on a pnicogen bond is more pronounced than that of a pnicogen bond on an anion-? bond. The enhancing mechanism is analyzed in views with the charge-transfer, electrostatic potential and electron density analysis. PMID:25698102

  8. Novel Fragmentation Pathways of Anionic Adducts of Steroids Formed by Electrospray Anion Attachment Involving Regioselective Attachment, Regiospecific Decompositions, Charge-Induced Pathways, and Ion-Dipole Complex Intermediates

    NASA Astrophysics Data System (ADS)

    Rannulu, Nalaka S.; Cole, Richard B.

    2012-09-01

    The analysis of several bifunctional neutral steroids, 5-?-pregnane diol (5-?-pregnane-3?-20?diol), estradiol (3,17?-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3?-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3?-ol-20-one), and pregnenolone acetate (5-pregnen-3?-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion]- adducts of these steroids revealed that fluoride adduct [M + F]- precursors first lose HF to produce [M - H]- and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d4-pregnenolone, are also discussed.

  9. Maxi-anion channel as a candidate pathway for osmosensitive ATP release from mouse astrocytes in primary culture.

    PubMed

    Liu, Hong-Tao; Toychiev, Abduqodir H; Takahashi, Nobuyuki; Sabirov, Ravshan Z; Okada, Yasunobu

    2008-05-01

    In the present study, we aimed to evaluate the pathways contributing to ATP release from mouse astrocytes during hypoosmotic stress. We first examined the expression of mRNAs for proteins constituting possible ATP-releasing pathways that have been suggested over the past several years. In RT-PCR analysis using both control and osmotically swollen astrocytes, amplification of cDNA fragments of expected size was seen for connexins (Cx32, Cx37, Cx43), pannexin 1 (Px1), the P2X7 receptor, MRP1 and MDR1, but not CFTR. Inhibitors of exocytotic vesicular release, gap junction hemi-channels, CFTR, MRP1, MDR1, the P2X7 receptor, and volume-sensitive outwardly rectifying chloride channels had no significant effects on the massive ATP release from astrocytes. In contrast, the hypotonicity-induced ATP release from astrocytes was most effectively inhibited by gadolinium (50 muM), an inhibitor of the maxi-anion channel, which has recently been shown to serve as a pathway for ATP release from several other cell types. Thus, we propose that the maxi-anion channel constitutes a major pathway for swelling-induced ATP release from cultured mouse astrocytes as well. PMID:18414449

  10. Mitochondrial 2-hydroxyglutarate metabolism.

    PubMed

    Engqvist, Martin K M; Eßer, Christian; Maier, Alexander; Lercher, Martin J; Maurino, Veronica G

    2014-11-01

    2-Hydroxyglutarate (2-HG) is a five-carbon dicarboxylic acid with a hydroxyl group at the alpha position, which forms a stereocenter in this molecule. Although the existence of mitochondrial D- and L-2HG metabolisms has long been known in different eukaryotes, the biosynthetic pathways, especially in plants, have not been completely elucidated. While D-2HG is involved in intermediary metabolism, L-2HG may not have a cellular function but it needs to be recycled through a metabolic repair reaction. Independent of their metabolic origin, D- and L-2HG are oxidized in plant mitochondria to 2-ketoglutarate through the action of two stereospecific enzymes, D- and L-2-hydroxyacid dehydrogenases. While plants are to a large extent unaffected by high cellular concentrations of D-2HG, deficiencies in the metabolism of D- and L-2HG result in fatal disorders in humans. We present current data gathered on plant D- and L-2HG metabolisms and relate it to existing knowledge on 2HG metabolism in other organisms. We focus on the metabolic origin of these compounds, the mitochondrial catabolic steps catalyzed by the stereospecific dehydrogenases, and phylogenetic relationships between different studied 2-hydroxyacid dehydrogenases. PMID:24561575

  11. Epigenetics and metabolism.

    PubMed

    Keating, Samuel T; El-Osta, Assam

    2015-02-13

    The molecular signatures of epigenetic regulation and chromatin architectures are fundamental to genetically determined biological processes. Covalent and post-translational chemical modification of the chromatin template can sensitize the genome to changing environmental conditions to establish diverse functional states. Recent interest and research focus surrounds the direct connections between metabolism and chromatin dynamics, which now represents an important conceptual challenge to explain many aspects of metabolic dysfunction. Several components of the epigenetic machinery require intermediates of cellular metabolism for enzymatic function. Furthermore, changes to intracellular metabolism can alter the expression of specific histone methyltransferases and acetyltransferases conferring widespread variations in epigenetic modification patterns. Specific epigenetic influences of dietary glucose and lipid consumption, as well as undernutrition, are observed across numerous organs and pathways associated with metabolism. Studies have started to define the chromatin-dependent mechanisms underlying persistent and pathophysiological changes induced by altered metabolism. Importantly, numerous recent studies demonstrate that gene regulation underlying phenotypic determinants of adult metabolic health is influenced by maternal and early postnatal diet. These emerging concepts open new perspectives to combat the rising global epidemic of metabolic disorders. PMID:25677519

  12. Metabolic rate measurement system

    NASA Technical Reports Server (NTRS)

    Koester, K.; Crosier, W.

    1980-01-01

    The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus.

  13. Oncogenic alterations of metabolism

    Microsoft Academic Search

    Chi V. Dang; Gregg L. Semenza

    1999-01-01

    Over seven decades ago, classical biochemical studies showed that tumors have altered metabolic profiles and display high rates of glucose uptake and glycolysis. Although these metabolic changes are not the fundamental defects that cause cancer, they might confer a common advantage on many different types of cancers, which allows the cells to survive and invade. Recent molecular studies have revealed

  14. The metabolic syndrome

    Microsoft Academic Search

    Robert H Eckel; Scott M Grundy; Paul Z Zimmet

    2005-01-01

    This constellation of metabolic disturbances, all risk factors for cardiovascular disease, was first described in the 1920s by Kylin, a Swedish physician, as the clustering of hypertension, hyperglycaemia, and gout. 2 Later, in 1947, Vague drew attention to upper body adiposity (android or male-type obesity) as the obesity phenotype that was commonly associated with metabolic abnormalities associated with type 2

  15. DIABETES, OBESITY AND METABOLISM INSTITUTE

    E-print Network

    Engman, David M.

    DIABETES, OBESITY AND METABOLISM INSTITUTE AT NORTHWESTERN MEDICINE THE INSTITUTES AT NORTHWESTERN MEDICINE #12;THE INSTITUTES AT NORTHWESTERN MEDICINE DIABETES, OBESITY AND METABOLISM INSTITUTE AT NORTHWESTERN MEDICINE "As we launch the Diabetes, Obesity and Metabolism Institute at Northwestern Medicine, I

  16. [Dynamics of ultrastructure changes in sheet plate fiber flax with braking transport assimilate by nitrate-anion].

    PubMed

    Abdrakhimov, F A; Batasheva, S N; Bakirova, G G; Chikov, V I

    2008-01-01

    Changes in leaf mesophyll cell ultrastructure under nitrate feeding into the apoplast of common flax (Linum usitatissimum L.) in the form of 50 mM KNO3 solution were studied. In 30 min after the beginning of nitrate feeding through the transpiration water stream, swelling of mitochondrial and microbodies, clarification of their matrices, and curling of dictyosome discs into annular structures were observed. These events characterized symplastic domain formed by mesophyll, bundle sheath and phloem parenchyma cells, and were not found in companion cell-sieve element complex. Simultaneously, formation of large central vacuoles in companion cells was noted. Restoration of organelle structures in assimilating cells and phloem parenchyma in 1-2 h after treatment was accompanied by enhancement of morphological changes in phloem elements and companion cells and signs of plasmolysis in the mesophyll cells. It was supposed that the two-phase character of changes in leaf organelle ultrastructure and photosynthesis might reflect duality of leaf cell response to nitrate ion. The rapid alterations of the structure can be coupled with direct influence of the anion on cell metabolism and(or) with signal-regulatory functions of oxidized nitrogen forms, while the slower ones reflect the result of suppression of photoassimilate export from leaves by the anion. PMID:18822790

  17. Uranyl nitrate-exposed rat alveolar macrophages cell death: influence of superoxide anion and TNF ? mediators.

    PubMed

    Orona, N S; Tasat, D R

    2012-06-15

    Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5-200 ?M). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO? 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO?. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O??). At high doses it provokes the secretion of TNF? and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O?? may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O?? may be blocked, prevailing damage to DNA by the TNF? route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium-related diseases. PMID:22561334

  18. Metabolic Engineering VII Conference

    SciTech Connect

    Kevin Korpics

    2012-12-04

    The aims of this Metabolic Engineering conference are to provide a forum for academic and industrial researchers in the field; to bring together the different scientific disciplines that contribute to the design, analysis and optimization of metabolic pathways; and to explore the role of Metabolic Engineering in the areas of health and sustainability. Presentations, both written and oral, panel discussions, and workshops will focus on both applications and techniques used for pathway engineering. Various applications including bioenergy, industrial chemicals and materials, drug targets, health, agriculture, and nutrition will be discussed. Workshops focused on technology development for mathematical and experimental techniques important for metabolic engineering applications will be held for more in depth discussion. This 2008 meeting will celebrate our conference tradition of high quality and relevance to both industrial and academic participants, with topics ranging from the frontiers of fundamental science to the practical aspects of metabolic engineering.

  19. Metabolic Syndrome and Cancer

    PubMed Central

    Pothiwala, Pooja; Jain, Sushil K.

    2009-01-01

    Abstract Since its first description by Reavan in 1988, accepted criteria for clinical identification of the components of metabolic syndrome have been promulgated by the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) and the World Health Organization (WHO) as well as the International Diabetes Federation (IDF), and the American Association of Clinical Endocrinologists (AACE). Insulin resistance is a common metabolic abnormality underlying type 2 diabetes mellitus and is also an independent risk factor for cardiovascular disease. Although ATP III identified cardiovascular disease (CVD) as the primary clinical outcome of the metabolic syndrome, we now have evidence that metabolic syndrome is associated with type 2 diabetes mellitus, polycystic ovarian disease, nonalcoholic fatty liver disease, and possibly some cancers. This review summarizes evidence in support of the relationship between metabolic syndrome and various cancers and possible underlying mechanisms and therapeutic interventions. PMID:19284314

  20. Metabolism of halophilic archaea

    PubMed Central

    Falb, Michaela; Müller, Kerstin; Königsmaier, Lisa; Oberwinkler, Tanja; Horn, Patrick; von Gronau, Susanne; Gonzalez, Orland; Pfeiffer, Friedhelm; Bornberg-Bauer, Erich

    2008-01-01

    In spite of their common hypersaline environment, halophilic archaea are surprisingly different in their nutritional demands and metabolic pathways. The metabolic diversity of halophilic archaea was investigated at the genomic level through systematic metabolic reconstruction and comparative analysis of four completely sequenced species: Halobacterium salinarum, Haloarcula marismortui, Haloquadratum walsbyi, and the haloalkaliphile Natronomonas pharaonis. The comparative study reveals different sets of enzyme genes amongst halophilic archaea, e.g. in glycerol degradation, pentose metabolism, and folate synthesis. The carefully assessed metabolic data represent a reliable resource for future system biology approaches as it also links to current experimental data on (halo)archaea from the literature. Electronic supplementary material The online version of this article (doi:10.1007/s00792-008-0138-x) contains supplementary material, which is available to authorized users. PMID:18278431

  1. Emplacement Gantry Gap Analysis Study

    SciTech Connect

    R. Thornley

    2005-05-27

    To date, the project has established important to safety (ITS) performance requirements for structures, systems, and components (SSCs) based on the identification and categorization of event sequences that may result in a radiological release. These performance requirements are defined within the ''Nuclear Safety Design Bases for License Application'' (NSDB) (BSC 2005 [DIRS 171512], Table A-11). Further, SSCs credited with performing safety functions are classified as ITS. In turn, assurance that these SSCs will perform as required is sought through the use of consensus codes and standards. This gap analysis is based on the design completed for license application only. Accordingly, identification of ITS SSCs beyond those defined within the NSDB are based on designs that may be subject to further development during detail design. Furthermore, several design alternatives may still be under consideration to satisfy certain safety functions, and final selection will not be determined until further design development has occurred. Therefore, for completeness, alternative designs currently under consideration will be discussed throughout this study. This gap analysis will evaluate each code and standard identified within the ''Emplacement Gantry ITS Standards Identification Study'' (BSC 2005 [DIRS 173586]) to ensure each ITS performance requirement is fully satisfied. When a performance requirement is not fully satisfied, a gap is highlighted. This study will identify requirements to supplement or augment the code or standard to meet performance requirements. Further, this gap analysis will identify nonstandard areas of the design that will be subject to a design development plan. Nonstandard components and nonstandard design configurations are defined as areas of the design that do not follow standard industry practices or codes and standards. Whereby, assurance that an SSC will perform as required may not be readily sought though the use of consensus standards. This gap analysis is prepared by the Emplacement and Retrieval (E&R) project team and is intended for the sole use of the Engineering department in work regarding the emplacement gantry. Yucca Mountain Project personnel from the E&R project team should be consulted before use of this gap analysis for purposes other than those stated herein or by individuals other than authorized by the Engineering department.

  2. Process for separating and recovering an anionic dye from an aqueous solution

    SciTech Connect

    Rogers, R.; Horwitz, E.P.; Bond, A.H.

    1998-01-13

    A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution. 7 figs.

  3. Tunable cytotoxicity of rhodamine 6G via anion variations.

    PubMed

    Magut, Paul K S; Das, Susmita; Fernand, Vivian E; Losso, Jack; McDonough, Karen; Naylor, Brittni M; Aggarwal, Sita; Warner, Isiah M

    2013-10-23

    Chemotherapeutic agents with low toxicity to normal tissues are a major goal in cancer research. In this regard, the therapeutic activities of cationic dyes, such as rhodamine 6G, toward cancer cells have been studied for decades with observed toxicities toward normal and cancer cells. Herein, we report rhodamine 6G-based organic salts with varying counteranions that are stable under physiological conditions, display excellent fluorescence photostability, and more importantly have tunable chemotherapeutic properties. Our in vitro studies indicate that the hydrophobic compounds of this series allow production of nanoparticles which are nontoxic to normal cells and toxic to cancer cells. Furthermore, the anions, in combination with cations such as sodium, were observed to be nontoxic to both normal and cancer cells. To the best of our knowledge, this is the first demonstration that both the cation and anion play an extremely important and cooperative role in the antitumor properties of these compounds. PMID:24059469

  4. [Modification of MSWI fly ash by using anionic chelating surfactant].

    PubMed

    Zhang, Hou-Hu; Qian, Guang-Ren; Zhang, Xiao-Lan

    2005-07-01

    This paper aims at the reutilization and stabilization of municipal solid waste incineration (MSWI) fly ash to produce a high value added product. The effects of anionic chelating surfactants on the surface modification and fixing capacity of MSWI fly ash were primarily explored. Based on the indexes of active ratio and analysis of IR-spectrometer, the active ratio of ACS1 modified fly ash can be found higher than 95% under the condition of surfactant dosage at 7.0mL/100g fly ash, modification time at 15min and temperature at 75 degrees C . Moreover, Anionic chelating surfactant shows a strong fixing capacity for heavy metals by the United States Environmental Protection Agency's Toxicity Characteristic Leaching Procedure (TCLP). PMID:16212196

  5. Tryptophan-based chromophore in fluorescent proteins can be anionic

    PubMed Central

    Sarkisyan, Karen S.; Yampolsky, Ilia V.; Solntsev, Kyril M.; Lukyanov, Sergey A.; Lukyanov, Konstantin A.; Mishin, Alexander S.

    2012-01-01

    Cyan fluorescent proteins (CFP) with tryptophan66-based chromophore are widely used for live cell imaging. In contrast to green and red fluorescent proteins, no charged states of the CFP chromophore have been described. Here, we studied synthetic CFP chromophore and found that its indole group can be deprotonated rather easily (pKa 12.4).We then reproduced this effect in the CFP mCerulean by placing basic amino acids in the chromophore microenvironment. As a result, green-emitting variant with an anionic chromophore and key substitution Val61Lys was obtained. This is the first evidence strongly suggesting that tryptophan-based chromophores in fluorescent proteins can exist in an anionic charged state. Switching between protonated and deprotonated Trp66 in fluorescent proteins represents a new unexplored way to control their spectral properties. PMID:22934131

  6. Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth

    NASA Astrophysics Data System (ADS)

    Foster, Jonathan A.; Piepenbrock, Marc-Oliver M.; Lloyd, Gareth O.; Clarke, Nigel; Howard, Judith A. K.; Steed, Jonathan W.

