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Sample records for clavulanic acids

  1. New approaches to the analysis of clavulanic acid

    International Nuclear Information System (INIS)

    Clavulanic acid is an effective beta-lactamase inhibitor. Therefore, it has the potential to be used against antibiotic resistance in cases where bacteria have gained the ability to produce beta-lactamases. Clavulanic acid is synthesized biotechnologically by streptomyces clavuligerus-strains, which have to be optimized to a high clavulanic acid output. Efficient analytical techniques for clavulanic acid, its biosynthesis precursors and side products are essential for respective research. For determination of clavulanic acid in fermentation broth a rapid and efficient capillary electrophoresis method with UV-detection at 200 nm was established. Analysis could be done within less than 5 minutes. The separation itself only requires one minute. The accuracy of the method was estimated by comparison with an existing HPLC-method. In order to improve selective and sensitive detection in chromatography for the precursors and side products of clavulanic acid, derivatizations were investigated systematically. For compounds with a bicyclus structure like clavulanic acid this was done by the reaction with imidazole. The derivatization products were analyzed by capillary electrophoresis, reversed phase chromatography, ion exchange chromatography and ion pair chromatography. Detection took place by UV-absorption at 312 nm. The chromatographic techniques were hyphenated with electrospray mass spectrometry for identification of the derivatives. By employing perfluorinated detergents this was possible for ion pair chromatography too. For those biosynthesis precursors which contain a guanidino group, a pre-column derivatization method with ninhydrin was generated. The appropriate reaction products were analyzed by reversed phase chromatography und fluorescence detection. The proposed structures could be proved by coupling with electrospray mass spectrometry. Another part of this dissertation deals with the identification of decomposition products of clavulanic acid. The

  2. Biosynthetic studies on clavulanic acid: its biopathway and stereochemical course

    Energy Technology Data Exchange (ETDEWEB)

    Mao, S.S.

    1987-01-01

    A degradative analysis allowed determination of the stereochemistry at C-9 of clavulanic acid produced by Streptomyces clavuigerus. An over-all inversion of configuration from the C/sub 5/-unit precursor ornithine was observed. The diastereomeric (1R,2R)- and (1S,2R)-(1-/sup 3/H)-glycerols were separately synthesized and administered. Complementary results demonstrated an overall retention of configuration paralleling cysteine incorporation in the biosynthesis of penicillin. 3-Hydroxyornithine, a potential precursor to clavulanic acid, was prepared by a 1,3-dipolar addition of a nitrone and vinylglycine. However, 3-hydroxyornithine was not taken up by the organism and this possible intermediate could not be shown to be a specific precursor to clavulanic acid. (2-/sup 3/H)-L-Ornithine displays a preferential incorporation relative to D-ornithine. An epimerization by a one-base mechanism is suggested by the retention of half the tritium activity. ..beta..-Alanine, a potential precursor of the ..beta..-lactam segment was examined and shown not to play a direct role in the biosynthesis. Further, 3-hydroxypropionyl-ornithine, a parallel amide to the tripeptide intermediate in penicillin biosynthesis, was not incorporated into clavulanic acid. The role of 3-hydroxypropionate and glycerol were examined in both starch and triglyceride fermentation media.

  3. Biosynthetic studies on clavulanic acid: its biopathway and stereochemical course

    International Nuclear Information System (INIS)

    A degradative analysis allowed determination of the stereochemistry at C-9 of clavulanic acid produced by Streptomyces clavuigerus. An over-all inversion of configuration from the C5-unit precursor ornithine was observed. The diastereomeric (1R,2R)- and (1S,2R)-[1-3H]-glycerols were separately synthesized and administered. Complementary results demonstrated an overall retention of configuration paralleling cysteine incorporation in the biosynthesis of penicillin. 3-Hydroxyornithine, a potential precursor to clavulanic acid, was prepared by a 1,3-dipolar addition of a nitrone and vinylglycine. However, 3-hydroxyornithine was not taken up by the organism and this possible intermediate could not be shown to be a specific precursor to clavulanic acid. [2-3H]-L-Ornithine displays a preferential incorporation relative to D-ornithine. An epimerization by a one-base mechanism is suggested by the retention of half the tritium activity. β-Alanine, a potential precursor of the β-lactam segment was examined and shown not to play a direct role in the biosynthesis. Further, 3-hydroxypropionyl-ornithine, a parallel amide to the tripeptide intermediate in penicillin biosynthesis, was not incorporated into clavulanic acid. The role of 3-hydroxypropionate and glycerol were examined in both starch and triglyceride fermentation media

  4. Is the standard dose of amoxicillin-clavulanic acid sufficient?

    OpenAIRE

    Haeseker, Michiel; Havenith, Thomas; Stolk, Leo; Neef, Cees; Bruggeman, Cathrien; Verbon, Annelies

    2014-01-01

    Background The pharmacodynamic (PD) efficacy target of amoxicillin is 40% time above the minimal inhibition concentration (40%T > MIC). Recent studies of other antibiotics have shown that PD-efficacy targets are not always reached. The aim of this study was to evaluate the percentage of hospitalised patients, using amoxicillin/clavulanic acid intravenously (iv), that reach the pharmacodynamic efficacy target 40%T > MIC. Additionally, the association of demographic anthropomorphic and clinical...

  5. Differential effect of impaired renal function on the kinetics of clavulanic acid and amoxicillin.

    OpenAIRE

    Horber, F. F.; Frey, F J; Descoeudres, C; Murray, A T; Reubi, F C

    1986-01-01

    Amoxicillin and clavulanic acid are prescribed as a fixed drug combination. The purpose of the present study was to assess the influence of various degrees of renal insufficiency (glomerular filtration rate [GFR], less than 5 to greater than 75 ml/min per 1.73 m2) on the pharmacokinetics of amoxicillin and clavulanic acid following oral (500 and 125 mg of amoxicillin and clavulanic acid, respectively) and intravenous (1,000 and 200 mg, respectively) dosing. The volume of distribution and the ...

  6. Fermentation Conditions that Affect Clavulanic Acid Production in Streptomyces clavuligerus: A Systematic Review.

    Science.gov (United States)

    Ser, Hooi-Leng; Law, Jodi Woan-Fei; Chaiyakunapruk, Nathorn; Jacob, Sabrina Anne; Palanisamy, Uma Devi; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2016-01-01

    The β-lactamase inhibitor, clavulanic acid is frequently used in combination with β-lactam antibiotics to treat a wide spectrum of infectious diseases. Clavulanic acid prevents drug resistance by pathogens against these β-lactam antibiotics by preventing the degradation of the β-lactam ring, thus ensuring eradication of these harmful microorganisms from the host. This systematic review provides an overview on the fermentation conditions that affect the production of clavulanic acid in the firstly described producer, Streptomyces clavuligerus. A thorough search was conducted using predefined terms in several electronic databases (PubMed, Medline, ScienceDirect, EBSCO), from database inception to June 30th 2015. Studies must involve wild-type Streptomyces clavuligerus, and full texts needed to be available. A total of 29 eligible articles were identified. Based on the literature, several factors were identified that could affect the production of clavulanic acid in S. clavuligerus. The addition of glycerol or other vegetable oils (e.g., olive oil, corn oil) could potentially affect clavulanic acid production. Furthermore, some amino acids such as arginine and ornithine, could serve as potential precursors to increase clavulanic acid yield. The comparison of different fermentation systems revealed that fed-batch fermentation yields higher amounts of clavulanic acid as compared to batch fermentation, probably due to the maintenance of substrates and constant monitoring of certain entities (such as pH, oxygen availability, etc.). Overall, these findings provide vital knowledge and insight that could assist media optimization and fermentation design for clavulanic acid production in S. clavuligerus. PMID:27148211

  7. Fermentation Conditions that Affect Clavulanic Acid Production in Streptomyces clavuligerus: A Systematic Review

    Science.gov (United States)

    Ser, Hooi-Leng; Law, Jodi Woan-Fei; Chaiyakunapruk, Nathorn; Jacob, Sabrina Anne; Palanisamy, Uma Devi; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2016-01-01

    The β-lactamase inhibitor, clavulanic acid is frequently used in combination with β-lactam antibiotics to treat a wide spectrum of infectious diseases. Clavulanic acid prevents drug resistance by pathogens against these β-lactam antibiotics by preventing the degradation of the β-lactam ring, thus ensuring eradication of these harmful microorganisms from the host. This systematic review provides an overview on the fermentation conditions that affect the production of clavulanic acid in the firstly described producer, Streptomyces clavuligerus. A thorough search was conducted using predefined terms in several electronic databases (PubMed, Medline, ScienceDirect, EBSCO), from database inception to June 30th 2015. Studies must involve wild-type Streptomyces clavuligerus, and full texts needed to be available. A total of 29 eligible articles were identified. Based on the literature, several factors were identified that could affect the production of clavulanic acid in S. clavuligerus. The addition of glycerol or other vegetable oils (e.g., olive oil, corn oil) could potentially affect clavulanic acid production. Furthermore, some amino acids such as arginine and ornithine, could serve as potential precursors to increase clavulanic acid yield. The comparison of different fermentation systems revealed that fed-batch fermentation yields higher amounts of clavulanic acid as compared to batch fermentation, probably due to the maintenance of substrates and constant monitoring of certain entities (such as pH, oxygen availability, etc.). Overall, these findings provide vital knowledge and insight that could assist media optimization and fermentation design for clavulanic acid production in S. clavuligerus. PMID:27148211

  8. In vitro activity of amoxicillin in combination with clavulanic acid against Mycobacterium tuberculosis.

    OpenAIRE

    Cynamon, M H; Palmer, G S

    1983-01-01

    The comparative in vitro activity of amoxicillin alone and in combination with clavulanic acid against 15 isolates of Mycobacterium tuberculosis was evaluated by broth dilution susceptibility testing. Amoxicillin inhibited 4 of 15 isolates at 8 micrograms/ml or less but was not bactericidal against any of the isolates at that concentration. Amoxicillin in combination with clavulanic acid was bactericidal for 14 of 15 isolates tested at an amoxicillin concentration of 4 micrograms/ml or less a...

  9. Pharmacokinetics of amoxicillin and clavulanic acid administered alone and in combination.

    OpenAIRE

    D. Adam; Visser, I.; Koeppe, P

    1982-01-01

    The pharmacokinetics of amoxicillin and clavulanic acid, administered alone and in combination, were studied in six male and six female normal human volunteers. Each ingested 500 mg of amoxicillin or 125 mg of clavulanic acid or the above agents in combination in randomized sequences. The results indicate that most of the parameters tested for either substance are essentially independent of the presence of the other one.

  10. Distribution of amoxicillin and clavulanic acid in infected animals and efficacy against experimental infections.

    OpenAIRE

    Boon, R J; Beale, A S; Comber, K. R.; Pierce, C V; Sutherland, R.

    1982-01-01

    The therapeutic effects produced by formulations of amoxicillin plus clavulanic acid (BRL 25 000A and BRL 25 000G) were compared with those of amoxicillin and clavulanic acid separately against a variety of infections produced by amoxicillin-susceptible and beta-lactamase-producing (amoxicillin-resistant) bacteria. The infection models studied included intraperitoneal infections, a mouse pneumonia, experimental pyelonephritis, and local lesions caused by Staphylococcus aureus and Bacteroides ...

  11. Screening of wild type Streptomyces isolates able to overproduce clavulanic acid

    Directory of Open Access Journals (Sweden)

    Daniela A. Viana Marques

    2014-09-01

    Full Text Available The selection of new microorganisms able to produce antimicrobial compounds is hoped for to reduce their production costs and the side effects caused by synthetic drugs. Clavulanic acid is a β-lactam antibiotic produced by submerged culture, which is widely used in medicine as a powerful inhibitor of β-lactamases, enzymes produced by bacteria resistant to antibiotics such penicillin and cephalosporin. The purpose of this work was to select the best clavulanic acid producer among strains of Streptomyces belonging to the Microorganism Collection of the Department of Antibiotics of the Federal University of Pernambuco (DAUFPE. Initially, the strains were studied for their capacity to inhibit the action of β-lactamases produced by Klebsiella aerogenes ATCC 15380. From these results, five strains were selected to investigate the batch kinetics of growth and clavulanic acid production in submerged culture carried out in flasks. The results were compared with the ones obtained by Streptomyces clavuligerus ATCC 27064 selected as a control strain. The best clavulanic acid producer was Streptomyces DAUFPE 3060, molecularly identified as Streptomyces variabilis, which increased the clavulanic acid production by 28% compared to the control strain. This work contributes to the enlargement of knowledge on new Streptomyces wild strains able to produce clavulanic acid by submerged culture.

  12. False-Positive Aspergillus Galactomannan Enzyme-Linked Immunosorbent Assay Results In Vivo during Amoxicillin-Clavulanic Acid Treatment

    OpenAIRE

    Mattei, Daniele; Rapezzi, Davide; Mordini, Nicola; Cuda, Federica; Lo Nigro, Cristiana; Musso, Maura; Arnelli, Aldo; Cagnassi, Sebastiano; Gallamini, Andrea

    2004-01-01

    Positive Platelia Aspergillus test results were observed in consecutive serum samples from an immunocompromised host during amoxicillin-clavulanic acid treatment, and a correlation between plasmatic amoxicillin concentration and galactomannan optical density index was observed. Amoxicillin-clavulanic acid vials tested positive for galactomannan but were negative for Aspergillus DNA.

  13. Prophylactic antibiotics for hysterectomy and cesarean section: amoxicillin-clavulanic acid versus cefazolin

    Directory of Open Access Journals (Sweden)

    Jyoti Malik

    2016-04-01

    Conclusions: Broad spectrum amoxicillin-clavulanic acid was not superior to cefazolin in prevention of post-operative infection when given as prophylaxis in hysterectomy and elective cesarean section. [Int J Reprod Contracept Obstet Gynecol 2016; 5(4.000: 980-983

  14. Amoxycillin and clavulanic acid induced Stevens-Johnson syndrome: a case report

    Directory of Open Access Journals (Sweden)

    Ravi Shankar Manchukonda

    2016-06-01

    Full Text Available Stevens-Johnson syndrome (SJS is an immune complex mediated hypersensitivity complex that typically involves the skin and the mucous membranes. Various etiologic factors (e.g., infection, drugs and malignancies have been implicated as causes of Stevens-Johnson syndrome. However, as many as half of the cases are idiopathic. Bastuji and Roujeau proposed that the denomination of Stevens-Johnson syndrome should be used for a syndrome characterized by mucous membrane erosions and widespread small blisters that arise on erythematous or purpuric maculae that are different from classic targets. In this case report, a 6 year old girl who was administered a cough syrup (containing bromhexine, guaiphenesin, diphenhydramine and phenylephrine and amoxycillin and clavulanic acid dispersible tablet for the treatment of cough developed pruritic skin eruptions all over the body along with painful erosions on the tongue, buccal mucosa, genital and anal mucosa. A diagnosis of Stevens-Johnson syndrome was made. Amoxycillin and clavulanic acid combination was identified as the culprit based on the temporal relationship between the drug administration and the appearance of the rashes and based on a number of SJS reports implicating amoxycillin and clavulanic acid having been published before. The cough syrup and amoxycillin and clavulanic acid combination tablets were immediately stopped. Symptomatic treatment was administered. The child improved and was later discharged. Causality assessment using Naranjo adverse drug reaction probability scale revealed that amoxycillin and clavulanic acid combination was a possible cause for the harmful cutaneous adverse reaction with a score of 4. [Int J Basic Clin Pharmacol 2016; 5(3.000: 1140-1144

  15. Clavulanic acid: a competitive inhibitor of beta-lactamases with novel anxiolytic-like activity and minimal side effects.

    Science.gov (United States)

    Kim, Deog J; King, Jean A; Zuccarelli, Lisa; Ferris, Craig F; Koppel, Gary A; Snowdon, Charles T; Ahn, Chang H

    2009-08-01

    Clavulanic acid is a member of the beta lactam family of antibiotics with little or no intrinsic antibacterial activity of its own; instead, it is used to enhance the activity of antibiotics by blocking bacterial beta-lactamases. Because clavulanic acid by itself is very safe, orally active and shows good brain penetrance, we sought to determine if it had any potential as a psychotherapeutic. Clavulanic acid was a tested across three mammalian species, hamsters, rats and cotton-top tamarin monkeys in a series of behavioral assays designed to screen for anxiolytic activity. In addition, several studies were done in rodents to compare the behavioral profile of clavulanic acid to the commonly prescribed benzodiazepines, particularly with respect to their unwanted side effects of motor depression, amnesia and neuroendocrine dysregulation. Our findings show that clavulanic acid is a highly potent anxiolytic in rodents without altering motor activity in the open field test, normal learning and memory in the Morris water maze, or normal stress hormone release. Orally administered clavulanic acid significantly reduces measures of anxiety in male/female pairs of cotton-top tamarins. In addition, male tamarins showed a highly significant increase in sexual arousal as measured by the number of penile erections. The fact clavulanic acid has anxiolytic activity in the tamarin holds the promise that this drug may be an effective therapeutic for the treatment of anxiety disorders in humans. PMID:19394358

  16. In vitro and in vivo synergism between amoxicillin and clavulanic acid against ampicillin-resistant Haemophilus influenzae type b.

    OpenAIRE

    Yogev, R; Melick, C; Kabat, W J

    1981-01-01

    Eight strans of ampicillin-resistant beta-lactamase-producing Haemophilus influenzae type b were studied in vitro for synergy between amoxicillin and clavulanic acid. The minimal inhibitory concentrations for amoxicillin alone were 6.25 to 12.5 microgram/ml, and for clavulanic acid alone they were 12.5 to 25 microgram/ml. However, seven of eight strains were inhibited by a combination of 0.36 microgram of amoxicillin and 0.36 microgram of clavulanic acid per ml. Infant rat models of bacteremi...

  17. [Comparison between penicillin and amoxicillin-clavulanic acid for the treatment of recurrent tonsillopharyngitis in childhood].

    Science.gov (United States)

    Asensi, F; López-Hontangas, J L; Otero, M; Santos, M; Román, J; Pérez-Tamarit, D

    1999-09-01

    Fifty-one children aged 2-14 years with recurrent tonsillopharyngitis, presenting dysphagia, fever and lymphadenitis, with more than two similar episodes in the last three years and showing a beta-hemolytic group A streptococci in the pharyngeal smear, were studied. They underwent random treatment for ten days with phenoxymethylpenicillin (40-60 mg/kg/day) (n = 28) or amoxicillin-clavulanic acid (20-40 mg/kg/day) (n = 23) taken orally three times a day. Clinical and bacteriological tests were carried out at 10 days and 2, 6 and 12 months post-treatment. The clinical and bacteriological results showed the superiority of the amoxicillin-clavulanic acid treatment both in the short term (disappearance of symptoms) and in the long term (decrease in recurrence). These results support the idea that betalactamases produced by the pharyngeal flora play an important role in the failures of penicillin. PMID:10878510

  18. [Properties of a cephalosporinase produced by Proteus penneri inhibited by clavulanic acid].

    Science.gov (United States)

    Miro, E; Barthelemy, M; Peduzzi, J; Reynaud, A; Morand, A; Prats, G; Labia, R

    1994-05-01

    P. penneri produces an inducible cephalosporinase, as many Enterobacteriaceae. Nevertheless this betalactamase is susceptible to clavulanic acid which is an exception also encountered for P. vulgaris. The authors studied the enzyme produced by P. penneri 14HBC resistant to cefotaxime (MIC 16 mg/l) isolated in Spain in 1992. This betalactamase of isoelectric point 6.65 hydrolyzes first generation cephalosporins, amoxycillin and poorly ticarcillin as it occurs for all cephalosporinases. However, this enzyme hydrolyzes strongly oxyimino-cephalosporins: cefuroxime, cefotaxime, cefepime, cefpirome as it occurs with extended-spectrum betalactamases. Cephamycins and imipenem are not substrates. Clavulanic acid has a very good affinity for this betalactamase which is inactivated progressively. These properties are similar to those of the enzyme of P. vulgaris Ro104 of isoelectric point 8.3 which, contrarily to other cephalosporinases, belongs to the structural Ambler's class A. PMID:7824319

  19. Assay of amoxicillin and clavulanic acid, the components of Augmentin, in biological fluids with high-performance liquid chromatography.

    OpenAIRE

    Foulstone, M; Reading, C

    1982-01-01

    Augmentin is a new antibacterial formulation comprised of amoxicillin and the beta-lactamase inhibitor clavulanic acid. In the present paper, the use of high-performance liquid chromatography (HPLC) to provide a rapid assay of the components of Augmentin in body fluids is described. Clavulanic acid was assayed by reacting the sample with imidazole, which readily produces a derivative absorbing at 311 nm. This derivative chromatographs on reverse-phase HPLC columns clear of interfering compone...

  20. Amoxicillin-clavulanic acid in treatment of urinary tract infection due to gram-negative bacteria resistant to penicillin.

    OpenAIRE

    Martinelli, R; A.A. Lopes; Oliveira, M.M.; Rocha, H

    1981-01-01

    Twenty-two adult patients with urinary tract infections caused by penicillin-resistant bacteria completed treatment with amoxicillin alone or amoxicillin plus clavulanic acid in a randomized double-blind clinical trial. Of the 13 patients treated with amoxicillin plus clavulanic acid, the absence of bacteriuria within 7 days of therapy was observed in 85%, as compared with only 25% of the 8 patients receiving amoxicillin only. There were no significant side effects nor any clinical, biochemic...

  1. Effects of packaging and storage conditions on the quality of amoxicillin-clavulanic acid – an analysis of Cambodian samples

    OpenAIRE

    Khan, Mohiuddin Hussain; Hatanaka, Kirara; Sovannarith, Tey; Nivanna, Nam; Casas, Lidia Cecilia Cadena; Yoshida, Naoko; Tsuboi, Hirohito; Tanimoto, Tsuyoshi; Kimura, Kazuko

    2013-01-01

    Background The use of substandard and degraded medicines is a major public health problem in developing countries such as Cambodia. A collaborative study was conducted to evaluate the quality of amoxicillin–clavulanic acid preparations under tropical conditions in a developing country. Methods Amoxicillin-clavulanic acid tablets were obtained from outlets in Cambodia. Packaging condition, printed information, and other sources of information were examined. The samples were tested for quantity...

  2. A combination of amoxicillin and clavulanic acid in the treatment of pyoderma in children

    Directory of Open Access Journals (Sweden)

    Kar P

    1996-01-01

    Full Text Available The efficacy and safety of amoxicillin plus clavulanic acid was compared with that of amoxicillin, erythromycin and co-trimoxazole in an open label, randomized trial in 50 children in each group (total 200 with mild to severe pyodermas. Majority (47% had impetigo. Fifty (25% children had mild pyoderma, 56 (28% had moderate and 94 (47% children had severe pyoderma. Pure growth of S aureus was isolated in 130 (65% children, S pyogenes in 42 (21% and both organisms in 28 (14% children. In mild to moderate pyoderma either of the drug tried was equally effective. In severe pyoderma, 24 of twenty five (96% children receiving amoxicillin plus clavulanic acid, 18 of twenty (90% children in amoxicillin group, 20 of twenty four (83.3% children in erythromycin group and 13 of twenty five (52% children in co-trimoxazole group showed clinical cure of therapy. Amoxicillin combined with clavulanic acid was well tolerated in children and there was no significant side effect except mild diarrhoea in two cases (4% which was well controlled by taking the drug with meals.

  3. An improved HPLC-DAD method for clavulanic acid quantification in fermentation broths of Streptomyces clavuligerus.

    Science.gov (United States)

    Ramirez-Malule, Howard; Junne, Stefan; López, Carlos; Zapata, Julian; Sáez, Alex; Neubauer, Peter; Rios-Estepa, Rigoberto

    2016-02-20

    Clavulanic acid (CA) is an important secondary metabolite commercially produced by cultivation of Streptomyces clavuligerus (Sc). It is a potent inhibitor of bacterial β-lactamases. In this work, a specific and improved high performance liquid chromatography (HPLC) method, using a C-18 reversed phase column, diode array detector and gradient elution for CA quantification in fermentation broths of Sc, was developed and successfully validated. Samples were imidazole-derivatized for the purpose of creating a stable chromophore (clavulanate-imidazole). The calibration curve was linear over a typical range of CA concentration between 0.2 and 400mg/L. The detection and quantification limits were 0.01 and 0.02mg/L, respectively. The precision of the method was evaluated for CA spiked into production media and a recovery of 103.8%, on average, was obtained. The clavulanate-imidazole complex was not stable when the samples were not cooled during the analysis. The recovery rate was 39.3% on average. This assay was successfully tested for CA quantification in samples from Sc fermentation, using both, a chemically defined and a complex medium. PMID:26760242

  4. Amoxicillin/Clavulanic Acid for the Treatment of Odontogenic Infections: A Randomised Study Comparing Efficacy and Tolerability versus Clindamycin

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    Archiel Launch Tancawan

    2015-01-01

    Full Text Available Background. Treatment of odontogenic infections includes surgical drainage and adjunctive antibiotics. This study was designed to generate efficacy and safety data to support twice daily dosing of amoxicillin/clavulanic acid compared to clindamycin in odontogenic infections. Methods. This was a phase IV, randomised, observer blind study; 472 subjects were randomised to receive amoxicillin/clavulanic acid (875 mg/125 mg BID, n=235 or clindamycin (150 mg QID, n=237 for 5 or 7 days based on clinical response. The primary endpoint was percentage of subjects achieving clinical success (composite measure of pain, swelling, fever, and additional antimicrobial therapy required at the end of treatment. Results. The upper limit of two-sided 95% confidence interval for the treatment difference between the study arms (7.7% was within protocol specified noninferiority margin of 10%, thus demonstrating noninferiority of amoxicillin/clavulanic acid to clindamycin. Secondary efficacy results showed a higher clinical success rate at Day 5 in the amoxicillin/clavulanic acid arm. Most adverse events (raised liver enzymes, diarrhoea, and headache were similar across both arms and were of mild to moderate intensity. Conclusion. Amoxicillin/clavulanic acid was comparable to clindamycin in achieving clinical success (88.2% versus 89.7% in acute odontogenic infections and the safety profile was consistent with the known side effects of both drugs. Trial Registration. This trial is registered with Clinicaltrials.gov identifier: NCT02141217.

  5. Safety and Tolerability of Nebulized Amoxicillin-Clavulanic Acid in Patients with COPD (STONAC 1 and STONAC 2).

    Science.gov (United States)

    Nijdam, L C; Assink, M D M; Kuijvenhoven, J C; de Saegher, M E A; van der Valk, P D L P M; van der Palen, J; Brusse-Keizer, M G J; Movig, K L L

    2016-08-01

    The safety and tolerability of nebulized amoxicillin clavulanic acid were determined in patients with stable COPD and during severe exacerbations of COPD. Nine stable COPD patients received doses ranging from 50:10 mg up to 300:60 mg amoxicillin clavulanic acid and eight patients hospitalised for a COPD exacerbation received fixed doses 200/40 mg twice daily. Safety was evaluated by spirometry before and after inhalation. Tolerability was evaluated by questionnaire. Plasma and expectorated sputum samples were assayed for amoxicillin content. Seventeen patients underwent in total 100 nebulizations with amoxicillin clavulanic acid. In this safety and tolerability study no clinically relevant deteriorations in FEV1 were observed. Nebulized amoxicillin clavulanic acid produces sputum concentrations well above the Minimal Inhibiting Concentration of 90% for potential pathogenic micro-organisms, with low concentrations in the central compartment (low systemic exposure). Based on spirometry and reported side effects, inhalation of nebulized amoxicillin clavulanic acid seems to be safe and well tolerated, both in stable patients with COPD as in those experiencing a severe exacerbation. Levels of amoxicillin were adequate. PMID:26744171

  6. Evaluation of restoration of sensitivities of resistant staphylococcus aureus isolates by using cefuroxime and clavulanic acid in combination

    International Nuclear Information System (INIS)

    The present study was planned to observe the activity of cefuroxime, a second generation cephalosporin after combining it with a beta-lactamase inhibitor calvulanic acid. The study was conducted to evaluate the restoration or increase in sensitivity of beta-lactamase producing isolates of Staphylococcus aureus. Staphylococcus aureus were identified by standard procedures. For beta-lactamase detection chromogenic Nitrocefin impregnated sticks were used. The sensitivity of the bacteria to the antibiotic disks was measured by disk diffusion method using standard zone diameter criteria given by National Committee of Clinical Laboratory Standards. The disks of cefuroxime with clavulanic acid had developed larger zones of inhibition. The activity of cefuroxime against Staphylococcus areus was significantly increased by clavulanic acid. Clavulanic acid if used in combination with cefuroxime, can improve the antimicrobial activity of cefuroxime against beta - lactamase producing Staphylococcus aureus. (author)

  7. Phenomenological model of the clavulanic acid production process utilizing Streptomyces clavuligerus

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    A. Baptista-Neto

    2000-12-01

    Full Text Available The kinetics of clavulanic acid production process by Streptomyces clavuligerus NRRL 3585 was studied. Experiments were carried out in a 4 liters bioreactor, utilizing 2 complex media containing glycerol as the carbon and energy source, and peptone or Samprosoy 90NB (soybean protein as nitrogen source. Temperature was kept at 28°C and the dissolved oxygen was controlled automatically at 40 % saturation value. Samples were withdrawn for determination of cell mass (only peptone medium, glycerol and product concentrations. Gas analyzers allowed on line determination of CO2 and O2 contents in the exit gas. With Samprosoy, cell mass was evaluated by determining glycerol consumption and considering the cell yield, Y X/S, as being the same for both cases. Oxygen uptake and CO2 production rates were strongly related to growth and substrate consumption, allowing determination of stoichiometric constants in relation to growth, substrate, oxygen, product and carbon dioxide.