    2010-12-01

    We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

  7. Local Impermeant Anions Establish the Neuronal Chloride Concentration

    PubMed Central

    Glykys, J; Dzhala, V; Egawa, K; Balena, T; Saponjian, Y; Kuchibhotla, KV; Bacskai, BJ; Kahle, KT; Zeuthen, T; Staley, KJ

    2014-01-01

    Neuronal chloride concentration [Cl?]i is an important determinant of GABAA receptor (GABAAR)-mediated inhibition and cytoplasmic volume regulation. Equilibrative cation-chloride cotransporters (CCC) move Cl? across the membrane, but accumulating evidence suggests factors other than the bulk concentrations of transported ions determine [Cl?]i. Measurement of [Cl?]i in murine brain slice preparations expressing the transgenic fluorophore Clomeleon demonstrated that cytoplasmic impermeant anions ([A]i) and polyanionic extracellular matrix glycoproteins ([A]o) constrain the local [Cl?]. CCC inhibition had modest effects on [Cl?]i and neuronal volume, but substantial changes were produced by alterations of the balance between [A]i and [A]o. Therefore, CCC are important elements of Cl? homeostasis, but local impermeant anions determine the homeostatic set-point for [Cl?], and hence, neuronal volume and the polarity of local GABAAR signaling. PMID:24503855

  8. Membrane characterization of anion-selective CHEMFETs by impedance spectroscopy.

    PubMed

    Antonisse, M M; Snellink-Ruël, B H; Lugtenberg, R J; Engbersen, J F; van den Berg, A; Reinhoudt, D N

    2000-01-15

    Impedance spectroscopy can be used to determine the influence of several membrane parameters on the membrane resistance of anion selective CHEMFETs. The concentration of the ammonium sites in the membrane, the anion-receptor complex stoichiometry, and the polarity of the membrane matrix are of particular importance. In general the resistance of polysiloxane membranes is higher than that of PVC membranes. However, in polysiloxane membranes the membrane polarity can be influenced by the type or concentration of polar substituents on the polysiloxane chain. Polysiloxane ion-exchange membranes with 25 mol% of polar sulfone substituents exhibit the same conductance as NPOE plasticized PVC membranes. Remarkably, the membrane resistance of cation-selective polysiloxane membranes is much lower and is much less dependent on the substituents. PMID:10658329

  9. Virus capture using anionic polymer-coated magnetic beads (review).

    PubMed

    Sakudo, Akikazu; Onodera, Takashi

    2012-07-01

    The recent incidence of emerging and re-emerging viruses is a serious health concern worldwide. The development of transportation systems, such as air travel, has increased the risk of a global pandemic caused by emerging viruses. Agents causing novel infections are often zoonotic, crossing from the natural host into the human population. Hence, comprehensive surveillance of virus-infected animals as well as humans is required. However, the number of virus particles in clinical and environmental samples is usually very low. Thus, a method to concentrate the virus is sometimes required in order to enable detection. We recently reported that magnetic beads coated with an anionic polymer, poly(methyl vinyl ether-maleic anhydride) can be used to facilitate the rapid and sensitive detection of viruses. In this review, we describe recent developments for concentrating viruses using anionic magnetic beads. PMID:22505019

  10. Bifunctional Crosslinking Agents Enhance Anion Exchange Membrane Efficacy for Vanadium Redox Flow Batteries.

    PubMed

    Wang, Wenpin; Xu, Min; Wang, Shubo; Xie, Xiaofeng; Lv, Yafei; Ramani, Vijay K

    2014-06-01

    A series of cross-linked fluorinated poly (aryl ether oxadiazole) membranes (FPAEOM) derivatized with imidazolium groups were prepared. Poly (N-vinylimidazole) (PVI) was used as the bifunctional cross-linking agent to: a) lower vanadium permeability, b) enhance dimensional stability, and c) concomitantly provide added ion exchange capacity in the resultant anion exchange membranes. At a molar ratio of PVI to FPAEOM of 1.5, the resultant membrane (FPAEOM-1.5 PVI) had an ion exchange capacity of 2.2 meq g-1, a vanadium permeability of 6.8×10-7 cm2 min-1, a water uptake of 68 wt.%, and an ionic conductivity of 22.0 mS cm-1, all at 25°C. Single cells prepared with the FPAEOM-1.5 PVI membrane exhibited a higher coulombic efficiency (> 92%) and energy efficiency (> 86%) after 40 test cycles in vanadium redox flow battery. The imidazolium cation showed high chemical stability in highly acidic and oxidizing vanadium solution as opposed to poor stability in alkaline solutions. Based on our DFT studies, this was attributed to the lower HOMO energy (-7.265 eV) of the HSO4- ion (compared to the OH- ion; -5.496 eV) and the larger HOMO-LUMO energy gap (6.394 eV) of dimethylimidazolium bisulfate ([DMIM] [HSO4]) as compared to [DMIM] [OH] (5.387 eV). PMID:24884171

  11. MICROMACHINED AMPEROMETRIC NITRATE SENSOR WITH AN ANION PERMEABLE MEMBRANE

    Microsoft Academic Search

    Dohyun Kim; Ira B. Goldberg; Jack W. Judy

    A nitrate-sensing system that consists of a micromachined sensor substrate, anion-permeable membrane, integrated microfluidic channels, and standard fluidic connectors has been designed, fabricated, assembled, and tested. Our microsensor was designed for in-situ monitoring of nitrate concentrations in ground water. A silver electrode was patterned for amperometric nitrate detection. An electrochemically oxidized silver electrode was used as a reference electrode. Microfluidic

  12. Photodissociation and photoinduced electron detachment in dinuclear metal carbonyl anions

    SciTech Connect

    Cooper, B.T.; Johnson, J.A.; Buckner, S.W. [Univ. of Arizona, Tucson, AZ (United States)

    1995-10-11

    The results of visible and near-infrared photochemistry studies of M{sub 2}(CO){sub n}{sup {minus}} compounds (M = Cr, Mn, Fe, Co, 4 {le} n {le} 9) are presented. The authors show that {open_quotes}neutral metal atom loss{close_quotes} from representative anions in this class occurs by electron detachment followed by loss of a neutral metal carbonyl. It is further shown that the electron detachment process can be vibrationally driven.

  13. Combined effects of anions on arsenic removal by iron hydroxides

    Microsoft Academic Search

    Xiaoguang Meng; George P. Korfiatis; Sunbaek Bang; Ki Woong Bang

    2002-01-01

    Batch experiments were conducted to investigate the combined effects of phosphate, silicate, and bicarbonate on the removal of arsenic from Bangladesh groundwater (BGW) and simulated groundwater by iron hydroxides. The apparent adsorption constants indicated that the affinity of the anions for iron hydroxide sites decreased in the following order arsenate>phosphate>arsenite>silicate>bicarbonate. Phosphate, silicate, and bicarbonate decreased the removal of As(III) even

  14. The sorption of quercetin by high-basicity anion exchangers

    NASA Astrophysics Data System (ADS)

    Udalova, N. A.; Karpov, S. I.; Selemenev, V. F.; Sharmar, I. A.

    2009-06-01

    The sorption of quercetin on anionites with various porosities in the OH- and Cl- forms was studied under static conditions. The equilibrium (distribution coefficients K p) and kinetic (effective diffusion coefficients D eff) parameters of quercetin sorption on AV-17-2P and AV-17-6M anionites in the Cl- and OH- forms were calculated. The mechanism of quercetin interactions with the anion exchangers was studied by electron microscopy and IR spectroscopy.

  15. Kinetics of precipitation of surfactants. II. Anionic surfactant mixtures

    Microsoft Academic Search

    Cheryl H. Rodriguez; John F. Scamehorn

    2001-01-01

    Precipitation kinetics were measured for calcium-induced precipitation of mixtures of two anionic surfactants. The overall\\u000a time required for precipitation to occur increased dramatically in specific ranges of compositions for the surfactant mixtures\\u000a when compared to single components. Adsorption of the nonprecipitating surfactant onto the precipitate surface was shown to\\u000a be responsible for this remarkable synergism. The higher the supersaturation of

  16. Colloidal flocculation of micellar solutions of anionic surfactants

    Microsoft Academic Search

    P. Paton; F. I. Talens-Alesson

    1998-01-01

    Micellar solutions of anionic surfactants usually precipitate in the presence of cations, following a mechanism by which initially\\u000a cations bind themselves to the micellar surface until saturation is achieved. At higher cation concentrations, unbound cations\\u000a precipitate with surfactant monomers. In a few cases cations, and especially Al3+, cause surfactant micelles to flocculate. These flocs have properties as adsorbents of acidic

  17. New anionic alkylaryl surfactants based on olefin sulfonic acids

    Microsoft Academic Search

    Paul D. Berger; Christie H. Lee

    2002-01-01

    A new family of anionic surfactants has been produced by the simultaneous sulfonation and alkylation of aromatic compounds\\u000a using olefin sulfonic acid(s). This new process does not require the conventional alkylation unit and the strong acid catalysts,\\u000a such as AlCl3 or HF, normally used for alkylation. The resulting alkylaryl sulfonic acids differ from existing prodeucts by having the\\u000a sulfonate group

  18. Development of anion-selective membranes. [for energy storage

    NASA Technical Reports Server (NTRS)

    Lacey, R. E.; Cowsar, D. R.

    1975-01-01

    Methods were studied of preparing anion-exchange membranes that would have low resistance, high selectivity, and physical and chemical stability when used in acidic media in a redox energy storage system. Of the twelve systems selected for study, only the system that was based on crosslinked poly-4-vinylpyridinium chloride produced physically strong membranes when equilibrated in l M HCl. The resistivity of the best membrane was 12 ohm-cm, and the transference number for chloride ions was 0.81.

  19. ADSORPTION OF ANIONIC SURFACTANT BY A LOW-COST ADSORBENT

    Microsoft Academic Search

    Paritosh Das Purakayastha; Anjali Pal; Manas Bandyopadhyay

    2002-01-01

    This study was undertaken to evaluate the efficiency of rubber granule, a low-cost adsorbent for the removal of sodium dodecyl sulfate (SDS) that is a representative member of anionic surfactant (AS). In the batch experiments conducted at an initial concentration range of 2–6 mg\\/l, it was found that the rubber granules selected could remove SDS from water up to 90%. Kinetic

  20. A method for production of new anion exchangers

    NASA Astrophysics Data System (ADS)

    Behrendt, G.; Hunger, H. D.

    1991-12-01

    The invention relates to a method for the production of new anion exchangers that can be used in molecular biology, genetic engineering, biotechnology, and phytopathology. According to the invention, halogen-containing polyurethanes are reacted with one or more tertiary amines. By the method, polyurethane shapes with positive surface charges are produced from preformed shapes, with preservation of the form and properties thereof. The products have thermally stable bonds with biomolecules together with high binding capacity.

  1. Anion receptor compounds for non-aqueous electrolytes

    DOEpatents

    Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

    2000-09-19

    A new family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI.sup.+ ion in alkali metal batteries.

  2. Identifying Branched Metabolic Pathways by Merging Linear Metabolic Pathways

    NASA Astrophysics Data System (ADS)

    Heath, Allison P.; Bennett, George N.; Kavraki, Lydia E.

    This paper presents a graph-based algorithm for identifying complex metabolic pathways in multi-genome scale metabolic data. These complex pathways are called branched pathways because they can arrive at a target compound through combinations of pathways that split compounds into smaller ones, work in parallel with many compounds, and join compounds into larger ones. While most previous work has focused on identifying linear metabolic pathways, branched metabolic pathways predominate in metabolic networks. Automatic identification of branched pathways has a number of important applications in areas that require deeper understanding of metabolism, such as metabolic engineering and drug target identification. Our algorithm utilizes explicit atom tracking to identify linear metabolic pathways and then merges them together into branched metabolic pathways. We provide results on two well-characterized metabolic pathways that demonstrate that this new merging approach can efficiently find biologically relevant branched metabolic pathways with complex structures.

  3. Electronic gap sensor and method

    DOEpatents

    Williams, Robert S. (Fairfield, OH); King, Edward L. (Trenton, OH); Campbell, Steven L. (Middletown, OH)

    1991-01-01

    An apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces.

  4. Electronic gap sensor and method

    DOEpatents

    Williams, R.S.; King, E.L.; Campbell, S.L.

    1991-08-06

    Disclosed are an apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. 5 figures.

  5. Modification of MSW fly ash by anionic chelating surfactant.

    PubMed

    Qian, Guangren; Zhang, Houhu; Zhang, Xiaolan; Chui, Peng-Cheong

    2005-05-20

    This paper elucidates a study on the re-utilization and stabilization of municipal solid waste (MSW) fly ash in producing a high value-added product by the surface modification of anionic chelating surfactant on the particles. After modification, MSW fly ash can be expected using as a filler of ultra-high molecular weight polymers. The effects of anionic chelating surfactants (ACS) on surface modification of MSW fly ash and fixing capacity for heavy metals were explored. Meanwhile, the interaction mechanism between surfactants and MSW fly ash was suggested. The results showed that anionic chelating surfactants can be used to effectively modify MSW fly ash particles and achieve a high active ratio. At the same time, they also exhibited a strong fixing capacity for heavy metals. Of the two modified MSW fly ash, ED3A-modified MSW fly ash has a much higher active ratio than MAP-modified MSW fly ash at over 95%, although its fixing capacity for heavy metals was a shade lower than MAP-modified MSW fly ash. PMID:15885429

  6. Didehydro radical anions from ketones via O- chemical ionization

    NASA Astrophysics Data System (ADS)

    Lin, Mingxiang; Grabowski, Joseph J.

    2004-10-01

    Gas-phase ion-molecule reactions of the atomic oxygen radical anion, O- with selected ketones are investigated to explore a strategy to 1,3-distonic radical anions. These O- chemical ionization reactions, especially that of cyclopentanone, are examined in detail under the well-defined thermal energy conditions uniquely available by using the flowing afterglow technique. To further understanding of the reaction mechanism, a series of related ketones (acetone, 3-pentanone, 2-butanone, 2,4-dimethyl-3-pentanone, cyclohexanone) are also examined in detail. Rate constants for each ketone reaction are measured and products from each ketone examined are identified and their branching ratios are reported. Based on these results, a detailed reaction scheme for each ketone reaction studied is proposed. The individual reaction schemes are summarized in a composite O-/ketone reaction scheme and the specific reaction pathways are discussed. A strategy is developed to differentiate 1,1- and 1,3-H2+-abstraction products and to establish the absolute yields of 1,3-distonic radical anions from appropriate ketones.

  7. Coumarin benzothiazole derivatives as chemosensors for cyanide anions

    NASA Astrophysics Data System (ADS)

    Wang, Kangnan; Liu, Zhiqiang; Guan, Ruifang; Cao, Duxia; Chen, Hongyu; Shan, Yanyan; Wu, Qianqian; Xu, Yongxiao

    2015-06-01

    Four coumarin benzothiazole derivatives, N-(benzo[d]thiazol-2-yl)-2-oxo-2H-chromene-3-carboxamide (1), (Z)-N-(3-methylbenzo[d]thiazol-2(3H)-ylidene)-2-oxo-2H-chromene-3-carboxamide (2), 7-(diethylamino)-N-(benzo[d]thiazol-2-yl)-2-oxo-2H-chromene-3-carboxamide (3) and (Z)-7-(diethylamino)-N-(3-methylbenzo[d]thiazol-2(3H)-ylidene)-2-oxo-2H-chromene-3-carboxamide) (4), have been synthesized. Their crystal structures, photophysical properties in acetonitrile and recognition properties for cyanide anions have been investigated. All the compounds are generally planar, especially compound 1 exhibits perfect planarity with dihedral angle between benzothiazolyl group and coumarin group being only 3.63°. Coumarin benzothiazole compounds 1 and 3 can recognize cyanide anions by Michael addition reaction and compound 3 exhibits color change from yellow to colorless and green fluorescence was quenched completely, which can be observed by naked eye. Coumarin benzothiazolyliden compound 4 can recognize cyanide anions with fluorescence turn-on response based on the copper complex ensemble displacement mechanism.

  8. Collection of ambient air phenols using an anion exchange membrane

    SciTech Connect

    Nishioka, M.; Burkholder, H. [Battelle, Columbus, OH (United States); Reynolds, S.; Burdick, N. [South Carolina Dept. of Health and Environmental Control, Columbia, SC (United States); Pleil, J. [Environmental Protection Agency, Research Triangle Park, NC (United States)

    1994-12-31

    The authors have previously demonstrated the feasibility of collecting vapor phase ambient air phenols by reversible chemical reaction with a solid sorbent. The authors report here enhanced detection limits for ambient phenols using an anion exchange membrane that allows high collection efficiency at 10 L/min sampling rate. The membrane consists of 5 {micro}m particles of the anion exchange resin enmeshed in a Teflon microfibril matrix. This membrane is similar to Empore membranes, with the addition of the anion exchange capacity. Sampling is accomplished using a 10.5 cm (diameter) membrane and a General Metal Works PS-1 sampler. A Teflon-coated glass fiber filter, spiked with deutered phenols, and placed ahead of the membrane, is used to deliver these surrogate recovery standards to the membrane during the sampling. Following sampling, membranes are shaken gently in an acidified mixture of methanol and dichloromethane. The extract is derivatized with BSTFA and analyzed using either GC/FID or EI GC/MS. Analytical methodology allows detection at the 0.02 ppbv level for 12 hrs of sampling ({approximately} 0.1 {micro}g/m{sup 3}).

  9. Structure and electronic spectra of the C C6- anion

    NASA Astrophysics Data System (ADS)

    Hammoutene, D.; Hochlaf, M.; Senent, M. L.

    2012-08-01

    Ab initio calculations are employed for determining structures, spectroscopic parameters and transitions to the excited electronic states of the astrophysical relevant C C6- anion, which is a potential intermediate of chemical processes involving carbon chains and polycyclic aromatic hydrocarbons. Calculations confirm the prominent stability of linear carbon chain anions which guarantees their formation. The lowest doublet potential energy surface of C? displays six isomers, whereas in the lowest quartet potential energy surface, a unique minimum energy geometry is found. The most stable form is the linear anion l-C? (X2?u) followed by the c-C?(X2A1')at 9291 cm-1 above in energy, which presents a distorted D3h structure. The other isomers are also located at more than 9000 cm-1 above l-C? (X2?u). For each isomer, a set of spectroscopic parameters including their equilibrium structures, rotational constants at equilibrium, harmonic wavenumbers, dipole moments and electron affinities are predicted. For linear C?, eight electronic states lying below the electron detachment threshold, are computed. Four doublet electronic states, which play important roles in the C? reactivity, lie below 2 eV. Spin-orbit constants for the upper electronic states of l-C? are predicted.

  10. Anion-Dependent Stimulation of CYP3A4 Monooxygenase.

    PubMed

    Sevrioukova, Irina F; Poulos, Thomas L

    2015-07-01

    We co-crystallized human cytochrome P450 3A4 (CYP3A4) with progesterone (PRG) under two different conditions, but the resulting complexes contained only one PRG molecule bound to the previously identified peripheral site. A novel feature in one of our structures is a citrate ion, originating from the crystallization solution. The citrate-binding site is located in an area where the N-terminus splits from the protein core and, thus, is suitable for the interaction with the anionic phospholipids of the microsomal membrane. We investigated how citrate affects the function of a soluble CYP3A4 monooxygenase system consisting of equimolar amounts of CYP3A4 and cytochrome P450 reductase (CPR). Citrate was found to affect the properties of both redox partners and stimulated their catalytic activities in a concentration-dependent manner via a complex mechanism. CYP3A4-substrate binding, reduction of CPR with NADPH, and interflavin and interprotein electron transfer were identified as citrate-sensitive steps. Comparative analysis of various negatively charged organic compounds indicated that, in addition to alterations caused by changes in ionic strength, anions modulate the properties of CYP3A4 and CPR through specific anion-protein interactions. Our results help to better understand previous observations and provide new mechanistic insights into CYP3A4 function. PMID:26066995

  11. Depth profile of halide anions under highly charged biological membrane

    NASA Astrophysics Data System (ADS)

    Sung, Woongmo; Wang, Wenjie; Lee, Jonggwan; Vaknin, David; Kim, Doseok

    2015-03-01

    Halide ion (Cl- and I-) distribution under a cationic Langmuir monolayer consisting of 1,2-dipalmitoyl-3 trimethylammonium-propane (DPTAP) molecules was investigated by vibrational sum-frequency generation (VSFG) and X-ray spectroscopy. From VSFG spectra, it was observed that large halide anions (I-) screen surface charge more efficiently so that interfacial water alignment becomes more randomized. On the other hand, number density of ions directly measured by X-ray fluorescence spectroscopy at grazing incidence angle reveals that the ion densities within 6 ~ 8 nm are the same for both I- and Cl-. Since the observed ion densities in both cases are almost equal to the charge density of the DPTAP monolayer, we propose that larger halide anions are attracted closer to the surface making direct binding with the charged headgroups of the molecules in the monolayer, accomplishing charge neutrality in short distance. This direct adsorption of anions also disturbs the monolayer structure both in terms of the conformation of alkyl chains and the vertical configuration of the monolayer, with iodine having the stronger effect. Our study shows that the length scale that ions neutralize a charged interface varies significantly and specifically even between monovalent ions.

  12. Intervalence near-IR spectra of delocalized dinitroaromatic radical anions.

    PubMed

    Nelsen, Stephen F; Konradsson, Asgeir E; Weaver, Michael N; Telo, João P

    2003-10-15

    The Class III (delocalized) intervalence radical anions of 1,4-dinitrobenzene, 2,6-dinitronaphthalene, 2,6-dinitroanthracene, 9,9-dimethyl-2,7-dinitrofluorene, 4,4'-dinitrobiphenyl, and 1,5-dinitronaphthalene show charge-transfer bands in their near-IR spectra. The dinitroaromatic radical anions have comparable but slightly larger electronic interactions (H(ab) values) through the same aromatic bridges as do the corresponding dianisylamino-substituted radical cations. H(ab) values range from 5410 cm(-)(1) (1,4- dinitrobenzene) to 3400 cm(-)(1) (9,9-dimethyl-2,7-dinitrofluorene), decreasing as the number of bonds between the nitro groups increases, except for the 1,5-dinitronaphthalene radical-anion, which has a coupling similar to that of 9,9-dimethyl-2,7-dinitrofluorene. All charge-transfer bands show vibrational fine structure. The vertical excitation energies (lambda(v)) were estimated from the vibrational components, obtained by simulation of the entire band. The large 2H(ab)/lambda(v) values confirm these radicals to be Class III delocalized mixed-valence species. Analysis using Cave and Newton's generalized Mulliken-Hush theory relating the transition dipole moment to the distance on the diabatic surfaces suggests that the electron-transfer distance on the diabatic surfaces, d(ab), is only 26-40% of the nitrogen-to-nitrogen distance, which implies that something may be wrong with our analysis. PMID:14531693

  13. New functions of an old protein: the eukaryotic porin or voltage dependent anion selective channel (VDAC).

    PubMed

    De Pinto, Vito; Messina, Angela; Accardi, Rosita; Aiello, Rita; Guarino, Francesca; Tomasello, Marianna Flora; Tommasino, Massimo; Tasco, Gianluca; Casadio, Rita; Benz, Roland; De Giorgi, Francesca; Ichas, François; Baker, Mark; Lawen, Alfons

    2003-03-01

    Mitochondrial porin or VDAC (Voltage Dependent Anion selective Channels) was identified for the first time in 1976, on the basis of the evolutionary similarity between the gram negative and mitochondrial outer membranes. Since this achievement VDAC has been extensively investigated: its functional features have been sharply defined upon reconstitution in artificial membranes and its sequence has been determined in many genomes. Unfortunately the tertiary structure has not yet been solved, mainly because it proved to be very difficult to get suitable crystals. Despite this established knowledge, in the last few years this protein has attracted renewed interest. There are two main reasons for this interest: the discovery, in most eukaryotes, of a family of genes encoding VDAC isoforms and the claims of VDAC involvement in the intrinsic pathway of apoptosis and in particular in the mechanism of cytochrome c release from mitochondria. We can affirm that nowadays the eukaryotic porin (or VDAC) is studied in a more general cellular contest, looking at the interactions and integration with other molecules, since VDAC is in a crucial position in the cell, forming the main interface between the mitochondrial and the cellular metabolisms. In this minireview we will briefly focus our attention onto the following topics: 1) recent advances about the structure of VDAC; 2) the VDAC-related multigene families; 3) the presence, targeting and function of VDAC in various cell membranes. PMID:12833633

  14. Structure of the voltage dependent anion channel: state of the art.

    PubMed

    De Pinto, Vito; Reina, Simona; Guarino, Francesca; Messina, Angela

    2008-06-01

    The eukaryotic porin or Voltage Dependent Anion-selective Channels (VDAC) is the protein forming the aqueous pore channel in the mitochondrial outer membrane. It can modulate the energy-dependent metabolism of the cell forming a diffusion barrier to ions, adenine-nucleotides and other metabolites and it is probably involved in the regulation of apoptotic-relevant events. For these reasons, VDAC co-responsibility in unphysiological events leading to important pathologies such as onset or sustainment of cancer has been envisaged very early. The knowledge of the VDAC atomic structure is thus a relevant step in the design of modern drugs acting upon the mitochondrial function and its related apoptotic balance. This goal, despite many efforts, has not been gained until now. Several predictive or descriptive techniques have been employed to obtain models or representations of the pore-structure. The results obtained are reported in this review. The emerging picture arising from these many results is coherent and sufficiently informative. From these efforts it appears that VDAC is functionally monomeric but can cluster in tight but regular groups; it is asymmetric with larger exposed domains on the cytosolic side of the outer mitochondrial membrane; the diameter of the pore is between 2.5-3.0 nm and it is apparently free from obstructions (in the open state); the channel wall is mainly formed by typical amphipathic beta-strands; mobile components (the N-terminal ?) can have functional relevance to the pore regulation. PMID:18668358

  15. The Arabidopsis voltage-dependent anion channel 2 is required for plant growth

    PubMed Central

    Tateda, Chika; Kusano, Tomonobu; Takahashi, Yoshihiro

    2012-01-01

    The voltage-dependent anion channels (VDACs), known as a major group of outer mitochondrial membrane proteins, are present in all eukaryotic species. In mammalian cells, they have been established as a key player in mitochondrial metabolism and apoptosis regulation. By contrast, little is known about the function of plant VDACs. Recently, we performed functional analysis of all VDAC gene members in Arabidopsis thaliana, and revealed that each AtVDAC member has a specialized function. Especially, in spite of similar subcellular localization and expression profiling of AtVDAC2 and AtVDAC4, both the T-DNA insertion knockout mutants of them, vdac2–2 and vdac4–2, showed severe growth retardation. These results suggest that AtVDAC2 and AtVDAC4 proteins clearly have distinct functions. Here, we introduced the AtVDAC2 gene into the vdac2–2 mutant, and demonstrated that the miniature phenotype of vdac2–2 plant is abolished by AtVDAC2 expression. PMID:22301963

  16. Myocardial heat shock gene expression in pigs is dependent on superoxide anion generated at reperfusion.

    PubMed

    Schoeniger, L O; Curtis, W; Esnaola, N F; Beck, S C; Gardner, T; Buchman, T G

    1994-01-01

    The heat shock response is a conserved response to cell injury. We sought to determine if ischemia alone versus events at reperfusion stimulated expression of the major heat shock protein (hsp-72) in a clinically relevant model of global myocardial ischemia in pigs. Pigs were placed on nonpulsatile cardiopulmonary bypass. Serial transmural cardiac biopsies were taken at baseline following 20 min of normothermic global ischemia (induced by crossclamping the aorta) and at 20, 40, and 60 min of reperfusion. Test animals received a bolus and subsequent aortic root infusion of superoxide dismutase (total 7,500 U/kg) beginning just prior to reperfusion. Hsp-72 mRNA abundance was estimated from Northern blots. We found that hsp-72 mRNA was not induced following 20 min of ischemia but accumulated to high levels within 20 min of reperfusion. Intravascular administration of superoxide dismutase at reperfusion eliminated hsp-72 mRNA induction. We conclude that in the postischemic myocardium, hsp-72 gene expression is dependent on superoxide anion generation at reperfusion. In this setting, hsp-72 gene expression may reflect a specific response to oxidative injury rather than a more general response to metabolic stress associated with ischemia. PMID:7743325

  17. Energy Gaps in Graphene Nanoribbons

    Microsoft Academic Search

    Young-Woo Son; Marvin L. Cohen; Steven G. Louie

    2006-01-01

    Based on a first-principles approach, we present scaling rules for the band\\u000agaps of graphene nanoribbons (GNRs) as a function of their widths. The GNRs\\u000aconsidered have either armchair or zigzag shaped edges on both sides with\\u000ahydrogen passivation. Both varieties of ribbons are shown to have band gaps.\\u000aThis differs from the results of simple tight-binding calculations or solutions

  18. Mason's theorem and syzygy gaps

    Microsoft Academic Search

    Paul Monsky

    2006-01-01

    From Mason's theorem on rational function fields (the progenitor of the abc-conjecture) we immediately derive upper bounds for “syzygy gaps” (Theorems 3, 8, 11, and Corollary 9). These in turn quickly give:(1)The author's conjecture Z(l), used in the study of Hilbert–Kunz series.(2)A lower bound for certain “F-pure thresholds.”(3)Han's explicit description of the 3-dimensional p-fractal attached to x, y and x+y.(4)Some

  19. 30 CFR 56.6603 - Air gap.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6603 Air gap. At least a 15-foot air gap shall be provided between the blasting circuit and the electric...

  20. 30 CFR 57.6603 - Air gap.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

  1. 30 CFR 57.6603 - Air gap.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

  2. 30 CFR 56.6603 - Air gap.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6603 Air gap. At least a 15-foot air gap shall be provided between the blasting circuit and the electric...

  3. 30 CFR 57.6603 - Air gap.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

  4. 30 CFR 57.6603 - Air gap.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6603 Air gap. At least a 15-foot air gap shall be provided between the...

  5. 30 CFR 56.6603 - Air gap.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6603 Air gap. At least a 15-foot air gap shall be provided between the blasting circuit and the electric...

  6. Direct Band Gap Wurtzite Gallium Phosphide Nanowires

    PubMed Central

    2013-01-01

    The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555–690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality. PMID:23464761

  7. Direct band gap wurtzite gallium phosphide nanowires.

    PubMed

    Assali, S; Zardo, I; Plissard, S; Kriegner, D; Verheijen, M A; Bauer, G; Meijerink, A; Belabbes, A; Bechstedt, F; Haverkort, J E M; Bakkers, E P A M

    2013-04-10

    The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555-690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality. PMID:23464761

  8. Molecular Structures and Energetics of the (ZrO?)n and (HfO?)n (n = 1-4) Clusters and Their Anions

    SciTech Connect

    Li, Shenggang; Dixon, David A.

    2010-02-25

    The group IVB transition-metal dioxide clusters and their anions, (MO?)n and (MO?)n? (M = Zr, Hf; n = 1-4), are studied with coupled cluster (CCSD(T)) theory and density functional theory (DFT). Similar to the results for M = Ti, these oxide clusters have a number of low-lying isomeric structures, which can make it difficult to predict the ground electronic state especially for the anion. Electron affinities for the low-lying structures are calculated and compared with those for M = Ti. Electron affinities of these clusters depend strongly on the cluster structures. Anion photoelectron spectra are calculated for the monomer and dimer and demonstrate the possibility for structural identification at a spectral line width of ?0.05 eV. Electron excitation energies from the low-lying states to the singlet and triplet excited states are calculated self-consistently, as well as by the time-dependent DFT and equation-of-motion coupled cluster (EOM-CCSD) methods. The calculated excitation energies are compared to the band energies of bulk oxides, indicating that the excitation energy is not yet converged for n = 4 for these clusters. The excitation energies of the low-lying isomeric clusters are less than the bulk metal oxide band gaps and suggest that these clusters could be useful photocatalysts with a visible light source.

  9. Cloning, Expression, and Ontogeny of Mouse Organic Anion-Transporting Polypeptide5, a Kidney-Specific Organic Anion Transporter

    Microsoft Academic Search

    Supratim Choudhuri; Kenichiro Ogura; Curtis D. Klaassen

    2001-01-01

    The full-length coding sequence of mouse organic anion-transporting polypeptide (designated mouse Oatp-5) has been cloned from mouse kidney cDNA library. Analysis of the 5?-untranslated region (5?-UTR) of Oatp-5 cDNA through capsite cloning reveals two possible transcription start sites that are 4-bp apart. The 3?-untranslated region (3?-UTR) of Oatp-5 cDNA contains an early polyadenylation signal, indicating the possibility that mRNAs with

  10. Wide Band Gap Gallium Phosphide Solar Cells

    Microsoft Academic Search

    Xuesong Lu; Susan Huang; Martin B. Diaz; Nicole Kotulak; Ruiying Hao; Robert Opila; Allen Barnett

    2012-01-01

    Gallium phosphide (GaP), with its wide band gap of 2.26 eV, is a good candidate for the top junction solar cell in a multijunction solar cell system. Here, we design, fabricate, characterize, and analyze GaP solar cells. Liquid phase epitaxy is used to grow the semiconductor layers. Four generations of GaP solar cells are developed and fabricated with each solar

  11. The GAP Online LGBT Mental Health Curriculum

    Microsoft Academic Search

    Mary E. Barber; Jack Drescher; Vernon Rosario

    2012-01-01

    The authors describe the development and publication of an online curriculum to teach psychiatry trainees about important topics in LGBT mental health (www.aglp.org\\/gap). The curriculum was written by members of the LGBT Committee of the Group for Advancement of Psychiatry (GAP, www.ourgap.org). This paper outlines the history and mission of GAP and the history of the GAP LGBT Committee. The

  12. Forest gap dynamics and tree regeneration

    Microsoft Academic Search

    Shin-Ichi Yamamoto

    2000-01-01

    When one or a few canopy trees die (or are injured) in a forest, small openings, which are called ‘gaps,’ are formed in the\\u000a forest canopy and are then filled with other trees. This sort of forest dynamics is termed gap dynamics; a large number of\\u000a papers and data on gap dynamics have been accumulated since the 1970’s, and gap

  13. Spark gap with low breakdown voltage jitter

    SciTech Connect

    Rohwein, Gerald J. (Albuquerque, NM); Roose, Lars D. (Albuquerque, NM)

    1996-01-01

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed.

  14. Spark gap with low breakdown voltage jitter

    DOEpatents

    Rohwein, G.J.; Roose, L.D.

    1996-04-23

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed. 13 figs.