  8. Studies on the rheology and oxygen mass transfer in the clavulanic acid production by Streptomyces clavuligerus

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    E. R. Gouveia

    2000-12-01

    Full Text Available In the present work rheological characteristics and volumetric oxygen transfer coefficient (kLa were investigated during batch cultivations of Streptomyces clavuligerus NRRL 3585 for production of clavulanic acid. The experimental rheological data could be adequately described in terms of the power law model and logistic equation. Significant changes in the rheological parameters consistency index (K and flow behavior index (n were observed with the fermentation evolution. Interesting correlations between the consistency index (K/biomass concentration (C X and the flow behavior index (n/biomass concentration were proposed. Volumetric oxygen mass transfer coefficient (kLa was determined by the gas balance method. Classical correlation relating the volumetric oxygen mass transfer coefficient to the operating conditions, physical and to transport properties, including apparent viscosity (muap, could be applied to the experimental results.

  9. Effects of amoxicillin/clavulanic acid on the pharmacokinetics of valproic acid

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    Lee SY

    2015-08-01

    Full Text Available Soo-Yun Lee,1 Wooseong Huh,2 Jin Ah Jung,3 Hye Min Yoo,2 Jae-Wook Ko,1,2 Jung-Ryul Kim2,4 1Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, 2Department of Clinical Pharmacology and Therapeutics, Samsung Medical Center, Seoul, 3Department of Clinical Pharmacology, Inje University, Busan Paik Hospital, Busan, 4Department of Clinical Research and Evaluation, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea Abstract: Valproic acid (VPA is mainly metabolized via glucuronide, which is hydrolyzed by β-glucuronidase and undergoes enterohepatic circulation. Amoxicillin/clavulanic acid (AMC administration leads to decreased levels of β-glucuronidase-producing bacteria, suggesting that these antibiotics could interrupt enterohepatic circulation and thereby alter the pharmacokinetics of VPA. This study aimed to evaluate the effects of AMC on the pharmacokinetics of VPA. This was an open-label, two-treatment, one-sequence study in 16 healthy volunteers. Two treatments were evaluated; treatment VPA, in which a single dose of VPA 500 mg was administered, and treatment AMC + VPA, in which multiple doses of AMC 500/125 mg were administered three times daily for 7 days and then a single dose of VPA was administered. Blood samples were collected up to 48 hours. Pharmacokinetic parameters were calculated using noncompartmental methods. Fifteen subjects completed the study. Systemic exposures and peak concentrations of VPA were slightly lower with treatment AMC + VPA than with treatment VPA (AUClast, 851.0 h·mg/L vs 889.6 h·mg/L; Cmax, 52.1 mg/L vs 53.0 mg/L. There were no significant between-treatment effects on pharmacokinetics (95% confidence interval [CI] of AUClast and Cmax (95.7 [85.9–106.5] and 98.3 [91.6–105.6], respectively. Multiple doses of AMC had no significant effects on the pharmacokinetics of VPA; thus, no dose adjustment is necessary. Keywords: drug–drug interaction, pharmacokinetics

  10. Oral Amoxicillin-Clavulanic Acid Treatment in Urinary Tract Infections Caused by Extended-Spectrum Beta-Lactamase–Producing Organisms

    OpenAIRE

    Beytur, Ali; Yakupogullari, Yusuf; Oguz, Fatih; Otlu, Baris; Kaysadu, Halim

    2014-01-01

    Background: Extended-spectrum β-lactamases (ESBLs) are increasing problems. The involvement of ESBL-producing organisms is associated with higher rates of carbapenem usage in urinary tract infections (UTIs). Though some strains are susceptible to amoxicillin-clavulanic acid (AMC) in vitro, there is very less data about the consequences of AMC usage for such infections. Objectives: The purpose of this study was to evaluate the clinical and microbiological outcomes of AMC treatment in UTIs caus...

  11. Synergistic effects of dicloxacillin or clavulanic acid in combination with penicillin G or cephalothin against Yersinia enterocolitica.

    OpenAIRE

    Jimenez-Valera, M; Ruiz-Bravo, A; Ramos-Cormenzana, A.

    1986-01-01

    Cultures of Yersinia enterocolitica grown at 22 degrees C produced beta-lactamases, whereas cultures grown at 37 degrees C produced these enzymes much less effectively. Both dicloxacillin and clavulanic acid inhibited the beta-lactamase activity of bacterial crude extracts and potentiated the activity of penicillin G or cephalothin against 14 Y. enterocolitica strains. It appeared that the beta-lactamase activity present in Y. enterocolitica cells grown at 37 degrees C was great enough to pla...

  12. Proteomics analysis of global regulatory cascades involved in clavulanic acid production and morphological development in Streptomyces clavuligerus.

    Science.gov (United States)

    Ferguson, Nicole L; Peña-Castillo, Lourdes; Moore, Marcus A; Bignell, Dawn R D; Tahlan, Kapil

    2016-04-01

    The genus Streptomyces comprises bacteria that undergo a complex developmental life cycle and produce many metabolites of importance to industry and medicine. Streptomyces clavuligerus produces the β-lactamase inhibitor clavulanic acid, which is used in combination with β-lactam antibiotics to treat certain β-lactam resistant bacterial infections. Many aspects of how clavulanic acid production is globally regulated in S. clavuligerus still remains unknown. We conducted comparative proteomics analysis using the wild type strain of S. clavuligerus and two mutants (ΔbldA and ΔbldG), which are defective in global regulators and vary in their ability to produce clavulanic acid. Approximately 33.5 % of the predicted S. clavuligerus proteome was detected and 192 known or putative regulatory proteins showed statistically differential expression levels in pairwise comparisons. Interestingly, the expression of many proteins whose corresponding genes contain TTA codons (predicted to require the bldA tRNA for translation) was unaffected in the bldA mutant. PMID:26790415

  13. A study on clavulanic acid production by Streptomyces clavuligerus in batch, fed-batch and continuous processes

    Directory of Open Access Journals (Sweden)

    A. B. Neto

    2005-12-01

    Full Text Available Clavulanic acid (CA is a potent inhibitor of beta-lactamases, enzymes that are responsible for the hydrolysis of beta-lactam antibiotics. It is a secondary metabolite produced by the filamentous aerobic bacterium Streptomyces clavuligerus in submerged cultivations. In the present work clavulanic acid production in batch, fed-batch and continuous bioreactors was studied with the objective of increasing productivity. The operating conditions: temperature, aeration and agitation, were the same in all cases, 28º C, 0.5 vvm and 800 rpm, respectively. The CA concentration obtained in the fed-batch culture, 404 mg L-1, was ca twice the value obtained in the batch culture, 194 mg L-1, while 293 mg L-1 was obtained in the continuous culture. The highest productivity was obtained in the continuous cultivation, 10.6 mg L-1 h-1, as compared with 8.8 mg L-1 h-1 in the fed-batch process and 3.5 mg L-1 h-1 in the batch process, suggesting that continuous culture of Streptomyces clavuligerus is a promising strategy for clavulanic acid production.

  14. Simultaneous liquid chromatography-mass spectrometry quantification of cefixime and clavulanic acid in human plasma.

    Science.gov (United States)

    Dubala, Anil; Nagarajan, Janaki Sankarachari Krishnan; Vimal, Chandran Sathish; George, Renjith

    2015-01-01

    A simple and specific liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) assay method has been developed and fully validated for the simultaneous quantification of cefixime (CX) and clavulanic acid (CA) in human plasma. Analytes and internal standard were extracted from human plasma by a solid phase extraction technique using a Sam prep (3 mL, 100 mg) extraction cartridge. The extracted samples were chromatographed on a reverse phase C18 column using a mixture of methanol : acetonitrile : 2 mM ammonium acetate (pH 3.5) (25 : 25 : 50, v/v/v) as the mobile phase at a flow rate of 0.8 mL/min. Quantification of the analytes were carried out using single quadrupole LC-APCI-MS through selected ion monitoring at m/z 452 and 198, respectively, for CX and CA. The assay was linear over the concentration range of 0.05-10.0 and 0.1-10.0 μg/mL, respectively, for CX and CA. The mean plasma extraction recoveries of the CX and CA were found to be 95.20-96.27% and 94.67-95.58%, respectively. The method was successfully applied for the determination of pharmacokinetics of CX and CA after oral administration of single dosage CX/CA (200/125 mg) pill to the humans (n = 12). PMID:25209681

  15. A Combination Of Amoxicillian And Clavulanic Acid In The Treatment Of Impetigo In Children

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    P K Kar Col

    1998-01-01

    Full Text Available Amoxicillin plus clavulanic acid (ACA a combination of potentially effective antibiotic against beta-lactamase producing bacteria was compared with that of amoxicillin, erythomycin and co-trimoxazole in an open label, randomized trial in 100 children with mild to severe impetigo. 22% children had mild, 25% had moderate and 53% children had severe impetigo. Pure growth of S. aureus was isolated in 68% children, S.pyogenes in 26% and both staphyto and streptococci in 6% children. In mild to moderate infection 100% children receiving ACA were cured clinically after first week, whereas 7 out of 15(46.6% children in amoxicillin group, 7 out of 13(53.1% children in erythromycin group and 4 out 12 (33.3% children in co-trimoxazole group showed clinical cure after first week. In severe impetigo 46.1% children receiving ACA, 20% children in amoxicillin group, 16.6% children inerythromycin group and 7.6% in co-trimoxazole group showed clinical cure on therapy after one week. ACA was well tolerated in children.

  16. Influence of glycerol and ornithine feeding on clavulanic acid production by Streptomyces clavuligerus

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    J. C. Teodoro

    2010-12-01

    Full Text Available The influence of glycerol and ornithine feeding on clavulanic acid (CA production by Streptomyces clavuligerus was investigated. In batch experiments, CA maximum concentration (Cp max ranged randomly from 430 to 560 mg.L-1, with a maximum increase of 10% in relation to the control run, without ornithine. However, the maximum volumetric productivity of CA (Pp max of 13.7 mg.L-1.h-1 was obtained with 0.66 g.L-1 of ornithine, 44.2% higher than the Pp max in the control run. In fed-batch experiments, Cp max varied within the narrow range from 1.254 to 1.405 g.L-1, 2.5 times higher than that obtained in the control run. The presence of ornithine increased the Pp max, although it influenced only slightly the Cp max. Concerning glycerol, the highest CA production of 1.6 g.L-1 was obtained in the fed-batch with glycerol and ornithine (180 and 3.7 g.L−1 in a 10-L bioreactor, showing a positive effect of ornithine and glycerol, in the proper proportion (48.6:1, on CA biosynthesis.

  17. Production of clavulanic acid and cephamycin C by Streptomyces clavuligerus under different fed-batch conditions

    Directory of Open Access Journals (Sweden)

    C. Bellão

    2013-06-01

    Full Text Available The effect of carbon source and feeding conditions on the production of clavulanic acid (CA and cephamycin C (CephC by Streptomyces clavuligerus was investigated. In fed-batch experiments performed with glycerol feeding, production of CA exceeded that of CephC, and reached 1022 mg.L-1. Highest CephC production (566.5 mg.L-1 was obtained in fed-batch cultivation with glycerol feeding. In fed-batch experiments performed with starch feeding, the production of CephC was in general higher than that of CA. A dissociation index (DI was used to identify feeding conditions that favored production of CephC relative to CA. In all cultures with glycerol, DI values were less than unity, indicating higher production of CA compared to CephC. Conversely, in cultures fed with starch, the DI values obtained were greater than unity. However, no carbon source or feeding condition was able to completely dissociate the production of CA from that of CephC.

  18. Clavulanic acid production by the MMS 150 mutant obtained from wild type Streptomyces clavuligerus ATCC 27064

    Directory of Open Access Journals (Sweden)

    Eliton da Silva Vasconcelos

    2013-12-01

    Full Text Available Clavulanic acid (CA is a powerful inhibitor of the beta-lactamases, enzymes produced by bacteria resistants to penicillin and cefalosporin. This molecule is produced industrially by strains of Streptomyces clavuligerus in complex media which carbon and nitrogen resources are supplied by inexpensive compounds still providing high productivity. The genetic production improvement using physical and chemical mutagenic agents is an important strategy in programs of industrial production development of bioactive metabolites. However, parental strains are susceptible to loss of their original productivity due genetic instability phenomenona. In this work, some S. clavuligerus mutant strains obtained by treatment with UV light and with MMS are compared with the wild type (Streptomyces clavuligerus ATCC 27064. The results indicated that the random mutations originated some strains with different phenotypes, most divergent demonstrated by the mutants strains named AC116, MMS 150 and MMS 54, that exhibited lack of pigmentation in their mature spores. Also, the strain MMS 150 presented a larger production of CA when cultivated in semi-synthetics media. Using other media, the wild type strain obtained a larger CA production. Besides, using the modifed complex media the MMS 150 strain showed changes in its lipolitic activity and a larger production of CA. The studies also allowed finding the best conditions for a lipase activity exhibited by wild type S. clavuligerus and the MMS150 mutant.

  19. Dissociation of cephamycin C and clavulanic acid biosynthesis by 1,3-diaminopropane in Streptomyces clavuligerus.

    Science.gov (United States)

    Leite, Carla A; Cavallieri, André P; Baptista, Amanda S; Araujo, Maria L G C

    2016-01-01

    Streptomyces clavuligerus produces simultaneously cephamycin C (CephC) and clavulanic acid (CA). Adding 1,3-diaminopropane to culture medium stimulates production of beta-lactam antibiotics. However, there are no studies on the influence of this diamine on coordinated production of CephC and CA. This study indicates that 1,3-diaminopropane can dissociate CephC and CA productions. Results indicated that low diamine concentrations (below 1.25 g l(-1)) in culture medium increased CA production by 200%, but not that of CephC. Conversely, CephC production increased by 300% when 10 g l(-1) 1,3-diaminopropane was added to culture medium. Addition of just L-lysine (18.3 g l(-1)) to culture medium increased both biocompounds. On the other hand, while L-lysine plus 7.5 g l(-1) 1,3-diaminopropane increased volumetric production of CephC by 1100%, its impact on CA production was insignificant. The combined results suggest that extracellular concentration of 1,3-diaminopropane may trigger the dissociation of CephC and CA biosynthesis in S. clavuligerus. PMID:26564965

  20. Shear conditions in clavulanic acid production by Streptomyces clavuligerus in stirred tank and airlift bioreactors.

    Science.gov (United States)

    Cerri, M O; Badino, A C

    2012-08-01

    In biochemical processes involving filamentous microorganisms, the high shear rate may damage suspended cells leading to viability loss and cell disruption. In this work, the influence of the shear conditions in clavulanic acid (CA) production by Streptomyces clavuligerus was evaluated in a 4-dm(3) conventional stirred tank (STB) and in 6-dm(3) concentric-tube airlift (ALB) bioreactors. Batch cultivations were performed in a STB at 600 and 800 rpm and 0.5 vvm (cultivations B1 and B2) and in ALB at 3.0 and 4.1 vvm (cultivations A1 and A2) to define two initial oxygen transfer conditions in both bioreactors. The average shear rate ([Formula: see text]) of the cultivations was estimated using correlations of recent literature based on experimental data of rheological properties of the broth (consistency index, K, and flow index, n) and operating conditions, impeller speed (N) for STB and superficial gas velocity in the riser (UGR) for ALB. In the same oxygen transfer condition, the [Formula: see text] values for ALB were higher than those obtained in STB. The maximum [Formula: see text] presented a strong correlation with a maximum consistency index (K (max)) of the broth. Close values of maximum CA production were obtained in cultivations A1 and A2 (454 and 442 mg L(-1)) with similar maximum [Formula: see text] values of 4,247 and 4,225 s(-1). In cultivations B1 and B2, the maximum CA production of 269 and 402 mg L(-1) were reached with a maximum [Formula: see text] of 904 and 1,786 s(-1). The results show that high values of average shear rate increase the CA production regardless of the oxygen transfer condition and bioreactor model. PMID:22271253

  1. The role of IgE recognition in allergic reactions to amoxicillin and clavulanic acid.

    Science.gov (United States)

    Torres, M J; Montañez, M I; Ariza, A; Salas, M; Fernandez, T D; Barbero, N; Mayorga, C; Blanca, M

    2016-02-01

    Betalactam (BL) antibiotics are the drugs most frequently involved in IgE-mediated reactions. The culprit BL varies according to consumption patterns, with amoxicillin (AX) more prevalent in Southern Europe and penicillin V in Scandinavian countries. Nowadays, the combination of AX and clavulanic acid (CLV) is the most highly consumed BL containing medicine worldwide. Both BLs, AX and CLV, can independently be involved in reactions, which poses a diagnostic challenge. In patients with immediate allergic reactions to AX, two patterns of responses have been described, those responding to benzylpenicillin (cross-reactors) and those selective to AX. In addition, selective reactions to CLV account for around 30% of allergic reactions to the combination AX-CLV. These patterns of IgE recognition could be related to differences in the haptenation process, in the immunological response, or in the BL involved in the first sensitization. In this regard, patients with selective responses to CLV are generally younger than those allergic to AX or benzylpenicillin. So far, no evidence of cross-reactivity between CLV and other BLs has been reported. This shows the importance of an accurate diagnosis of CLV allergy, as patients with selective reactions to CLV could take other BLs including AX. Diagnosis can be performed in vivo and in vitro, although no immunoassay currently exists. Research regarding the CLV antigenic determinants and protein conjugates is essential to improve diagnosis. BLs need to covalently bind to a carrier protein to be immunogenic. The antigenic determinant of AX is the amoxicilloyl amide, but CLV leads to unstable structures, many of which are unknown. Moreover, the nature of the BL-protein conjugates plays an important role in IgE recognition. This review aims to summarize current knowledge on the immunochemistry, diagnostic approaches as well as chemical and proteomic studies for both AX and CLV. PMID:26662186

  2. Simultaneous determination of amoxicillin and clavulanic acid in the human plasma by high performance liquid chromatography: Mass spectrometry (UPLC/MS

    Directory of Open Access Journals (Sweden)

    Ćirić Biljana

    2010-01-01

    Full Text Available Background/Aim. Quantitative analysis of amoxicillin and clavulanic acid in biological matrices requires sensitive and specific methods which allow determination of therapeutic concentration in μg/mL range. Analytical methods for determination of their concentrations in body fluids described in literature include high performance liquid chromatography coupled to UV detector (HPLC-UV and liquid chromatography-mass spectrometry (LC-MS. The aim of this study was to develop sensitive and specific ultra performance liquid chromatography/ mass spectrometry (UPLC/MS method which could be used for the spectral identification and quantification of the low concentrations of amoxicillin and clavulanic acid in the human plasma. Method. A sensitive and specific UPLC/MS method for amoxicillin and clavulanic acid determination was developed in this study. The samples were taken from the adult healthy volunteers receiving per os one tablet of amoxicillin (875 mg in combination with clavulanic acid (125 mg. Results. Plasma samples were pretreated by direct deproteinization with perchloric acid. Quantification limit of 0.01 μg/ml for both amoxicillin and clavulanic acid was achieved. The method was reproducible day by day (RSD < 7 %. Analytical recoveries for amoxicillin ranged from 98.82% to 100.9% (for concentrations of 1, 5 and 20 μg/mL, and recoveries for clavulanic acid were 99,89% to 100.1% (for concentrations of 1, 2 and 5 μg/mL. This assay was successfully applied to a pilot pharmacokinetic study in healthy volunteers after a single-oral administration of amoxicillin/ clavulanic combination. The determined plasma concentrations of both amoxicillin and clavulanic acid were in the range of the expected values upon the literature data for HPLC-UV and LC-MS methods. Conclusion. The described method provided a few advantages comparing with LC/MS-MS method. The method is faster using running time of 5 minute, has lower limit of quantification (LOQ and it

  3. A stable liquid–liquid extraction system for clavulanic acid using polymer-based aqueous two-phase systems

    OpenAIRE

    Pereira, Jorge F. B.; Santos, Valéria Carvalho; Johansson, Hans-Olof; J. A. Teixeira; Pessoa Júnior, Adalberto

    2012-01-01

    The partitioning of Clavulanic Acid (CA) in a novel inexpensive and stable aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The aqueous two-phase systems are formed by mixing both polymers with a salt (NaCl or Na2SO4) and an aqueous solution of CA. The stability of CA on the presence of both polymers was investigated and it was observed that these polymers do not degrade the biomolecule. The effect of PEG-molecular ...

  4. Two proteins with ornithine acetyltransferase activity show different functions in Streptomyces clavuligerus: Oat2 modulates clavulanic acid biosynthesis in response to arginine.

    Science.gov (United States)

    de la Fuente, A; Martín, J F; Rodríguez-García, A; Liras, P

    2004-10-01

    The oat2 gene, located in the clavulanic acid gene cluster in Streptomyces clavuligerus, is similar to argJ, which encodes N-acetylornithine:glutamic acid acetyltransferase activity. Purified proteins obtained by expression in Escherichia coli of the argJ and oat2 genes of S. clavuligerus posses N-acetyltransferase activity. The kinetics and substrate specificities of both proteins are very similar. Deletion of the oat2 gene did not affect the total N-acetylornithine transferase activity and slightly reduced the formation of clavulanic acid under standard culture conditions. However, the oat2 mutant produced more clavulanic acid than the parental strain in cultures supplemented with high levels (above 1 mM) of arginine. The purified S. clavuligerus ArgR protein bound the arginine box in the oat2 promoter, and the expression of oat2 was higher in mutants with a disruption in argR (arginine-deregulated), confirming that the Arg boxes of oat2 are functional in vivo. Our results suggest that the Oat2 protein or one of its reaction products has a regulatory role that modulates clavulanic acid biosynthesis in response to high arginine concentrations. PMID:15375131

  5. 21 CFR 520.88g - Amoxicillin trihydrate and clavulanate potassium film-coated tablets.

    Science.gov (United States)

    2010-04-01

    ... milligrams of amoxicillin and 12.5 milligrams clavulanic acid, or 100 milligrams of amoxicillin and 25 milligrams clavulanic acid, or 200 milligrams amoxicillin and 50 milligrams clavulanic acid or 300 milligrams amoxicillin and 75 milligrams clavulanic acid. (b) Sponsor. See No. 000069 in § 510.600(c) of this chapter....

  6. Effects of amoxicillin/clavulanic acid on the pharmacokinetics of valproic acid

    OpenAIRE

    Lee SY; Huh W; Jung JA; Yoo HM; Ko JW; Kim JR

    2015-01-01

    Soo-Yun Lee,1 Wooseong Huh,2 Jin Ah Jung,3 Hye Min Yoo,2 Jae-Wook Ko,1,2 Jung-Ryul Kim2,4 1Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, 2Department of Clinical Pharmacology and Therapeutics, Samsung Medical Center, Seoul, 3Department of Clinical Pharmacology, Inje University, Busan Paik Hospital, Busan, 4Department of Clinical Research and Evaluation, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea Abstract: Valproic acid (VPA) is mainly meta...

  7. 21 CFR 520.88h - Amoxicillin trihydrate and clavulanate potassium for oral suspension.

    Science.gov (United States)

    2010-04-01

    ... of amoxicillin with clavulanate potassium equivalent to 12.5 milligrams of clavulanic acid. (b... milligrams (equivalent to 5 milligrams amoxicillin and 1.25 milligrams clavulanic acid) per pound of body....5 milligrams (1 milliliter) (50 milligrams of amoxicillin and 12.5 milligrams clavulanic acid)...

  8. In vitro activity of cefmetazole, cefotetan, amoxicillin-clavulanic acid, and other antimicrobial agents against anaerobic bacteria from endometrial cultures of women with pelvic infections.

    OpenAIRE

    Ohm-Smith, M J; Sweet, R. L.

    1987-01-01

    The MICs of the new antimicrobial agents cefmetazole, cefotetan, and amoxicillin-clauvulanic acid were compared with the MICs of other antimicrobial agents against anaerobic bacteria from endometrial cultures from women with pelvic inflammatory disease or endometritis. The activity of cefmetazole was similar to that of cefoxitin and generally greater than that of cefotetan. Amoxicillin-clavulanic acid was generally more active than all cephamycins tested.

  9. Two Proteins with Ornithine Acetyltransferase Activity Show Different Functions in Streptomyces clavuligerus: Oat2 Modulates Clavulanic Acid Biosynthesis in Response to Arginine

    OpenAIRE

    de la Fuente, A.; Martín, J F; Rodríguez-García, A.; Liras, P

    2004-01-01

    The oat2 gene, located in the clavulanic acid gene cluster in Streptomyces clavuligerus, is similar to argJ, which encodes N-acetylornithine:glutamic acid acetyltransferase activity. Purified proteins obtained by expression in Escherichia coli of the argJ and oat2 genes of S. clavuligerus posses N-acetyltransferase activity. The kinetics and substrate specificities of both proteins are very similar. Deletion of the oat2 gene did not affect the total N-acetylornithine transferase activity and ...

  10. [In vitro and in vivo activity of a combination of clavulanic acid and amoxicillin against Klebsiella pneumoniae producing extended broad-spectrum betalactamase (CTX-1, SHV-3, SHV-4)].

    Science.gov (United States)

    Migueres, M L; Ronco, E; Guenounou, M; Philippon, A

    1989-05-01

    In vitro activity of an aminopenicillin (amoxicillin or ampicillin) combined with a betalactamase inhibitor (clavulanic acid or sulbactam, 2 mg/l) was examined against 39 strains of K. pneumoniae producing 3 types of extended broad spectrum betalactamases (CTX-1, SHV-3, SHV-4). Clavulanic acid produces the best synergistic effect. The in vivo activity of Augmentin (amoxicillin + clavulanic acid), 1 g once or twice a day, during 10 +/- 3 days was evaluated on 10 cases urinary tract infections in paraplegic patients. After 3 days, no leucocyturia was observed and bacteria were no more detected. The inhibitory effect of clavulanic acid for the extended broad-spectrum betalactamases shows that such an association could be probably chosen as well for treatment urinary infection. PMID:2674869

  11. Comparative efficacy of amoxicillin/clavulanic acid and levofloxacin in the reduction of postsurgical sequelae after third molar surgery: a randomized, double-blind, clinical trial in a Nigerian university teaching hospital

    Directory of Open Access Journals (Sweden)

    Kizito Chioma Ndukwe

    2016-01-01

    Full Text Available Background: The most common sequelae after surgical removal of mandibular third molar are pain, trismus, swelling, and dysphagia. However, these symptoms can also signal the onset of surgical site infection and alveoli osteitis. The aim of this study was to evaluate the efficacy of prophylactic amoxicillin/clavulanic acid and levofloxacin and preemptive therapy of amoxicillin/clavulanic acid in the reduction of postinflammatory complications, surgical site infection, and alveolar osteitis following the third molar surgery. Patients and Methods: A total of 135 patients were randomized into three equal groups: Group A (preemptive therapy of amoxicillin/clavulanic acid with preoperative dose of 875/125 mg amoxicillin/clavulanic acid followed by 500/125 mg amoxicillin/clavulanic acid 12 hourly for 5 days, Group B (amoxicillin/clavulanic acid prophylaxis with a single preoperative dose of amoxicillin/clavulanic acid 875/125 mg tablets, and Group C (levofloxacin prophylaxis with a single preoperative dose of levofloxacin 1000 mg tablets. All patients had ostectomy using surgical handpiece and burs and received same analgesics (tabs ibuprofen 400 mg 8 hourly for 3 days. Results: No case of surgical site infection or alveoli osteitis was recorded in the study groups. There were no statistically significant differences between the treatment groups with regard to pain, mouth opening, postoperative facial dimension, and body temperature. Conclusion: Amoxicillin/clavulanic acid as a single preoperative bolus should be adequate for the prevention of postoperative wound infection and alveoli osteitis following the third molar extraction as there is no need for an extension of the antibiotic. Moreover, levofloxacin can be utilized as prophylaxis in patients undergoing mandibular third molar extraction if such patients are allergic to penicillins.

  12. Response of Streptococcus pyogenes to therapy with amoxicillin or amoxicillin-clavulanic acid in a mouse model of mixed infection caused by Staphylococcus aureus and Streptococcus pyogenes.

    OpenAIRE

    Boon, R J; Beale, A S

    1987-01-01

    The response of Streptococcus pyogenes to amoxicillin or amoxicillin-clavulanic acid (Augmentin; Beecham Group) therapy of a mixed streptococcal-staphylococcal infection was studied in a surgical wound in mice. A superficial wound was produced on the backs of anesthetized mice, and a suture infected with S. pyogenes, Staphylococcus aureus, or a mixed inoculum of both organisms was inserted. Oral therapy was started 4 h after infection and continued for 3 days. Both amoxicillin and amoxicillin...

  13. Two Sets of Paralogous Genes Encode the Enzymes Involved in the Early Stages of Clavulanic Acid and Clavam Metabolite Biosynthesis in Streptomyces clavuligerus

    OpenAIRE

    Tahlan, Kapil; Park, Hyeon Ung; Wong, Annie; Beatty, Perrin H.; Jensen, Susan E.

    2004-01-01

    Recently, a second copy of a gene encoding proclavaminate amidinohydrolase (pah1), an enzyme involved in the early stages of clavulanic acid and clavam metabolite biosynthesis in Streptomyces clavuligerus, was identified and isolated. Using Southern analysis, we have now isolated second copies of the genes encoding the carboxyethylarginine synthase (ceaS) and β-lactam synthetase (bls) enzymes. These new paralogues are given the gene designations ceaS1 and bls1 and are located immediately upst...

  14. Simultaneous detection and comparative pharmacokinetics of amoxicillin, clavulanic acid and prednisolone in cows' milk by UPLC-MS/MS.

    Science.gov (United States)

    Liu, Yuan; Zhu, Kui; Wang, Jianfen; Huang, Xiaoyong; Wang, Guanlin; Li, Congying; Cao, Jie; Ding, Shuangyang

    2016-01-01

    Amoxicillin (AMOX), clavulanic acid (CLAV) and prednisolone (PSL) are widely used in combination for the treatment of mastitis in lactating dairy cows. However, no method has been reported to detect these three chemicals in milk in a single assay. In the present work, a reliable and sensitive UPLC-MS/MS method was developed and validated for simultaneous determination of AMOX, CLAV and PSL in cow's milk. The analytes were determined by a positive and negative ionization electrospray mass spectrometer via multiple reaction monitoring. The linear ranges of AMOX, CLAV and PSL were from 2 to 1000ng/mL, 20-1000ng/mL and 1-1000ng/mL, respectively, with the correlation coefficients greater than 0.999. The limits of quantification (LOQs) were 2ng/mL (AMOX), 20ng/mL (CLAV) and 1ng/mL (PSL). Recoveries of the analytes of interest in milk samples were in the ranges of 84.2-101.4%. The intra-day and inter-day precisions ranged from 1.8% to 11.9%. This method was successfully applied to investigate the pharmacokinetics of AMOX, CLAV and PSL in milk from healthy and mastitic cows. The elimination times of AMOX and PSL in mastitic cows were longer than that in healthy cows, but the elimination times of CLAV did not show significant difference. PMID:26638031

  15. Clavulanic acid enhances glutamate transporter subtype I (GLT-1) expression and decreases reinforcing efficacy of cocaine in mice.

    Science.gov (United States)

    Kim, Jae; John, Joel; Langford, Dianne; Walker, Ellen; Ward, Sara; Rawls, Scott M

    2016-03-01

    The β-lactam antibiotic ceftriaxone (CTX) reduces cocaine reinforcement and relapse in preclinical assays through a mechanism involving activation of glutamate transporter subtype 1 (GLT-1). However, its poor brain penetrability and intravenous administration route may limit its therapeutic utility for indications related to CNS diseases. An alternative is clavulanic acid (CA), a structural analog of CTX that retains the β-lactam core required for GLT-1 activity but displays enhanced brain penetrability and oral activity relative to CTX. Here, we tested the hypothesis that CA (1, 10 mg/kg ip) would enhance GLT-1 expression and decrease cocaine self-administration (SA) in mice, but at lower doses than CTX. Experiments revealed that GLT-1 transporter expression in the nucleus accumbens of mice treated with repeated CA (1, 10 mg/kg) was enhanced relative to saline-treated mice. Repeated CA treatment (1 mg/kg) reduced the reinforcing efficacy of cocaine (0.56 mg/kg/inf) in mice maintained on a progressive-ratio (PR) schedule of reinforcement but did not affect acquisition of cocaine SA under fixed-ratio responding or acquisition or retention of learning. These findings suggest that the β-lactamase inhibitor CA can activate the cellular glutamate reuptake system in the brain reward circuit and reduce cocaine's reinforcing efficacy at 100-fold lower doses than CTX. PMID:26543027

  16. The Role of Chronic Exposure to Amoxicillin/Clavulanic Acid on the Developmental Enamel Defects in Mice.

    Science.gov (United States)

    Mihalaş, Eugeniu; Matricala, Lavinia; Chelmuş, Alina; Gheţu, Nicolae; Petcu, Ana; Paşca, Sorin

    2016-01-01

    Amoxicillin used in early childhood may be associated with enamel hypomineralization. Our aim was to assess disturbances of amelogenesis in mice lower incisors induced by chronic administration of amoxicillin/clavulanic acid (AMC). Twenty-eight C57BL/6 male mice, of similar age, randomly divided into a control and 3 treatment groups (n = 7) received subcutaneous injection, once per day, for 60 days: 50, 100, and 150 mg/kg BW of AMC. Scanning electron microscopy/energy dispersive X-ray spectroscopy analysis in AMC treatment groups showed higher content in F and a decrease in P and Ca. Morphology changes ranged from scratched patterns, and small isolated pits-like enamel loss, to generalized demineralized enamel surface, giving a rough, foamy, scaly, or even cracked eggshell appearance to the affected areas. Histological analysis showed disturbances of maturation ameloblasts, which were less organized, with increased amounts of clear vacuoles in the cytoplasm and slightly more elongated and less condensed nucleus. Additionally, they were often detached from the enamel matrix. Transitional ameloblasts formed underlying the cysts of varied sizes. In conclusion, AMC dose-dependently affect ameloblast functions especially in the maturation phase, causing hypomineralized enamel formation with quantitative and/or qualitative defects. PMID:26534941

  17. Ticarcillin and Clavulanate Injection

    Science.gov (United States)

    ... combination of ticarcillin and clavulanate eliminates bacteria that cause many kinds of infections, including pneumonia and gynecological, urinary tract, skin, stomach, bone, joint, and blood infections. ...

  18. Comparison of the activity of imipenem and beta-lactams combined with sulbactam and clavulanic acid in beta-lactamase-producing strains of Bacteroides fragilis.

    Science.gov (United States)

    Martín, M A; Castillo, A M; Liébana, J; Marín, A; Alados, J C; Piédrola, G

    1991-01-01

    We compared the "in vitro" activity of imipenem with 14 beta-lactams, both alone and in combination with clavulanic acid, and sulbactam against 110 beta-lactamase-producing strains of Bacteroides fragilis. The following antibiotics were tested: amoxycillin, penicillin, mezlocillin, piperacillin, cephalothin, cephazolin, cefamandole, cefmetazole, cefonicid, cefoxitin, cefotaxime, ceftazidime, ceftizoxime, and ceftriaxone. In all cases, except those of cefoxitin and cefmetazole, these combinations showed a statistically significant increase in beta-lactam activity, which was, however, never higher than that of imipenem, the antibiotic which performed best against Bacteroides fragilis. PMID:1940333

  19. Evaluation of ticarcillin/clavulanic acid versus ceftriaxone plus amikacin for fever and neutropenia in pediatric patients with leukemia and lymphoma

    Directory of Open Access Journals (Sweden)

    Petrilli Antonio Sérgio

    2003-01-01

    Full Text Available BACKGROUND: The empirical use of antibiotic treatments is widely accepted as a means to treat cancer patients in chemotherapy who have fever and neutropenia. Intravenous monotherapy, with broad spectrum antibiotics, of patients with a high risk of complications is a possible alternative. METHODS: We conducted a prospective open-label, randomized study of patients with lymphoma or leukemia who had fever and neutropenia during chemotherapy. Patients received either monotherapy with ticarcillin/clavulanic acid (T or ceftriaxone plus amikacin (C+A. RESULTS: Seventy patients who presented 136 episodes were evaluated, 68 in each arm of the study. The mean neutrophil counts at admission were 217cells/mm³ (T and 201cells/mm³ (C+A. The mean duration of neutropenia was 8.7 days (T and 7.6 days (C+A. Treatment was successful without the need for modifications in 71% of the episodes in the T group and 81% in the C+A group (p=0.23. Treatment was considered to have failed because of death in two episodes (3% in the T group and three episodes (4% in the C+A group, and because of a change in the drug applied in one episode in the T group and two episodes in the C+A group. Overall success was 96% (T and 93% (C+A. Adverse events that occurred in group T were not related to the drugs used in this study. CONCLUSION: In pediatric and adolescent patients with leukemia or lymphoma, who presented with fever and neutropenia, during chemotherapy, ticarcillin/clavulanic acid was as successful as the combination of ceftriaxone plus amikacin. It should be considered an appropriate option for this group of patients at high risk for infections.

  20. Old Drugs To Treat Resistant Bugs: Methicillin-Resistant Staphylococcus aureus Isolates with mecC Are Susceptible to a Combination of Penicillin and Clavulanic Acid.

    Science.gov (United States)

    Ba, Xiaoliang; Harrison, Ewan M; Lovering, Andrew L; Gleadall, Nicholas; Zadoks, Ruth; Parkhill, Julian; Peacock, Sharon J; Holden, Matthew T G; Paterson, Gavin K; Holmes, Mark A

    2015-12-01

    β-Lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is mediated by the expression of an alternative penicillin-binding protein 2a (PBP2a) (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA, known as mecC, was identified in MRSA isolates from both humans and animals. In this study, we demonstrate that mecC-encoded PBP2c does not mediate resistance to penicillin. Rather, broad-spectrum β-lactam resistance in MRSA strains carrying mecC (mecC-MRSA strains) is mediated by a combination of both PBP2c and the distinct β-lactamase encoded by the blaZ gene of strain LGA251 (blaZLGA251), which is part of mecC-encoding staphylococcal cassette chromosome mec (SCCmec) type XI. We further demonstrate that mecC-MRSA strains are susceptible to the combination of penicillin and the β-lactam inhibitor clavulanic acid in vitro and that the same combination is effective in vivo for the treatment of experimental mecC-MRSA infection in wax moth larvae. Thus, we demonstrate how the distinct biological differences between mecA- and mecC-encoded PBP2a and PBP2c have the potential to be exploited as a novel approach for the treatment of mecC-MRSA infections. PMID:26392513

  1. Pharmacokinetics of potassium clavulanate in combination with amoxicillin in pediatric patients.

    OpenAIRE

    Nelson, J.D.; Kusmiesz, H; Shelton, S

    1982-01-01

    Two dosages of a liquid suspension formulation of amoxicillin and potassium clavulanate were tested in 34 infants and children. The smaller dosage resulted in suboptimal plasma concentrations. With a greater dosage (3.3 mg of clavulanate per kg and 13.3 mg of amoxicillin per kg), the mean peak plasma concentrations were 1.6 micrograms clavulanic acid per ml and 4.9 micrograms amoxicillin per ml.

  2. Comparative Bacteriological Efficacy of Pharmacokinetically Enhanced Amoxicillin-Clavulanate against Streptococcus pneumoniae with Elevated Amoxicillin MICs and Haemophilus influenzae

    OpenAIRE

    Berry, Valerie; Hoover, Jennifer; Singley, Christine; Woodnutt, Gary

    2005-01-01

    A new pharmacokinetically enhanced formulation of amoxicillin-clavulanate (2,000 mg of amoxicillin/125 mg of clavulanate twice a day; ratio 16:1) has been designed, with sustained-release technology, to allow coverage of bacterial strains with amoxicillin-clavulanic acid MICs of at least 4/2 μg/ml. The bacteriological efficacy of amoxicillin-clavulanate, 2,000/125 mg twice a day, ratio 16:1, was compared in a rat model of respiratory tract infection versus four other amoxicillin-clavulanate f...

  3. Inversion of the stereochemical configuration (3S, 5S)-clavaminic acid into (3R, 5R)-clavulanic acid: A computationally-assisted approach based on experimental evidence.

    Science.gov (United States)

    Ramirez-Malule, Howard; Restrepo, Albeiro; Cardona, Wilson; Junne, Stefan; Neubauer, Peter; Rios-Estepa, Rigoberto

    2016-04-21

    Clavulanic acid (CA), a potent inhibitor of β-lactamase enzymes, is produced by Streptomyces clavuligerus (Sc) cultivation processes, for which low yields are commonly obtained. Improved knowledge of the clavam biosynthetic pathway, especially the steps involved in the inversion of 3S-5S into 3R-5R stereochemical configuration, would help to eventually identify bottlenecks in the pathway. In this work, we studied the role of acetate in CA biosynthesis by a combined continuous culture and computational simulation approach. From this we derived a new model for the synthesis of N-acetyl-glycyl-clavaminic acid (NAG-clavam) by Sc. Acetylated compounds, such as NAG-clavam and N-acetyl-clavaminic acid, have been reported in the clavam pathway. Although the acetyl group is present in the β-lactam intermediate NAG-clavam, it is unknown how this group is incorporated. Hence, under the consideration of the experimentally proven accumulation of acetate during CA biosynthesis, and the fact that an acetyl group is present in the NAG-clavam structure, a computational evaluation of the tentative formation of NAG-clavam was performed for the purpose of providing further understanding. The proposed reaction mechanism consists of two steps: first, acetate reacts with ATP to produce a reactive acylphosphate intermediate; second, a direct nucleophilic attack of the terminal amino group of N-glycyl-clavaminic on the carbonyl carbon of the acylphosphate intermediate leads to a tetrahydral intermediate, which collapses and produces ADP and N-acetyl-glycyl-clavaminic acid. The calculations suggest that for the proposed reaction mechanism, the reaction proceeds until completion of the first step, without the direct action of an enzyme, where acetate and ATP are involved. For this step, the computed activation energy was ≅2.82kcal/mol while the reaction energy was ≅2.38kcal/mol. As this is an endothermic chemical process with a relatively small activation energy, the reaction rate

  4. Treating gonococcal urethritis in men: oral amoxycillin potentiated by clavulanate compared with intramuscular procaine penicillin.

    OpenAIRE

    Latif, A S; Sithole, J.; Bvumbe, S; Gumbo, B; Kawemba, M; Summers, R S

    1984-01-01

    In a study of 121 men with uncomplicated gonococcal urethritis, 64 were treated orally with a single dose of 3 g amoxycillin and 250 mg of the specific beta-lactamase inhibitor, clavulanic acid, and 57 with a single intramuscular injection of 2.4 MU procaine penicillin. After seven days, six (9.4%) patients treated with amoxycillin and clavulanic acid were still culture positive for Neisseria gonorrhoeae, compared with 26.3% of those treated with procaine penicillin.

  5. Comparison of the boronic acid disk potentiation test and cefepime-clavulanic acid method for the detection of ESBL among AmpC-producing Enterobacteriaceae

    Directory of Open Access Journals (Sweden)

    R M Shoorashetty

    2011-01-01

    Full Text Available Purpose: Extended spectrum β-lactamase (ESBL and AmpC β-lactamase are important mechanisms of betalactam resistance among Enterobacteriaceae . The ESBL confirmation test described by Clinical Laboratory Standards Institute (CLSI is in routine use. This method fails to detect ESBL in the presence of AmpC. Therefore, we compared two different ESBL detection methods against the CLSI confirmatory test. Materials and Methods: A total 200 consecutive clinical isolates of Enterobacteriaceae from various clinical samples were tested for ESBL production using (i CLSI described phenotypic confirmatory test (PCT, (ii boronic acid disk potentiation test and (iii cefepime-CA disk potentiation method. AmpC confirmation was done by a modified three-dimensional test. Results: Among total 200 Enterobacteriaceae isolates, 82 were only ESBL producers, 12 were only AmpC producers, 55 were combined ESBL and AmpC producers, 14 were inducible AmpC producers and 37 isolates did not harboured any enzymes. The CLSI described PCT detected ESBL-producing organisms correctly but failed to detect 36.3% of ESBLs among combined enzyme producers. The boronic acid disk potentiation test reliably detected all ESBL, AmpC, and combined enzyme producers correctly. The cefepime-CA method detected all ESBLs correctly but another method of AmpC detection has to be adopted. Conclusion: The use of boronic acid in disk diffusion testing along with the CLSI described PCT enhances ESBL detection in the presence of AmpC betalactamases.

  6. Studies on the formation and forming mechanism of the related substance E in potassium clavulanate production by HPLC-MS/MS

    OpenAIRE

    Chuanqing Zhong; Guangxiang Cao; Xiaoqing Jin; Fengshan Wang

    2014-01-01

    The objective of this study was to investigate the formation and forming mechanism of the related substance E in potassium clavulanate production. The impurity with retention time of 11.1 min in potassium clavulanate final product was confirmed as the related substance E by high performance liquid chromatography with tandem mass spectrometric detection (HPLC-MS/MS).The related substance E analysis during the production of clavulanic acid showed that this impurity could be formed during both t...

  7. 75 FR 76016 - Determination That AUGMENTIN `125' (Amoxicillin; Clavulanate Potassium) Chewable Tablet and Six...

    Science.gov (United States)

    2010-12-07

    ... HUMAN SERVICES Food and Drug Administration Determination That AUGMENTIN `125' (Amoxicillin; Clavulanate Potassium) Chewable Tablet and Six Other AUGMENTIN (Amoxicillin; Clavulanate Potassium) Drug Products Were... (amoxicillin; clavulanate potassium) drug products listed in this notice were not withdrawn from sale...

  8. Treatment of Cervical Chlamydial Infection With Amoxicillin/Clavulanate Potassium

    OpenAIRE

    Mann, Melinda S.; Sebastian Faro; Maccato, Maurizio L.; Kaufman, Raymond H.

    1993-01-01

    Objective: To determine if amoxicillin/clavulanate potassium is effective in the treatment of Chlamydia trachomatis endocervicitis. Methods: Thirty-two patients with culture-proven endocervical infection were treated with amoxicillin/clavulanate potassium, 500 mg orally 3 times a day for 10 days. Post-treatment endocervical specimens were obtained at 2, 4, and 6 weeks for culture of C. trachomatis. Male partners were treated with doxycycline, 100 mg orally twice daily for 10 days. The couples...

  9. Acute cholestatic hepatitis caused by amoxicillin/clavulanate.

    Science.gov (United States)

    Beraldo, Daniel Oliveira; Melo, Joanderson Fernandes; Bonfim, Alexandre Vidal; Teixeira, Andrei Alkmim; Teixeira, Ricardo Alkmim; Duarte, André Loyola

    2013-12-14

    Amoxicillin/clavulanate is a synthetic penicillin that is currently commonly used, especially for the treatment of respiratory and cutaneous infections. In general, it is a well-tolerated oral antibiotic. However, amoxicillin/clavulanate can cause adverse effects, mainly cutaneous, gastrointestinal, hepatic and hematologic, in some cases. Presented here is a case report of a 63-year-old male patient who developed cholestatic hepatitis after recent use of amoxicillin/clavulanate. After 6 wk of prolonged use of the drug, he began to show signs of cholestatic icterus and developed severe hyperbilirubinemia (total bilirubin > 300 mg/L). Diagnostic investigation was conducted by ultrasonography of the upper abdomen, serum tests for infection history, laboratory screening of autoimmune diseases, nuclear magnetic resonance (NMR) of the abdomen with bile duct-NMR and transcutaneous liver biopsy guided by ultrasound. The duration of disease was approximately 4 mo, with complete resolution of symptoms and laboratory changes at the end of that time period. Specific treatment was not instituted, only a combination of anti-emetic (metoclopramide) and cholestyramine for pruritus. PMID:24379601

  10. Protoplast formation and regeneration from Streptomyces clavuligerus NRRL 3585 and clavulanic acid production Formação e regeneração de protoplastos de Streptomyces clavuligerus NRRL 3585 e produção de ácido clavulânico

    Directory of Open Access Journals (Sweden)

    Maria das Graças Carneiro-da-Cunha

    2002-12-01

    Full Text Available Protoplasts of the wild type Streptomyces clavuligerus NRRL 3585 (ATCC 27064 were formed from spores cultures obtained in the lag, exponential and stationary growth phases by using 0.5% glycine in the culture medium. The protoplasts were obtained by treatment of the cells with lysozyme (EC-3.2.1.17 40,000 U (1mg/mL, in an osmotic solution for 90 min at 28ºC. The frequency of regenerated protoplasts in the lag phase was 1.7x10³ CFU/mL (28.97%, in the beginning of the exponential phase 0.4x10² CFU/mL (31.67%, in the exponential growth phase 2.5x10³ CFU/mL (46.30% and 1.0x10(5 CFU/mL in stationary phase (48.45%. Antibiotic production and activity of regenerated protoplasts were observed in all phases, except in the lag phase. The protoplast formation and regeneration techniques resulted in a new isolate strain of Streptomyces clavuligerus that produced approximately 2.5 fold more clavulanic acid.Protoplastos foram formados a partir de esporos da amostra selvagem de Streptomyces clavuligerus durante a fase lag, exponencial e estacionária de crescimento, utilizando glicina a 0.5% como meio de cultura. Os protoplastos foram obtidos pelo tratamento das células com lisozima (EC-3.2.1.17 40.000 U (1mg/mL em solução osmótica de sorbitol e TES, por 90 min a 28ºC. A freqüência de protoplastos regenerados na fase lag foi de 1,7x10³ UFC/mL (28,97%, no início da fase exponencial correspondeu a 0,4x10² UFC/mL (31,67%, no final da fase exponencial observou-se 2,5x10³ UFC/mL (46,30% e para a fase estacionária de crescimento apresentou 1,0x10(5 UFC/mL (48,45%. A produção do antibiótico e a atividade antibiótica dos protoplastos regenerados foram observadas em todas as fases de crescimento, exceto na fase lag. As técnicas de formação de protoplastos e regeneração resultaram em uma nova linhagem de Streptomyces clavuligerus produzindo 2,5 vezes mais ácido clavulânico.

  11. Effects of amoxicillin-clavulanate combination on the motility of the small intestine in human beings.

    OpenAIRE

    Caron, F.; Ducrotte, P; Lerebours, E.; Colin, R; Humbert, G; Denis, P

    1991-01-01

    The amoxicillin-clavulanate combination (Augmentin) frequently induces gastric complaints and diarrhea by an unknown mechanism. The aim of this study was to assess the effects of two orally therapeutic regimens of amoxicillin-clavulanate on small bowel motility in human beings. Duodeno-jejunal manometric recordings were performed in six healthy subjects treated in a cross-over double-blind study with placebo; amoxicillin-clavulanate, 1 g plus 250 mg per os every 12 h for 3 days; or amoxicilli...

  12. Comparative study of cephradine and amoxicillin-clavulanate in the treatment of recurrent urinary tract infections.

    OpenAIRE

    Brumfitt, W; Hamilton-Miller, J M

    1990-01-01

    Eighty-eight female patients with a history of recurrent urinary tract infections were treated according to a randomization scheme with either 1 g of cephradine every 12 h (47 patients) or 375 mg of amoxicillin-clavulanate every 8 h (41 patients) for 7 days. The treatments were equally effective (cure rates of 89% for cephradine and 88% for amoxicillin-clavulanate) and showed similar relapse rates (cephradine, 14%; amoxicillin-clavulanate, 11%). Adverse effects were similar in both groups (ce...

  13. Resistance to amoxicillin-clavulanate and its relation to virulence-related factors in Yersinia enterocolitica biovar 1A.

    Science.gov (United States)

    Singhal, N; Kumar, M; Virdi, J S

    2016-01-01

    Recent studies have reported that the virulence factors (VFs) were detected more frequently in amoxicillin-clavulanate (AMC) susceptible clinical isolates of Escherichia coli. Here, we have evaluated the relationship between VFs and AMC-resistance phenotype in clinical isolates of Y. enterocolitica biovar 1A. The presence/absence of VFs was compared with their minimum inhibitory concentrations for AMC in strains of two serovars. We observed that the strains of the serovar O: 6, 30-6, 31 showed a similar relationship between the number of VFs and resistance to clavulanic acid as in E. coli but not of serovar O: 6, 30. Variations in the promoters/complete coding sequences (CCDSs) of β-lactamase gene (bla A) or the serological characteristics could not account for unusual susceptibility to AMC displayed by the strains of the serovar O: 6, 30. Therefore, we speculate that since the clinical strains of serovar O: 6, 30-6, 31 originated from the environment they were less exposed to antibiotics compared to clinical strains of serovar O: 6, 30. Thus, AMC susceptibility seems to be influenced by factors other than serotypes or promoters/CCDS of β-lactamase genes. PMID:26776125

  14. Resistance to amoxicillin-clavulanate and its relation to virulence-related factors in Yersinia enterocolitica biovar 1A

    Directory of Open Access Journals (Sweden)

    N Singhal

    2016-01-01

    Full Text Available Recent studies have reported that the virulence factors (VFs were detected more frequently in amoxicillin-clavulanate (AMC susceptible clinical isolates of Escherichia coli. Here, we have evaluated the relationship between VFs and AMC-resistance phenotype in clinical isolates of Y. enterocolitica biovar 1A. The presence/absence of VFs was compared with their minimum inhibitory concentrations for AMC in strains of two serovars. We observed that the strains of the serovar O: 6, 30-6, 31 showed a similar relationship between the number of VFs and resistance to clavulanic acid as in E. coli but not of serovar O: 6, 30. Variations in the promoters/complete coding sequences (CCDSs of β-lactamase gene (bla A or the serological characteristics could not account for unusual susceptibility to AMC displayed by the strains of the serovar O: 6, 30. Therefore, we speculate that since the clinical strains of serovar O: 6, 30-6, 31 originated from the environment they were less exposed to antibiotics compared to clinical strains of serovar O: 6, 30. Thus, AMC susceptibility seems to be influenced by factors other than serotypes or promoters/CCDS of β-lactamase genes.

  15. Effect of amoxicillin-clavulanate and cephradine on the fecal flora of healthy volunteers not exposed to a hospital environment.

    OpenAIRE

    Brumfitt, W; Franklin, I; Grady, D.; Hamilton-Miller, J M

    1986-01-01

    A 7-day course of either cephradine or amoxicillin-clavulanate treatment caused no significant change in fecal flora composition, except that staphylococci were virtually eliminated in both groups. Some amoxicillin-resistant coliforms were isolated after treatment in both groups, but cephradine- or amoxicillin-clavulanate-resistant coliforms were rarely isolated.