  15. Study of the ArBr-, AC, and Krl-anions and the corresponding neutral van der Waals complexes by anion zero electron kinetic energy

    E-print Network

    Neumark, Daniel M.

    as for the anion, and these interaction potentials are compared to potentials obtained from scattering and ion interacting species has been a central goal of a wide range of scattering and spectroscopy studies over by anion zero electron kinetic energy spectroscopy Yuexing Zhao, Ivan Yourshaw, Georg Reiser, Caroline C

  16. Physiology of iron metabolism.

    PubMed

    Waldvogel-Abramowski, Sophie; Waeber, Gérard; Gassner, Christoph; Buser, Andreas; Frey, Beat M; Favrat, Bernard; Tissot, Jean-Daniel

    2014-06-01

    A revolution occurred during the last decade in the comprehension of the physiology as well as in the physiopathology of iron metabolism. The purpose of this review is to summarize the recent knowledge that has accumulated, allowing a better comprehension of the mechanisms implicated in iron homeostasis. Iron metabolism is very fine tuned. The free molecule is very toxic; therefore, complex regulatory mechanisms have been developed in mammalian to insure adequate intestinal absorption, transportation, utilization, and elimination. 'Ironomics' certainly will be the future of the understanding of genes as well as of the protein-protein interactions involved in iron metabolism. PMID:25053935

  17. Cellular and metabolic engineering

    Microsoft Academic Search

    Douglas C. Cameron; I-Teh Tong

    1993-01-01

    Metabolic engineering is defined as the purposeful modification of intermediary metabolism using recombinant DNA techniques.\\u000a Cellular engineering, a more inclusive term, is defined as the purposeful modification of cell properties using the same techniques.\\u000a Examples of cellular and metabolic engineering are divided into five categories:\\u000a \\u000a \\u000a 1. \\u000a \\u000a Improved production of chemicals already produced by the host organism;\\u000a \\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a Extended substrate range

  18. Enhanced liquid-liquid anion exchange using macrocyclic anion receptors: effect of receptor structure on sulphate-nitrate exchange selectivity

    SciTech Connect

    Moyer, Bruce A [ORNL; Sloop Jr, Frederick {Fred} V [ORNL; Fowler, Christopher J [ORNL; Haverlock, Tamara [ORNL; Kang, Hyun Ah [ORNL; Delmau, Laetitia Helene [ORNL; Bau, Diadra [ORNL; Hossain, Alamgir [University of Kansas; Bowman-James, Kristin [University of Kansas; Shriver, James A. [University of Texas; Gross, Mr. Dustin E. [University of Texas, Austin; Bill, Nathan [University of Texas, Austin; Marquez, Manuel [University of Texas; Lynch, Vincent M. [University of Texas, Austin; Sessler, Jonathan L. [University of Texas

    2010-01-01

    When certain macrocyclic anion receptors are added to a chloroform solution of the nitrate form of a lipophilic quaternary ammonium salt (methyltri-C8,10-ammonium nitrate, Aliquat 336N), the extraction of sulphate from an aqueous sodium nitrate solution via exchange with the organic-phase nitrate is significantly enhanced. Eight macrocycles were surveyed, including two derivatives of a tetraamide macrocycle, five derivatives of calix[4]pyrrole and -decafluorocalix[5]pyrrole. Under the hypothesis that the enhancement originates from sulphate binding by the anion receptors in the chloroform phase, it was possible to obtain reasonable fits to the sulphate distribution survey data based on the formation of 1:1 and 2:1 receptor:sulphate complexes in the chloroform phase. Apparent 1:1 sulphate-binding constants obtained from the model in this system fell in the range . Comparison of the results for the various anion receptors included in this study reveals that sulphate binding is sensitive to the nature of the substituents on the parent macrocycle scaffolds in a way that does not follow straightforwardly from simple chemical expectations, such as electron-withdrawing effects on hydrogen-bond donor strength.

  19. Determination of arsenate in water by anion selective membrane electrode using polyurethane-silica gel fibrous anion exchanger composite.

    PubMed

    Khan, Asif Ali; Shaheen, Shakeeba

    2014-01-15

    Polyurethane (PU)-silica (Si gel) based fibrous anion exchanger composites were prepared by solid-gel polymerization of polyurethane in the presence of different amounts of silica gel. The formation of PU-Si gel fibrous anion exchanger composite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM) and elemental analysis. The membrane having a composition of 5:3 (PU:Si gel) shows best results for water content, porosity, thickness and swelling. Our studies show that the present ion selective membrane electrode is selective for arsenic, having detection limit (1×10(-8)M to 1×10(-1)M), response time (45s) and working pH range (5-8). The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO4(3-)) over interfering anions. The accuracy of the detection limit results was compared by PCA-Arsenomat. PMID:24275475

  20. Identifying Branched Metabolic Pathways by Merging Linear Metabolic Pathways

    E-print Network

    Kavraki, Lydia E.

    applications in fields such as metabolic engineering, which focuses on discovering and implementing newIdentifying Branched Metabolic Pathways by Merging Linear Metabolic Pathways Allison P. Heath1 presents a graph-based algorithm for identify- ing complex metabolic pathways in multi-genome scale

  1. Subgroup Achievement and Gap Trends: Oklahoma, 2010

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper profiles the student subgroup achievement and gap trends in Oklahoma for 2010. Oklahoma made progress in narrowing achievement gaps for most major subgroups on the End-of-Instruction (EOI) test in Algebra I. Trends in achievement gaps could not be determined for other grades in math, or for any grades in reading, because the state…

  2. The evolution of the gender wage gap

    Microsoft Academic Search

    Astrid Kunze

    2005-01-01

    This article examines the evolution of the gender wage gap by the decomposition of the gap at various experience levels. For the analysis, we use rich administrative data on wage and work histories for West-German workers with apprenticeship training. We find a pronounced gap at entry into first employment, which stays virtually constant throughout the early career. Sex segregation in

  3. Low band gap polymers for organic photovoltaics

    Microsoft Academic Search

    Eva Bundgaard; Frederik C. Krebs

    2007-01-01

    Low band gap polymer materials and their application in organic photovoltaics (OPV) are reviewed. We detail the synthetic approaches to low band gap polymer materials starting from the early methodologies employing quinoid homopolymer structures to the current state of the art that relies on alternating copolymers of donor and acceptor groups where strategies for band gap design are possible. Current

  4. Generation Gaps in Engineering? David J. Kim

    E-print Network

    Gabrieli, John

    Generation Gaps in Engineering? by David J. Kim B.S., Computer Science and Engineering;3 Generation Gaps in Engineering? by David J. Kim Submitted to the System Design and Management Program on May in Engineering and Management ABSTRACT There is much enthusiastic debate on the topic of generation gaps

  5. New Evidence on the Motherhood Wage Gap

    Microsoft Academic Search

    Catalina Amuedo-Dorantes; Jean Kimmel

    2008-01-01

    Using data from the 1979 National Longitudinal Survey of Youth, we assess the role of employment-based health insurance offers in explaining the motherhood wage gap. Researchers have been aware of the existence of a motherhood gap for many years; yet, the literature has failed to address the role of non-wage compensation in explaining the motherhood wage gap despite the increasing

  6. New seismic gap hypothesis: Five years after

    Microsoft Academic Search

    Y. Y. Kagan; D. D. Jackson

    1995-01-01

    We use earthquake data from 1989-1994 to test a forecast by Nishenko based on the seismic gap theory. We refer to this forecast as the 'New Seismic Gap' hypothesis, because it is the first global forecast based on the seismic gap hypothesis that considers the recurrence time and characteristic earthquake magnitude specific to each plate boundary segment. Nishenko's forecasts gave

  7. Reducing the White-Nonwhite Achievement Gap.

    ERIC Educational Resources Information Center

    Ramey, Madelaine

    It is well documented that there continues to be a gap between white and nonwhite student achievement. A study develops and tests a measure of white-nonwhite achievement gap reduction. The ultimate purpose is to use the measure as the dependent variable in a qualitative study of what works in reducing the gap. The strategy used in addressing this…

  8. Gapping in Farsi: A Crosslinguistic Investigation

    ERIC Educational Resources Information Center

    Farudi, Annahita

    2013-01-01

    This dissertation explores a longstanding challenge in work on gapping through the empirical lens of gapping in Farsi (the Tehrani variant of Modern Persian). While gapping has much in common with more uncontroversial elliptical constructions such as VPE and sluicing, it also differs from ellipsis in ways that accounts combining TP or CP…

  9. On the importance of the band gap bowing in Boron-based III V ternary alloys

    NASA Astrophysics Data System (ADS)

    Azzi, S.; Zaoui, A.; Ferhat, M.

    2007-11-01

    The optical band gap bowing of eighteen III-V compound alloys containing boron is calculated by means of a recent phenomenological model [M. Ferhat, Phys. Status Solidi b 241 (2004) R38]. The optical band gap bowing is found to be strong for the all studied III-V boron alloys. In particular, we find that BNSb shows an important optical band gap bowing of 19.78 eV. Parallel to this, we also introduce ab initio pseudopotential plane wave calculations with large relaxed supercells to check the validity of our phenomenological model for BNSb. This gives an optical bowing of 21.19 eV, in fairly good agreement with the model used. Results suggest that the III-V boron alloys are characterized by a strong competition between the volume deformation (b), charge transfer (b), and structural relaxation (b) effects. For the common cation alloys b dominates b, and b is relatively weak; whereas for the common anion alloys, the structural effect ( b and b) appears to control the total optical band gap bowing.

  10. Simultaneous determination of NH4+, NO2(-) and NO3(-) by ion-exclusion/anion-exchange chromatography on a strongly basic anion-exchange resin with basic eluent.

    PubMed

    Mori, Masanobu; Hironaga, Takahiro; Itabashi, Hideyuki; Nakatani, Nobutake; Kozaki, Daisuke; Tanaka, Kazuhiko

    2012-04-01

    Ion-exclusion/anion-exchange chromatography (IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH(-)-form with basic eluent has been developed. The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase. This system is useful for simultaneous separation and determination of ammonium ion (NH4+), nitrite ion (NO2(-)), and nitrate ion (NO3(-)) in water samples. The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column. In this study, several separation columns, which consisted of different particle sizes, different functional groups and different anion-exchange capacities, were compared. As the results, the separation column with the smaller anion-exchange capacity (TSKgel Super IC-Anion) showed well-resolved separation of cations and anions. In the optimization of the basic eluent, lithium hydroxide (LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L, considering the resolution of analyte ions and the whole retention times. In the optimal conditions, the relative standard deviations of the peak areas and the retention times of NH4+, NO2(-), and NO3(-) ranged 1.28% - 3.57% and 0.54% - 1.55%, respectively. The limits of detection at signal-to-noise of 3 were 4.10 micromol/L for NH4+, 1.87 micromol/L for NO2(-) and 2.83 micromol/L for NO3(-). PMID:22799190

  11. MEASURING AND MODELLING METABOLISM

    EPA Science Inventory

    The use of QSAR with potential metabolism (bioactivation or deactivation) is an experimental approach for exploring toxicity pathways and estimating the relative toxicity of chemicals within a pathway. This conference will hear and discuss the potential and limitations of these ...

  12. Engineering of metabolic control

    DOEpatents

    Liao, James C.

    2004-03-16

    The invention features a method of producing heterologous molecules in cells under the regulatory control of a metabolite and metabolic flux. The method can enhance the synthesis of heterologous polypeptides and metabolites.

  13. Engineering of metabolic control

    DOEpatents

    Liao, James C.

    2006-10-17

    The invention features a method of producing heterologous molecules in cells under the regulatory control of a metabolite and metabolic flux. The method can enhance the synthesis of heterologous polypeptides and metabolites.

  14. Abdominal obesity and metabolic syndrome

    Microsoft Academic Search

    Jean-Pierre Després; Isabelle Lemieux

    2006-01-01

    Metabolic syndrome is associated with abdominal obesity, blood lipid disorders, inflammation, insulin resistance or full-blown diabetes, and increased risk of developing cardiovascular disease. Proposed criteria for identifying patients with metabolic syndrome have contributed greatly to preventive medicine, but the value of metabolic syndrome as a scientific concept remains controversial. The presence of metabolic syndrome alone cannot predict global cardiovascular disease

  15. Exercise testing in metabolic myopathies.

    PubMed

    Tarnopolsky, Mark

    2012-02-01

    Metabolic myopathies are a group of genetic disorders specifically affecting glucose/glycogen, lipid, and mitochondrial metabolism. The main metabolic myopathies that are evaluated in this article are the mitochondrial myopathies, fatty acid oxidation defects, and glycogen storage disease. This article focuses on the usefulness of exercise in the evaluation of genetic metabolic myopathies. PMID:22239882

  16. Diphosphoinositol Polyphosphates: Metabolic Messengers?

    PubMed Central

    Shears, Stephen B.

    2009-01-01

    The diphosphoinositol polyphosphates (“inositol pyrophosphates”) are a specialized subgroup of the inositol phosphate signaling family. This review proposes that many of the current data concerning the metabolic turnover and biological effects of the diphosphoinositol polyphosphates are linked by a common theme: these polyphosphates act as metabolic messengers. This review will also discuss the latest proposals concerning possible molecular mechanisms of action of this intriguing class of molecules. PMID:19439500

  17. Obesity and Metabolic Comorbidities: Environmental Diseases?

    PubMed Central

    Lubrano, Carla; Genovesi, Giuseppe; Specchia, Palma; Costantini, Daniela; Mariani, Stefania; Petrangeli, Elisa; Lenzi, Andrea; Gnessi, Lucio

    2013-01-01

    Obesity and metabolic comorbidities represent increasing health problems. Endocrine disrupting compounds (EDCs) are exogenous agents that change endocrine function and cause adverse health effects. Most EDCs are synthetic chemicals; some are natural food components as phytoestrogens. People are exposed to complex mixtures of chemicals throughout their lives. EDCs impact hormone-dependent metabolic systems and brain function. Laboratory and human studies provide compelling evidence that human chemical contamination can play a role in obesity epidemic. Chemical exposures may increase the risk of obesity by altering the differentiation of adipocytes. EDCs can alter methylation patterns and normal epigenetic programming in cells. Oxidative stress may be induced by many of these chemicals, and accumulating evidence indicates that it plays important roles in the etiology of chronic diseases. The individual sensitivity to chemicals is variable, depending on environment and ability to metabolize hazardous chemicals. A number of genes, especially those representing antioxidant and detoxification pathways, have potential application as biomarkers of risk assessment. The potential health effects of combined exposures make the risk assessment process more complex compared to the assessment of single chemicals. Techniques and methods need to be further developed to fill data gaps and increase the knowledge on harmful exposure combinations. PMID:23577225

  18. Effect of tumor promoting stimuli on gap junction permeability and connexin 43 expression in ARL 18 rat liver cell line

    Microsoft Academic Search

    Irina V. Budunovat; Gary M. Williams; David C. Spray

    1993-01-01

    The ARL18 rat liver cell line has previously been used for screening tumor promoters in the metabolic cooperation assay (Williams 1980; Williams et al. 1981; Telang et al. 1982). These cells display high levels of gap junctional communication, as assessed functionally and immunologically. Intracellularly injected Lucifer Yellow diffused extensively and there was rapid fluorescent recovery after photobleaching. Moreover, expression of

  19. Psoriasis and Metabolic Syndrome

    PubMed Central

    Malkic Salihbegovic, Eldina; Hadzigrahic, Nermina; Cickusic, Amra Jakubovic

    2015-01-01

    Introduction: Psoriasis is a chronic skin ailment which can be connected with an increased occurrence of other illnesses, including the metabolic syndrome. Examinees and methods: A prospective study has been conducted which included 70 patients affected by psoriasis, both genders, older than 18 years. Average age being 47,14 (SD=±15,41) years, from that there were 36 men or 51,43 and 34 women or 48,57%. The average duration of psoriasis was 15,52 (SD= ±12,54) years. For purposes of diagnosing the metabolic syndrome, the criteria of National Cholesterol Education Program Adult Treatment Panel III, (NCEP ATP III) were used. For purposes of detecting the severity and spread of psoriasis, Psoriasis Area and Severity Index (PASI) was used. Results: The incidence of metabolic syndrome in patients with psoriasis was 38,57%. Average values of PASI score were 16,65. The increase in values of PASI score and metabolic syndrome were statistically highly connected. (r=0,3, p=0,0001). Conclusion: Psoriasis is connected with metabolic syndrome, there is a positive correlation between the severity of psoriasis and frequency of metabolic syndrome. PMID:26005254

  20. Metabolic cutis laxa syndromes.

    PubMed

    Mohamed, Miski; Kouwenberg, Dorus; Gardeitchik, Thatjana; Kornak, Uwe; Wevers, Ron A; Morava, Eva

    2011-08-01

    Cutis laxa is a rare skin disorder characterized by wrinkled, redundant, inelastic and sagging skin due to defective synthesis of elastic fibers and other proteins of the extracellular matrix. Wrinkled, inelastic skin occurs in many cases as an acquired condition. Syndromic forms of cutis laxa, however, are caused by diverse genetic defects, mostly coding for structural extracellular matrix proteins. Surprisingly a number of metabolic disorders have been also found to be associated with inherited cutis laxa. Menkes disease was the first metabolic disease reported with old-looking, wrinkled skin. Cutis laxa has recently been found in patients with abnormal glycosylation. The discovery of the COG7 defect in patients with wrinkled, inelastic skin was the first genetic link with the Congenital Disorders of Glycosylation (CDG). Since then several inborn errors of metabolism with cutis laxa have been described with variable severity. These include P5CS, ATP6V0A2-CDG and PYCR1 defects. In spite of the evolving number of cutis laxa-related diseases a large part of the cases remain genetically unsolved. In metabolic cutis laxa syndromes the clinical and laboratory features might partially overlap, however there are some distinct, discriminative features. In this review on metabolic diseases causing cutis laxa we offer a practical approach for the differential diagnosis of metabolic cutis laxa syndromes. PMID:21431621

  1. Measurement of plasma flows into tile gaps

    NASA Astrophysics Data System (ADS)

    Dejarnac, R.; Komm, M.; Stöckel, J.; Panek, R.