  16. Evaluation of Cefixime-Clavulanate Combination by Comparative Disk Diffusion Method in Klebsiella pneumoniae Clinical Isolates-An In-Vitro Study

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    Gajul S.V

    2015-04-01

    Full Text Available Background: Resistance to cephalosporins due to β-lactamases is a major concern worldwide. However recent trend is to use β-lactamase inhibitor combinations. Potential combination is cefiximeclavulanate. Objective: Present study aims at the comparative evaluation of Fixed-Dose Combination (FDC of cefixime‑clavulanate and cefixime-alone in Klebsiella pneumoniae clinical isolates. Material and Methods: Study included 200 clinical isolates of K. pneumoniae. The Comparative Antimicrobial Susceptibility Test (AST of cefixime‑clavulanate (5µg/10µg combination and cefixime-alone(5µg was done by measurement and comparison of zone of lysis produced by both. All values were expressed in mean ± SD. Paired‘t’ test was used to determine statistical difference between different groups under study. P values < 0.05 were considered statistically significant. Isolates were tested for ExtendedSpectrum β-lactamase (ESBL, AmpC β-lactamase (AmpC and metallo β-lactamase (MBL production by Clinical Laboratory Standards Institute - Phenotypic Disk Confirmatory Test (CLSI-PDCT, AmpC β-lactamase sterile disk test and Imipenem-Ethylene Di-amine Tetracetic Acid – Double disk synergy test (Imipenem-EDTA DDST respectively. Results: Comparative AST resulted in statistically significant (P < 0.001 increased zones in cefixime‑clavulanate combination than cefixime-alone in all isolates studied. When zones were evaluated separately only in three β-lactamase producing isolates; cefiximeclavulanate combination showed much higher zones in ESBL-producers (n=30 (P < 0.001, but not in AmpC-producers (n=32 (P = 0.5559 and MBLproducers (n=06 (P = 0.7815. Conclusion: Present study demonstrates the best bactericidal killing effect of cefixime-clavulanate compared to cefixime-alone. It is also of therapeutic significance in the treatment of infections caused by K. pneumoniae producing ESBLs. We recommend comparative AST method when commercially available newer

  17. Eficácia e segurança de Sultamicilina (Ampicilina/Sulbactam e Amoxacilina/Clavulanato no tratamento das infecções de via aéreas superiores em adultos: um estudo multicêntrico, aberto e randomizado Efficacy and safety of Sultamicillin (Ampicillin/Sulbactan and Amoxicillin/Clavulanic Acid in the treatment of upper respiratory tract infections in adults: an open-label, multicentric, randomized trial

    Directory of Open Access Journals (Sweden)

    João Batista Ferreira

    2006-02-01

    pro-drug of Ampicillin/Sulbactan, is a potent beta-lactamase inhibitor which can face this challenge. AIM: evaluate efficacy, safety and tolerability of Ampicillin/Sulbactan compared to Amoxicillin/Clavulanate in upper respiratory tract infections in adults. METHODS: 102 patients were enrolled and randomized to receive Ampicillin/Sulbactan or Amoxicillin/Clavulanate during 10 days. They were evaluated 10 and 30 days after treatment to learn about the therapeutic response. RESULTS: There were no differences between the two groups respecting cure at the end of treatment (visit 2 or at the end of the study (visit 3. Cure ratio was 61.7% and 93.2% (visits 2 and 3 in the Amoxicillin/Clavulanate group compared to 64.4% and 97.4%, respectively, in Ampicillin/Sulbactan group. The adverse events ratio for the two groups was the same (p=0.940. The number of patients with diarrhea was greater in the group of patients receiving Amoxicillin/Clavulanate (70.6% than in the group receiving Ampicillin/Sulbactan (29.4% (p=0.0164. CONCLUSIONS: Ampicillin/Sulbactan is as safe and efficient as Amoxicillin/Clavulanate in the empiric treatment of upper respiratory infections in adults. The low occurrence of diarrhea in the group receiving Ampicillin/Sulbactan needs confirmation in other studies.

  18. Susceptibilities of 540 anaerobic gram-negative bacilli to amoxicillin, amoxicillin-BRL 42715, amoxicillin-clavulanate, temafloxacin, and clindamycin.

    OpenAIRE

    Appelbaum, P. C.; Spangler, S K; Shiman, R; Jacobs, M R

    1992-01-01

    Agar dilution MIC testing of amoxicillin, amoxicillin-BRL 42715, amoxicillin-clavulanate, temafloxacin, and clindamycin against 496 beta-lactamase-producing anaerobic gram-negative rods revealed MICs for 90% of the strains tested of 256.0 (amoxicillin), 2.0 (amoxicillin-BRL 42715 and amoxicillin-clavulanate), and 4.0 (temafloxacin and clindamycin) microgram/ml. Amoxicillin, temafloxacin, and clindamycin inhibited all 44 beta-lactamase-negative strains (MICs for 90% of the strains tested, less...

  19. Efficacy of amoxycillin versus amoxycillin/clavulanate in acute exacerbations of chronic pulmonary obstructive disease in primary care

    Science.gov (United States)

    Llor, Carl; Hernández, Silvia; Ribas, Anna; Álvarez, Carmen; Cots, Josep Maria; Bayona, Carolina; González, Isabel; Miravitlles, Marc

    2009-01-01

    Background Amoxycillin/clavulanate is considered first-line treatment for ambulatory exacerbations of COPD. However, narrow-spectrum antibiotics may be as useful for mild to moderate patients. Objective To compare the clinical efficacy of amoxycillin versus amoxicyllin/clavulanate in exacerbations of COPD in primary care. Methods A randomized, double-blind, noninferiority clinical trial was carried out in eight primary care centers in Catalonia, Spain. Spirometrically-diagnosed patients older than 40 years with COPD, without criteria of hospitalization and Anthonisen’s types I or II exacerbations were included. The main outcome was clinical cure at the end of treatment (EOT) visit on day 10. Results A total of 137 patients were enrolled in the study (68 assigned to amoxycillin and 69 to amoxycillin/clavulanate). The mean forced expiratory flow in one second was 61.6% and the mean age was 71.4 years. At EOT, 92.8% of patients in the amoxycillin/clavulanate and 90.9% in the amoxycillin group were considered clinically cured, a statistically non-significant difference. Adverse effects were observed in 11 subjects, 3 in the amoxycillin group and 8 in the amoxycillin/clavulanate group, 2 of whom required a change in treatment. Conclusions Amoxycillin was at least as effective clinically and as safe as amoxycilin/ clavulanate in the treatment of acute exacerbations of COPD in mild to moderate patients in primary care. PMID:19436696

  20. Comparative trial between the use of amoxicillin and amoxicillin clavulanate in the removal of third molars

    OpenAIRE

    Iglesias Martin, Fernando; García-Perla García, Alberto; Yáñez Vico, Rosa María; Aced Jiménez, Elena; Arjona Gerveno, Esther; J.D. González Padilla; Gutiérrez Pérez, José Luis; Torres Lagares, Daniel

    2014-01-01

    Objectives: The purpose of this study was to compare the use of amoxicillin (1g) vs amoxicillin and clavulanate (875/125mg) after extraction of retained third molars for prevention of infectious complications. Study Design: The study involved 546 patients attending for removal a retained third molar and divided in to two groups: Group 1 - amoxicillin and clavunate (875/125mg) group (n=257) and Group 2 - amoxicillin (1g) group (n=289). All patients were recalled for investigating the possibili...

  1. Comparative evaluation of loracarbef and amoxicillin-clavulanate for acute otitis media.

    OpenAIRE

    Gan, V N; Kusmiesz, H; Shelton, S; Nelson, J.D.

    1991-01-01

    One hundred five infants and children with acute otitis media were randomized to therapy with loracarbef, an experimental carbacephem antibiotic, or amoxicillin-clavulanate (Augmentin), an approved drug for this disease. Ninety-two were evaluable (46 in each group). Middle ear fluid samples obtained for culture before therapy grew Haemophilus spp. in 30% of cases, pneumococci in 29% of cases, and Moraxella catarrhalis in 15% of cases. beta-Lactamase-producing bacteria were found in 37% of pat...

  2. Epidemiological and clinical complexity of amoxicillin-clavulanate-resistant Escherichia coli.

    Science.gov (United States)

    Rodríguez-Baño, Jesús; Oteo, Jesús; Ortega, Adriana; Villar, Macarena; Conejo, M Carmen; Bou, Germán; Aranzamendi-Zaldumbide, Maitane; Cercenado, Emilia; Gurguí, Mercè; Martínez-Martínez, Luis; Merino, María; Rivera, Alba; Oliver, Antonio; Weber, Irene; Pascual, Alvaro; Bartolomé, Rosa M; Gónzalez-López, Juan José; Campos, José

    2013-07-01

    Two hundred twelve patients with colonization/infection due to amoxicillin-clavulanate (AMC)-resistant Escherichia coli were studied. OXA-1- and inhibitor-resistant TEM (IRT)-producing strains were associated with urinary tract infections, while OXA-1 producers and chromosomal AmpC hyperproducers were associated with bacteremic infections. AMC resistance in E. coli is a complex phenomenon with heterogeneous clinical implications. PMID:23637303

  3. In Vivo Activities of Amoxicillin and Amoxicillin-Clavulanate against Streptococcus pneumoniae: Application to Breakpoint Determinations

    OpenAIRE

    Andes, D.; Craig, W. A.

    1998-01-01

    The in vivo activities of amoxicillin and amoxicillin-clavulanate against 17 strains of Streptococcus pneumoniae with penicillin MICs of 0.12–8.0 mg/liter were assessed in a cyclophosphamide-induced neutropenic murine thigh infection model. Renal impairment was produced by administration of uranyl nitrate to prolong the amoxicillin half-life in the mice from 21 to 65 min, simulating human pharmacokinetics. Two hours after thigh infection with 105 to 106 CFU, groups of mice were treated with 7...

  4. Bioequiwalence of clavulanate Potassium and Amoxicillin(1:7) dispersible tablets in healthy volunteers

    Institute of Scientific and Technical Information of China (English)

    胡国新; 代宗顺; 龙利红; 韩颖; 侯淑贤; 吴立

    2002-01-01

    Summary: To study the bioequivalence of Clavulanate Potassium and Amoxicillin (1: 7) dispersible tablets, a randomized cross - over study was conducted in 18 healthy volunteers. A single oral dose of 1000 mg Clavulanate Potassium and Amoxicillin (1:7) dispersible tablets (Tested formulation, T) or Augmentin syrup (Reference formulation, R). Concentrations in plasma were determined with high-performance liquid chromatography. The main paramaters of T were: for Clavu lanate Potassium and Amoxicillin, Cmax: 2. 46±1.11 μg/ml and 18. 81±7. 26 μg/ml, Tmax 1. 12±0. 23h and 1. 30±0. 34h, AUC(0- 6h): 5. 18±2.24 μg * h/ml and 45. 09±14. 53 μg * h/ml, t1/2:1.43±0. 44 h and 1. 09±0.22 h. , respectively. The relative bioavailability of T to R were 96. 5±19. 2 % and 98. 4±26. 1 % , respectively. Statistical analysis showed that the two formulations were bioequivalent.

  5. Potassium clavulanate

    Directory of Open Access Journals (Sweden)

    Kotaro Fujii

    2010-08-01

    Full Text Available The title salt, K+·C8H8NO5− [systematic name: potassium (2R,5R,Z-3-(2-hydroxyethylidene-7-oxo-4-oxa-1-azabicyclo[3.2.0]heptane-2-carboxylate], a widely used β-lactam antibiotic, is usually chemically unstable even in the solid state owing to its tendency to be hydrolysed. In the crystal structure, the potassium cations are arranged along the a axis, forming interactions to the carboxylate and hydroxy groups, resulting in one-dimensional ionic columns. These columns are arranged along the b axis, connected by O—H...O hydrogen bonds, forming a layer in the ab plane.

  6. Efficacy of amoxycillin versus amoxycillin/clavulanate in acute exacerbations of chronic pulmonary obstructive disease in primary care

    Directory of Open Access Journals (Sweden)

    Carl Llor

    2008-10-01

    Full Text Available Carl Llor1, Silvia Hernández1, Anna Ribas2, Carmen Álvarez3, Josep Maria Cots4, Carolina Bayona5, Isabel González6, Marc Miravitlles7, BRAMOX Study Group 1Primary Care Centre Jaume I, Tarragona, Spain; 2Primary Care Centre Santa Eugènia de Berga, Spain; 3Primary Care Centre Manlleu, Spain; 4Primary Care Centre La Marina, Barcelona, Spain; 5Primary Care Centre Valls, Spain; 6Primary Care Centre Maragall, Barcelona, Spain; 7Pneumology Department. Institut Clínic del Tòrax (IDIBAPS, Hospital Clínic, Barcelona, CIBER de Enfermedades Respiratorias (CIBERES, SpainBackground: Amoxycillin/clavulanate is considered first-line treatment for ambulatory exacerbations of COPD. However, narrow-spectrum antibiotics may be as useful for mild to moderate patients.Objective: To compare the clinical efficacy of amoxycillin versus amoxicyllin/clavulanate in exacerbations of COPD in primary care.Methods: A randomized, double-blind, noninferiority clinical trial was carried out in eight primary care centers in Catalonia, Spain. Spirometrically-diagnosed patients older than 40 years with COPD, without criteria of hospitalization and Anthonisen’s types I or II exacerbations were included. The main outcome was clinical cure at the end of treatment (EOT visit on day 10.Results: A total of 137 patients were enrolled in the study (68 assigned to amoxycillin and 69 to amoxycillin/clavulanate. The mean forced expiratory flow in one second was 61.6% and the mean age was 71.4 years. At EOT, 92.8% of patients in the amoxycillin/clavulanate and 90.9% in the amoxycillin group were considered clinically cured, a statistically non-significant difference. Adverse effects were observed in 11 subjects, 3 in the amoxycillin group and 8 in the amoxycillin/clavulanate group, 2 of whom required a change in treatment.Conclusions: Amoxycillin was at least as effective clinically and as safe as amoxycilin/clavulanate in the treatment of acute exacerbations of COPD in mild to

  7. Establishing the validity of different susceptibility testing methods to evaluate the in vitro activity of amoxicillin-clavulanate against Escherichia coli.

    Science.gov (United States)

    María, Díez-Aguilar; María-Isabel, Morosini; María-Carmen, Conejo; Álvaro, Pascual; Jorge, Calvo; Luis, Martínez-Martínez; Francesc, Marco; Jordi, Vila; Adriana, Ortega; Jesús, Oteo; Rafael, Cantón

    2016-04-01

    Amoxicillin-clavulanate MICs of 160 Escherichia coli isolates with characterized resistance mechanisms were obtained by 2 MIC gradient strip brands, 3 automated systems, and reference ISO microdilution method using EUCAST (fixed 2μg/mL clavulanate) and CLSI (2:1 ratio) criteria. Discrepancies, mainly obtained with gradient strips, lead to an essential agreement range of 76.2-92.5. PMID:26830054

  8. Ex Vivo Pharmacodynamics of Amoxicillin-Clavulanate against β-Lactamase-Producing Escherichia coli in a Yucatan Miniature Pig Model That Mimics Human Pharmacokinetics

    OpenAIRE

    Bronner, Stéphane; Murbach, Valérie; Peter, Jean-Daniel; Levêque, Dominique; Elkhaïli, Hassan; Salmon, Yves; Dhoyen, Nathalie; Monteil, Henri; Woodnutt, Gary; Jehl, François

    2002-01-01

    The objective of the present study was to investigate the potential bactericidal activity of amoxicillin-clavulanate against β-lactamase-producing Escherichia coli strains and to elucidate the extent to which enzyme production affects the activity. Six adult Yucatan miniature pigs received a single intravenous dose of 1.1 g of amoxicillin-clavulanate as an intravenous infusion over 30 min. The pharmacokinetic parameters were determined for the serum samples and compared to the published data ...

  9. Eradication of Streptococcus pneumoniae in the Nasopharyngeal Flora of Children with Acute Otitis Media after Amoxicillin-Clavulanate Therapy

    OpenAIRE

    Brook, Itzhak; Gober, Alan E.

    2004-01-01

    Nasopharyngeal cultures were obtained from 60 children with acute otitis media before and after treatment with either 45 or 90 mg of amoxicillin (given as amoxicillin-clavulanate) per kg of body weight per day for 10 days. The number of Streptococcus pneumoniae isolates in the 45-mg/kg group was reduced from 12 to 6 and was reduced from 14 to 1 (P = 0.0261) in the 90-mg/kg group.

  10. Simultaneous quantification of amoxicillin and potassium clavulanate in different commercial drugs using PIXE technique

    Science.gov (United States)

    Bejjani, A.; Roumié, M.; Akkad, S.; El-Yazbi, F.; Nsouli, B.

    2016-03-01

    We have demonstrated, in previous studies that Particle Induced X-ray Emission (PIXE) is one of the most rapid and accurate choices for quantification of an active ingredient, in a solid drug, from the reactions induced on its specific heteroatom using pellets made from original tablets. In this work, PIXE is used, for the first time, for simultaneous quantification of two active ingredients, amoxicillin trihydrate and potassium clavulanate, in six different commercial antibiotic type of drugs. Since the quality control process of a drug covers a large number of samples, the scope of this study was also to found the most rapid and low cost sample preparation needed to analyze these drugs with a good precision. The chosen drugs were analyzed in their tablets' "as received" form, in pellets made from the powder of the tablets and also in pellets made from the powder of the tablets after being heated up to 70 °C to avoid any molecular destruction until constant weight and removal of humidity. The quantification validity related to the aspects of each sample preparation (homogeneity of the drug components and humidity) are presented and discussed.

  11. High-Dose Amoxicillin with Clavulanate for the Treatment of Acute Otitis Media in Children

    Directory of Open Access Journals (Sweden)

    Chia-Huei Chu

    2014-01-01

    Full Text Available Objective. This study uses the acute otitis media clinical practice guideline proposed in 2004 as a reference to evaluate whether antibiotics doses that are in line with the recommendations lead to better prognosis. The study also attempts to clarify possible factors that influence the outcome. Study Design. Retrospective cohort study. Subjects and Methods. A total of 400 children with acute otitis media were enrolled. The dosage of amoxicillin was considered to be appropriate when in accord with clinical practice guidelines, that is, 80–90 mg/kg/day. The outcome was defined according to the description of tympanic membrane on medical records. Multivariate logistic regression was used to analyze the relationship between antibiotic dosage and prognosis after adjusting for baseline factors. Results. The majority of prescriptions were under dosage (89.1% but it was not noticeably associated with outcome (P= 0.41. The correlation between under dosage and poor prognosis was significant in children below 20 kg with bilateral acute otitis media (odds ratio 1.63; 95% CI 1.02–2.59, P=0.04. Conclusion. Treating acute otitis media in children, high-dose amoxicillin with clavulanate as recommended in the clinical practice guideline was superior to conventional doses only in children under 20 kg with bilateral diseases.

  12. Efficacy and Safety of Pharmacokinetically Enhanced Amoxicillin-Clavulanate at 2,000/125 Milligrams Twice Daily for 5 Days versus Amoxicillin-Clavulanate at 875/125 Milligrams Twice Daily for 7 Days in the Treatment of Acute Exacerbations of Chronic Bronchitis

    OpenAIRE

    Sethi, Sanjay; Breton, John; Wynne, Brian

    2005-01-01

    This randomized, controlled trial was designed to show that a short, 5-day course of pharmacokinetically enhanced amoxicillin-clavulanate at 2,000/125 mg (Augmentin XR) is as effective clinically as a longer, 7-day course of conventional amoxicillin-clavulanate at 875/125 mg (both given twice daily) in the treatment of acute exacerbations of chronic bronchitis (AECB). Amoxicillin-clavulanate at 2,000/125 mg was designed to extend the therapeutic levels of amoxicillin in serum over the 12-h do...

  13. [The efficacy and safety of cefixime and amoxicillin/clavulanate in the treatment of asymptomatic bacteriuria in pregnant women: a randomized, prospective, multicenter study].

    Science.gov (United States)

    Rafal'skiĭ, V V; Dovgan', E V; Kozyrev, Iu V; Gustovarova, T A; Khlybova, S V; Novoselova, A V; Filippenko, N G; Likhikh, D G

    2013-01-01

    The study was aimed to the evaluation of efficacy and safety of cefixime and amoxicillin/clavulanate in the treatment of asymptomatic bacteriuria in pregnant women. A prospective, multicenter, randomized study that included 112 pregnant women with asymptomatic bacteriuria was performed. 58 women were randomized in group 1 (cefixime [suprax solutab] 400 mg 1 time a day, 7 days), 54 women were included in group 2 (amoxicillin/clavulanate [amoksiklav] 625 mg 3 times a day, 7 days). The average age of the patients in group 1 was 25.2 +/- 6.6; in group 2--26.6 +/- 5.8 years. Physical examination, evaluation of complaints, collection of data on adverse reactions, and bacteriological analysis of urine were performed after enrollment in the study at visit 2 (day 10 +/- 1) and 3 (day 35 +/- 2). Comparable effectiveness of cefixime and amoxicillin/clavulanate in the treatment of asymptomatic bacteriuria in pregnant women was found. Eradication of the pathogen and sustained bacteriological response were observed in 94.8 and 92.7% of women treated with cefixime, and in 98.2 and 92.5% of women treated with amoxicillin/clavulanate, respectively (P > 0.05). At the same time, the use of amoxicillin/clavulanate compared with cefixime significantly higher was followed by the development of adverse reactions (13% and 1.7; respectively; P = 0.02). Seven-day courses of cefixime at a dose 400 mg 1 time a day and amoxicillin/clavulanate at a dose of 625 mg 3 times a day are high-effective treatment regimens for asymptomatic bacteriuria in pregnant women in Russia. The use of amoxicillin/clavulanate is significantly more often accompanied by the development of adverse reactions compared with cefixime. PMID:24437236

  14. Systematic Review and Meta-Analysis: Macrolides- and Amoxicillin/Clavulanate-induced Acute Liver Injury.

    Science.gov (United States)

    Ferrer, Pili; Amelio, Justyna; Ballarín, Elena; Sabaté, Mònica; Vidal, Xavi; Rottenkolber, Marietta; Schmiedl, Sven; Laporte, Joan-Ramon; Ibáñez, Luisa

    2016-07-01

    Antibacterials are frequently associated with idiosyncratic drug-induced liver injury (DILI). The objective of this study was to estimate the risk of macrolides and amoxicillin/clavulanate (AMC) on DILI. We conducted a systematic review (SR) and meta-analysis (MA) with studies retrieved from PubMed, Cochrane Library Plus, Web of Knowledge, clinicaltrials.gov, Livertox and Toxline (1980-2014). We searched for macrolides, AMC and MeSH and synonym terms for DILI. We included all study designs except case reports/series, all population ages and studies with a placebo/non-user comparator. We summarized the evidence with a random-effects MA. Quality of the studies was appraised with a checklist developed for SR of adverse effects. Heterogeneity and publication bias were assessed with different exploratory tools. We finally included 10 (two randomized clinical trials, six case-control, one cohort and one case-population studies) and 9 (case-population excluded) articles in the SR and MA, respectively. The overall summary relative risk of DILI for macrolides was 2.85 [95% confidence interval (CI) 1.81-4.47], p studies were perceived to be missing in the area of low statistical significance. Year of study and selected exposure window partly explained the variability between studies. For AMC, the risk of DILI was 9.38 (95% CI 0.65-135.41) p = 0.3, I2 = 95%. In conclusion, although spontaneous reports and case series have long established an association between macrolides and AMC with acute liver injury, these SR and MA have assessed the magnitude of this association. The low incidence of DILI and the therapeutic place of these antibiotics might tilt the balance in favour of their benefits. PMID:26707367

  15. Double-Blind, Randomized Study of the Efficacy and Safety of Oral Pharmacokinetically Enhanced Amoxicillin-Clavulanate (2,000/125 Milligrams) versus Those of Amoxicillin-Clavulanate (875/125 Milligrams), Both Given Twice Daily for 7 Days, in Treatment of Bacterial Community-Acquired Pneumonia in Adults

    OpenAIRE

    File, T M; Lode, H; Kurz, H.; Kozak, R; H. Xie; Berkowitz, E

    2004-01-01

    This randomized, double-blind, noninferiority trial was designed to demonstrate that pharmacokinetically enhanced amoxicillin-clavulanate (2,000/125 mg) was at least as effective clinically as amoxicillin-clavulanate 875/125 mg, both given twice daily for 7 days, in the treatment of community-acquired pneumonia in adults. In total, 633 clinically and radiologically confirmed community-acquired pneumonia patients (intent-to-treat population) were randomized to receive either oral amoxicillin-c...

  16. Cefotaxime and Amoxicillin-Clavulanate Synergism against Extended-Spectrum-β-Lactamase-Producing Escherichia coli in a Murine Model of Urinary Tract Infection.

    Science.gov (United States)

    Rossi, B; Soubirou, J F; Chau, F; Massias, L; Dion, S; Lepeule, R; Fantin, B; Lefort, A

    2016-01-01

    We investigated the efficacies of cefotaxime (CTX) and amoxicillin (AMX)-clavulanate (CLA) (AMC) against extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli in vitro and in a murine model of urinary tract infection (UTI). MICs, the checkerboard dilution method, and time-kill curves were used to explore the in vitro synergism between cefotaxime and amoxicillin-clavulanate against two isogenic E. coli strains-CFT073-RR and its transconjugant, CFT073-RR Tc bla(CTX-M-15)-harboring a bla(CTX-M-15) plasmid and a bla(OXA-1) plasmid. For in vivo experiments, mice were separately infected with each strain and treated with cefotaxime, amoxicillin, and clavulanate, alone or in combination, or imipenem, using therapeutic regimens reproducing time of free-drug concentrations above the MIC (fT≥MIC) values close to that obtained in humans. MICs of amoxicillin, cefotaxime, and imipenem were 4/>1,024, 0.125/1,024, and 0.5/0.5 mg/liter, for CFT073-RR and CFT073-RR Tc bla(CTX-M-15), respectively. The addition of 2 mg/liter of clavulanate (CLA) restored the susceptibility of CFT073-RR Tc bla(CTX-M-15) to CTX (MICs of the CTX-CLA combination, 0.125 mg/liter). The checkerboard dilution method and time-kill curves confirmed an in vitro synergy between amoxicillin-clavulanate and cefotaxime against CFT073-RR Tc bla(CTX-M-15). In vivo, this antibiotic combination was similarly active against both strains and as effective as imipenem. In conclusion, the cefotaxime and amoxicillin-clavulanate combination appear to be an effective, easy, and already available alternative to carbapenems for the treatment of UTI due to CTX-M-producing E. coli strains. PMID:26525800

  17. Spanish multicenter study of the epidemiology and mechanisms of amoxicillin-clavulanate resistance in Escherichia coli.

    Science.gov (United States)

    Ortega, Adriana; Oteo, Jesús; Aranzamendi-Zaldumbide, Maitane; Bartolomé, Rosa M; Bou, Germán; Cercenado, Emilia; Conejo, M Carmen; González-López, Juan José; Marín, Mercedes; Martínez-Martínez, Luis; Merino, María; Navarro, Ferran; Oliver, Antonio; Pascual, Alvaro; Rivera, Alba; Rodríguez-Baño, Jesús; Weber, Irene; Aracil, Belén; Campos, José

    2012-07-01

    We conducted a prospective multicenter study in Spain to characterize the mechanisms of resistance to amoxicillin-clavulanate (AMC) in Escherichia coli. Up to 44 AMC-resistant E. coli isolates (MIC ≥ 32/16 μg/ml) were collected at each of the seven participant hospitals. Resistance mechanisms were characterized by PCR and sequencing. Molecular epidemiology was studied by pulsed-field gel electrophoresis (PFGE) and by multilocus sequence typing. Overall AMC resistance was 9.3%. The resistance mechanisms detected in the 257 AMC-resistant isolates were OXA-1 production (26.1%), hyperproduction of penicillinase (22.6%), production of plasmidic AmpC (19.5%), hyperproduction of chromosomic AmpC (18.3%), and production of inhibitor-resistant TEM (IRT) (17.5%). The IRTs identified were TEM-40 (33.3%), TEM-30 (28.9%), TEM-33 (11.1%), TEM-32 (4.4%), TEM-34 (4.4%), TEM-35 (2.2%), TEM-54 (2.2%), TEM-76 (2.2%), TEM-79 (2.2%), and the new TEM-185 (8.8%). By PFGE, a high degree of genetic diversity was observed although two well-defined clusters were detected in the OXA-1-producing isolates: the C1 cluster consisting of 19 phylogroup A/sequence type 88 [ST88] isolates and the C2 cluster consisting of 19 phylogroup B2/ST131 isolates (16 of them producing CTX-M-15). Each of the clusters was detected in six different hospitals. In total, 21.8% of the isolates were serotype O25b/phylogroup B2 (O25b/B2). AMC resistance in E. coli is widespread in Spain at the hospital and community levels. A high prevalence of OXA-1 was found. Although resistant isolates were genetically diverse, clonality was linked to OXA-1-producing isolates of the STs 88 and 131. Dissemination of IRTs was frequent, and the epidemic O25b/B2/ST131 clone carried many different mechanisms of AMC resistance. PMID:22491692

  18. An Open-label, Randomized Comparison of Levofloxacin and Amoxicillin/ Clavulanate plus Clarithromycin for the Treatment of Hospitalized Patients with Community-acquired Pneumonia

    OpenAIRE

    Han-Pin Kuo; Ling-Ling Hsieh; Chih-Ten Yu; Horng-Chyuan Lin; Chien-Ying Liu; Min-Li Chang; Chun-Hua Wang; Yu-Min Wang; Chih-Jan Wang; Hao-Cheng Chen; Shu-Min Lin; Ting-Yu Lin; Chien-Da Huang

    2007-01-01

    Background: Anti-pneumococcal fluoroquinolone has been used to treat communityacquiredpneumonia (CAP) frequently because of its broad antimicrobialspectrum.Methods: This randomized, open-label study was conducted in a tertiary teaching hospital.Eligible patients were randomized to levofloxacin 500 mg IV q24h followedby 500 mg orally q24h or a combination of amoxicillin/clavulanate500 mg/100 mg IV q8h with oral clarithromycin 500 mg q12h and then oralamoxicillin/clavulanate 250 mg/125 mg q8h w...

  19. Fosfomycin in a single dose versus a 7-day course of amoxicillin-clavulanate for the treatment of asymptomatic bacteriuria during pregnancy.

    Science.gov (United States)

    Estebanez, A; Pascual, R; Gil, V; Ortiz, F; Santibáñez, M; Pérez Barba, C

    2009-12-01

    The purpose of this paper was to compare the efficacy of a single dose of 3 g of fosfomycin to that of a 7-day regimen of amoxicillin-clavulanate in the treatment of asymptomatic bacteriuria during pregnancy. A randomised, prospective, interventional, analytical, longitudinal study was undertaken, in which the efficacy of two antibiotic regimens (one short and the other long) in the treatment of pregnant women with asymptomatic bacteriuria is compared. One hundred and nine patients were randomly assigned to two groups: 56 were treated with amoxicillin-clavulanate and 53 with fosfomycin. The two groups were similar in terms of co-morbidity, treatments received during pregnancy, obstetric, gynaecological and surgical history and laboratory data. The efficacy of the two regimens was similar and the eradication rate was over 80% in both groups (P = 0.720) (relative risk [RR] 1.195, 95% confidence interval [CI]: 0.451-3.165). The number of reinfections was greater in the amoxicillin-clavulanate group (P = 0.045). The secondary effects were lower in the fosfomycin group (P = 0.008). There were no significant differences in the number of persistences (P = 0.39), development of symptomatic urinary infections (P = 0.319) or recurrences (P = 0.96). Treatment with a single dose of fosfomycin is as effective as the standard course of treatment with amoxicillin-clavulanate and may be preferable due to its simpler administration and the smaller number of reinfections. PMID:19768649

  20. Influence of clavulanic acid on the activity of amoxicillin against an experimental Streptococcus pneumoniae-Staphylococcus aureus mixed respiratory infection.

    OpenAIRE

    Smith, G.M; Boon, R J; Beale, A S

    1990-01-01

    An experimental respiratory infection caused by Streptococcus pneumoniae was established in weanling rats by intrabronchial instillation. Treatment of this infection with amoxicillin rapidly eliminated the pneumococci from the lung tissue. A beta-lactamase-producing strain of Staphylococcus aureus, when inoculated in a similar manner, did not persist adequately in the lungs long enough to permit a reasonable assessment of the therapy, but staphylococcal survival was extended in the lungs of r...

  1. Susceptibilities of 200 penicillin-susceptible and -resistant pneumococci to piperacillin, piperacillin-tazobactam, ticarcillin, ticarcillin-clavulanate, ampicillin, ampicillin-sulbactam, ceftazidime, and ceftriaxone.

    OpenAIRE

    Pankuch, G A; Jacobs, M. R.; Appelbaum, P C

    1994-01-01

    MICs of eight beta-lactams (piperacillin, piperacillin-tazobactam, ticarcillin, ticarcillin-clavulanate, ampicillin, ampicillin-sulbactam, ceftazidime, and ceftriaxone) were determined by agar dilution against 64 penicillin-susceptible, 70 intermediately penicillin-resistant, and 66 fully penicillin-resistant pneumococci. The MICs of piperacillin with and without tazobactam for 90% of the susceptible, intermediately resistant, and resistant strains tested (MIC90s) were < or = 0.064, 2.0, and ...

  2. Two Pharmacodynamic Models for Assessing the Efficacy of Amoxicillin-Clavulanate against Experimental Respiratory Tract Infections Caused by Strains of Streptococcus pneumoniae

    OpenAIRE

    Woodnutt, Gary; Berry, Valerie

    1999-01-01

    Two models of respiratory tract infection were used to investigate the pharmacodynamics of amoxicillin-clavulanate against Streptococcus pneumoniae. Eight strains of S. pneumoniae were used in a mouse model in which the animals were infected intranasally and were then treated with a range of doses and dose intervals. The time that the plasma amoxicillin concentration remained above the MIC (T>MIC) correlated well with bacterial killing, such that if T>MIC was below 20% there was no effect on ...

  3. Ticarcillin and Clavulanate Injection

    Science.gov (United States)

    ... is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.Your health care provider (doctor, nurse, or pharmacist) may measure the effectiveness and side effects of ...

  4. Comparison of the boronic acid disk potentiation test and cefepime-clavulanic acid method for the detection of ESBL among AmpC-producing Enterobacteriaceae

    OpenAIRE

    R M Shoorashetty; T Nagarathnamma; J Prathibha

    2011-01-01

    Purpose: Extended spectrum β-lactamase (ESBL) and AmpC β-lactamase are important mechanisms of betalactam resistance among Enterobacteriaceae . The ESBL confirmation test described by Clinical Laboratory Standards Institute (CLSI) is in routine use. This method fails to detect ESBL in the presence of AmpC. Therefore, we compared two different ESBL detection methods against the CLSI confirmatory test. Materials and Methods: A total 200 consecutive clinical isolates of Enterobacteriaceae from v...

  5. A randomized trial of the efficacy and safety of sequential intravenous/oral moxifloxacin monotherapy versus intravenous piperacillin/tazobactam followed by oral amoxicillin/clavulanate for complicated skin and skin structure infections

    NARCIS (Netherlands)

    Gyssens, I.C.J.; Dryden, M.; Kujath, P.; Nathwani, D.; Schaper, N.; Hampel, B.; Reimnitz, P.; Alder, J.; Arvis, P.

    2011-01-01

    OBJECTIVES: The primary aim of the RELIEF study was to evaluate the efficacy and safety of two sequential intravenous (iv)/oral regimens: moxifloxacin iv/oral versus piperacillin/tazobactam (TZP) iv followed by oral amoxicillin/clavulanate (AMC). PATIENTS AND METHODS: The study had a prospective, ra

  6. First series of patients with XDR and pre-XDR TB treated with regimens that included meropenen-clavulanate in Argentina.

    Science.gov (United States)

    Palmero, Domingo; González Montaner, Pablo; Cufré, Mónica; García, Ana; Vescovo, Marisa; Poggi, Susana

    2015-10-01

    XDR (extensively drug-resistant) and pre-XDR tuberculosis (TB) seriously compromise prognosis and treatment possibilities, and inevitably require the use of group V drugs (World Health Organization). The progress of all patients with XDR and pre-XDR TB seen in a specialized unit during 2012 and 2013 and treated with regimens that included at least 6 months of meropenem-clavulanate (MPC), capreomycin, moxifloxacin, linezolid, clofazimine, high-dose isoniazid, PAS, and bedaquiline in 1 case, were retrospectively analysed. Ten patients were treated, 9 with an extensive pattern of resistance to at least 6 drugs, and 1 because of adverse reactions and drug interactions leading to a similar situation. Eight of the 10 patients treated achieved bacteriological sputum conversion (2 consecutive negative monthly cultures) over a period of 2-7 months, while 2 died. No adverse reactions attributable to prolonged administration of MPC were observed. PMID:26026689

  7. Treatment of hospitalized patients with complicated skin and skin structure infections: double-blind, randomized, multicenter study of piperacillin-tazobactam versus ticarcillin-clavulanate. The Piperacillin/Tazobactam Skin and Skin Structure Study Group.

    OpenAIRE

    Tan, J S; Wishnow, R M; Talan, D A; Duncanson, F P; Norden, C W

    1993-01-01

    We compared the efficacy and safety of two beta-lactam-beta-lactamase inhibitor combinations, namely, piperacillin-tazobactam and ticarcillin-clavulanate, in the treatment of complicated bacterial infections of skin that required hospitalization. The study was a randomized, double-blind, comparative trial involving 20 centers. The infections were classified as (i) cellulitis with drainage, (ii) cutaneous abscess, (iii) diabetic or ischemic foot infection, and (iv) infected wounds and ulcers w...

  8. A randomized trial of the efficacy and safety of sequential intravenous/oral moxifloxacin monotherapy versus intravenous piperacillin/tazobactam followed by oral amoxicillin/clavulanate for complicated skin and skin structure infections

    OpenAIRE

    Gyssens, Inge C; Dryden, Matthew; Kujath, Peter; Nathwani, Dilip; Schaper, Nicolaas; Hampel, Barbara; Reimnitz, Peter; Alder, Jeff; Arvis, Pierre

    2011-01-01

    Objectives The primary aim of the RELIEF study was to evaluate the efficacy and safety of two sequential intravenous (iv)/oral regimens: moxifloxacin iv/oral versus piperacillin/tazobactam (TZP) iv followed by oral amoxicillin/clavulanate (AMC). Patients and methods The study had a prospective, randomized, double-dummy, double-blind, multicentre design. Patients ≥18 years were prospectively stratified according to complicated skin and skin structure infection (cSSSI) subtype/diagnosis (major ...

  9. Amoxicillin and amoxicillin/clavulanate reduce ethanol intake and increase GLT-1 expression as well as AKT phosphorylation in mesocorticolimbic regions.

    Science.gov (United States)

    Goodwani, Sunil; Rao, P S S; Bell, Richard L; Sari, Youssef

    2015-10-01

    Studies have shown that administration of the β-lactam antibiotic ceftriaxone (CEF) attenuates ethanol consumption and cocaine seeking behavior as well as prevents ethanol-induced downregulation of glutamate transporter 1 (GLT-1) expression in central reward brain regions. However, it is not known if these effects are compound-specific. Therefore, the present study examined the effects of two other β-lactam antibiotics, amoxicillin (AMOX) and amoxicillin/clavulanate (Augmentin, AUG), on ethanol drinking, as well as GLT-1 and phosphorylated-AKT (pAKT) levels in the nucleus accumbens (Acb) and medial prefrontal cortex (mPFC) of alcohol-preferring (P) rats. P rats were exposed to free-choice of ethanol (15% and 30%) for five weeks and were given five consecutive daily i.p. injections of saline vehicle, 100 mg/kg AMOX or 100mg/kg AUG. Both compounds significantly decreased ethanol intake and significantly increased GLT-1 expression in the Acb. AUG also increased GLT-1 expression in the mPFC. Results for changes in pAKT levels matched those for GLT-1, indicating that β-lactam antibiotic-induced reductions in ethanol intake are negatively associated with increases in GLT-1 and pAKT levels within two critical brains regions mediating drug reward and reinforcement. These findings add to a growing literature that pharmacological increases in GLT-1 expression are associated with decreases in ethanol intake and suggest that one mechanism mediating this effect may be increased phosphorylation of AKT. Thus, GLT-1 and pAKT may serve as molecular targets for the treatment of alcohol and drug abuse/dependence. PMID:26168897

  10. Antimicrobial resistance of coagulase-negative staphylococci and lactic acid bacteria from industrially produced dairy products

    Directory of Open Access Journals (Sweden)

    Nevijo Zdolec

    2013-03-01

    Full Text Available In this research, the susceptibility to clindamycin, tetracycline, amikacin, amoxicillin + clavulanic acid, enrofloxacine, vancomycin, trimethoprim + sulphametoxazol, tobramycin, chloramphenicol, ciprofloxacin, erythromycin, penicillin and trimethoprim was tested in coagulase-negative staphylococci (n=78 and lactic acid bacteria (n=30 by means of disk diffusion test and E-test. The isolates were collected from soft and hard cheeses, butter and brine. All isolates of coagulase-negative staphylococci were susceptible to clindamycin, amikacin, amoxicillin + clavulanic acid, enrofloxacine, vancomycin, chloramphenicol and ciprofloxacin according to CLSI breakpoints. A total of 30 staphylococci isolates (38.46 % were resistant to erythromycin, 18 to penicillin (23.07 %, 4 to tetracycline (5.12 %, and one isolate to trimethoprim, tobramicin and trimethoprim + sulphametoxazol (1.28 %. Among 78 tested staphylococci, 35 of them were resistant to at least one antimicrobial substance (44.87 %. The rate of resistant isolates of different soft cheese types ranged from 22 to 70 %, while resistant staphylococci were absent in hard cheese and brine. The growth of lactic acid bacteria was not influenced by trimethoprim + sulphametoxazol (n=29, vancomycin (n=29, trimethoprim (n=28, amikacin (n=10 and tobramycin (n=10. The results show that significant part of apathogenic microbiota in different dairy products is phenotypically resistant to antimicrobial agents.

  11. CTX-M-Type Extended-Spectrum β-Lactamase That Hydrolyzes Ceftazidime through a Single Amino Acid Substitution in the Omega Loop

    OpenAIRE

    Poirel, Laurent; Naas, Thierry; Le Thomas, Isabelle; Karim, Amal; Bingen, Edouard; Nordmann, Patrice

    2001-01-01

    Escherichia coli ILT-1, Klebsiella pneumoniae ILT-2, and K. pneumoniae ILT-3 were isolated in May 1999 in Paris, France, from a rectal swab of a hospitalized 5-month-old girl. These isolates had a clavulanic acid-inhibited substrate profile that included expanded-spectrum cephalosporins. The MICs of cefotaxime were higher for E. coli ILT-1 and K. pneumoniae ILT-2 than for K. pneumoniae ILT-3, while the opposite was found for the MICs of ceftazidime. Genetic and biochemical analyses revealed t...

  12. Efficacy and safety of IV/PO moxifloxacin and IV piperacillin/tazobactam followed by PO amoxicillin/clavulanic acid in the treatment of diabetic foot infections: results of the RELIEF study

    NARCIS (Netherlands)

    Schaper, N.C.; Dryden, M.; Kujath, P.; Nathwani, D.; Arvis, P.; Reimnitz, P.; Alder, J.; Gyssens, I.C.J.

    2013-01-01

    OBJECTIVE: The aim was to compare the efficacy and safety of two antibiotic regimens in patients with diabetic foot infections (DFIs). METHODS: Data of a subset of patients enrolled in the RELIEF trial with DFIs requiring surgery and antibiotics were evaluated retrospectively. DFI was diagnosed on t

  13. Prediction of piperacillin-tazobactam susceptibility among Enterobacteriaceae, Pseudomonas aeruginosa, and other bacteria using ticarcillin-clavulanic acid, ceftazidime, and other broad-spectrum antimicrobial in vitro test results.

    Science.gov (United States)

    Jones, R N; Sutton, L D; Cantrell, H F; Lankford, R B

    1994-11-01

    The ability of various in vitro beta-lactam susceptibility test results to predict the susceptibility of piperacillin-tazobactam (a new beta-lactam-beta-lactamase inhibitor combination) was assessed using more than 46,000 recent clinical isolates. The organisms were tested by reference-quality National Committee for Clinical Laboratory Standards (NCCLS) broth microdilution procedures and interpreted by the currently published NCCLS criteria. The recommended antimicrobial tests that would accurately predict the piperacillin-tazobactam in vitro efficacy had an overall very major, false-susceptible rate of only 0.6% (sulbactam (1.8%) results; for Haemophilus influenzae and Moraxella catarrhalis use cefotaxime or cefuroxime or ceftriaxone (1.5%); and for staphylococci use oxacillin by NCCLS recommendations. When the piperacillin-tazobactam testing reagents become available, the direct testing of this combination should be applied to relevant clinical isolates. The piperacillin-tazobactam break points should be reassessed as indicated by the cited minimum inhibitory concentration population analysis to improve predictive accuracy; H. influenzae susceptibility modified to < or = 2/4 micrograms/ml and Enterococcus species susceptibility tested at < or = 16/4 micrograms. PMID:7874881

  14. 阿莫西林-克拉维酸注射剂及其在猪体内的药物动力学研究%Study on Amoxycillin-Clavulanic Acid Suspension and its Pharmacokinetics in Swine

    Institute of Scientific and Technical Information of China (English)

    汤树生; 肖希龙

    2004-01-01

    以阿莫西林(AMO)和克拉维酸(CLA)为原料,以注射用大豆油为溶媒,成功研制出AMO-CLA注射用混悬剂.采用加温加湿试验和光加速试验对制剂进行稳定性研究,结果表明该制剂稳定性良好,AMO和CLA的相对标示量均在90%以上、样品的外观色泽、粒度、分解产物等指标均无明显变化.在药物动力学研究中,用HPLC-UV法测定在血浆中AMO和CLA的含量.血药浓度数据经3p97软件处理,静注AMO和CLA水溶液在猪体内的药物动力学过程均符合一级吸收一室模型,肌注自制AMO-CLA注射用混悬剂、辉瑞公司的AMO-CLA注射用混悬剂及单方AMO注射用混悬剂在猪体内的动力学过程均符合一级吸收二室模型,且吸收良好,半衰期长.AMO在猪体内的持效时间(C>0.3 μg/mL)超过48 h,缓释作用显著.自制AMO-CLA注射用混悬剂的主要动力学参数与辉瑞公司的AMO-CLA注射用混悬剂的动力学参数比较差异不显著.

  15. 阿莫西林-克拉维酸注射用混悬剂的药效学研究%Pharmacodynamics of amoxyxicillin-clavulanic acid suspension in swine

    Institute of Scientific and Technical Information of China (English)

    汤树生; 肖希龙

    2004-01-01

    阿莫西林(Amoxycillin,AMO)为兽医临床上普遍应用的半合成广谱青霉素,为β-内酰胺类抗生素。β-内酰胺类抗生素因为具有高效、广谱、低毒的特点,是当前临床上应用最多的一类抗菌药物之一。但AMO不耐酶,细菌对其易产生耐药性,细菌对AMO的耐药机理最主要的是产生β-内酰胺酶,

  16. Inhibitor-resistant TEM- and OXA-1-producing Escherichia coli isolates resistant to amoxicillin-clavulanate are more clonal and possess lower virulence gene content than susceptible clinical isolates.

    Science.gov (United States)

    Oteo, Jesús; González-López, Juan José; Ortega, Adriana; Quintero-Zárate, J Natalia; Bou, Germán; Cercenado, Emilia; Conejo, María Carmen; Martínez-Martínez, Luis; Navarro, Ferran; Oliver, Antonio; Bartolomé, Rosa M; Campos, José

    2014-07-01

    In a previous prospective multicenter study in Spain, we found that OXA-1 and inhibitor-resistant TEM (IRT) β-lactamases constitute the most common plasmid-borne mechanisms of genuine amoxicillin-clavulanate (AMC) resistance in Escherichia coli. In the present study, we investigated the population structure and virulence traits of clinical AMC-resistant E. coli strains expressing OXA-1 or IRT and compared these traits to those in a control group of clinical AMC-susceptible E. coli isolates. All OXA-1-producing (n = 67) and IRT-producing (n = 45) isolates were matched by geographical and temporal origin to the AMC-susceptible control set (n = 56). We performed multilocus sequence typing and phylogenetic group characterization for each isolate and then studied the isolates for the presence of 49 virulence factors (VFs) by PCR and sequencing. The most prevalent clone detected was distinct for each group: group C isolates of sequence type (ST) 88 (C/ST88) were the most common in OXA-1 producers, B2/ST131 isolates were the most common in IRT producers, and B2/ST73 isolates were the most common in AMC-susceptible isolates. The median numbers of isolates per ST were 3.72 in OXA-1 producers, 2.04 in IRT producers, and 1.69 in AMC-susceptible isolates; the proportions of STs represented by one unique isolate in each group were 19.4%, 31.1%, and 48.2%, respectively. The sum of all VFs detected, calculated as a virulence score, was significantly higher in AMC-susceptible isolates than OXA-1 and IRT producers (means, 12.5 versus 8.3 and 8.2, respectively). Our findings suggest that IRT- and OXA-1-producing E. coli isolates resistant to AMC have a different and less diverse population structure than AMC-susceptible clinical E. coli isolates. The AMC-susceptible population also contains more VFs than AMC-resistant isolates. PMID:24777096

  17. Amino acids

    Science.gov (United States)

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  18. Oral antibiotics for infections due to multidrug-resistant Gram-negative organisms.

    Science.gov (United States)

    Glasser, Jessie S; Markelz, Ana E; Zera, Wendy C; Beckius, Miriam L; Mende, Katrin; Murray, Clinton K

    2011-08-01

    We determined minimum inhibitory concentrations of rifampicin, nitrofurantoin, amoxicillin-clavulanic acid, and cefdinir, plus a combination of amoxicillin-clavulanic acid and cefdinir by broth microdilution for mainly wound isolates of Escherichia coli and Klebsiella pneumoniae. E. coli and K. pneumoniae susceptibilities increased by combining amoxicillin-clavulanic acid and cefdinir. PMID:21466257

  19. Acid Rain.

    Science.gov (United States)

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  20. Antibiotic Resistance of Probiotic Strains of Lactic Acid Bacteria Isolated from Marketed Foods and Drugs

    Institute of Scientific and Technical Information of China (English)

    CHANG LIU; ZHUO-YANG ZHANG; KE DONG; JIAN-PING YUAN; XIAO-KUI GUO

    2009-01-01

    Objective To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probioties. Methods Antimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR. Results Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis. Conclusion Antibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.

  1. Folic Acid

    Science.gov (United States)

    ... found naturally in some foods, including leafy vegetables, citrus fruits, beans (legumes), and whole grains. Folic acid ... mcg of folic acid every day for good health. But older adults need to be sure they ...

  2. Ibotenic acid and thioibotenic acid

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte;

    2004-01-01

    In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines....... Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid with...... the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for...

  3. [Gastric Acid].

    Science.gov (United States)

    Ruíz Chávez, R

    1996-01-01

    Gastric acid, a product of parietal cells secretion, full fills multiple biological roles which are absolutely necessary to keep corporal homeostasis. The production of the acid depends upon an effector cellular process represented in the first step by histamine, acetilcholine and gastrin, first messengers of the process. These interact with specific receptors than in sequence activate second messengers -cAMP and the calcium-calmodulin system- which afterwards activate a kinase. An specific protein is then phosphorilated by this enzyme, being the crucial factor that starts the production of acid. Finally, a proton bomb, extrudes the acid towards the gastric lumen. The secretion process mentioned above, is progressive lyactivated in three steps, two of which are stimulators -cephalic and gastric phases- and the other one inhibitor or intestinal phase. These stages are started by mental and neurological phenomena -thought, sight, smell or memory-; by food, drugs or other ingested substances; and by products of digestion. Changes in regulation of acid secretion, in the structure of gastro-duodenal mucosal barrier by a wide spectrum of factors and agents including food, drugs and H. pylori, are the basis of acid-peptic disease, entity in which gastric acid plays a fundamental role. From the therapeutic point of view, so at the theoretical as at the practical levels, t is possible to interfere with the secretion of acid by neutralization of some of the steps of the effector cellular process. An adequate knowledge of the basics related to gastric acid, allows to create strategies for the clinical handling of associated pathology, specifically in relation to peptic acid disease in all of the known clinical forms. PMID:12165790

  4. The comparative analysis on the curative effect of amoxicillin clavulanate combined with compound pholcodine syrup for children with acute bacterial upper respiratory tract infection%阿莫西林克拉维酸钾联合复方福尔可定治疗小儿急性细菌性上呼吸道感染的临床疗效随机对照分析

    Institute of Scientific and Technical Information of China (English)

    王冰; 徐洁; 唐新业; 姚红兵

    2014-01-01

    Objective To observe the curative effect of amoxicillin clavulanate combined with compound phol-codine syrup for children with acute bacterial upper respiratory tract infection.Methods One hundred and sixty chil-dren with acute bacterial upper respiratory tract infection were chosen,and divided into treatment group(80 cases) and control group(80 cases)randomly.Amoxicillin clavulanic(7∶1)combined with compound pholcodine syrup were enrolled in the treatment group,while amoxicillin clavulanic(7∶1)combined with lung cough syrup were in the con-trol group.The bacterial clearance rate,oral secretory SIgA and total effective rate were compared before and after the treatment for 7 days.Results There was no significant difference in the bacterial clearance rate in the two groups (P >0.05).The oral secretory SigA increased after treatment comparing with that before treatment(P 0.05)in the control one.The total effective rate in the treatment group was higher than that in the control one(93.75% vs.86.25%)(P <0.05).No serious side effect occurred in the two groups.Conclusion It has significant effect using amoxicillin clavulanic combined with compound pholcodine syrup in treatment of pediatric acute bacterial upper respiratory tract infection.%目的:观察阿莫西林克拉维酸钾干混悬剂联合复方福尔可定治疗小儿急性细菌性上呼吸道感染的临床疗效。方法选择急性细菌性上呼吸道感染患儿160例,分为治疗组(80例)和对照组(80例),治疗组选用阿莫西林克拉维酸钾干混悬剂(7∶1)+复方福尔可定口服溶液,对照组选用阿莫西林克拉维酸钾干混悬剂(7∶1)+肺力咳糖浆。治疗疗程均为7 d,比较治疗前后两组细菌清除率、口腔分泌性 SIgA 和总有效率。结果细菌清除率两组差异无统计学意义(P >0.05),治疗后实验组患儿口腔分泌性 SIgA 较治疗前有升高(P <0.05),而对照组

  5. 阿莫西林克拉维酸钾联合复方福尔可定治疗小儿急性细菌性上呼吸道感染的临床疗效随机对照分析%The comparative analysis on the curative effect of amoxicillin clavulanate combined with compound pholcodine syrup for children with acute bacterial upper respiratory tract infection

    Institute of Scientific and Technical Information of China (English)

    王冰; 徐洁; 唐新业; 姚红兵

    2014-01-01

    目的:观察阿莫西林克拉维酸钾干混悬剂联合复方福尔可定治疗小儿急性细菌性上呼吸道感染的临床疗效。方法选择急性细菌性上呼吸道感染患儿160例,分为治疗组(80例)和对照组(80例),治疗组选用阿莫西林克拉维酸钾干混悬剂(7∶1)+复方福尔可定口服溶液,对照组选用阿莫西林克拉维酸钾干混悬剂(7∶1)+肺力咳糖浆。治疗疗程均为7 d,比较治疗前后两组细菌清除率、口腔分泌性 SIgA 和总有效率。结果细菌清除率两组差异无统计学意义(P >0.05),治疗后实验组患儿口腔分泌性 SIgA 较治疗前有升高(P <0.05),而对照组差异无统计学意义(P >0.05),治疗组总有效率93.75%。显著高于对照组86.25%(P <0.05),两组患儿均无严重的不良反应发生。结论阿莫西林克拉维酸钾干混悬剂联合复方福尔可定治疗小儿急性细菌性上呼吸道感染疗效显著。%Objective To observe the curative effect of amoxicillin clavulanate combined with compound phol-codine syrup for children with acute bacterial upper respiratory tract infection.Methods One hundred and sixty chil-dren with acute bacterial upper respiratory tract infection were chosen,and divided into treatment group(80 cases) and control group(80 cases)randomly.Amoxicillin clavulanic(7∶1)combined with compound pholcodine syrup were enrolled in the treatment group,while amoxicillin clavulanic(7∶1)combined with lung cough syrup were in the con-trol group.The bacterial clearance rate,oral secretory SIgA and total effective rate were compared before and after the treatment for 7 days.Results There was no significant difference in the bacterial clearance rate in the two groups (P >0.05).The oral secretory SigA increased after treatment comparing with that before treatment(P 0.05)in the control one.The total effective rate in the treatment group was higher than that

  6. Folic acid

    Science.gov (United States)

    ... include leafy vegetables (such as spinach, broccoli, and lettuce), okra, asparagus, fruits (such as bananas, melons, and ... Pyrimethamine (Daraprim)Pyrimethamine (Daraprim) is used to treat parasite infections. Folic acid might decrease the effectiveness of ...

  7. Folic Acid

    Medline Plus

    Full Text Available ... March of Dimes Premature Birth Report Card Grades Cities, Counties; Focuses on Racial and Ethnic Disparities March ... your baby. Learn how you can get the right amout of folic acid before and during pregnancy ...

  8. ACID RAIN

    Science.gov (United States)

    Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating diff...

  9. Folic Acid

    Medline Plus

    Full Text Available ... Just a moment, please. You've saved this page It's been added to your dashboard . Folic acid ... Map Premature birth report card Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness ...

  10. Folic Acid

    Medline Plus

    Full Text Available ... Folic acid Description | Related videos | Most played video E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  11. Okadaic acid

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H; Severinsen, Mai C K

    2014-01-01

    Okadaic acid (OA) is a polyether fatty acid produced by marine dinoflagellates and the causative agent of diarrhetic shellfish poisoning. The effect of OA on apical endocytosis in the small intestine was studied in organ cultured porcine mucosal explants. Within 0.5-1 h of culture, the toxin caused...... endosomes (TWEEs) occurred unimpeded in the presence of OA, FM condensed in larger subapical structures by 1 h, implying a perturbed endosomal trafficking/maturation. The fluorescent lysosomotropic agent Lysotracker revealed induction of large lysosomal structures by OA. Endocytosis from the brush border...