    2008-11-01

    Particle fluxes falling into narrow gaps are of high interest since international thermonuclear experimental reactor plasma facing components will be castellated. In order to investigate the plasma deposition in gaps between tiles, we have developed a special probe that recreates a gap and that can measure the ion saturation current profiles along its both sides. Measurements were performed in the tokamak Czech Academy of Sciences TORus and are compared with a self-consistent kinetic model. The simulations reproduce well the observed asymmetry of the plasma deposition in both poloidal and toroidal gaps and the intensity of the collected currents is well-estimated. However, the agreement is less perfect for poloidal gaps due to the presence of a positive peak on the negative potential inside the gap. Therefore, the plasma deposition does not decay exponentially like in toroidal gaps. Nevertheless, this unique set of experiments confirms globally the results of our model.

  2. Stomatal closure by fast abscisic acid signaling is mediated by the guard cell anion channel SLAH3 and the receptor RCAR1.

    PubMed

    Geiger, Dietmar; Maierhofer, Tobias; Al-Rasheid, Khaled A S; Scherzer, Sönke; Mumm, Patrick; Liese, Anja; Ache, Peter; Wellmann, Christian; Marten, Irene; Grill, Erwin; Romeis, Tina; Hedrich, Rainer

    2011-01-01

    S-type anion channels are direct targets of abscisic acid (ABA) signaling and contribute to chloride and nitrate release from guard cells, which in turn initiates stomatal closure. SLAC1 was the first component of the guard cell S-type anion channel identified. However, we found that guard cells of Arabidopsis SLAC1 mutants exhibited nitrate conductance. SLAH3 (SLAC1 homolog 3) was also present in guard cells, and coexpression of SLAH3 with the calcium ion (Ca2+)-dependent kinase CPK21 in Xenopus oocytes mediated nitrate-induced anion currents. Nitrate, calcium, and phosphorylation regulated SLAH3 activity. CPK21-dependent SLAH3 phosphorylation and activation were blocked by ABI1, a PP2C-type protein phosphatase that is inhibited by ABA and inhibits the ABA signaling pathway in guard cells. We reconstituted the ABA-stimulated phosphorylation of the SLAH3 amino-terminal domain by CPK21 in vitro by including the ABA receptor-phosphatase complex RCAR1-ABI1 in the reactions. We propose that ABA perception by the complex consisting of ABA receptors of the RCAR/PYR/PYL family and ABI1 releases CPK21 from inhibition by ABI1, and then CPK21 is further activated by an increase in the cytosolic Ca2+ concentration, leading to its phosphorylation of SLAH3. Thus, the identification of SLAH3 as the nitrate-, calcium-, and ABA-sensitive guard cell anion channel provides insights into the relationship among stomatal response to drought, signaling by nitrate, and nitrate metabolism. PMID:21586729

  3. Comparative Study of Some Layered Hydroxide Salts Containing Exchangeable Interlayer Anions

    NASA Astrophysics Data System (ADS)

    Newman, Steven P.; Jones, William

    1999-11-01

    Anion-exchange reactions of layered Zn, Cu, Ni, or La hydroxide nitrates with the organic anions acetate, terephthalate, and benzoate are compared. Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetry combined with mass spectrometry (TG-MS) are used to characterize the materials. Exchange of the interlayer nitrate anions for these organic anions is generally possible, although no exchange is observed for the parent nickel hydroxide material. The organo derivatives obtained may be considered inorganic-organic hybrids, consisting of alternating hydroxide and A- layers, where A is the incorporated organic anion. The materials are structurally similar to the layered double hydroxide family of materials, which also exhibit an anion-exchange capacity.

  4. Transmission electron microscopy and structural phase transitions in anion-deficient perovskite-based oxides.

    PubMed

    Hadermann, Joke

    2005-01-01

    This review deals with the structural transitions arising in anion-deficient Mn- and Cu-based perovskites when changing the anion content. Special attention is devoted to the local structure of such materials, studied with electron diffraction and high-resolution electron microscopy. Using examples of three-dimensional or layered manganites and cuprates, it is shown that oxidation/reduction reactions in such compounds are accompanied by the formation of domain structures. Fragmentation into domains can have intrinsic reasons, related to the loss of symmetry elements due to the ordering of anion vacancies, or because of the simultaneous realization of several different anion ordering patterns with close formation energies. When extra anions are inserted at low temperatures, limited diffusion ability also results in the appearance of domains of different structures arising from a local inhomogeneity in the anion distribution. The relevance of the investigation of the local structure for a correct structure interpretation is discussed. PMID:15613755

  5. Sixfold interpenetrated diamondoid network of Cu(I): Synthesis, structure, selective anion exchange and luminescence properties

    NASA Astrophysics Data System (ADS)

    Vyasamudri, Sameer Y.; Maji, Tapas Kumar

    2009-05-01

    A novel metal-organic framework of Cu(I), {[Cu(bphz) 2] · 2BF 4} n ( 1) (bphz = 1,2-bis(4-pyridylmethylene)hydrazine) has been synthesized and structurally characterized. Structure determination reveals a 3D diamondoid network with 1D channels filled with the BF4- anions which undergoes F⋯F interactions forming 1D ( BF4-) n chains in the crystallographic c-axis. The six independent 3D diamondoid networks are sixfold interpenetrating, forming a rare example of sixfold interpenetrated 3D diamondoid network. The framework also exhibits photoluminescence properties and selective reversible anion exchange ability with the NO3- anions, but not with the ClO4- and PF6- anions. The highly selective anion exchange ability is correlated with the size and shape of the anions compare to the channel aperture.

  6. Anion-directed assembly: Framework conversion in dimensionality and photoluminescence

    NASA Astrophysics Data System (ADS)

    Gong, Yun; Liu, Tianfu; Tang, Wang; Wu, Fengjing; Gao, Wenliang; Hu, Changwen

    2007-04-01

    Six novel Ni(II)-fluconazole complexes formulated as (C 13H 11N 6OF 2) 2Ni 2(NO 3) 2 ( 1), (C 13H 12N 6OF 2) 2Ni(NO 3) 2·H 2O ( 2), (C 13H 12N 6OF 2)Ni(SO 4)(DMF) 2(H 2O) ( 3), (C 13H 12N 6OF 2) 2Ni(H 2O) 2(SO 4)·4H 2O ( 4), (C 13H 12N 6OF 2) 2NiCl 2·2(CH 3OH) ( 5), (C 13H 12N 6OF 2) 4Ni 2 (MoO 4) 2·6H 2O ( 6) have been hydrothermally or solvothermally synthesized under similar conditions except different anions and solvents. They are structurally characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. Complex 1 is a molecular binuclear nickel cluster. Complex 2 exhibits a one-dimensional (1D) chain linked by double-stranded fluconazole-bridge. Complex 3 shows a novel 1D chain linked by double-stranded fluconazole-bridge and double-stranded SO 42--bridge. Complex 4 shows a three-dimensional (3D) architecture and SO 42- anions occupy the cavity. Complex 5 exhibits a two-dimensional (2D) structure constructed by alternating left- and right-handed helices. Complex 6 exhibits a 3D architecture, in which the 2D layers are pillared by {MoO 4} tetrahedra. Complex 2 can be irreversibly converted to complex 1 in the presence of DMF ( N, N'-dimethyllformamide). Complexes 1, 3 and 6 show antiferromagnetic interactions between the nickel (II) ions The photoluminescence properties of the six complexes indicated that the introduction of different anions can enhance or weaken the intra-ligand transitions of fluconazole.

  7. Interaction of Organic Cations with Organic Anion Transporters*

    PubMed Central

    Ahn, Sun-Young; Eraly, Satish A.; Tsigelny, Igor; Nigam, Sanjay K.

    2009-01-01

    Studies of the organic anion transporters (Oats) have focused mainly on their interactions with organic anionic substrates. However, as suggested when Oat1 was originally identified as NKT (Lopez-Nieto, C. E., You, G., Bush, K. T., Barros, E. J., Beier, D. R., and Nigam, S. K. (1997) J. Biol. Chem. 272, 6471–6478), since the Oats share close homology with organic cation transporters (Octs), it is possible that Oats interact with cations as well. We now show that mouse Oat1 (mOat1) and mOat3 and, to a lesser degree, mOat6 bind a number of “prototypical” Oct substrates, including 1-methyl-4-phenylpyridinium. In addition to oocyte expression assays, we have tested binding of organic cations to Oat1 and Oat3 in ex vivo assays by analyzing interactions in kidney organ cultures deficient in Oat1 and Oat3. We also demonstrate that mOat3 transports organic cations such as 1-methyl-4-phenylpyridinium and cimetidine. A pharmacophore based on the binding affinities of the tested organic cations for Oat3 was generated. Using this pharmacophore, we screened a chemical library and were able to identify novel cationic compounds that bound to Oat1 and Oat3. These compounds bound Oat3 with an affinity higher than the highest affinity compounds in the original set of prototypical Oct substrates. Thus, whereas Oat1, Oat3, and Oat6 appear to function largely in organic anion transport, they also bind and transport some organic cations. These findings could be of clinical significance, since drugs and metabolites that under normal physiological conditions do not bind to the Oats may undergo changes in charge and become Oat substrates during pathologic conditions wherein significant variations in body fluid pH occur. PMID:19737926

  8. Theoretical characterization of dihydrogen adducts with halide anions

    NASA Astrophysics Data System (ADS)

    Vitillo, Jenny G.; Damin, Alessandro; Zecchina, Adriano; Ricchiardi, Gabriele

    2006-06-01

    The interaction between a hydrogen molecule and the halide anions F-, Cl-, Br-, and I- has been studied at different levels of theory and with different basis sets. The most stable configurations of the complexes have a linear geometry, while the t-shaped complexes are saddle points on the potential energy surface, opposite to what is observed for alkali cations. An electrostatic analysis conducted on the resulting adducts has highlighted the predominance of the electrostatic term in the complexation energy and, in particular, of the quadrupole- and dipole-polarizability dependent contributions. Another striking difference with respect to the positive ions, is the fact that although the binding energies have similar values (ranging between 25 and 3kJ/mol for F- and I-, respectively), the vibrational shift of the ?˜H-H and in general the perturbation of the hydrogen molecule in complexes are much greater in the complexes with anions (??˜H-H ranges between -720 and -65cm-1). Another difference with respect to the interaction with cations is a larger charge transfer from the anion to the hydrogen molecule. The ??˜ is the result of the cooperative role of the electrostatics and of the charge transfer in the interaction. The correlation between binding energies and vibrational shift is far from linear, contrary to what is observed for cation complexes, in accordance with the higher polarizability and dynamic polarizability of the molecule along the molecular axis. The observed correlation may be valuable in the interpretation of spectra and thermodynamic properties of adsorbed H2 in storage materials.

  9. Tunable transport gap in phosphorene.

    PubMed

    Das, Saptarshi; Zhang, Wei; Demarteau, Marcel; Hoffmann, Axel; Dubey, Madan; Roelofs, Andreas

    2014-10-01

    In this article, we experimentally demonstrate that the transport gap of phosphorene can be tuned monotonically from ?0.3 to ?1.0 eV when the flake thickness is scaled down from bulk to a single layer. As a consequence, the ON current, the OFF current, and the current ON/OFF ratios of phosphorene field effect transistors (FETs) were found to be significantly impacted by the layer thickness. The transport gap was determined from the transfer characteristics of phosphorene FETs using a robust technique that has not been reported before. The detailed mathematical model is also provided. By scaling the thickness of the gate oxide, we were also able to demonstrate enhanced ambipolar conduction in monolayer and few layer phosphorene FETs. The asymmetry of the electron and the hole current was found to be dependent on the layer thickness that can be explained by dynamic changes of the metal Fermi level with the energy band of phosphorene depending on the layer number. We also extracted the Schottky barrier heights for both the electron and the hole injection as a function of the layer thickness. Finally, we discuss the dependence of field effect hole mobility of phosphorene on temperature and carrier concentration. PMID:25111042

  10. Electroactive Materials For Anion Separation-Technetium From Nitrate

    SciTech Connect

    William H. Smyrl, PI; Dr. Ann Gronda

    2003-10-10

    In order to increase the capacity of electroactive polymers for radioactive waste separations, we have focused on two ways of processing these polymers: phase inversion, and coating onto a porous conductive substrate. Both techniques are intended to increase the surface area for access of the guest anions to the intercalation host. Phase inversion of polyvinylferrocene (PVF) was unsuccessful, but we were able to use electroprecipitation to coat PVF onto porous carbon substrates such as Toray paper. Due to the wide molecular weight distribution and batch variations of commercial PVF, we have chosen to examine the more manageable polyaniline.

  11. Electron paramagnetic resonance examination of aqueous anthrasemiquinone radical anion

    NASA Astrophysics Data System (ADS)

    Hocking, M. B.; Mattar, S. M.

    Anthrasemiquinone radical anion (AQ -·) was prepared in strictly aqueous alkaline solutions using reducing sugars. It was found to be stable in this medium at room temperature in the absence of air for periods exceeding 1 year. Reduction using an equivalent of sodium dithionite required brief exposure of the solution of dianion to air to obtain AQ -. EPR observations are reported for these solutions over the temperature range -50 to +90°C in basic ethanol, aqueous ethanol, and water and are related to redox potential measurements and electron exchange processes operating under these conditions.

  12. Ion/Anion Pair Production from Electron Impact

    NASA Astrophysics Data System (ADS)

    Sartor, J.; Keiling, M.; Fogle, M.; Gay, T. J.; Landers, A. L.

    2013-05-01

    One of the least studied dissociation pathways of a neutral molecule is the decay to an ion/anion pair, yet these reactions can provide new insight into fundamental molecular dynamics. We initiate these reactions with the pulsed field from a fast electron, where in principle all ion/anion pair-production modes are accessible and not limited by photo-absorption selection rules. We accomplish this by intersecting a bunched electron beam with a jet of gas over a wide range of energies, and use a fast-switched electric field to guide the ion products towards two position sensitive detectors. Using the positions and flight times of the ions, we completely determine the final state momenta. This not only allows for the discrimination of this channel from dominant contaminant reactions (particularly the electron producing ionization channels), but also yields the kinetic energy release and product angular distribution. Preliminary results for the reaction e- +O2 ==>e- +O+ +O- will be presented along with additional measurements currently underway, including the fundamental case of hydrogen. One of the least studied dissociation pathways of a neutral molecule is the decay to an ion/anion pair, yet these reactions can provide new insight into fundamental molecular dynamics. We initiate these reactions with the pulsed field from a fast electron, where in principle all ion/anion pair-production modes are accessible and not limited by photo-absorption selection rules. We accomplish this by intersecting a bunched electron beam with a jet of gas over a wide range of energies, and use a fast-switched electric field to guide the ion products towards two position sensitive detectors. Using the positions and flight times of the ions, we completely determine the final state momenta. This not only allows for the discrimination of this channel from dominant contaminant reactions (particularly the electron producing ionization channels), but also yields the kinetic energy release and product angular distribution. Preliminary results for the reaction e- +O2 ==>e- +O+ +O- will be presented along with additional measurements currently underway, including the fundamental case of hydrogen. Supported by the Auburn University Undergraduate Research Fellowship Program and the US Department of Energy: Office of Basic Energy Sciences, Division of Chemical Sciences.

  13. Determining gold in water by anion-exchange batch extraction

    USGS Publications Warehouse

    McHugh, J.B.

    1986-01-01

    This paper describes a batch procedure for determining gold in natural waters. It is completely adaptable to field operations. The water samples are filtered and acidified before they are equilibrated with an anion-exchange resin by shaking. The gold is then eluted with acetone-nitric acid solution, and the eluate evaporated to dryness. The residue is taken up in hydrobromic acid-bromine solution and the gold is extracted with methyl isobutyl ketone. The extract is electrothermally atomized in an atomic-absorption spectrophotometer. The limit of determination is 1 ng 1. ?? 1986.

  14. Minority anion substitution by Ni in ZnO

    E-print Network

    Pereira, Lino Miguel da Costa; Correia, João Guilherme; Amorim, Lígia Marina; Silva, Daniel José; David-Bosne, Eric; Decoster, Stefan; da Silva, Manuel Ribeiro; Temst, Kristiaan; Vantomme, André

    2013-01-01

    We report on the lattice location of implanted Ni in ZnO using the $\\beta$? emission channeling technique. In addition to the majority substituting for the cation (Zn), a significant fraction of the Ni atoms occupy anion (O) sites. Since Ni is chemically more similar to Zn than it is to O, the observed O substitution is rather puzzling. We discuss these findings with respect to the general understanding of lattice location of dopants in compound semiconductors. In particular, we discuss potential implications on the magnetic behavior of transition metal doped dilute magnetic semiconductors.