  12. Perfluorooctanoic acid

    NARCIS (Netherlands)

    P. de Voogt

    2014-01-01

    Perfluorooctanoic acid (PFOA, 335-67-1) is used in fluoropolymer production and firefighting foams and persists in the environment. Human exposure to PFOA is mostly through the diet. PFOA primarily affects the liver and can cause developmental and reproductive toxic effects in test animals.

  13. Ascorbic Acid

    Science.gov (United States)

    Cevi-Bid® ... If you become pregnant while taking ascorbic acid, call your doctor. ... In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call ...

  14. Stearic Acid

    Science.gov (United States)

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.

  15. Mefenamic Acid

    Science.gov (United States)

    Mefenamic acid comes as a capsule to take by mouth. It is usually taken with food every 6 hours as needed for up to 1 week. Follow ... pain vomit that is bloody or looks like coffee grounds black, tarry, or bloody stools slowed breathing ...

  16. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  17. Understanding Acid Rain

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  18. Dehydroabietic acid

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  19. Retarded acid emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Fast, C.R.; Rixe, F.H.; Duffield, E.L. Jr.

    1972-08-01

    Compositions for use in acidizing hydrocarbon-bearing formations are described. Retarded acid emulsions of prolonged stability make it possible for the acid in this form to be displaced substantial distances out into the formation before becoming spent. The action of acid emulsions for use in acidizing hydrocarbon-bearing formations is prolonged by employing as the principal emulsifying agent an amine salt of dodecylbenzene sulfonic acid. Acid emulsions employing the amine salt of dodecylbenzene sulfonic acid exhibit greater stability than those employing the free acid. (8 claims)

  20. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  1. Acid Lipase Disease

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, ... Related NINDS Publications and Information What is Acid Lipase Disease ? Acid lipase disease or deficiency occurs when ...

  2. POLYELEOSTEARIC ACID VESICLES

    Institute of Scientific and Technical Information of China (English)

    LI Zichen; XIE Ximng; FAN Qinghua; FANG Yifei

    1992-01-01

    α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solutionofeleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

  3. Acid distribution in phosphoric acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  4. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Science.gov (United States)

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  5. Acid Deposition Phenomena

    International Nuclear Information System (INIS)

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO2) and nitrogen oxides (NOx). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H2SO4) and nitric acids (HNO3), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  6. Omega-6 Fatty Acids

    Science.gov (United States)

    ... Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other ... ACIDS are as follows:Improving mental development or growth in infants. Adding arachidonic acid (an omega-6 ...

  7. Zoledronic Acid Injection

    Science.gov (United States)

    ... experience a reaction during the first few days after you receive a dose of zoledronic acid injection. Symptoms ... symptoms may begin during the first 3 days after you receive a dose of zoledronic acid injection and ...

  8. Catalytic Synthesis Lactobionic Acid

    Directory of Open Access Journals (Sweden)

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  9. Plasma amino acids

    Science.gov (United States)

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  10. Omega-3 Fatty Acids

    Science.gov (United States)

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount ... the blood in people with very high triglycerides. Omega-3 fatty acids are in a class of medications ...

  11. The Acid Rain Reader.

    Science.gov (United States)

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  12. Acid Rain Study Guide.

    Science.gov (United States)

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  13. Immunoglobulin and fatty acids

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  14. Cleavage of nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor L. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2007-12-11

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  15. Cleavage of nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Waunakee, WI); Lyamichev, Victor I. (Madison, WI); Brow; Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2010-11-09

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  16. Nucleic acid detection compositions

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

    2008-08-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  17. Nucleic acid detection assays

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

    2005-04-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  18. Cleavage of nucleic acids

    Science.gov (United States)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2000-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  19. Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1978-10-31

    A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions. The rate at which a chlorocarboxylic acid salt hydrolyzes to form an acid provides the desired rate of acid-release. A more complete acid-base reaction by chloroacetic acid, as compared to formic, acetic, and proprionic, is due to its being a much stronger acid. The pKa of chloroacetic acid is 2.86, whereas that of formic acid is 3.75, and that of acetic acid is 4.75. The pKa of a solution of a weak acid is the pH exhibited when the concentration of undissociated acid equals the concentration of the acid anion. 14 claims.

  20. Nucleic acid detection kits

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

    2005-03-29

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

  1. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  2. Microorganisms for producing organic acids

    Energy Technology Data Exchange (ETDEWEB)

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  3. Sensitivity pattern of gram negative bacilli to three β-lactam/β-lactamase inhibitor combinations using the automated API system

    Directory of Open Access Journals (Sweden)

    Anuradha K

    2007-01-01

    Full Text Available Purpose : To evaluate the spectrum of activity of three β-lactamase inhibitors such as amoxicillin/ clavulanic acid, ticarcillin/ clavulanic acid and piperacillin/ tazobactam in comparison to cephalosporins against gram negative bacilli. Methods : Gram-negative bacilli isolated from the clinical specimens received in the laboratory were included in the study. Using the API system (bioMιrieux during a one-year period, a total of 1,252 Enterobacteriaceae and 385 non-fermenters were evaluated. Results : The percentage resistance of the Enterobacteriaceae isolates was 82.92% to amoxicillin/ clavulanic acid, 58.22% to ticarcillin/clavulanic acid and 22.44% to piperacillin/tazobactam respectively. Pseudomonas aeruginosa showed resistance of 96% to ticarcillin/ clavulanic acid and 61% to piperacillin/ tazobactam and Acinetobacter baumannii showed 49% resistance to ticarcillin/ clavulanic acid and 77% resistance to piperacillin/ tazobactam respectively. The isolates exhibited high resistance to all the generations of cephalosporins and the other groups of antibiotics except carbapenems. Conclusions : Piperacillin/tazobactam was found to be the most active combination of the three against Enterobacteriaceae and Pseudomonas spp. and ticarcillin/clavulanic acid against Acinetobacter spp. and Stenotrophomonas maltophilia .

  4. Bile acid sequestrants

    DEFF Research Database (Denmark)

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid and...... glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption of the...... enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...

  5. Docosahexaenoic Acid Neurolipidomics

    OpenAIRE

    Niemoller, Tiffany D.; Bazan, Nicolas G.

    2009-01-01

    Mediator lipidomics is a field of study concerned with the characterization, structural elucidation and bioactivity of lipid derivatives generated by enzymatic activity. Omega-3 fatty acids have beneficial effects for vision, brain function, cardiovascular function, and immune-inflammatory responses. Docosahexaenoic acid [DHA; 22:6(n-3)], the most abundant essential omega-3 fatty acid in the human body, is selectively enriched and avidly retained in the central nervous system as an acyl chain...

  6. Fatty acids and epigenetics

    OpenAIRE

    Burdge, Graham C; Lillycrop, Karen A.

    2014-01-01

    Purpose of review The purpose of this review is to assess the findings of recent studies on the effects of fatty acids on epigenetic process and the role of epigenetics in regulating fatty acid metabolism. Recent findings The DNA methylation status of the Fads2 promoter was increased in the liver of the offspring of mice fed an ?-linolenic acid-enriched diet during pregnancy. In rats, increasing total maternal fat intake during pregnancy and lactation induced persistent hypermethyl...

  7. USGS Tracks Acid Rain

    Science.gov (United States)

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  8. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  9. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also....... However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  10. The acid rain primer

    International Nuclear Information System (INIS)

    Acid rain continues to be a major problem in North America, and particularly in eastern Canada. This report introduced the topic of acid rain and discussed its formation, measurement, sources, and geographic distribution. The major sources of sulphur dioxide in Canada are smelting metals, burning coal for electrical power generation, industrial emissions (e.g., pulp and paper, petroleum and aluminum industry), and oil and gas extraction and refining. In Canada, the largest source of nitrogen oxide is the burning of fossil fuels by the transportation sector. Problem areas for acid rain in Canada were identified. The effects of acid rain were examined on lakes and aquatic ecosystems, forests and soils, human-made structures and materials, human health, and on visibility. Acid rain policies and programs were then presented from a historical and current context. Ecosystem recovery from acid rain was discussed with reference to acid rain monitoring, atmospheric response to reductions in acid-causing emissions, and ecosystem recovery of lakes, forests, and aquatic ecosystems. Challenges affecting ecosystem recovery were also presented. These challenges include drought and dry weather, decrease of base cations in precipitation, release of sulphate previously stored in soil, mineralization and immobilization of sulphur/sulphates. Last, the report discussed what still needs to be done to improve the problem of acid rain as well as future concerns. These concerns include loss of base cations from forested watersheds and nitrogen deposition and saturation. 21 refs., 2 tabs., 17 figs

  11. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    Science.gov (United States)

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  12. Molecular Interaction of Pinic Acid with Sulfuric Acid

    DEFF Research Database (Denmark)

    Elm, Jonas; Kurten, Theo; Bilde, Merete;

    2014-01-01

    We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... without the further possibility for attachment of either sulfuric acid or pinic acid. This suggests that pinic acid cannot be a key species in the first steps in nucleation, but the favorable interactions between sulfuric acid and pinic acid imply that pinic acid can contribute to the subsequent growth of...

  13. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  14. Science of acid rain

    International Nuclear Information System (INIS)

    In this report, the mechanism of forming acid rain in the atmosphere and the process of its fall to ground, the mechanism of withering forests by acid substances, and the process of acidifying lakes and marshes are explained. Moreover, the monitoring networks for acid rain and the countermeasures are described. Acid rain is the pollution phenomena related to all environment, that is, atmosphere, hydrosphere, soilsphere, biosphere and so on, and it is a local environmental pollution problem, and at the same time, an international, global environmental pollution problem. In Japan, acid rain has fallen, but the acidification of lakes and marshes is not clear, and the damage to forests is on small scale. However in East Asia region, the release of sulfur oxides and nitrogen oxides is much, and the increase of the effects of acid rain is expected. It is necessary to devise the measures for preventing the damage due to acid rain. The global monitoring networks of World Meteorological Organization and United Nations Environment Program, and those in Europe, USA and Japan are described. The monitoring of acid rain in Japan is behind that in Europe and USA. (K.I.)

  15. Peptide Nucleic Acid Synthons

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  16. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...

  17. Locked nucleic acid

    DEFF Research Database (Denmark)

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper;

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...

  18. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  19. Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  20. Peptide Nucleic Acids (PNA)

    DEFF Research Database (Denmark)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  1. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...

  2. Characterization of acid tars

    International Nuclear Information System (INIS)

    Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain.

  3. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    . However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  4. Canadian acid rain policy

    International Nuclear Information System (INIS)

    On March 13 of 1991, the Prime Minister of Canada, Brian Mulroney and the President of the United States of America, George Bush, signed an Agreement on Air Quality. This agreement enshrines Principle 21 of the 1972 Stockholm Declaration which states that countries are to ensure that activities within their jurisdiction do not cause damage to the environment of another country. This agreement also includes provisions for controlling acid rain. The Agreement on Air Quality followed years of discussion between the two countries and is a significant milestone in the history of Canadian acid rain policy. This paper begins by describing Canadian acid rain policy and its evolution. The paper also outlines the Canada-United States Air Quality Agreement and the effect of the acid rain provisions on deposition in Canada. Finally, it considers the future work that must be undertaken to further resolve the acid rain problem. 8 refs., 5 figs., 1 tab

  5. Synthesis of aminoaldonic acids

    DEFF Research Database (Denmark)

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures...... of 2,5-anhydrides and not the expected 2-acetamido-2-deoxy aldose phenylhydrazones. The acetylated phenylhydrazones were found to eliminate acetic acid when heated in aqueous ethanol and 1-phenylazoalkenes could be isolated by crystallisation. By this method the 17, 20, 23 and 25 were prepared from...... aziridino amides 43 and 51 were reductively cleaved with hydrazine to give 3-amino-2,3-dideoxyhexonhydrazides 83 and 85, which were easily converted into the corresponding lactone 84 and acid 86. The aziridine ring of 43 and 51 was also opened with acetic acid to give the 3-amino-3-deoxyhexonic acids 79 and...

  6. Fusidic acid in dermatology

    DEFF Research Database (Denmark)

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    Studies on the clinical efficacy of fusidic acid in skin and soft-tissue infections (SSTIs), notably those due to Staphylococcus aureus, are reviewed. Oral fusidic acid (tablets dosed at 250 mg twice daily, or a suspension for paediatric use at 20 mg/kg/day given as two daily doses) has shown good...... efficacy and tolerability. Similarly, plain fusidic acid cream or ointment used two or three times daily in SSTIs such as impetigo are clinically and bacteriologically effective, with minimal adverse events. Combination formulations of fusidic acid with 1% hydrocortisone or 0.1% betamethasone achieve...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  7. Sulfuric Acid on Europa

    Science.gov (United States)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  8. Difficult Decisions: Acid Rain.

    Science.gov (United States)

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  9. Folic acid in diet

    Science.gov (United States)

    ... green leafy vegetables Dried beans and peas (legumes) Citrus fruits and juices Fortified means that vitamins have ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Folic Acid Browse the Encyclopedia A.D. ...

  10. Citric acid urine test

    Science.gov (United States)

    ... usually done while you are on a normal diet. Ask your provider for more information. ... acidosis and a tendency to form calcium kidney stones. The ... acid levels: A high carbohydrate diet Estrogen therapy Vitamin D

  11. Stomach acid test

    Science.gov (United States)

    Gastric acid secretion test ... The test is done after you have not eaten for a while so fluid is all that remains in ... injected into your body. This is done to test the ability of the cells in the stomach ...

  12. Azelaic Acid Topical

    Science.gov (United States)

    ... pores and by decreasing production of keratin, a natural substance that can lead to the development of ... acid controls acne and rosacea but does not cure these conditions. It may take 4 weeks or ...

  13. Acid rain: An overview

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  14. Ethylenediaminetetraacetic acid in endodontics

    OpenAIRE

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-01-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for...

  15. Utilization of acid tars

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, A.F.; Denisova, T.L.; Aminov, A.N.

    1987-01-01

    Freshly produced acid tar (FPAT), obtained as refinery waste in treating petroleum oils with sulfuric acid and oleum, contains 80% or more sulfuric acid. Of such tars, pond acid tars, which contain up to 80% neutral petroleum products and sulfonated resins, are more stable, and have found applications in the production of binders for paving materials. In this article the authors are presenting results obtained in a study of the composition and reactivity of FPAT and its stability in storage in blends with asphalts obtained in deasphalting operations, and the possibility of using the FPAT in road construction has been examined. In this work, wastes were used which were obtained in treating the oils T-750, KhF-12, I-8A, and MS-14. Data on the change in group chemical composition of FPAT are shown, and the acidity, viscosity, needle penetration, and softening point of acid tars obtained from different grades of oils are plotted as functions of the storage time. It is also shown that the fresh and hardened FPATs differ in their solubilities in various solvents.

  16. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles of...

  17. Neutron Nucleic Acid Crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination. PMID:26227050

  18. Method for isolating nucleic acids

    Science.gov (United States)

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  19. Acidification and Acid Rain

    Science.gov (United States)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  20. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Science.gov (United States)

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  1. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  2. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  3. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  4. Determination of Sialic Acids by Acidic Ninhydrin Reaction

    Directory of Open Access Journals (Sweden)

    Yao,Kenzabroh

    1987-12-01

    Full Text Available A new acidic ninhydrin method for determining free sialic acids is described. The method is based on the reaction of sialic acids with Gaitonde's acid ninhydrin reagent 2 which yields a stable color with an absorption maximum at 470 nm. The standard curve is linear in the range of 5 to 500 nmol of N-acetylneuraminic acid per 0.9 ml of reaction mixture. The reaction was specific only for sialic acids among the various sugars and sugar derivatives examined. Some interference of this method by cysteine, cystine and tryptophan was noted, although their absorption maxima differed from that of sialic acids. The interference by these amino acids was eliminated with the use of a small column of cation-exchange resin. The acidic ninhydrin method provides a simple and rapid method for the determination of free sialic acids in biological materials.

  5. Chemistry and electrochemistry in trifluoroacetic acid. Comparison with acetic acid

    International Nuclear Information System (INIS)

    As the trifluoroacetic acid is, with the acetic acid, one of most often used carboxylic acids as solvent, notably in organic chemistry, this research thesis addresses some relatively simple complexing and redox reactions to highlight the peculiar feature of this acid, and to explain its very much different behaviour with respect to acetic acid. The author develops the notion of acidity level in solvents of low dielectric constant. The second part addresses a specific solvent: BF3(CH3COOH)2. The boron trifluoride strengthens the acidity of acetic acid and modifies its chemical and physical-chemical properties. In the third part, the author compares solvent properties of CF3COOH and CH3COOH. Noticed differences explain why the trifluoroacetic acid is a more interesting reaction environment than acetic acid for reactions such as electrophilic substitutions or protein solubilisation

  6. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    OpenAIRE

    Je Min Lee; Hyungjae Lee; SeokBeom Kang; Woo Jung Park

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human phys...

  7. Domoic Acid Epileptic Disease

    Directory of Open Access Journals (Sweden)

    John S. Ramsdell

    2014-03-01

    Full Text Available Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis.

  8. A Demonstration of Acid Rain

    Science.gov (United States)

    Fong, Man Wai

    2004-01-01

    A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

  9. Biological properties of lipoic acid

    OpenAIRE

    Anna Bilska; Lidia Włodek

    2002-01-01

    Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2) of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  10. Amino acid analysis.

    Science.gov (United States)

    Crabb, J W; West, K A; Dodson, W S; Hulmes, J D

    2001-05-01

    Amino acid analysis (AAA) is one of the best methods to quantify peptides and proteins. Two general approaches to quantitative AAA exist, namely, classical postcolumn derivatization following ion-exchange chromatography and precolumn derivatization followed by reversed-phase HPLC (RP-HPLC). Excellent instrumentation and several specific methodologies are available for both approaches, and both have advantages and disadvantages. This unit focuses on picomole-level AAA of peptides and proteins using the most popular precolumn-derivatization method, namely, phenylthiocarbamyl amino acid analysis (PTC-AAA). It is directed primarily toward those interested in establishing the technology with a modest budget. PTC derivatization and analysis conditions are described, and support and alternate protocols describe additional techniques necessary or useful for most any AAA method--e.g., sample preparation, hydrolysis, instrument calibration, data interpretation, and analysis of difficult or unusual residues such as cysteine, tryptophan, phosphoamino acids, and hydroxyproline. PMID:18429107

  11. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation and...... separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids...... bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD...

  12. Antibiotic prophylaxis for transrectal prostate biopsy-a new strategy

    DEFF Research Database (Denmark)

    Antsupova, Valeria; Nørgaard, Nis; Bisbjerg, Rasmus;

    2014-01-01

    BACKGROUND: Fluoroquinolones are extensively used as prophylaxis for transrectal ultrasound-guided biopsy of the prostate (TRUBP). Emerging fluoroquinolone resistance and selection of multiresistant organisms warrant new prophylactic strategies. Pivmecillinam and amoxicillin/clavulanic acid have...

  13. Comparative virulence genotyping and antimicrobial susceptibility profiling of environmental and clinical Salmonella enterica from Cochin, India

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Vijayan, J.; Murali, G.; Chandran, P.

    . Newport revealed multiple drug resistance to ampicillin, amoxicillin/clavulanic acid, trimethorprim-sulfamethoxazole, chloramphenicol, tetracycline, cephalothin, and cephalexin. In comparison, S. Typhi were susceptible to all clinically relevant...

  14. Antimicrobial resistance pattern of Escherichia coli isolated from patients with urinary tract infection (UTI in Yasuj city during 1391-1392.

    Directory of Open Access Journals (Sweden)

    A Sharifi

    2014-07-01

    Conclusion: It is recommended to treat urinary tract infections by using fewer antibiotics such as Amoxicillin / Clavulanic acid and co-trimoxazole, and administration of ciprofloxacin and gentamicin should be used with caution.

  15. [Nicotinic acid and nicotinamide].

    Science.gov (United States)

    Kobayashi, M; Shimizu, S

    1999-10-01

    Nicotinic acid and nicotinamide are called niacin. They are the antipellagra vitamin essential to many animals for growth and health. In human being, niacin is believed necessary together with other vitamins for the prevention and cure of pellagra. Niacin is widely distributed in nature; appreciable amounts are found in liver, fish, yeast and cereal grains. Nicotinamide is a precursor of the coenzyme NAD and NADP. Some of the most understood metabolic processes that involve niacin are glycolysis, fatty acid synthesis and respiration. Niacin is also related to the following diseases: Hartnup disease; blue diaper syndrome; tryptophanuria; hydroxykynureninuria; xanthurenic aciduria; Huntington's disease. PMID:10540864

  16. Whither Acid Rain?

    OpenAIRE

    Peter Brimblecombe

    2000-01-01

    Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and s...

  17. A very acid rocket

    Energy Technology Data Exchange (ETDEWEB)

    Benoit Browaeys, D.

    1996-04-01

    The french rocket Ariane is the cause of environmental pollution. These effects are discussed in this article. Chloric acid and aluminium are in question: chloric acid is responsible of leaves necrosis and pulmonary diseases among the rats. For the man, the danger would be that drinking water could be contaminated by aluminium, which is neuro toxic with serious chronic effects. It is implicated in Alzheimer disease. But no studies has been made to search aluminium in drinking water of Sinnamary and Kourou. (N.C.). 8 refs., 2 figs.

  18. Ethylenediaminetetraacetic acid in endodontics.

    Science.gov (United States)

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-09-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented. PMID:24966721

  19. Whither Acid Rain?

    Directory of Open Access Journals (Sweden)

    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  20. Boric acid concentration monitoring

    International Nuclear Information System (INIS)

    Boric acid concentration was measured by thermal neutron absorption in the study of the boric acid sorption and desorption curves on an anion exchange resin. Ra-Be 18.5 GBq and Am-Be 111 GBq sources and water as a moderator were used. The SNM 12 cylindrical corona detector with 10B placed in the middle of the measuring cell was used for neutron flux measurement. The HP 9600 E computer system was used for measured data collection and evaluation. (Ha)

  1. Polyunsaturated fatty acids and inflammation

    OpenAIRE

    Calder Philip C

    2004-01-01

    The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites) and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and ...

  2. Crystal Structures of KPC-2[beta]-Lactamase in Complex with 3-Nitrophenyl Boronic Acid and the Penam Sulfone PSR-3-226

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Wei; Bethel, Christopher R.; Papp-Wallace, Krisztina M.; Pagadala, Sundar Ram Reddy; Nottingham, Micheal; Fernandez, Daniel; Buynak, John D.; Bonomo, Robert A.; van den Akker, Focco (Case Western); (Stokes); (SMU)

    2012-08-01

    Class A carbapenemases are a major threat to the potency of carbapenem antibiotics. A widespread carbapenemase, KPC-2, is not easily inhibited by {beta}-lactamase inhibitors (i.e., clavulanic acid, sulbactam, and tazobactam). To explore different mechanisms of inhibition of KPC-2, we determined the crystal structures of KPC-2 with two {beta}-lactamase inhibitors that follow different inactivation pathways and kinetics. The first complex is that of a small boronic acid compound, 3-nitrophenyl boronic acid (3-NPBA), bound to KPC-2 with 1.62-{angstrom} resolution. 3-NPBA demonstrated a Km value of 1.0 {+-} 0.1 {micro}M (mean {+-} standard error) for KPC-2 and blocks the active site by making a reversible covalent interaction with the catalytic S70 residue. The two boron hydroxyl atoms of 3-NPBA are positioned in the oxyanion hole and the deacylation water pocket, respectively. In addition, the aromatic ring of 3-NPBA provides an edge-to-face interaction with W105 in the active site. The structure of KPC-2 with the penam sulfone PSR-3-226 was determined at 1.26-{angstrom} resolution. PSR-3-226 displayed a K{sub m} value of 3.8 {+-} 0.4 {micro}M for KPC-2, and the inactivation rate constant (kinact) was 0.034 {+-} 0.003 s{sup -1}. When covalently bound to S70, PSR-3-226 forms a trans-enamine intermediate in the KPC-2 active site. The predominant active site interactions are generated via the carbonyl oxygen, which resides in the oxyanion hole, and the carboxyl moiety of PSR-3-226, which interacts with N132, N170, and E166. 3-NPBA and PSR-3-226 are the first {beta}-lactamase inhibitors to be trapped as an acyl-enzyme complex with KPC-2. The structural and inhibitory insights gained here could aid in the design of potent KPC-2 inhibitors.

  3. Crystal Structures of KPC-2 and SHV-1 β-Lactamases in Complex with the Boronic Acid Transition State Analog S02030.

    Science.gov (United States)

    Nguyen, Nhu Q; Krishnan, Nikhil P; Rojas, Laura J; Prati, Fabio; Caselli, Emilia; Romagnoli, Chiara; Bonomo, Robert A; van den Akker, Focco

    2016-03-01

    Resistance to expanded-spectrum cephalosporins and carbapenems has rendered certain strains of Klebsiella pneumoniae the most problematic pathogens infecting patients in the hospital and community. This broad-spectrum resistance to β-lactamases emerges in part via the expression of KPC-2 and SHV-1 β-lactamases and variants thereof. KPC-2 carbapenemase is particularly worrisome, as the genetic determinant encoding this β-lactamase is rapidly spread via plasmids. Moreover, KPC-2, a class A enzyme, is difficult to inhibit with mechanism-based inactivators (e.g., clavulanate). In order to develop new β-lactamase inhibitors (BLIs) to add to the limited available armamentarium that can inhibit KPC-2, we have structurally probed the boronic acid transition state analog S02030 for its inhibition of KPC-2 and SHV-1. S02030 contains a boronic acid, a thiophene, and a carboxyl triazole moiety. We present here the 1.54- and 1.87-Å resolution crystal structures of S02030 bound to SHV-1 and KPC-2 β-lactamases, respectively, as well as a comparative analysis of the S02030 binding modes, including a previously determined S02030 class C ADC-7 β-lactamase complex. S02030 is able to inhibit vastly different serine β-lactamases by interacting with the conserved features of these active sites, which includes (i) forming the bond with catalytic serine via the boron atom, (ii) positioning one of the boronic acid oxygens in the oxyanion hole, and (iii) utilizing its amide moiety to make conserved interactions across the width of the active site. In addition, S02030 is able to overcome more distantly located structural differences between the β-lactamases. This unique feature is achieved by repositioning the more polar carboxyl-triazole moiety, generated by click chemistry, to create polar interactions as well as reorient the more hydrophobic thiophene moiety. The former is aided by the unusual polar nature of the triazole ring, allowing it to potentially form a unique C-H…O 2

  4. Acid Rain Investigations.

    Science.gov (United States)

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  5. Acid Rain Classroom Projects.

    Science.gov (United States)

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  6. The Acid Rain Game.

    Science.gov (United States)

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  7. The Acid Rain Debate.

    Science.gov (United States)

    Oates-Bockenstedt, Catherine

    1997-01-01

    Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

  8. Hyaluronic Acid Assays

    DEFF Research Database (Denmark)

    Itenov, Theis S; Kirkby, Nikolai S; Bestle, Morten H;

    2015-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  9. Koetjapic acid chloroform hemisolvate

    Directory of Open Access Journals (Sweden)

    Z. D. Nassar

    2010-06-01

    Full Text Available The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS-7-(2-carboxyethyl-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H...O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H...O hydrogen bonds. The dimers are stacked along the c axis.

  10. Lactic acid and lactates

    NARCIS (Netherlands)

    Schreurs, V.V.A.M.

    2010-01-01

    This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a perspec

  11. Acid dip for dosemeter

    International Nuclear Information System (INIS)

    Background signal in a PTFE based dosemeter caused by impurities in the PTFE and in the active component such as lithium fluoride is substantially reduced by treating the dosemeter with acid. The optimum treatment involves use of hydrofluoric acid at room temperature for approximately one minute, followed by thorough washing with methanol, and finally drying. This treatment is best applied after the original manufacture of the dosemeters. It may also be applied to existing dosemeters after they have been in use for some time. The treatment produces a permanent effect in reducing both the light induced signal and the non-light induced signal. The process may be applied to all types of dosemeter manufactured from PTFE or other plastics or resins which are able to resist brief exposure to acid. The treatment works particularly well with dosemeters based on PTFE and lithium fluoride. It is also applicable to dosemeters based on calcium sulphate, lithium borate and magnesium borate. Acids which may be used include hydrofluoric, hydrochloric, nitric, phosphoric and sulphuric. (author)

  12. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  13. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  14. Effect of hyperproduction of TEM-1 beta-lactamase on in vitro susceptibility of Escherichia coli to beta-lactam antibiotics.

    OpenAIRE

    Wu, P J; Shannon, K; Phillips, I

    1994-01-01

    The susceptibility of 173 TEM-1-producing isolates of Escherichia coli was assessed by determination of MICs by the agar dilution method. MICs of amoxicillin, mezlocillin, cephaloridine, and, to a smaller extent, amoxicillin-clavulanic acid (but not cephalexin, cefuroxime, cefotaxime, ceftazidime, or imipenem) were higher for isolates that produced large amounts of beta-lactamase than for isolates that produced smaller amounts. The effect of fixed concentrations of clavulanic acid on resistan...

  15. Origin of fatty acids

    International Nuclear Information System (INIS)

    The appearance of fatty acids and membranes is one of the most important events of the prebiotic world because genesis of life required the compartmentalization of molecules. Membranes allowed cells to become enriched with molecules relevant for their evolution and gave rise to gradients convertible into energy. By virtue of their hydrophobic/hydrophilic interface, membranes developed certain enzymatic activities impossible in the aqueous phase. A prebiotic cell is an energy unit but it is also an information unit. It has a past, a present and a future. The biochemistry of fatty acids involves acetylCoA, malonylCoA and an enzyme, acyl synthetase, which joins both molecules. After substitution of the acetyl group in place of the carboxyl group of malonyl derivatives, the chain is reduced and dehydrated to crotonyl derivatives. These molecules can again react with malonylCoA to form unsaturated chain; they can also undergo a new reduction step to form butyryl derivatives which can react with malonylCoA to form a longer aliphatic chain. The formation of malonylCoA consumes ATP. The reduction step needs NADPH and proton. Dehydration requires structural information because the reduction product is chiral (D configuration). It is unlikely that these steps were possible in a prebiotic environment. Thus we have to understand how fatty acids could appear in the prebiotic era. This hypothesis about the origin of fatty acids is based on the chemistry of sulfonium ylides and sulfonium salts. The most well-known among these molecules are S-melthyl-methionine and S-adenosyl methionine. The simplest sulfonium cation is the trimethylsulfonium cation. Chemists have evidence that these products can produce olefin when they are heated or flashed with UV light in some conditions. I suggest that these volatile products can allow the formation of fatty acids chains in atmospheric phase with UV and temperature using methanol as starting material. Different synthetic pathways will be

  16. Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations.

    Science.gov (United States)

    Ahmad, I; Ali Sheraz, M; Ahmed, S; Shad, Z; Vaid, F H M

    2012-06-01

    This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations. PMID:22296174

  17. Arterial Blood Carbonic Acid Inversely Determines Lactic and Organic Acids

    OpenAIRE

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    Objective: To establish that arterial blood carbonic acid varies inversely with lactic acid in accordance with bicarbonate exchanging for lactate across cell membranes through the anion exchange mechanism to maintain the Gibbs-Donnan equilibrium.

  18. Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells

    Directory of Open Access Journals (Sweden)

    Duan Rui-Dong

    2009-12-01

    Full Text Available Abstract Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-β-boswellic acids (AKBA, a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

  19. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    Science.gov (United States)

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis. PMID:27349116

  20. Acetic acid extraction from aqueous solutions using fatty acids

    NARCIS (Netherlands)

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  1. College Chemistry Students' Mental Models of Acids and Acid Strength

    Science.gov (United States)

    McClary, LaKeisha; Talanquer, Vicente

    2011-01-01

    The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research…

  2. N-(3-Methylphenylsuccinamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-02-01

    Full Text Available In the crystal structure of the title compound, C11H13NO3, the conformations of the N—H and C=O bonds in the amide segment are anti to each other, and that of the amide H atom is anti to the meta-methyl group in the benzene ring. Furthermore, the conformations of the amide oxygen and the carbonyl O atom of the acid segment are also anti to the adjacent –CH2 groups. The C=O and O—H bonds of the acid group are syn to each other. In the crystal, the molecules are packed into infinite chains through intermolecular N—H...O and O—H...O hydrogen bonds.

  3. [Progress in glucaric acid].

    Science.gov (United States)

    Qiu, Yuying; Fang, Fang; Du, Guocheng; Chen, Jian

    2015-04-01

    Glucaric acid (GA) is derived from glucose and commonly used in chemical industry. It is also considered as one of the "Top value-added chemicals from biomass" as carbohydrate monomers to produce various synthetic polymers and bioenergy. The demand for GA in food manufacture is increasing. GA has also attracted public attentions due to its therapeutic uses such as regulating hormones, increasing the immune function and reducing the risks of cancers. Currently GA is produced by chemical oxidation. Research on production of GA via microbial synthesis is still at preliminary stage. We reviewed the advances of glucaric acid applications, preparation and quantification methods. The prospects on production of GA by microbial fermentation were also discussed. PMID:26380405

  4. Studies on terreic acid.

    Science.gov (United States)

    Yamamoto, H; Moriyama, K; Jinnouchi, H; Yagishita, K

    1980-03-01

    It was found that Aspergillus sp. No. Y-8980 which was isolated from a soil sample collected at Yoron Island in Kagoshima Prefecture belonged to Aspergillus terreus group by morphological observation. The active substance produced by the strain was obtained with a high yield in sucrose-yeast extract medium and extracted by chloroform, ethyl acetate and n-butanol at pH 2.4 approximately 2.6 from the culture broth. The substance was crystallized from chloroform and ethyl acetate after charcoal treatment of the crude crystal. From various physico-chemical properties, it was found that the substance was identical to terreic acid. Terreic acid showed MICs of 25 approximately 100 mcg/ml, 12.5 mcg/ml and 50 mcg/ml against Gram-positive and Gram-negative bacteria, Xanthomonas oryzae and Xanthomonas citri, respectively, but it did not control Pseudomonas, fungi and yeast. The LD50 was 75 mg/kg i.p. and i.v. in mice. With regards to the anti-tumor effect, the morphological degeneration on HeLa cells (human carcinoma cells) was observed in the concentrations of more than 6.25 mcg/ml of terreic acid. An increase of body weight of mice caused by Ehrlich ascites carcinoma cells was not definitely observed by the daily administration of 150 mcg of terreic acid per mouse for 8 consecutive days. Above showed the enough survival effect in dd mice implanted with Ehrlich ascites carcinoma cells, and the effect also was demonstrated by anatomies of mice. PMID:7190624

  5. Electrochemistry of nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Bartošík, Martin

    2012-01-01

    Roč. 112, č. 6 (2012), s. 3427-3481. ISSN 0009-2665 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA MŠk(CZ) ME09038; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : nucleic acids electrochemistry * DNA biosensors * DNA damage Subject RIV: BO - Biophysics Impact factor: 41.298, year: 2012

  6. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2007-01-01

    Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness.......Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness....

  7. Pantothenic acid (Vitamin B5)

    Science.gov (United States)

    ... niacinamide), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cyanocobalamin), and folic acid. However, some products do ... for dandruff, depression, diabetic nerve pain, enhancing immune function, improving athletic performance, tongue infections, gray hair, headache, ...

  8. ACID ROCK DRAINAGE

    Directory of Open Access Journals (Sweden)

    Anca Ionce

    2010-10-01

    Full Text Available Acid rock drainage (ARD is an particularly important aspect for the evaluation of the decantation ponds’ safety, and which has been only once taken into consideration at the Tarnicioara decantation pond, year 2002, as a consequence of the apparition of a strong seepage on the deposit’s dump, that has chemically de-purified the water from the river Brateasa. We have observed ARD, which implies the release of acid solutions from the mining sterile deposits, from the underground mining works and from the quarries, in the following tailings dams: Tarnicioara, Valea Strajii, Poarta Veche- which served Tarniţa Preparation Enterprise and in the Dealu Negru and Paraul Cailor ponds- which, at their time served Fundu Moldovei Preparation Enterprise, both during the period of their functioning and the period after their closure. For the decantation pond Dumitrelu which served the Calimani preparation enterprise, acid seepages from the deposit were mentioned in a study made by SC ICPM SA Baia Mare in 1993. Subsequently to the closure of the objective such seepage did not take place anymore. Instead, by raining, there is a frequent plant sterile dragging from the contour retaining wall down to the trouble pond, situated upstream.

  9. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  10. Retinoic acid and cancer treatment

    OpenAIRE

    Chen, Mei-Chih; Hsu, Shih-Lan; Lin, Ho; Yang, Tsung-Ying

    2014-01-01

    Retinoic acid which belongs to the retinoid class of chemical compounds is an important metabolite of vitamin A in diets. It is currently understood that retinoic acid plays important roles in cell development and differentiation as well as cancer treatment. Lung, prostate, breast, ovarian, bladder, oral, and skin cancers have been demonstrated to be suppressed by retinoic acid. Our results also show that low doses and high doses of retinoic acid may respectively cause cell cycle arrest and a...

  11. Biological properties of lipoic acid

    Directory of Open Access Journals (Sweden)

    Anna Bilska

    2002-06-01

    Full Text Available Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2 of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  12. Sedimentation of sulfuric acid in acid tars from current production

    Energy Technology Data Exchange (ETDEWEB)

    Denisova, T.L.; Frolov, A.F.; Aminov, A.N.; Novosel' tsev, S.P.

    1987-09-01

    Acid tars obtained in treating T-750, KhF-12, and I-8A oils were investigated for purposes of recovering sulfuric acid and asphalt binders from the compositions and of determining the effects of storage time on the recovery. The consumption and sedimentation levels of sulfuric acid during storage for different periods and at different temperatures were assessed. The characteristics of an asphalt binder obtained by neutralizing acid tar with a paste consisting of asphalts from deasphalting operations and slaked lime, followed by oxidation of the mixture with atmospheric air, were determined. The sulfuric acid recovered in the settling process could be burned in order to purify it of organic contaminants.

  13. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  14. An Umbrella for Acid Rain.

    Science.gov (United States)

    Randal, Judith

    1979-01-01

    The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

  15. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B;

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation...

  16. Pantothenic acid biosynthesis in zymomonas

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  17. Acid Rain Limits Global Warming

    Institute of Scientific and Technical Information of China (English)

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  18. Self-neutralizing well acidizing

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.F.

    1974-07-30

    A process for acidizing a subterranean region by contacting it with an acidic solution is improved by dissolving in the solution a pH-increasing reactant that subsequently adjusts the pH of the solution to a selected relatively neutral value. Urea is an example of the acid neutralizer. (10 claims)

  19. Ionic liquid supported acid-catalysed esterification of lauric acid

    International Nuclear Information System (INIS)

    Ionic Liquid (IL) based on 1-n-butyl-3-methylimidazolium bis(trifluoro methylsulfonyl)imide (BMI.NTf2) under acidic condition was used as catalyst for the esterification reaction of fatty acid. Various acids namely sulphuric acid, perchloric acid, p-toulene sulphonic acid and various chloride salts such as zinc chloride (ZnCl2) and iron (III) chloride (FeCl3) immobilized in ionic liquid BMI.NTf2 gave acidic ILs. These acidic ILs were tested as catalysts for esterification reactions. Esterification of alcohol (methanol) with fatty acid (lauric acid) using ionic liquid BMI.NTf2 combined with H2SO4 (BMI.NTf2(H2SO4)) gave high activity (>85 %) and selectivity (100 %) observed over a period of 2 hours reaction with reaction temperature 70 degree Celsius. The ester became easily separated due to IL forming biphasic with product after the reaction where ester accumulated as the upper phase and IL with water produced after reaction at lower phase. Catalytic activities comparison also be studied between acidic ionic liquid BMI.NTf2 with acidic ionic liquid ChCl.2ZnCl2 and conventional acid catalyst. These ILs were characterised by using FTIR, NMR and TGA. Results from FTIR were showed no significant difference between ILs with ILs in acidic condition. The TGA curve show BMI.NTf2 thermals decomposition is ≥400 degree Celsius but when BMI.NTf2 combination with H2SO4, TGA curve show weight loss increase and becomes unstable. The advantages of ILs as catalyst are clean process and green chemistry due to its behaviour such as non-volatile, no loss of solvent through evaporation and reduced environmentally impact. This ILs-catalyst system can be recycle for further reaction. (author)

  20. Invasive cleavage of nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2002-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  1. Invasive cleavage of nucleic acids

    Science.gov (United States)

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  2. Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.

    Science.gov (United States)

    Raw, C. J. G.; And Others

    1983-01-01

    Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

  3. Polyunsaturated fatty acids and inflammation

    Directory of Open Access Journals (Sweden)

    Calder Philip C.

    2004-01-01

    Full Text Available The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and so available for eicosanoid production. Thus, n-3 polyunsaturated fatty acids act as arachidonic acid antagonists. Components of both natural and acquired immunity, including the production of key inflammatory cytokines, can be affected by n-3 polyunsaturated fatty acids. Although some of the effects of n-3 fatty acids may be brought about by modulation of the amount and types of eicosanoids made, it is possible that these fatty acids might elicit some of their effects by eicosanoid-independent mechanisms. Such n-3 fatty acid-induced effects may be of use as a therapy for acute and chronic inflammation, and for disorders that involve an inappropriately-activated immune response.

  4. Waste acid detoxification and reclamation

    International Nuclear Information System (INIS)

    Economically feasible processes that reduce the volume, quantity, and toxicity of metal-bearing waste acids by reclaiming, reusing, and recycling spent acids and metal salts are being developed and demonstrated. The acids used in the demonstrations are generated during metal-finishing operations used in nuclear fuel fabrication; HF-HNO3, HNO3, and HNO3-H2SO4 wastes result from Zr etching, Cu stripping, and chemical milling of U. At discharge, wastes contain high concentrations of acid and one major metal impurity. The waste minimization process used to reclaim acid from these three streams incorporates three processes for acid regeneration and reclamation. Normally, HNO3 remains in the bottoms when an aqueous acid solution is distilled; however, in the presence of H2SO4, HNO3 will distill to the overhead stream. In this process, nitrates and fluorides present as free acid and metal salts can be reclaimed as acid for recycle to the metal-finishing processes. Uranium present in the chemical milling solution can be economically recovered from distillation bottoms and refined. Using acid distillation, the volume of chemical milling solution discharged as waste can be reduced by as much as 60% depending on the H2SO4 concentration. A payback period of 2.2 years has been estimated for this process. The development and demonstration of precipitation and distillation processes for detoxification and reclamation of waste acid is supported by the US Department of Energy's Hazardous Waste Remedial Actions Program (HAZWRAP)

  5. Labeled bile acids

    International Nuclear Information System (INIS)

    A general short procedure for the introduction of 13C to the side chain of bile acids is described. Suitable (Z)-pregn-17(20)-enes are key intermediates, while the isotope is introduced by an ene reaction with [1,2,3-13C3]-methyl propiolate. For the labeling with tritium, the unlabeled product of the ene synthesis, a Δsup(5,16,22)-triene was saturated selectively at 16,17 and 22,23 with tritium gas. (author)

  6. N-(4-Isocyanophenylsuccinamic acid

    Directory of Open Access Journals (Sweden)

    Lauren E. Burnham

    2012-07-01

    Full Text Available In the crystal structure of the title compound, C11H10N2O3, inversion-related molecules are connected by pairs of O—H...O hydrogen bonds. With the exception of the atoms in the carboxylic acid group, the non-H atoms are roughly coplanar with a maximum deviation from the mean plane of 0.270 (1 Å for the C atom to which the carboxylic group is attached. The C atom of the carboxylic group lies 1.730 (2 Å from the mean plane.

  7. Nucleic Acid Vaccines

    Institute of Scientific and Technical Information of China (English)

    LU Shan

    2004-01-01

    @@ Anew method of immunization was discovered in the early 1990s. Several research groups independently demonstrated that direct inoculation of DNA plasmids coding for a specific protein antigen could elicit immune responses against that antigen[1-4].Since in theory the mRNA molecules also have the potential to be translated into the protein antigen, this vaccination approach was officially named by WHO as the nucleic acid vaccination even though the term DNA vaccine has been used more commonly in the literature. This novel approach is considered the fourth generation of vaccines after live attenuated vaccines, killed or inactivated vaccines and recombinant protein based subunit vaccines.

  8. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    OpenAIRE

    B. Syama Sundar; P.S.Radhakrishna murti

    2014-01-01

    Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation wi...

  9. Cryoprotection from lipoteichoic acid

    Science.gov (United States)

    Rice, Charles V.; Middaugh, Amy; Wickham, Jason R.; Friedline, Anthony; Thomas, Kieth J.; Johnson, Karen; Zachariah, Malcolm; Garimella, Ravindranth

    2012-10-01

    Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, and with a few exceptions, antifreeze proteins are missing. Survival has been attributed to external factors, such as the high salt concentration of brine veins and adhesion to particulates or ice crystal defects. We have discovered an endogenous cryoprotectant in the cell wall of bacteria, lipoteichoic acid biopolymers. Adding 1% LTA to bacteria cultures immediately prior to freezing provides 50% survival rate, similar to the results obtained with 1% glycerol. In the absence of an additive, bacterial survival is negligible as measured with the resazurin cell viability assay. The mode of action for LTA cryoprotection is unknown. With a molecular weight of 3-5 kDa, it is unlikely to enter the cell cytoplasm. Our observations suggest that teichoic acids could provide a shell of liquid water around biofilms and planktonic bacteria, removing the need for brine veins to prevent bacterial freezing.

  10. Growth of nitric acid hydrates on thin sulfuric acid films

    Science.gov (United States)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-05-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1 - 3 × 10-4 Torr H2O and 1 - 2.5 × 10-6 Torr HNO3) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  11. Growth of nitric acid hydrates on thin sulfuric acid films

    Science.gov (United States)

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  12. Caro's acid - its introduction to uranium acid leaching in Australia

    International Nuclear Information System (INIS)

    After extensive testing and plant trials to establish the benefits of Caro's acid (H2SO5) as an alternative oxidant, Queensland Mines Limited decided to replace pyrolusite with Caro's acid in its acid leach uranium treatment plant at Nabarlek. The decision was based on the reagent savings and environmental gains associated with the removal of manganese from the process liquors, as well as the labour savings and improved oxidation reduction potential control possible in leaching using the Caro's acid system. Some changes in operating parameters were necessary with the introduction of Caro's acid to the treatment plant. Operating results have confirmed the relationship between oxidant demand and uranium content of ore established during the trials. Acid savings have been as predicted from the plant trials. The major saving has been of hydrated lime required for tailings neutralisation

  13. Solid acid catalysis from fundamentals to applications

    CERN Document Server

    Hattori, Hideshi

    2014-01-01

    IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

  14. Amino Acid Decarboxylase Activity of Some Lactic Acid Bacteria

    OpenAIRE

    Pelin ERTÜRKMEN; Turhan, İlkay; Öner, Zübeyde

    2015-01-01

    Microorganisms which have decarboxylase activity can form biogenic amine by enzymatic decarboxylation of amino acids in foods. Histamine poisoning results from consumption of foods typically certain types of fish and cheeses that contain unusually high levels of histamine. Therefore, decarboxylase activity is an important problem at the selection of lactic acid bacteria as a starter culture in fermented products. In this study, decarboxylase activities of 161 lactic acid bacteria (LAB) strain...

  15. Synthesis of stearic acid triethanolamine ester over solid acid catalysts

    Institute of Scientific and Technical Information of China (English)

    Tao Geng; Qiu Xiao Li; Ya Jie Jiang; Wei Wang

    2010-01-01

    The synthesis of stearic acid triethanolamine ester over solid acid catalysts was investigated.The results showed that the catalytic activity and selectivity of zirconium sulfate supported on SBA-15(6)(pore diameter 6 nm)is better than that of commonly used hypophosphorous acid,zirconium sulfate supported on MCM-41 and zirconium sulfate supported on SBA-15(9)(pore diameter 9 nm).

  16. Bile acid interactions with cholangiocytes

    Institute of Scientific and Technical Information of China (English)

    Xuefeng Xia; Heather Francis; Shannon Glaser; Gianfranco Alpini; Gene LeSage

    2006-01-01

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2)is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3,an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, OstαOstβ. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliaryplexus back to hepatocytes for re-secretion into bile.This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5'-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines.Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogenactivated protein (MAP) kinase and extracellular signalregulated protein kinase (ERK) intracellular signals.Bile acids significantly alter cholangiocyte secretion,proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals,and in some instances trigger opposing effects on cholangiocyte secretion

  17. Molecular Simulation of Naphthenic Acid Removal on Acidic Catalyst Ⅱ. Experimental results of catalytic decarboxylation over acidic catalysts

    Institute of Scientific and Technical Information of China (English)

    Fu Xiaoqin; Tian Songbai; Hou Shuandi; Longjun; Wang Xieqing

    2008-01-01

    The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Br(o)nsted acid and Lewis acid were analyzed using molecular simulation technology.Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Br(o)nsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.

  18. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD......), atomic emission spectrometry, and mass spectrometry. For most environmental samples, chlorinated FAMEs must be enriched prior to GC. ELCD is a useful detection method for indicating halogenated FAMEs in the chromatograms, and tentative identification of the halogenated species can be obtained by...... calculation of retention indices. For closer identification of halogenated FAMEs, mass spectrometry (MS) is very useful, in particular when employing the chemical ionisation mode. MS identification, however, is highly facilitated if halogenated species are first indicated by element-selective methods....

  19. Polyunsaturated Fatty Acids in Children

    OpenAIRE

    Lee, Ji-Hyuk

    2013-01-01

    Polyunsaturated fatty acids (PUFAs) are the major components of brain and retina, and are the essential fatty acids with important physiologically active functions. Thus, PUFAs should be provided to children, and are very important in the brain growth and development for fetuses, newborn infants, and children. Omega-3 fatty acids decrease coronary artery disease and improve blood flow. PUFAs have been known to have anti-inflammatory action and improved the chronic inflammation such as auto-im...

  20. Allelopathic Interactions Involving Phenolic Acids

    OpenAIRE

    Blum, U.

    1996-01-01

    A major concern regarding allelopathic interactions involving phenolic acids in no-till systems pertains to the fact that concentrations of individual phenolic acids recoverable from field soils are well below levels required for inhibition of germination and seedling growth in laboratory bioassays. Field soils contain a variety of phenolic acids as well as other toxic and nontoxic organic compounds that are available to interact with seeds and roots; whereas in laboratory bioassays, with few...

  1. Fatty acid biosynthesis in actinomycetes

    OpenAIRE

    Gago, Gabriela; Diacovich, Lautaro; Arabolaza, Ana; Tsai, Shiou-Chuan; Gramajo, Hugo

    2011-01-01

    All organisms that produce fatty acids do so via a repeated cycle of reactions. In mammals and other animals, these reactions are catalyzed by a type I fatty acid synthase (FAS), a large multifunctional protein to which the growing chain is covalently attached. In contrast, most bacteria (and plants) contain a type II system in which each reaction is catalyzed by a discrete protein. The pathway of fatty acid biosynthesis in Escherichia coli is well established and has provided a foundation fo...

  2. Kojic acid in organic synthesis

    OpenAIRE

    ZIRAK, MARYAM; Eftekhari-Sis, Bagher

    2015-01-01

    The reactions of kojic acid in organic synthesis are reviewed. The aim of this review is to cover the literature up to the end of 2014, showing the distribution of publications involving kojic acid chemistry in the synthesis of various pyrone containing compounds, pyridine and pyridone heterocycles, and also other organic compounds. First, introductory text about the preparation, biological, and industrial applications, and the chemical properties of kojic acid is given. Then its uses in orga...

  3. [Total synthesis of nordihydroguaiaretic acid].

    Science.gov (United States)

    Wu, A X; Zhao, Y R; Chen, N; Pan, X F

    1997-04-01

    beta-Keto ester(5) was obtained from vanilin through etherification, oxidation and condensation with acetoacetic ester, (5) on oxidative coupling reaction by NaOEt/I2 produced dimer (6) in high yield. Acid catalyzed cyclodehydration of (6) gave the furan derivative(7), and by a series of selective hydrogenation nordihydroguaiaretic acid, furoguaiacin dimethyl ether and dihydroguaiaretic acid dimethyl ether were synthesized. PMID:11499030

  4. ACETIC ACID AND A BUFFER

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  5. Valproic Acid Induced Hyperammonaemic Encephalopathy

    International Nuclear Information System (INIS)

    Objective: To observe clinical and laboratory features of valproic acid-induced hyperammonaemic encephalopathy in patients taking valproic acid. Methods: Observational study was conducted at the Neurology Department, Dow University of Health Sciences, Civil Hospital, Karachi, from February 26, 2010 to March 20, 2011. Ten patients on valproic acid therapy of any age group with idiopathic or secondary epilepsy, who presented with encephalopathic symptoms, were registered and followed up during the study. Serum ammonia level, serum valproic acid level, liver function test, cerebrospinal fluid examination, electroencephalogram and brain imaging of all the patients were done. Other causes of encephalopathy were excluded after clinical and appropriate laboratory investigations. Microsoft Excel 2007 was used for statistical analysis. Results: Hyperammonaemia was found in all patients with encephalopathic symptoms. Rise in serum ammonia was independent of dose and serum level of valproic acid. Liver function was also found to be normal in 80% (n=8) of the patients. Valproic acid was withdrawn in all patients. Three (30%) patients improved only after the withdrawal of valproic acid. Six (60%) patients improved after L-Carnitine replacement, one (10%) after sodium benzoate. On followup, serum ammonia had reduced to normal in five (50%) patients and to more than half of the baseline level in two (20%) patients. Three (30%) patients were lost to followup after complete clinical improvement. Conclusion: Within therapeutic dose and serum levels, valproic acid can cause symptomatic hyperammonaemia resulting in encephalopathy. All patients taking valproic acid presenting with encephalopathic symptoms must be monitored for the condition. (author)

  6. Peptide Nucleic Acids Having Amino Acid Side Chains

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting of...

  7. Are Strong Bronsted Acids Necessarily Strong Lewis Acids?

    CERN Document Server

    Sen-Gupta, K; Roy, D R; Subramanian, V

    2006-01-01

    The Broensted and Lowry acid base theory is based on the capacity of proton donation or acceptance (in the presence or absence of a solvent) whereas the Lewis acid base theory is based on the propensity of electron pair acceptance or donation. We explore through DFT calculation the obvious question whether these two theories are in conformity with each other. We use pKa as the descriptor for the Broensted and Lowry acidity. The DFT descriptors like ionization potential, electron affinity, electronegativity, hardness and global electrophilicity are computed for 58 organic and inorganic acids. The fractional electron transfer, del(N) and the associated energy change, del(E) for the reaction of these acids with trimethyl amine (a strong base) are used as the possible descriptors for the Lewis acidity. A near exponential decrease in del(N) and (-del(E)) values is observed in general with an increase in pKa values. The findings reveal that a stronger Broensted acid in most cases behaves as a stronger Lewis acid as...

  8. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Directory of Open Access Journals (Sweden)

    Je Min Lee

    2016-01-01

    Full Text Available Polyunsaturated fatty acids (PUFAs are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism.

  9. Irreversible Inhibition of the Mycobacterium tuberculosis β-lactamase by Clavulanate

    OpenAIRE

    Hugonnet, Jean-Emmanuel; Blanchard, John S.

    2007-01-01

    The β-lactam class of antibiotics, which inhibit the bacterial d,d transpeptidases involved in cell wall biosynthesis, have never been used systematically in the treatment of Mycobacterium tuberculosis infections because of this organism’s resistance to β-lactams. The critical resistance factor is the constitutive production of a chromosomally encoded, Ambler class A β-lactamase, BlaC in M. tuberculosis. We show that BlaC is an extended spectrum β-lactamase (ESBL) with high levels of penicill...

  10. A comparison of chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1992-01-01

    Because of federal and state mandates restricting the use of hexavalent chromium, it was deemed worthwhile to compare the corrosion protection afforded 2219-T87 aluminum alloy by both Type I chromic acid and Type II sulfuric acid anodizing per MIL-A-8625. Corrosion measurements were made on large, flat 2219-T87 aluminum alloy sheet material with an area of 1 cm(exp 2) exposed to a corrosive medium of 3.5-percent sodium chloride at pH 5.5. Both ac electrochemical impedance spectroscopy and the dc polarization resistance techniques were employed. The results clearly indicate that the corrosion protection obtained by Type II sulfuric acid anodizing is superior, and no problems should result by substituting Type II sulfuric acid anodizing for Type I chromic acid anodizing.