  15. Regeneration of anion exchange resins by catalyzed electrochemical reduction

    DOEpatents

    Gu, Baohua (Oak Ridge, TN); Brown, Gilbert M. (Knoxville, TN)

    2002-01-01

    Anion exchange resins sorbed with perchlorate may be regenerated by a combination of chemical reduction of perchlorate to chloride using a reducing agent and an electrochemical reduction of the oxidized reducing agent. Transitional metals including Ti, Re, and V are preferred chemical reagents for the reduction of perchlorate to chloride. Complexing agents such as oxalate are used to prevent the precipitation of the oxidized Ti(IV) species, and ethyl alcohol may be added to accelerate the reduction kinetics of perchlorate. The regeneration may be performed by continuously recycling the regenerating solution through the resin bed and an electrochemical cell so that the secondary waste generation is minimized.

  16. Sorption of Phosphoric Acid by Anion-Exchange Membrane

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiroshi; Kikuchi, Ken-Ichi

    Sorption equilibrium of phosphoric acid by strongly basic anion-exchange membrane (SELEMION AMV) was studied to determine the selectivities of ionic species of phosphoric acid. The sorption of phosphoric acid by the membrane increased with increase in the phosphate concentration in the solution and pH. The sorption characteristics were successfully explained by the ion-exchange model considering the dissociation of phosphoric acid in the solution, electro-neutrality in the solution and in the membrane, and material balances of chemical species.

  17. Molecular Recognition: Preparation and Characterization of Two Tripodal Anion Receptors

    SciTech Connect

    Shokri, Alireza; Deng, Shihu; Wang, Xue B.; Kass, Steven R.

    2014-03-01

    Two new tripodal hydroxyl-based anion receptors (1 and 2) are reported and their molecular complexes with Cl–, H2PO4 –, and OAc– along with the (M–1)– ion of 1 were characterized by negative ion photoelectron spectroscopy in the gas phase and by binding constant determinations in four solvents (i.e., CDCl3, CD2Cl2, CD3COCD3, and CD3CN). An intramolecular hydrogen bond network (HBN) in hexaol 1 was found to diminish its binding whereas the triol 2 is the strongest aliphatic hydroxyl-based receptor to date.

  18. Medium effects on the isomerization of an anionic polymethine dye

    NASA Astrophysics Data System (ADS)

    Tatikolov, Alexander S.; Costa, Sílvia M. B.

    2007-05-01

    Strong effects of electrophilic solvents on the processes of photoisomerization and thermal back isomerization of the photoisomer were found for an anionic polymethine dye, 9-fluorosubstituted oxonol. In particular, the photoisomerization quantum yield and the Arrhenius activation energy for the back isomerization decrease with the increase of the Dimroth-Reichardt solvation parameter ET(30), whereas the back isomerization rate constant increases with growing ET(30). The effects can be explained considering the electronic structure of oxonols, which possess lone electron pairs on oxygen atoms susceptible to electrophilic solvation.

  19. Use of certain alcohol ethoxylates to maintain protease stability in the presence of anionic surfactants

    Microsoft Academic Search

    Geoffrey L. Russell; Larry N. Britton

    2002-01-01

    Anionic surfactants, including linear alkylbenzene sulfonate (LAS), are known to decrease the stability of detergent proteases,\\u000a possibly by hastening autoproteolytic processes. Thus, protease shelf life in enzyme-containing, heavy-duty liquid laundry\\u000a detergents (HDL) is typically maintained by adding stabilizers, by limiting the level of interfering anionics, or by utilizing\\u000a more compatible anionics, such as alcohol ethoxysulfates (AES). This study examines the

  20. Stationary phase for the determination of fluoride and other inorganic anions

    Microsoft Academic Search

    Joachim Weiss; Sabine Reinhard; Christopher Pohl; Charanjit Saini; Latha Narayaran

    1995-01-01

    A pellicular anion-exchange column was developed for the determination of inorganic anions including fluoride and oxyhalides such as chlorite, chlorate and bromate. Compared with conventional latex-agglomerated resins, the new anion exchanger allows the retention of fluoride well out of the water dip with elution of sulfate in less than 15 min using a carbonate-hydrogencarbonate eluent under isocratic conditions. Because the

  1. Formulating middle-phase microemulsions using mixed anionic and cationic surfactant systems

    Microsoft Academic Search

    T. Doan; E. Acosta; J. F. Scamehorn; D. A. Sabatini

    2003-01-01

    Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid\\u000a crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby\\u000a allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role\\u000a of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase

  2. Nitrite-Templated Synthesis of Lanthanide-Containing [2]Rotaxanes for Anion Sensing**

    PubMed Central

    Langton, Matthew J; Blackburn, Octavia A; Lang, Thomas; Faulkner, Stephen; Beer, Paul D

    2014-01-01

    The first anion-templated synthesis of a lanthanide-containing interlocked molecule is demonstrated by utilizing a nitrite anion to template initial pseudorotaxane formation. Subsequent stoppering of the interpenetrated assembly allows for the preparation of a lanthanide-functionalized [2]rotaxane in high yield. Following removal of the nitrite anion template, the europium [2]rotaxane host is demonstrated to recognize and sense fluoride selectively. PMID:24989322

  3. The influence of soluble anions upon some physical and physico-chemical properties of soils 

    E-print Network

    Longenecker, Donald Edwin

    1957-01-01

    and Evaporation .. o ?>.... ... ?0. o o. ?. o ............ 3 B. Effect of Soluble Anions on the Cation Exchange Equilibrium .......................... .......... 5 Co Effect of Soluble Anions on Dispersion and Flocculation of Clays ...e.6o0.o..ooo0.oeooooo... Rate of Water into Soils ........ 41 (a) Experimental Procedure ???????o*o?oooo????o 42 (b) Discussion of Results .................. . 43 Part IVo Influence of Soluble Anions upon the Cation Exchange Equilibrium ...... ........ 50 (a) Experimental...

  4. Developmental changes in multispecific organic anion transporter 1 expression in the rat kidney1

    Microsoft Academic Search

    Noriko Nakajima; Takashi Sekine; Seok Ho Cha; Akihiro Tojo; Makoto Hosoyamada; Yoshikatsu Kanai; Kunimasa Yan; Shouichi Awa; Hitoshi Endou

    2000-01-01

    Developmental changes in multispecific organic anion transporter 1 expression in the rat kidney.BackgroundThe cDNA of the multispecific organic anion transporter 1 (OAT1) responsible for the tubular secretion of organic anions was recently isolated. In the current study, we investigated the developmental changes in OAT1 expression in the rat kidney.MethodsOntogenic expression of rat OAT1 was investigated by Northern blot, in situ

  5. Mapping photoautotrophic metabolism with isotopically nonstationary 13C flux analysis

    PubMed Central

    Young, Jamey D.; Shastri, Avantika A.; Stephanopoulos, Gregory; Morgan, John A.

    2011-01-01

    Understanding in vivo regulation of photoautotrophic metabolism is important for identifying strategies to improve photosynthetic efficiency or re-route carbon fluxes to desirable end products. We have developed an approach to reconstruct comprehensive flux maps of photoautotrophic metabolism by computational analysis of dynamic isotope labeling measurements and have applied it to determine metabolic pathway fluxes in the cyanobacterium Synechocystis sp. PCC6803. Comparison to a theoretically predicted flux map revealed inefficiencies in photosynthesis due to oxidative pentose phosphate pathway and malic enzyme activity, despite negligible photorespiration. This approach has potential to fill important gaps in our understanding of how carbon and energy flows are systemically regulated in cyanobacteria, plants, and algae. PMID:21907300

  6. Pulse radiolysis study of the formation and the reactivity of baicalin radical anion, and in comparison with rutin, quercetin and acyrlate ester radical anions in ethanol

    NASA Astrophysics Data System (ADS)

    Sun, Gang; Wang, Wenfeng; Wu, Jilan

    2007-06-01

    The reaction of solvated electrons with baicalin in N 2-saturated ethanol has been studied by pulse radiolysis. The results show that a solvated electron can add to baicalin and generate a baicalin radical anion with a maximum UV absorbance peak at 360 nm. Its molar extinction coefficient at this wavelength is 1.3×10 4 M -1 cm -1. The rate constant for the build-up of the baicalin radical anion is 1.3(±0.4)×10 10 M -1 s -1. Decay of the radical anion is induced by a proton transfer reaction and a recombination reaction, which involves a pseudo-first-order reaction with rate constant 2.6(±0.4)×10 3 s -1 and a second-order reaction with rate constant 1.3(±0.2)×10 9 M -1 s -1. The effect of acetaldehyde on the decay of the baicalin radical anion was also investigated. Electron transfer between the baicalin radical anion and acetaldehyde was not observed, probably due to the low rate of electron transfer between the baicalin radical anion and acetaldehyde. Reactivity of the rutin, quercetin, baicalin and ethyl acrylate radical anions are also compared.

  7. Expression and function of renal and hepatic organic anion transporters in extrahepatic cholestasis

    PubMed Central

    Brandoni, Anabel; Hazelhoff, María Herminia; Bulacio, Romina Paula; Torres, Adriana Mónica

    2012-01-01

    Obstructive jaundice occurs in patients suffering from cholelithiasis and from neoplasms affecting the pancreas and the common bile duct. The absorption, distribution and elimination of drugs are impaired during this pathology. Prolonged cholestasis may alter both liver and kidney function. Lactam antibiotics, diuretics, non-steroidal anti-inflammatory drugs, several antiviral drugs as well as endogenous compounds are classified as organic anions. The hepatic and renal organic anion transport pathways play a key role in the pharmacokinetics of these compounds. It has been demonstrated that acute extrahepatic cholestasis is associated with increased renal elimination of organic anions. The present work describes the molecular mechanisms involved in the regulation of the expression and function of the renal and hepatic organic anion transporters in extrahepatic cholestasis, such as multidrug resistance-associated protein 2, organic anion transporting polypeptide 1, organic anion transporter 3, bilitranslocase, bromosulfophthalein/bilirubin binding protein, organic anion transporter 1 and sodium dependent bile salt transporter. The modulation in the expression of renal organic anion transporters constitutes a compensatory mechanism to overcome the hepatic dysfunction in the elimination of organic anions. PMID:23197884

  8. Radiation induced redox reactions and fragmentation of constituent ions in ionic liquids. I. Anions.

    SciTech Connect

    Shkrob, I. A.; Marin, T.; Chemerisov, S.; Wishart, J. (Chemical Sciences and Engineering Division); (BNL); (Benedictine Univ.)

    2011-04-14

    Room temperature ionic liquids (IL) find increasing use for the replacement of organic solvents in practical applications, including their use in solar cells and electrolytes for metal deposition, and as extraction solvents for the reprocessing of spent nuclear fuel. The radiation stability of ILs is an important concern for some of these applications, as previous studies suggested extensive fragmentation of the constituent ions upon irradiation. In the present study, electron paramagnetic resonance (EPR) spectroscopy has been used to identify fragmentation pathways for constituent anions in ammonium, phosphonium, and imidazolium ILs. Many of these detrimental reactions are initiated by radiation-induced redox processes involving these anions. Scission of the oxidized anions is the main fragmentation pathway for the majority of the practically important anions; (internal) proton transfer involving the aliphatic arms of these anions is a competing reaction. For perfluorinated anions, fluoride loss following dissociative electron attachment to the anion can be even more prominent than this oxidative fragmentation. Bond scission in the anion was also observed for NO{sub 3}{sup -} and B(CN){sub 4}{sup -} anions and indirectly implicated for BF{sub 4}{sup -} and PF{sub 6}{sup -} anions. Among small anions, CF{sub 3}SO{sub 3}{sup -} and N(CN){sub 2}{sup -} are the most stable. Among larger anions, the derivatives of benzoate and imide anions were found to be relatively stable. This stability is due to suppression of the oxidative fragmentation. For benzoates, this is a consequence of the extensive sharing of unpaired electron density by the {pi}-system in the corresponding neutral radical; for the imides, this stability could be the consequence of N-N {sigma}{sup 2}{sigma}*{sup 1} bond formation involving the parent anion. While fragmentation does not occur for these 'exceptional' anions, H atom addition and electron attachment are prominent. Among the typically used constituent anions, aliphatic carboxylates were found to be the least resistant to oxidative fragmentation, followed by (di)alkyl phosphates and alkanesulfonates. The discussion of the radiation stability of ILs is continued in the second part of this study, which examines the fate of organic cations in such liquids.

  9. Correction: Aromatic sulfonate anion-induced pseudorotaxanes: environmentally benign synthesis, selectivity, and structural characterization.

    PubMed

    Gong, Han-Yuan; Tang, Feng; Rambo, Brett M; Cao, Rui; Xiang, Jun-Feng; Sessler, Jonathan L

    2015-02-01

    Correction for 'Aromatic sulfonate anion-induced pseudorotaxanes: environmentally benign synthesis, selectivity, and structural characterization' by Han-Yuan Gong et al., Chem. Commun., 2015, DOI: . PMID:25504052

  10. Role of Anions Associated with the Formation and Properties of Silver Clusters.

    PubMed

    Wang, Quan-Ming; Lin, Yu-Mei; Liu, Kuan-Guan

    2015-06-16

    Metal clusters have been very attractive due to their aesthetic structures and fascinating properties. Different from nanoparticles, each cluster of a macroscopic sample has a well-defined structure with identical composition, size, and shape. As the disadvantages of polydispersity are ruled out, informative structure-property relationships of metal clusters can be established. The formation of a high-nuclearity metal cluster involves the organization of metal ions into a complex entity in an ordered way. To achieve controllable preparation of metal clusters, it is helpful to introduce a directing agent in the formation process of a cluster. To this end, anion templates have been used to direct the formation of high nuclearity clusters. In this Account, the role of anions played in the formation of a variety of silver clusters has been reviewed. Silver ions are positively charged, so anionic species could be utilized to control the formation of silver clusters on the basis of electrostatic interactions, and the size and shape of the resulted clusters can be dictated by the templating anions. In addition, since the anion is an integral component in the silver clusters described, the physical properties of the clusters can be modulated by functional anions. The templating effects of simple inorganic anions and polyoxometales are shown in silver alkynyl clusters and silver thiolate clusters. Intercluster compounds are also described regarding the importance of anions in determining the packing of the ion pairs and making contribution to electron communications between the positive and negative counterparts. The role of the anions is threefold: (a) an anion is advantageous in stabilizing a cluster via balancing local positive charges of the metal cations; (b) an anion template could help control the size and shape of a cluster product; (c) an anion can be a key factor in influencing the function of a cluster through bringing in its intrinsic properties. Properties including electron communication, luminescent thermochromism, single-molecule magnet, and intercluster charge transfer associated with anion-directed silver clusters have been discussed. We intend to attract chemists' attention to the role that anions could play in determining the structures and properties of metal complexes, especially clusters. We hope that this Account will stimulate more efforts in exploiting new role of anions in various metal cluster systems. Anions can do much more than counterions for charge balance, and they should be considered in the design and synthesis of cluster-based functional materials. PMID:25984753

  11. Reillex/trademark/ HPQ: A new, macroporous polyvinylpyridine resin for separating plutonium using nitrate anion exchange

    SciTech Connect

    Marsh, S.F.

    1989-01-01

    Anion exchange in nitric acid is the major aqueous process used to recover and purify plutonium from impure scrap materials. Most strong-base anion exchange resins incorporate a styrene-divinylbenzene copolymer. A newly available, macroporous anion exchange resin based on a copolymer of 1-methyl-4-vinylpyridine and divinylbenzene has been evaluated. Comparative data for Pu(IV) sorption kinetics and capacity are presented for this new resin and two other commonly used anion exchange resins. The new resin offers high capacity and rapid sorption kinetics for Pu(IV) from nitric acid, as well as greater stability to chemical and radiolytic degradation. 8 refs., 12 figs.

  12. GAPS IN THE GD-1 STAR STREAM

    SciTech Connect

    Carlberg, R. G. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Grillmair, C. J., E-mail: carlberg@astro.utoronto.ca, E-mail: carl@ipac.caltech.edu [Spitzer Science Center, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2013-05-10

    GD-1 is a long, thin, Milky Way star stream that has readily visible density variations along its length. We quantify the locations, sizes, and statistical significance of the density structure, i.e., gaps, using a set of scaled filters. The shapes of the filters are based on the gaps that develop in simulations of dark matter sub-halos crossing a star stream. The high Galactic latitude 8.4 kpc long segment of GD-1 that we examine has 8 {+-} 3 gaps of 99% significance or greater, with the error estimated on the basis of tests of the gap-filtering technique. The cumulative distribution of gaps more than three times the width of the stream is in good agreement with predictions for dark matter sub-halo encounters with cold star streams. The number of gaps narrower than three times the width of the GD-1 stream falls well below the cold stream prediction which is taken into account for the gap creation rate integrated over all sizes. Simple warm stream simulations scaled to GD-1 show that the falloff in gaps is expected for sub-halos below a mass of 10{sup 6} M{sub Sun }. The GD-1 gaps requires 100 sub-halos >10{sup 6} M{sub Sun} within 30 kpc, the apocenter of GD-1 orbit. These results are consistent with LCDM sub-halo predictions but further improvements in stream signal-to-noise and gap modeling will be welcome.

  13. Starch Metabolism in Arabidopsis

    PubMed Central

    Streb, Sebastian; Zeeman, Samuel C.

    2012-01-01

    Starch is the major non-structural carbohydrate in plants. It serves as an important store of carbon that fuels plant metabolism and growth when they are unable to photosynthesise. This storage can be in leaves and other green tissues, where it is degraded during the night, or in heterotrophic tissues such as roots, seeds and tubers, where it is stored over longer time periods. Arabidopsis accumulates starch in many of its tissues, but mostly in its leaves during the day. It has proven to be a powerful genetic system for discovering how starch is synthesised and degraded, and new proteins and processes have been discovered. Such work has major significance for our starch crops, whose yield and quality could be improved by the application of this knowledge. Research into Arabidopsis starch metabolism has begun to reveal how its daily turnover is integrated into the rest of metabolism and adapted to the environmental conditions. Furthermore, Arabidopsis mutant lines deficient in starch metabolism have been employed as tools to study other biological processes ranging from sugar sensing to gravitropism and flowering time control. This review gives a detailed account of the use of Arabidopsis to study starch metabolism. It describes the major discoveries made and presents an overview of our understanding today, together with some as-yet unresolved questions. PMID:23393426

  14. Design, crystal structures and magnetic properties of anionic salts containing fullerene C?? and indium(III) bromide phthalocyanine radical anions.

    PubMed

    Konarev, Dmitri V; Kuzmin, Alexey V; Khasanov, Salavat S; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

    2014-09-14

    Two salts containing fullerene C60 and indium(III) bromide phthalocyanine (Pc) radical anions have been obtained as single crystals: (TBA(+))3(C60?(-)){In(III)(Br)(Pc)?(-)}(Br(-))·C6H4Cl2 (1) and (TEA(+))2(C60?(-)){In(III)(Br)(Pc)?(-)}·C6H4Cl2·C6H14 (2) where TBA(+) and TEA(+) are tetrabutyl- and tetraethylammonium cations, respectively. The presence of both radical anions is supported by spectra of 1 and 2 in the NIR and IR-ranges. The salts contain zigzag C60?(-) chains with 10.136 and 10.383 Å center-to-center (ctc) distances in 1 and a uniform ctc distance of 10.186 Å in 2. In 1, the C60?(-) radical anions are dimerized in the 180-140 K range to form singly bonded (C60(-))2 dimers, whereas they remain monomeric in 2. Effective packing of planar In(Br)(Pc)?(-) and spherical C60?(-) is attained by introducing fullerene spheres between the phenylene substituents of Pc allowing the formation of multiple van der Waals contacts between them. The effective magnetic moment of 1 at 300 K is 2.35?(B), indicating a contribution of both C60?(-) and In(Br)(Pc)?(-) species having S = 1/2 spin state. There is strong antiferromagnetic coupling of spins between fullerenes in the chains and fullerenes and phthalocyanines in the monomeric phase of 1 with the Weiss temperature of -120 K in the 300-180 K range. The formation of diamagnetic (C60(-))2 dimers switches off magnetic coupling and magnetically isolates In(Br)(Pc)?(-) (Weiss temperature is only -1 K in the 140-10 K range). Magnetic behavior of 2 is described by the Curie-Weiss law with weak ferromagnetic coupling of spins with ? = +7.6 K in the 50-300 K range. Both salts manifest single Lorentzian EPR lines at room temperature with g = 1.9911 and a linewidth (?H) of 25.4 mT (1) and g = 1.9956 and ?H = 7.5 mT (2) which can be attributed to both C60?(-) and In(Br)(Pc)?(-) species having strong exchange interaction. An asymmetric signal with the main component at g = 1.989-1.965 in the dimeric phase of 1 was attributed to the In(Br)(Pc)?(-) radical anions. PMID:25037021

  15. Silver(I)-Polynitrile Network Solids for Anion Exchange: Anion-Induced Transformation of Supramolecular Structure in the

    E-print Network

    Paik Suh, Myunghyun

    topologies depend on the counteranion, [Ag(C14H20N6)(NO3)] (1), [Ag(C14H20N6)]CF3SO3 (2), and [Ag(C14H20N6)]ClO4 (3), have been prepared by the self-assembly of AgX (X ) NO3 -, CF3SO3 -, and ClO4, and 3, are five, four, and six, respectively. Interestingly, the CF3SO3 - anion of 2 is exchanged

  16. Crown compounds for anions. Spectroscopic and theoretical studies of complexation of borohydride anions with cyclic trimeric perfluoro- o-phenylenemercury

    Microsoft Academic Search

    L. N Saitkulova; E. V Bakhmutova; E. S Shubina; I. A Tikhonova; G. G Furin; V. I Bakhmutov; N. P Gambaryan; A. L Chistyakov; I. V Stankevich; V. B Shur; L. M Epstein

    1999-01-01

    It has been shown by IR and NMR spectroscopy that cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 (1) is capable of binding borohydride anions in THF and 1,2-dichloroethane solutions to form complexes {[(o-C6F4Hg)3](BH4)2}2? (2) and {[(o-C6F4Hg)3]2(BH4)}? (3). According to the IR data, complex 2 contains both terminal and coordinated B–H bonds while all four B–H bonds of the BH4? ion are coordinated with

  17. Reactions between CO and small molybdenum suboxide cluster anions

    SciTech Connect

    Wyrwas, Richard B.; Robertson, Erika M.; Jarrold, Caroline Chick [Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405 (United States)

    2007-06-07

    Reaction products resulting from small molybdenum suboxide cluster anions and carbon monoxide were studied with both mass spectrometry and anion photoelectron (PE) spectroscopy. In addition to the C{sub 6}O{sub 6}{sup -} product proposed previously, a number of unsaturated carbonyls were identified as terminal products in these reactions. A new PE spectrum of what may be C{sub 6}O{sub 6}{sup -}, in which the contribution from the Fe(CO){sub 4}{sup -} contaminant is subtracted, is reported. Additionally, the PE spectra of Mo(CO){sub 5}{sup -}, MoO(CO){sub 3}{sup -}, and MoO{sub 2}(CO){sub n}{sup -} (n=1 and 2) are presented, along with a new PE spectrum of an additional contaminant, Ni(CO){sub 3}{sup -}. Evidence of photodissociation of MoO(CO){sub 3}{sup -} to MoO{sup -}+3 CO is observed in the PE spectrum of MoO(CO){sub 3}{sup -}.

  18. Cation and anion selectivity of zwitterionic salicylaldoxime metal salt extractants.

    PubMed

    Forgan, Ross S; Davidson, James E; Fabbiani, Francesca P A; Galbraith, Stuart G; Henderson, David K; Moggach, Stephen A; Parsons, Simon; Tasker, Peter A; White, Fraser J

    2010-02-21

    3-Dialkylaminomethyl substituted salicylaldoximes are efficient metal salt extractants, and, in contrast to related "salen"-based reagents, are sufficiently stable to acid hydrolysis to allow commercial application in base metal recovery. Crystal structures show that metal salts are bound by a zwitterionic form of the reagents, with copper(II) nitrate, tetrafluoroborate and trifluoroacetate forming [Cu()(2)X(2)] assemblies in a tritopic arrangement with a trans-disposition of the anions outwith the coordination sphere. Copper(II) chloride, bromide and zinc(II) chloride form 1:1 assemblies, [Cu()X(2)], with the halides in the inner coordination sphere of the metal, leading to high chloride selectivity and very good mass transport efficiencies of CuCl(2). Introduction of the anion-binding sites into the salicylaldoxime extractants changes their cation selectivities; the ligands co-extract small amounts of Fe(III) along with Cu(II) from mixed metal aqueous feed solutions, an issue which will need to be addressed prior to industrial application. PMID:20449420

  19. Photo-Detachment of a Noncollinear Triatomic Anion

    NASA Astrophysics Data System (ADS)

    Afaq, A.; Farooq, K.

    2014-12-01

    Photo-detachment of a noncollinear triatomic anion is investigated by considering each atom of the molecular anion as a coherent source of detached-electron waves, originating in all possible directions. The waves traveling along three different trajectories result in a quantum interference that displays on a screen placed at a very large distance from the system. To explain this quantum interference, an analytical formula of detached-electron flux is derived using a collinear three-center model recently published. The detached-electron flux versus laser photon energy expression displays molecular geometry-dependent oscillatory structures on an observation plane. This oscillatory behavior in the result can be explained using the semiclassical closed-orbit theory. The outgoing electron waves produced from one coherent center are propagated in the vicinity of the sources at other two coherent centers which cause these oscillations. It is also observed that in a particular case, the noncollinear triatomic system reduces to the collinear three-center system.

  20. Biocompatible anionic polyelectrolyte for improved liposome based gene transfection.

    PubMed

    Chen, Ming; Zeng, Zhiying; Qu, Xiaohuan; Tang, Yaqin; Long, Qipeng; Feng, Xuli

    2015-07-25

    Cationic liposomes have been widely used as efficient gene carriers. However, the serious cytotoxicity caused by exposed positive charges restricts the further application of those kinds of gene vectors. Thus, it is challenging to develop biocompatiable non-positive charge carriers to achieve high gene transfection efficiencies. Herein, we report a novel design by pasting biocompatible anionic polyelectrolyte, namely alginic acid, hyaluronic acid, pectin and polyglutamic acid, to the positive charge surface of liposome/pDNA complex. Through shielding the positive charges, the new gene carriers show decreased cytotoxicity while still maintaining high transfection efficiency. To be noted, the complex formed by coating polyglutamic acid to the surface of liposome/pDNA greatly enhanced the transfection efficiency in HepG2 cells, and the use of pectin shows increased transfection in MCF-7 cells. Hemolysis assay proved a possible mechanism that when the new gene complex was internalized into cells, as acidity increases, more side chains become hydrophobic, and thus destabilizing the endosomal membrane to accelerate DNA escape. The present results suggest that such anionic polyelectrolyte covered liposome based carrier possess promising application for clinical gene delivery. PMID:26004001

  1. Encapsulation of Halocarbons in a Tetrahedral Anion Cage.

    PubMed

    Yang, Dong; Zhao, Jie; Zhao, Yanxia; Lei, Yibo; Cao, Liping; Yang, Xiao-Juan; Davi, Martin; de Sousa Amadeu, Nader; Janiak, Christoph; Zhang, Zhibin; Wang, Yao-Yu; Wu, Biao

    2015-07-20

    Caged supramolecular systems are promising hosts for guest inclusion, separation, and stabilization. Well-studied examples are mainly metal-coordination-based or covalent architectures. An anion-coordination-based cage that is capable of encapsulating halocarbon guests is reported for the first time. This A4 L4 -type (A=anion) tetrahedral cage, [(PO4 )4 L4 ](12-) , assembled from a C3 -symmetric tris(bisurea) ligand (L) and phosphate ion (PO4 (3-) ), readily accommodates a series of quasi-tetrahedral halocarbons, such as the Freon components CFCl3 , CF2 Cl2 , CHFCl2 , and C(CH3 )F3 , and chlorocarbons CH2 Cl2 , CHCl3 , CCl4 , C(CH3 )Cl3 , C(CH3 )2 Cl2 , and C(CH3 )3 Cl. The guest encapsulation in the solid state is confirmed by crystal structures, while the host-guest interactions in solution were demonstrated by NMR techniques. PMID:26053734

  2. [Permeability of pannexin 1 channels to large anions].

    PubMed

    Romanov, R A; Rogachevskaia, O A; Kolesnikova, A S; Khokhlov, A A; Kolesnikov, S S

    2012-12-01

    It is widely accepted that ATP secretion in diverse cells involves pannexin 1 (Panx1) that functions as an ATP-permeable channel. We analyzed the permeability of Panx1 channels heterologically expressed in HEK-293 cells to a variety of anions, including ATP. As was demonstrated in electrophysiological experiments, relative permeabilities of studied species follow the sequence: C1- > MeSO4 > gluconate > HEPES. This sequence suggests that ATP, which is more than twice as large as HEPES by mass, is most likely to be negligibly permeable to Panx1 channels. This inference was verified in experiments, where ATP secretion from Panx1-positive HEK-293 cells was assayed with the ATP-biosensor approach. It was shown that the heterologous expression of Panx1 in HEK-293, which normally are not ATP-secretive, did not endow transfected cells with the ability to liberate ATP in response to stimulation. Our data indicate that Panx1 alone forms anion channels with too low ATP permeability to mediate the secretory function. Nevertheless, the possibility still remains that certain ATP-permeable channels are heteromers of Panx1 and some other channel subunit(s). PMID:23461201

  3. Valence calculations of lanthanide anion binding energies: a comprehensive study

    NASA Astrophysics Data System (ADS)

    O'Malley, Steven M.; Beck, Donald R.

    2009-05-01

    We have applied a methodology of universal jls restrictions on the 4f^n subgroup of relativistic configuration-interaction calculations of progressively more complex lanthanide anionsootnotetextS. M. O'Malley and D. R. Beck, Phys. Rev. A 77, 012505 (2008).^,ootnotetextS. M. O'Malley and D. R. Beck, Phys. Rev. A 78, 012510 (2008).^,ootnotetextS. M. O'Malley and D. R. Beck, Phys. Rev. A, in press.. Our completed study of the row predicts bound 6p attachments to all lanthanide ground state configurations except Yb, additional 6p attachments to excited opposite parity configurations in Tb and Lu, and 6s attachments to excited open-6s thresholds in La, Ce, Pr, and Gd. In total we predict more than 100 bound states for the lanthanide anions, and we hope this comprehensive study encourages further experimentalootnotetexte.g. V. T. Davis et al., Nucl. Instrum. Methods Phys. Res. B 241, 118 (2005).^,ootnotetexte.g. C. W. Walter et al., Phys. Rev. A 76, 052702 (2007). interest in these anions. Such measurements will be useful in ``fine tuning'' these ab initio binding energies to account for missing core-valence correlation and the approximations that were necessary in these complex calculations.

  4. k-Gap Interval Graphs

    E-print Network

    Fomin, Fedor V; Golovach, Petr; Suchan, Karol; Szeider, Stefan; van Leeuwen, Erik Jan; Vatshelle, Martin; Villanger, Yngve

    2011-01-01

    We initiate the study of a new parameterization of graph problems. In a multiple interval representation of a graph, each vertex is associated to at least one interval of the real line, with an edge between two vertices if and only if an interval associated to one vertex has a nonempty intersection with an interval associated to the other vertex. A graph on n vertices is a k-gap interval graph if it has a multiple interval representation with at most n+k intervals in total. In order to scale up the nice algorithmic properties of interval graphs (where k=0), we parameterize graph problems by k, and find FPT algorithms for several problems, including Feedback Vertex Set, Dominating Set, Independent Set, Clique, Clique Cover, and Multiple Interval Transversal. The Coloring problem turns out to be W[1]-hard and we design an XP algorithm for the recognition problem.

  5. Enhancement of Anion Binding in Lanthanide Optical Sensors

    PubMed Central

    Cable, Morgan L.; Kirby, James P.; Gray, Harry B.; Ponce, Adrian

    2013-01-01

    In the design of molecular sensors, researchers exploit binding interactions that are usually defined in terms of topology and charge complementarity. The formation of complementary arrays of highly cooperative, noncovalent bonding networks facilitates protein-ligand binding, leading to motifs such as the ‘lock-and-key.’ Synthetic molecular sensors often employ metal complexes as key design elements as a way to construct a binding site with the desired shape and charge to achieve target selectivity. In transition metal complexes, coordination number, structure and ligand dynamics are governed primarily by a combination of inner-sphere covalent and outer-sphere noncovalent interactions. These interactions provide a rich variable space that researchers can use to tune structure, stability and dynamics. In contrast, lanthanide(III)-ligand complex formation and ligand-exchange dynamics are dominated by reversible electrostatic and steric interactions, because the unfilled f shell is shielded by the larger, filled d shell. Luminescent lanthanides such as terbium, europium, dysprosium and samarium display many photophysical properties that make them excellent candidates for molecular sensor applications. Complexes of lanthanide ions act as receptors that exhibit a detectable change in metal-based luminescence upon binding of an anion. In our work on sensors for detection of dipicolinate, the unique biomarker of bacterial spores, we discovered that the incorporation of an ancillary ligand (AL) can enhance binding constants of target anions to lanthanide ions by as much as two orders of magnitude. In this Account, we show that selected ALs in lanthanide/anion systems greatly improve sensor performance for medical, planetary science and biodefense applications. We suggest that the observed anion binding enhancement could result from an AL-induced increase in positive charge at the lanthanide ion binding site. This effect depends on lanthanide polarizability, which can be established from the ionization energy of Ln3+ ? Ln4+. These results account for the order Tb3+ > Dy3+ > Eu3+ ? Sm3+. As with many lanthanide properties, ranging from hydration enthalpy to vaporization energy, this AL-induced enhancement shows a large discrepancy between Tb3+ and Eu3+ despite their similarity in size, a phenomenon known as the ‘gadolinium break.’ This discrepancy, based on the unusual stabilities of the Eu2+ and Tb4+ oxidation states, results from the half-shell effect, as both of these ions have half-filled 4f-shells. The high polarizability of Tb3+ explains the extraordinarily large increase in the binding affinity of anions for terbium compared to other lanthanides. We recommend that researchers consider this AL-induced enhancement when designing lanthanide-macrocycle optical sensors. Ancillary ligands also can reduce the impact of interfering species such as phosphate) commonly found in environmental and physiological samples. PMID:24032446

  6. Imaging metabolic syndrome

    PubMed Central

    Han, Weiping; Chuang, Kai-Hsiang; Chang, Young-Tae; Olivo, Malini; Velan, S Sendhil; Bhakoo, Kishore; Townsend, David; Radda, George K

    2010-01-01

    Metabolic syndrome is a fast growing public health burden for almost all the developed countries and many developing nations. Despite intense efforts from both biomedical and clinical scientists, many fundamental questions regarding its aetiology and development remain unclear, partly due to the lack of suitable imaging technologies to visualize lipid composition and distribution, insulin secretion, ?-cell mass and functions in vivo. Such technologies would not only impact on our understanding of the complexity of metabolic disorders such as obesity and diabetes, but also aid in their diagnosis, drug development and assessment of treatment efficacy. In this article we discuss and propose several strategies for visualization of physiological and pathological changes that affect pancreas and adipose tissue as a result of the development of metabolic diseases. PMID:20533426

  7. Metabolism of phencyclidine

    SciTech Connect

    Hoag, M.K.P.

    1987-01-01

    Phencyclidine (PCP) is a drug of abuse which may produce, in some users, a persistent schizophreniform psychosis. The possibility that long term effects of PCP are mediated by metabolic activation of the parent compound to reactive species is consistent with the demonstration of metabolism-dependent covalent binding of radiolabeled PCP in vivo and in vitro to macromolecules in rodent lung, liver, and kidney. Formation of the electrophilic iminium ion metabolite of PCP is believed to be critical for covalent binding since binding was inhibited by cyanide ion at concentrations which did not inhibit metabolism of PCP but did trap the iminium ion to form the corresponding alpha-aminonitrile. The present studies were designed to characterize further the biological fate of PCP by identifying possible macromolecular targets of the reactive metabolite(s).

  8. FGFs and metabolism.

    PubMed

    Kharitonenkov, Alexei

    2009-12-01

    Although the first fibroblast growth factor (FGF) was discovered as a mitogen on 3T3 fibroblasts [Gospodarowicz D: Localization of a fibroblast growth factor and its effect alone and with hydrocortisone on 3T3 cell growth. Nature 1974, 249:123-127], this name is functionally misleading. This group of secreted proteins consisting now of 22 members was composed based on common structural characteristics rather than on functional similarity. Thus, only a few members of the human FGF family promote growth and strictly act on fibroblasts. While the research in the last century firmly established FGFs as key players in development, morphogenesis, angiogenesis, hematopoiesis, and survival, this decade provided clues on FGF roles in metabolism. In particular, 'hormone-like' FGF19, FGF21, and FGF23, were shown to be involved in glucose, lipid, bile acid, phosphate, and vitamin D metabolism but the mechanisms underlying their functions as metabolic regulators are still being defined. PMID:19683963

  9. Metabolism at Evolutionary Optimal States

    PubMed Central

    Rabbers, Iraes; van Heerden, Johan H.; Nordholt, Niclas; Bachmann, Herwig; Teusink, Bas; Bruggeman, Frank J.

    2015-01-01

    Metabolism is generally required for cellular maintenance and for the generation of offspring under conditions that support growth. The rates, yields (efficiencies), adaptation time and robustness of metabolism are therefore key determinants of cellular fitness. For biotechnological applications and our understanding of the evolution of metabolism, it is necessary to figure out how the functional system properties of metabolism can be optimized, via adjustments of the kinetics and expression of enzymes, and by rewiring metabolism. The trade-offs that can occur during such optimizations then indicate fundamental limits to evolutionary innovations and bioengineering. In this paper, we review several theoretical and experimental findings about mechanisms for metabolic optimization. PMID:26042723

  10. Metabolism at evolutionary optimal States.

    PubMed

    Rabbers, Iraes; van Heerden, Johan H; Nordholt, Niclas; Bachmann, Herwig; Teusink, Bas; Bruggeman, Frank J

    2015-01-01

    Metabolism is generally required for cellular maintenance and for the generation of offspring under conditions that support growth. The rates, yields (efficiencies), adaptation time and robustness of metabolism are therefore key determinants of cellular fitness. For biotechnological applications and our understanding of the evolution of metabolism, it is necessary to figure out how the functional system properties of metabolism can be optimized, via adjustments of the kinetics and expression of enzymes, and by rewiring metabolism. The trade-offs that can occur during such optimizations then indicate fundamental limits to evolutionary innovations and bioengineering. In this paper, we review several theoretical and experimental findings about mechanisms for metabolic optimization. PMID:26042723

  11. Ontogeny and sorafenib metabolism

    PubMed Central

    Zimmerman, Eric I.; Roberts, Justin L.; Li, Lie; Finkelstein, David; Gibson, Alice; Chaudhry, Amarjit S.; Schuetz, Erin G.; Rubnitz, Jeffrey E.; Inaba, Hiroto; Baker, Sharyn D.

    2012-01-01

    Purpose To investigate the role of ontogeny in sorafenib metabolism to the equipotent active metabolite sorafenib N-oxide. Experimental Design Steady-state pharmacokinetic studies of sorafenib and metabolites were performed in thirty children and young adults (17 males; median age, 9.5 years) receiving sorafenib 150 mg/m2 or 200 mg/m2 twice daily. Sorafenib metabolism was evaluated in vitro at 10 µM using a panel of purified human cytochrome P450 (CYP) enzymes. Sorafenib metabolism and CYP3A4 expression was evaluated in 52 human liver samples from donors ? 20 years old. The drug-drug interaction potential between sorafenib and azole antifungal agents was evaluated in vitro and in vivo. Results No age-related differences in sorafenib apparent oral clearance were observed. Mean sorafenib N-oxide metabolite ratio was 0.27±0.14. In children ? 10 years of age, boys had approximately 2-fold higher N-oxide ratios than girls (0.40±0.15 versus 0.22±0.12, P = 0.026). Of the CYPs evaluated, sorafenib was exclusively metabolized to sorafenib N-oxide by CYP3A4. A trend for increased N-oxide formation in boys was observed in liver samples, which correlated with CYP3A4 mRNA expression. Posaconazole and voriconazole potently inhibited sorafenib N-oxide formation in vitro, and reduced sorafenib N-oxide formation in 3 children given sorafenib concurrent with azoles. Conclusion We have identified several factors affecting inter-patient variability in sorafenib metabolism to the active N-oxide metabolite including age, sex, and concurrent treatment with azole antifungals. This knowledge may provide important considerations for the clinical use of sorafenib in children and possibly other kinase inhibitors undergoing CYP3A4-mediated metabolism. PMID:22927483

  12. Nitrile Metabolizing Yeasts

    NASA Astrophysics Data System (ADS)

    Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

    Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing enzymes of yeasts.

  13. Ecology of tropical butterflies in rainforest gaps

    Microsoft Academic Search

    J. Hill; K. Hamer; J. Tangah; M. Dawood

    2001-01-01

    Tropical forest gaps are ephemeral and patchily distributed within forest areas and have very different light environments compared with closed-canopy forest. We used fruit-baited traps to investigate if gaps are exploited by more opportunistic butterfly species compared with closed-canopy forest. Gaps supported a higher diversity of butterflies in terms of species evenness but closed-canopy sites contained species with more restricted

  14. The gap theory in forest dynamics

    Microsoft Academic Search

    Shin-Ichi Yamamoto

    1992-01-01

    Since the late 1970s, ecologists interested in forest dynamics have focused their attention to the responses of individuals,\\u000a populations and communities to “gaps” which are openings created in the forest canopy. This review intended to introduce some\\u000a collective knowledge on major subjects of the gap theory in forest dynamics, in relation to gap-disturbance regimes, tree\\u000a regeneration behaviour and community structure.

  15. Equine metabolic syndrome.

    PubMed

    Frank, Nicholas

    2011-04-01

    The concept of an equine metabolic syndrome (EMS) was first proposed in 2002. This concept has developed over time, and EMS was recently described in a consensus statement released by the American College of Veterinary Internal Medicine. In human medicine, metabolic syndrome (MetS) refers to a set of risk factors that predict the risk of cardiovascular disease, including obesity, glucose intolerance and insulin resistance (IR), dyslipidemia, microalbuminuria, and hypertension. EMS shares some of the features of MetS, including increased adiposity, hyperinsulinemia, IR, but differs in that laminitis is the primary disease of interest. PMID:21392655

  16. Drug metabolism and ageing

    PubMed Central

    Kinirons, M T; O'Mahony, M S

    2004-01-01

    Important changes in drug metabolism occur with ageing. Age-associated reductions in function of some but not all cytochrome P450 enzymes (CYPs) have been described. Induction and inhibition of CYPs needs to be revisited in light of recent advances. The function and pharmacology of transporters have not yet been examined for an age-related effect. Finally, the concept of frailty is being underpinned by studies documenting a decline in drug metabolism and changes in disposition in frail older people compared with either healthy elderly or the young. PMID:15089805

  17. Structural Dynamics of Tropical Moist Forest Gaps.

    PubMed

    Hunter, Maria O; Keller, Michael; Morton, Douglas; Cook, Bruce; Lefsky, Michael; Ducey, Mark; Saleska, Scott; de Oliveira, Raimundo Cosme; Schietti, Juliana

    2015-01-01

    Gap phase dynamics are the dominant mode of forest turnover in tropical forests. However, gap processes are infrequently studied at the landscape scale. Airborne lidar data offer detailed information on three-dimensional forest structure, providing a means to characterize fine-scale (1 m) processes in tropical forests over large areas. Lidar-based estimates of forest structure (top down) differ from traditional field measurements (bottom up), and necessitate clear-cut definitions unencumbered by the wisdom of a field observer. We offer a new definition of a forest gap that is driven by forest dynamics and consistent with precise ranging measurements from airborne lidar data and tall, multi-layered tropical forest structure. We used 1000 ha of multi-temporal lidar data (2008, 2012) at two sites, the Tapajos National Forest and Ducke Reserve, to study gap dynamics in the Brazilian Amazon. Here, we identified dynamic gaps as contiguous areas of significant growth, that correspond to areas > 10 m2, with height <10 m. Applying the dynamic definition at both sites, we found over twice as much area in gap at Tapajos National Forest (4.8 %) as compared to Ducke Reserve (2.0 %). On average, gaps were smaller at Ducke Reserve and closed slightly more rapidly, with estimated height gains of 1.2 m y-1 versus 1.1 m y-1 at Tapajos. At the Tapajos site, height growth in gap centers was greater than the average height gain in gaps (1.3 m y-1 versus 1.1 m y-1). Rates of height growth between lidar acquisitions reflect the interplay between gap edge mortality, horizontal ingrowth and gap size at the two sites. We estimated that approximately 10 % of gap area closed via horizontal ingrowth at Ducke Reserve as opposed to 6 % at Tapajos National Forest. Height loss (interpreted as repeat damage and/or mortality) and horizontal ingrowth accounted for similar proportions of gap area at Ducke Reserve (13 % and 10 %, respectively). At Tapajos, height loss had a much stronger signal (23 % versus 6 %) within gaps. Both sites demonstrate limited gap contagiousness defined by an increase in the likelihood of mortality in the immediate vicinity (~6 m) of existing gaps. PMID:26168242

  18. Structural Dynamics of Tropical Moist Forest Gaps

    PubMed Central

    Hunter, Maria O.; Keller, Michael; Morton, Douglas; Cook, Bruce; Lefsky, Michael; Ducey, Mark; Saleska, Scott; de Oliveira, Raimundo Cosme; Schietti, Juliana

    2015-01-01

    Gap phase dynamics are the dominant mode of forest turnover in tropical forests. However, gap processes are infrequently studied at the landscape scale. Airborne lidar data offer detailed information on three-dimensional forest structure, providing a means to characterize fine-scale (1 m) processes in tropical forests over large areas. Lidar-based estimates of forest structure (top down) differ from traditional field measurements (bottom up), and necessitate clear-cut definitions unencumbered by the wisdom of a field observer. We offer a new definition of a forest gap that is driven by forest dynamics and consistent with precise ranging measurements from airborne lidar data and tall, multi-layered tropical forest structure. We used 1000 ha of multi-temporal lidar data (2008, 2012) at two sites, the Tapajos National Forest and Ducke Reserve, to study gap dynamics in the Brazilian Amazon. Here, we identified dynamic gaps as contiguous areas of significant growth, that correspond to areas > 10 m2, with height <10 m. Applying the dynamic definition at both sites, we found over twice as much area in gap at Tapajos National Forest (4.8 %) as compared to Ducke Reserve (2.0 %). On average, gaps were smaller at Ducke Reserve and closed slightly more rapidly, with estimated height gains of 1.2 m y-1 versus 1.1 m y-1 at Tapajos. At the Tapajos site, height growth in gap centers was greater than the average height gain in gaps (1.3 m y-1 versus 1.1 m y-1). Rates of height growth between lidar acquisitions reflect the interplay between gap edge mortality, horizontal ingrowth and gap size at the two sites. We estimated that approximately 10 % of gap area closed via horizontal ingrowth at Ducke Reserve as opposed to 6 % at Tapajos National Forest. Height loss (interpreted as repeat damage and/or mortality) and horizontal ingrowth accounted for similar proportions of gap area at Ducke Reserve (13 % and 10 %, respectively). At Tapajos, height loss had a much stronger signal (23 % versus 6 %) within gaps. Both sites demonstrate limited gap contagiousness defined by an increase in the likelihood of mortality in the immediate vicinity (~6 m) of existing gaps. PMID:26168242

  19. Organic anion transporting polypeptides in the hepatic uptake of PBDE congeners in mice

    SciTech Connect

    Pacyniak, Erik [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States)] [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); Hagenbuch, Bruno [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States) [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); The University of Kansas Cancer Center, Kansas City, KS (United States); Klaassen, Curtis D. [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States)] [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); Lehman-McKeeman, Lois [Bristol Myers Squibb Co., Princeton, NJ (United States)] [Bristol Myers Squibb Co., Princeton, NJ (United States); Guo, Grace L., E-mail: lguo@kumc.edu [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States)

    2011-11-15

    BDE47, BDE99 and BDE153 are the predominant polybrominated diphenyl ether (PBDE) congeners detected in humans and can induce drug metabolizing enzymes in the liver. We have previously demonstrated that several human liver organic anion transporting polypeptides (humans: OATPs; rodents: Oatps) can transport PBDE congeners. Mice are commonly used to study the toxicity of chemicals like the PBDE congeners. However, the mechanism of the hepatic PBDE uptake in mice is not known. Therefore, the purpose of the current study was to test the hypothesis that BDE47, BDE99, and BDE153 are substrates of mouse hepatic Oatps (Oatp1a1, Oatp1a4, Oatp1b2, and Oatp2b1). We used Human Embryonic Kidney 293 (HEK293) cells transiently expressing individual Oatps and quantified the uptake of BDE47, BDE99, and BDE153. Oatp1a4, Oatp1b2, and Oatp2b1 transported all three PBDE congeners, whereas Oatp1a1 did transport none. Kinetic studies demonstrated that Oatp1a4 and Oatp1b2 transported BDE47 with the greatest affinity, followed by BDE99 and BDE153. In contrast, Oatp2b1 transported all three PBDE congeners with similar affinities. The importance of hepatic Oatps for the liver accumulation of BDE47 was confirmed using Oatp1a4-, and Oatp1b2-null mice. -- Highlights: Black-Right-Pointing-Pointer PBDE congeners are substrates of OATPs expressed in human hepatocytes. Black-Right-Pointing-Pointer Mice are commonly used to study the toxicity of chemicals like the PBDE congeners. Black-Right-Pointing-Pointer Oatp1a4, Oatp1b2, and Oatp2b1 transported all three PBDE congeners in vitro. Black-Right-Pointing-Pointer In vivo Oatp1a4 plays a minor and Oatp1b2 a major role in BDE47 liver accumulation.

  20. Erythroid anion transporter assembly is mediated by a developmentally regulated recruitment onto a preassembled membrane cytoskeleton

    PubMed Central

    1987-01-01

    Analysis of the expression and assembly of the anion transporter by metabolic pulse-chase and steady-state protein and RNA measurements reveals that the extent of association of band 3 with the membrane cytoskeleton varies during chicken embryonic development. Pulse-chase studies have indicated that band 3 polypeptides do not associate with the membrane cytoskeleton until they have been transported to the plasma membrane. At this time, band 3 polypeptides are slowly recruited, over a period of hours, onto a preassembled membrane cytoskeletal network and the extent of this cytoskeletal assembly is developmentally regulated. Only 3% of the band 3 polypeptides are cytoskeletal-associated in 4-d erythroid cells vs. 93% in 10-d erythroid cells and 36% in 15-d erythroid cells. This observed variation appears to be regulated primarily at the level of recruitment onto the membrane cytoskeleton rather than by different transport kinetics to the membrane or differential turnover of the soluble and insoluble polypeptides and is not dependent upon the lineage or stage of differentiation of the erythroid cells. Steady-state protein and RNA analyses indicate that the low levels of cytoskeletal band 3 very early in development most likely result from limiting amounts of ankyrin and protein 4.1, the membrane cytoskeletal binding sites for band 3. As embryonic development proceeds, ankyrin and protein 4.1 levels increase with a concurrent rise in the level of cytoskeletal band 3 until, on day 10 of development, virtually all of the band 3 polypeptides are cytoskeletal bound. After day 10, the levels of total and cytoskeletal band 3 decline, whereas ankyrin and protein 4.1 continue to accumulate until day 18, indicating that the cytoskeletal association of band 3 is not regulated solely by the availability of membrane cytoskeletal binding sites at later stages of development. Thus, multiple mechanisms appear to regulate the recruitment of band 3 onto the erythroid membrane cytoskeleton during chicken embryonic development. PMID:3654759