  11. Carbonic Acid Retreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Baylor university

    2003-06-01

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for

  12. Carbonic Acid Pretreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  13. Ghrelin and gastric acid secretion

    Institute of Scientific and Technical Information of China (English)

    Koji Yakabi; Junichi Kawashima; Shingo Kato

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric add secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  14. Origin of nucleic acids

    International Nuclear Information System (INIS)

    The appearance of nucleic acids is the first event after the birth of membranes which made it possible to assure the perenniality of information. The complexity of these molecules has led some scientists to propose that they were not prebiotic but rather derived a more simple and achiral primitive ancestor. This hypothesis suggests that ribose possesses properties that allowed the formation of certain polysaccharides which evolved to RNA. The first step of the hypothesis is the selection and concentration of ribofuranose. This sugar has chelating properties and its alpha-ribofuranose is favoured in the chelating position. The density of the sugar with a heavy cation is greater than water and thus the complex can escape the UV radiation at the surface of the ocean. The particularity of ribose is to be able to form a homochiral regular array of these basic chelating structures with pyrophosphite. These arrays evolve towards the formation of polysaccharides (poly ribose phosphate) which have a very organized structure. These polysaccharides in turn evolve to RNA by binding of adenine and deoxyguanine which are HCN derivatives that can react with the polysaccharides. The primitive RNA is methylated and oxidized to form prebiotic RNA with adenosine, cytidine, 7methyl-guanosine and ribothymidine as nucleic bases. The pathway of biosynthesis of DNA form RNA will be studied. I suggest that the appearance of DNA results form the interaction between prebiotic double stranded RNA and proteins. DNA could be a product of RNA degradation by proteins. The catabolism of RNA to DNA requires a source of free radicals, protons and hydrides. RNA cannot produce free radicals, which are provided by the phenol group of the amino acid tyrosien. Protons are provided by the medium and hydrides are provided by 7-methyl-guanosine which can fix hydrides coming from hydrogen gas and donate them for the transformation of a riboside to a deoxyriboside. This pathway suggests that DNA appeared at

  15. Cocrystals of fenamic acids with nicotinamide

    OpenAIRE

    Fábián, László; Hamill, Noel; Eccles, Kevin S; Moynihan, Humphrey A; Maguire, Anita R.; McCausland, Linda; Lawrence, Simon E.

    2011-01-01

    Cocrystal formation between nicotinamide and five fenamic acid derivative drugs (flufenamic acid, niflumic tolfenamic acid, mefenamic acid and meclofenamic acid) was investigated using solution-based and solid-state preparation methods. It was anticipated that the well-known acid-aromatic nitrogen heterosynthon would provide a sufficient driving force for cocrystallization. The experiments yielded cocrystals with four of the five acids. Although the structures of these molecules are similar, ...

  16. Caffeic acid derivatives from Bupleurum chinense

    OpenAIRE

    Haghi, G.; Hatami, A.; Mehran, M.; Hosseini, H

    2014-01-01

    In this study, caffeic acid (CA) and its three derivatives including 3-caffeoylquinic acid (3-CQA, neochlorogenic acid), 4-caffeoylquinic acid (4-CQA, cryptochlorogenic acid), and 5-caffeoylquinic acid (5-CQA, chlorogenic acid) were identified in Bupleurum chinense aerial parts using reverse-phase high-performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detector, reference compounds and chemical reactions. Separation was performed on a C18 column using gradient elution wit...

  17. Acid Tests and Basic Fun.

    Science.gov (United States)

    McBride, John W.

    1995-01-01

    Explores acids and bases using different indicators, such as turmeric, purple grape juice, and lichens. Because some of these indicators are not as sensitive as cabbage juice or litmus paper, determining to which acids and bases each indicator is sensitive presents an enjoyable, problem-solving challenge for students. Presents directions for…

  18. Acid Rain: The Scientific Challenge.

    Science.gov (United States)

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  19. Acid Rain: An Educational Opportunity?

    Science.gov (United States)

    Marion, James I.

    1984-01-01

    Deals with how educators can handle the subject of acid rain; illustrates suggestions with experiences of grade nine students visiting Frost Valley Environmental Education Center (Oliverea, New York) to learn scientific concepts through observation of outdoor phenomena, including a stream; and discusses acid rain, pH levels, and pollution control…

  20. Acid Rain: What's the Forecast?

    Science.gov (United States)

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  1. Pantothenic acid (Vitamin B5)

    Science.gov (United States)

    ... suggests that taking pantothenic acid in combination with pantethine and thiamine does not improve muscular strength or ... Pantothenic Acid, D-Pantothenyl Alcohol, Dexpanthenol, Dexpanthénol, Dexpanthenolum, ... Pantothenate, Pantothénate, Pantothénate de Calcium, Pantothenol, ...

  2. Bile acids for viral hepatitis

    DEFF Research Database (Denmark)

    Chen, Weikeng; Liu, J; Gluud, C

    2003-01-01

    The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.......The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness....

  3. Folic Acid: Data and Statistics

    Science.gov (United States)

    ... acid fortification in the United States Recently, the American Journal of Preventive Medicine published a new study looking at the costs ... acid fortification and spina bifida in the U.S. American Journal of Preventive Medicine. January 2016 [epub ahead of print]. Related Links ...

  4. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    Directory of Open Access Journals (Sweden)

    B.Syama Sundar

    2014-06-01

    Full Text Available Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation with Mn (VII in case of DL-Mandelic acid. The following order of reactivity is observed: DL-Mandelic acid > Phenyl acetic acid. The high reactivity of DL-Mandelic acid over phenyl acetic acid may be due to different mechanisms operating with the two substrates and benzaldehyde is the final product in both the cases.

  5. N-(3-Nitrophenylmaleamic acid

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2010-07-01

    Full Text Available In the title compound, C10H8N2O5, the molecule is slightly distorted from planarity. The molecular structure is stabilized by two intramolecular hydrogen bonds. The first is a short O—H...O hydrogen bond (H...O distance = 1.57 Å within the maleamic acid unit and the second is a C—H...O hydrogen bond (H...O distance = 2.24 Å which connects the amide group with the benzene ring. The nitro group is twisted by 6.2 (2° out of the plane of the benzene ring. The crystal structure manifests a variety of hydrogen bonding. The packing is dominated by a strong intermolecular N—H...O interaction which links the molecules into chains running along the b axis. The chains within a plane are further assembled by three additional types of intermolecular C—H...O hydrogen bonds to form a sheet parallel to the (overline{1}01 plane.

  6. Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    ToddKlaenhammer

    2013-04-01

    Full Text Available Lactic acid bacteria (LAB are a diverse group of Gram-positive bacteria found in a vast array of environments including dairy products and the human gastrointestinal tract. In both niches, surface proteins play a crucial role in mediating interactions with the surrounding environment. The sortase enzyme is responsible for covalently coupling a subset of surface dependent proteins (SDPs to the cell wall of Gram-positive organisms through recognition of a conserved C-terminal LPXTG motif. Genomic sequencing of LAB and annotation has allowed for the identification of sortase and SDPs. Historically, sortase and SDPs were predominately investigated for their role in mediating pathogenesis. Identification of these proteins in LAB has shed light on their important roles in mediating nutrient acquisition through proteinase P as well as positive probiotic attributes including adhesion, mucus barrier function, and immune signaling. Furthermore, sortase expression signals in LAB have been exploited as a means to develop oral vaccines targeted to the gastrointestinal tract. In this review, we examine the collection of studies which evaluate sortase and SDPs in select species of dairy associated and health promoting LAB.

  7. Microfluidics in amino acid analysis.

    Science.gov (United States)

    Pumera, Martin

    2007-07-01

    Microfluidic devices have been widely used to derivatize, separate, and detect amino acids employing many different strategies. Virtually zero-dead volume interconnections and fast mass transfer in small volume microchannels enable dramatic increases in on-chip derivatization reaction speed, while only minute amounts of sample and reagent are needed. Due to short channel path, fast subsecond separations can be carried out. With sophisticated miniaturized detectors, the whole analytical process can be integrated on one platform. This article reviews developments of lab-on-chip technology in amino acid analysis, it shows important design features such as sample preconcentration, precolumn and postcolumn amino acid derivatization, and unlabeled and labeled amino acid detection with focus on advanced designs. The review also describes important biomedical and space exploration applications of amino acid analysis on microfluidic devices. PMID:17542043

  8. Molten fatty acid based microemulsions.

    Science.gov (United States)

    Noirjean, Cecile; Testard, Fabienne; Dejugnat, Christophe; Jestin, Jacques; Carriere, David

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound. PMID:27241163

  9. Hypocholesterolemic Effects of Eicosapentaenoic Acid and Docosahexaenoic Acid in Rats

    OpenAIRE

    KANAZAWA, Akio; TESHIMA, Shin-ichi; TOKIWA, Shigeru; IMATANAKA, Nobuya; カナザワ, アキオ; テシマ, シンイチ; トキワ, シゲル; イマタナカ, ノブヤ; 金沢, 昭夫; 手島, 新一; 常盤, 繁; 今田中, 伸哉

    1984-01-01

    Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) methylesters (ME) were preparedfrom a squid-liver oil and their hypocholesterolemic activities examined with rats. The supplementof 0.3% EPA-ME to the diet containing 1.0% cholesterol and 4.0% butter as lipids reduced a serum-cholesterollevel markedly, whereas DHA-ME gave almost no effect on the serum-cholesterol level.Both EPA-ME and DHA-ME reduced the liver-cholesterol level as effectively as linoleic acid did.The supplement of smal...

  10. Analytical application of aminohydroxamic acids

    International Nuclear Information System (INIS)

    Anthranilic hydroxamic acid was prepared by coupling of methylanthranilate (prepared by esterification of anthranilic acid with methyl alcohol using the fisher-speir method) with freshly prepared hydroxylamine. The lignad was characterized by the usual reaction of hydroxamic acid with acidic V(V) and Fe(III) solutions that gives blood-red colour in amyl alcohol and deep-violet colour in aqueous solution, respectively. The absorbance of Fe(III)-hydroxamic acids complexes increases with increase of pH. In this study, the effect of pH on the absorbance of Fe(III)-anthranilic hydroxamic acid was in accordance with this trend. The maximum absorbance was obtained at pH 5.0 at maximum wavelength of 482 nm. For Cu(II)-anthranilic hydroxamic acid complex, the use of acidic basic pH lead to precipitation of Cu(II)-ligand complex. But when using buffer pH (acetic acid/sodium acetate) a clear green colour of Cu(II)-ligand complex was obtained. The maximum wavelength of 390 nm. V(V)-anthranilic hydroxamic acid complex was extracted in acidic medium in amyl alcohol at pH 2.0 because in aqueous solution V(V)-anthranilic hydroxamic acid complex has not clear colour. It was observed the the maximum extraction in acidic medium decrease sharply with the increasing of pH value. The maximum wavelength for maximum absorbance was recorded at 472 nm. V(V) interfered with determination of Fe(III)) above concentration of 2 ppm, whereas Cu(II) interferes slightly with the determination of Fe(III) ions even at a high concentration of the Cu(II) ions. Both Cu(II) and Ni(II) do not interfere with the determination of V(V) ions even at high concentrations, Fe(III) ion produced slight interference, while Mo(VI) ions have a pronounced interference. Both V(V) and Fe(III) ions interfered markedly with the determination of Cu(II) ions, and made impractical under conditions. However, the calibration curves for the three metal ions produced a practical linear dynamic range.(Author)

  11. The Property and Application of Arachidonic Acid

    Institute of Scientific and Technical Information of China (English)

    王相勤; 姚建铭; 袁成凌; 王纪; 余增亮

    2002-01-01

    Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). This paper mainly introduced the structure, distribution, source, physiologic healthcare function and application of AA.

  12. The property and application of arachidonic acid

    International Nuclear Information System (INIS)

    Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). The author mainly introduced the structure, distribution, source, physiologic health care function and application of AA

  13. Diabetes and alpha lipoic acid

    Directory of Open Access Journals (Sweden)

    IssyLaher

    2011-11-01

    Full Text Available Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E and glutathione. It also boosts antioxidant defense system through Nrf2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that a lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.

  14. Boronic acid-based autoligation of nucleic acids

    DEFF Research Database (Denmark)

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.;

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible...

  15. Docosahexaenoic acid affects arachidonic acid uptake in megakaryocytes

    Energy Technology Data Exchange (ETDEWEB)

    Schick, P.K.; Webster, P.

    1987-05-01

    Dietary omega 3 fatty acids are thought to prevent atherosclerosis, possibly by modifying platelet (PT) function and arachidonic acid (20:4) metabolism. The study was designed to determine whether omega 3 fatty acids primarily affect 20:4 metabolism in megakaryocytes (MK), bone marrow precursors of PT, rather than in circulating PT. MK and PT were isolated from guinea pigs and incubated with (/sup 14/C)-20:4 (0.13uM). Docosahexaenoic acid (22:6) is a major omega 3 fatty acid in marine oils. The incubation of MK with 22:6 (0.1, 1.0 uM) resulted in the decrease of incorporation of (/sup 14/C)-20:4 into total MK phospholipids, 16% and 41% respectively. Alpha-linolenic acid (18:3), a major omega 3 fatty acid present in American diets, had no effect on 20:4 uptake in MK. 22:6 primarily affected the uptake of (/sup 14/C)-20:4 into phosphatidylethanolamine (PE) and phosphatidylserine (PS) in MK. In MK, 22:6 (0.1, 1.0 uM) caused a decrease of incorporation of (/sup 14/C)-20:4 into PE, 21% and 55% respectively; a decrease into PS, 16% and 48% respectively; but only a decrease of 4% and 18%, respectively, into phosphatidylcholine; and a decrease of 3% and 21% into phosphatidylinositol 22:6 (3.0 uM) had no effect on the uptake of AA into PT phospholipids. The study shows that 22:6 has a selective effect on AA uptake in MK and that the acylation or transacylation of PE and PS are primarily affected. 22:6 and other marine omega 3 fatty acids appear to primarily affect megakaryocytes which may result in the production of platelets with abnormal content and compartmentalization of AA.

  16. Amino Acids from a Comet

    Science.gov (United States)

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  17. PHARMACOLOGICAL ACTIVITIES OF PROTOCATECHUIC ACID.

    Science.gov (United States)

    Khan, Abida Kalsoom; Rashid, Rehana; Fatima, Nighat; Mahmood, Sadaf; Mir, Sadullah; Khan, Sara; Jabeen, Nyla; Murtaza, Ghulam

    2015-01-01

    Protocatechuic acid (3,4-dihydroxybenzoic acid, PCA) is a simple phenolic acid. It is found in a large variety of edible plants and possesses various pharmacological activities. This article aims to review the modern trends in phytochemical isolation and extraction of PCA from plants and other natural resources. Moreover, this article also encompasses pharmacological and biological activities of PCA. It is well known to have anti-inflammatory, antioxidant, anti-hyperglycemia, antibacterial, anticancer, anti-ageing, anti-athro- genic, anti-tumoral, anti-asthma, antiulcer, antispasmodic and neurological properties. PMID:26647619

  18. Treatment of acid mine wastewaters

    International Nuclear Information System (INIS)

    Acid mine drainage often results from the oxidation sulfide minerals to form sulfuric acid. As a consequence, high concentrations of metals in the both the suspended and dissolved state result from the low pH water. This paper discusses several of the more common treatment methods for acid mine drainage including the use of chemical precipitation agents, pH correction agents, filtration methods, and biodegradation methods. Advanced treatment technologies are also briefly described and include microfiltration, reverse osmosis, ion exchange, and electrodialysis

  19. Macromolecular organic acids in the Murchison meteorite

    OpenAIRE

    Watson, J.S.; Sephton, M.A.; Gilmour, I.

    2005-01-01

    This study has detected bound organic acids within the Murchison meteorite organic macromolecule. Benzoic acid was the most abundant compound; other abundant compounds include C1 and C2 benzoic acids. Their origin and significance will be discussed.

  20. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.;

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good......The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2...

  1. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  2. Treatment of hydrofluoric acid burns

    Energy Technology Data Exchange (ETDEWEB)

    Thiele, B.; Winter, U.J.; Mahrle, G.; Steigleder, G.K.

    1986-01-31

    A chemical-plant worker sustained hydrofluoric acid burns during cleaning procedures. Intra-arterial perfusion and intralesional injections of calcium gluconate solution prevented progression of the burns into deeper tissue layers.

  3. [Treatment of hydrofluoric acid burns].

    Science.gov (United States)

    Thiele, B; Winter, U J; Mahrle, G; Steigleder, G K

    1986-01-31

    A chemical-plant worker sustained hydrofluoric acid burns during cleaning procedures. Intra-arterial perfusion and intralesional injections of calcium gluconate solution prevented progression of the burns into deeper tissue layers. PMID:3943470

  4. Main: Amino acid Analysis [KOME

    Lifescience Database Archive (English)

    Full Text Available Amino acid Analysis UniProt search ... blastx result Result of blastx search ... against UniProt protein ... database kome_uniprot_search _blastx_result.zip kome_uniprot_search _blastx_resul ...

  5. Main: Amino acid Analysis [KOME

    Lifescience Database Archive (English)

    Full Text Available Amino acid Analysis SwissProt search ... result Result of blastx search ... against SwissProt protein da ... tabase kome_swissprot_search _result.zip kome_swissprot_search _result ...

  6. Biotechnological production of citric acid

    Directory of Open Access Journals (Sweden)

    Belén Max

    2010-12-01

    Full Text Available This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid.

  7. The Nucleic Acid Database (NDB)

    Czech Academy of Sciences Publication Activity Database

    Berman, H. M.; Feng, Z.; Schneider, Bohdan; Westbrook, J.; Zardecki, C.

    Vol. F. Dordrecht : Kluwer Academic, 2001 - (Rossmann, M.; Arnold, E.), s. 657-682 Institutional research plan: CEZ:AV0Z4040901 Keywords : database * nucleic acid Subject RIV: CF - Physical ; Theoretical Chemistry

  8. Structural features of lignohumic acids

    Czech Academy of Sciences Publication Activity Database

    Novák, František; Šestauberová, Martina; Hrabal, R.

    2015-01-01

    Roč. 1093, August (2015), s. 179-185. ISSN 0022-2860 Institutional support: RVO:60077344 Keywords : C-13 NMR * FTIR * humic acids * lignohumate * lignosulfonate * structure Subject RIV: DF - Soil Science Impact factor: 1.602, year: 2014

  9. Acid Rain - Acidification and Recovery

    Czech Academy of Sciences Publication Activity Database

    Norton, S. A.; Kopáček, Jiří; Fernandez, I. J.

    2. Elsevier, 2014 - (Holland., H.; Turekian, K.), s. 379-414 Institutional support: RVO:60077344 Keywords : acid ification * nitrogen * nutrients * sulfur * trace metals Subject RIV: DJ - Water Pollution ; Quality

  10. Uranium extraction from phosphoric acid

    International Nuclear Information System (INIS)

    A study has been carried out for the extraction of uranium from phosphoric acid produced in Algeria. First of all, the Algerian phosphoric acid produced in Algeria by SONATRACH has been characterised. This study helped us to synthesize a phosphoric acid that enabled us to pass from laboratory tests to pilot scale tests. We have then examined extraction and stripping parameters: diluent, DZEPHA/TOPO ratio and oxidising agent. The laboratory experiments enabled us to set the optimum condition for the choice of diluent, extractant concentration, ratio of the synergic mixture, oxidant concentration, redox potential. The equilibrium isotherms lead to the determination of the number of theoretical stages for the uranium extraction and stripping of uranium, then the extraction from phosphoric acid has been verified on a pilot scale (using a mixer-settler)

  11. Bile acid sequestrants for cholesterol

    Science.gov (United States)

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  12. MedlinePlus: Folic Acid

    Science.gov (United States)

    ... Tests Homocysteine Test (American Association for Clinical Chemistry) Vitamin B12 and Folate Test (American Association for Clinical Chemistry) Related Issues Folic Acid Supplements: Can They Slow Cognitive Decline? (Mayo Foundation for Medical Education and Research) Genetics ...

  13. Branched-Chain Amino Acids

    Czech Academy of Sciences Publication Activity Database

    Pátek, Miroslav

    Berlin : Springer-Verlag Berlin Heidelberg, 2007, s. 129-162. ISBN 978-3-540-48595-7 Institutional research plan: CEZ:AV0Z50200510 Keywords : amino acids * homologous reactions Subject RIV: EE - Microbiology, Virology

  14. Acid diffusion through polymer films

    Science.gov (United States)

    Zhang, P. Linda; Eckert, Andrew R.; Willson, C. Grant; Webber, Stephen E.; Byers, Jeffrey D.

    1997-07-01

    In order to perform 0.2 micrometer processes, one needs to study the diffusion of photoacid generators within the photoresist system, since diffusion during post exposure bake time has an influence on the critical dimension (CD). We have developed a new method to study the diffusion of photoacid generators within a polymer film. This new method is based on monitoring the change of the fluorescence intensity of a pH- sensitive fluorescent dye caused by the reaction with photoacid. A simplified version of this experiment has been conducted by introducing acid vapor to quench the fluorescence intensity of this pH sensor. A thin polymer film is spin cast onto the sensor to create a barrier to the acid diffusion process. During the acid diffusion process, the fluorescence intensity of this pH sensor is measured in situ, using excitation and emission wavelengths at 466 nm and 516 nm, respectively. Fluoresceinamine, the pH sensitive fluorescent dye, is covalently bonded onto the treated quartz substrate to form a single dye layer. Poly(hydroxystyrene) (Mn equals 13k, Tg equals 180 degrees Celsius) in PGMEA (5% - 18% by weight) is spin cast onto this quartz substrate to form films with varying thickness. The soft bake time is 60 seconds at 90 degrees Celsius and a typical film has a thickness of 1.4 micrometers. Trifluoroacetic acid is introduced into a small chamber while the fluorescence from this quartz window is observed. Our study focuses on finding the diffusion constant of the vaporized acid (trifluoroacetic acid) in the poly(hydroxystyrene) polymer film. By applying the Fick's second law, (It - Io)/(I(infinity ) - Io) equals erfc [L/(Dt)1/2] is obtained. The change of fluorescence intensity with respect to the diffusion time is monitored. The above equation is used for the data analysis, where L represents the film thickness and t represents the average time for the acid to diffuse through the film. The diffusion constant is calculated to be at the order of 10

  15. Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography

    NARCIS (Netherlands)

    Qin, X.P.; Liu, F.; Wang, G.C.; Weng, L.P.

    2012-01-01

    An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used

  16. Nucleic Acid Aptamers Against Proteases

    DEFF Research Database (Denmark)

    Dupont, D M; Andersen, L M; Bøtkjær, Kenneth Alrø;

    2011-01-01

    Proteases are potential or realized therapeutic targets in a wide variety of pathological conditions. Moreover, proteases are classical subjects for studies of enzymatic and regulatory mechanisms. We here review the literature on nucleic acid aptamers selected with proteases as targets. Designing...... strategies and of new principles for regulating the activity of the inhibitory action of aptamers of general interest to researchers working with nucleic acid aptamers...

  17. Piperidine nucleoside phosphonic acid derivatives

    Czech Academy of Sciences Publication Activity Database

    Kovačková, Soňa; Dračínský, Martin; Rejman, Dominik

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i., 2011 - (Hocek, M.), s. 372-374 ISBN 978-80-86241-37-1. - (Collection Symposium Series. 12). [Chemistry of Nucleic Acid Components /15./. Český Krumlov (CZ), 05.06.2011-10.06.2011] Institutional research plan: CEZ:AV0Z40550506 Keywords : piperidine nucleoside * nucleoside phosphonic acids * nucleoside diphosphate analogs * nucleotide analogs Subject RIV: CC - Organic Chemistry

  18. Aqueous Photochemistry of Glyoxylic Acid.

    Science.gov (United States)

    Eugene, Alexis J; Xia, Sha-Sha; Guzman, Marcelo I

    2016-06-01

    Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging of photoproducts is studied by UV-visible and fluorescence spectroscopies to reveal that the optical properties are altered by the glyoxal produced. The optical properties display periodicity in the time domain of the UV-visible spectrum of chromophores with absorption enhancement (thermochromism) or loss (photobleaching) during nighttime and daytime cycles, respectively. During irradiation, excited state glyoxylic acid can undergo α-cleavage or participate in hydrogen abstractions. The use of (13)C nuclear magnetic resonance spectroscopy (NMR) analysis shows that glyoxal is an important intermediate produced during direct photolysis. Glyoxal quickly reaches a quasi-steady state as confirmed by UHPLC-MS analysis of its corresponding (E) and (Z) 2,4-dinitrophenylhydrazones. The homolytic cleavage of glyoxylic acid is proposed as a fundamental step for the production of glyoxal. Both carbon oxides, CO2(g) and CO(g) evolving to the gas-phase, are quantified by FTIR spectroscopy. Finally, formic acid, oxalic acid, and tartaric acid photoproducts are identified by ion chromatography (IC) with conductivity and electrospray (ESI) mass spectrometry (MS) detection and (1)H NMR spectroscopy. A reaction mechanism is proposed based on all experimental observations. PMID:27192089

  19. Deoxyribonucleic acid methylation in mycobacteria.

    OpenAIRE

    R. Srivastava; Gopinathan, K P; Ramakrishnan, T.

    1981-01-01

    Deoxyribonucleic acid modification in six strains of mycobacteria was investigated. The presence of 5-methylcytosine in the virulent strain Mycobacterium tuberculosis H37Rv and its absence in the avirulent strain M. tuberculosis H37Ra and other saprophytic, fast-growing mycobacteria appear to be the salient features. However, deoxyribonucleic acid from M. smegmatis SN2 lysogenized with the temperature phage I3 showed the presence of 5-methylcytosine. All of the strains had N6-methyladenine.

  20. Bacillus subtilis Deoxyribonucleic Acid Gyrase

    OpenAIRE

    Sugino, A; Bott, K F

    1980-01-01

    Bacillus subtilis 168 was shown to contain a deoxyribonucleic acid (DNA) gyrase activity which closely resembled those of the enzymes isolated from Escherichia coli and Micrococcus luteus in its enzymatic requirements, substrate specificity, and sensitivity to several antibiotics. The enzyme was purified from the wild type and nalidixic acid-resistant and novobiocin-resistant mutants of B. subtilis and was functionally characterized in vitro. The genetic loci nalA and novA but not novB were s...

  1. Regulatory aspects of acid rain

    International Nuclear Information System (INIS)

    On November 15, 1990, President Bush signed the 1990 Clean Air Act (CAA) amendments into law. This was a historical document which marked the beginning of a concerted effort to address a most pressing environmental problem of this century, namely acid rain. Acid rain is the generic term used to describe the phenomenon by which sulfur dioxides (SO2) and nitrogen oxides (NOx) react in the atmosphere in the presence of sunlight to form acids which are scrubbed out of the atmosphere during a precipitation event. When this happens the pH of the precipitation falls considerably below 7.0. Years of research have shown that acid rain has a very detrimental effect on soils, vegetation, and marine life. The large amounts of SO2 and NOx being released by coal-fired utility boilers have largely incriminated utility companies as being the culprits. Most of the research work has been in Canada because the direction of the jet stream across the US is such that the emissions from the midwestern and northeastern US are carried into southeastern Canada. An interim report from the National Acid Precipitation Assessment Program (NAPAP) has assessed that power plants contribute up to 65% of the national annual emissions of SO2, and up to 29% of the NOx emissions. It is for these reasons that acid rain control has been given such a priority by legislators

  2. Specific bile acid radioimmunoassays for separate determinations of unconjugated cholic acid, conjugated cholic acid and conjugated deoxycholic acid in serum and their clinical application

    International Nuclear Information System (INIS)

    Specific radioimmunoassays have been developed for separate determinations of unconjugated cholic acid, conjugated cholic acid and conjugated deoxycholic acid in serum. Before carrying out the radioimmunoassay, the serum bile acids were extracted with Amberlite XAD-2. Unconjugated cholic acid was separated from glyco- and taurocholic acids by thin-layer chromatography. At 50% displacement of bound labelled glyco-[3H]-cholic acid, using antiserum obtained after immunization with cholic acid-bovine serum albumin-conjugate, the cross-reactivity of taurocholic acid was 100%, cholic acid 80%, glycochenodeoxycholic acid 10%, chenodeoxycholic acid 7%, conjugated deoxycholic acid 3% and conjugated lithocholic acid 3H]-cholic acid in the solid-phase radioimmunoassay was linear on a logit-log plot from 5 to 200 pmol of unlabelled cholic acid. The coefficient of variation between samples was 5%. The clinical application of these bile acid radioimmunoassays is shown by an ''oral cholate tolerance test'', which is a sensitive indicator of liver function, and by an ''oral cholylglycine tolerance test'' which is a useful test for bile acid absorption. (author)

  3. Performance of Different Acids on Sandstone Formations

    Directory of Open Access Journals (Sweden)

    M. A. Zaman

    2013-12-01

    Full Text Available Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Some of these reactions may result in formation damage. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. It is a mixture of hydrofluoric (HF and hydrochloric (HCl acids designed to dissolve clays and siliceous fines accumulated in the near-wellbore region. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50% to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid – Hydrofluoric with Concentration (3% HF – 12% HCl. This paper presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results calculated are porosity, permeability, and FESEM Analysis and Strength tests. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  4. An Efficient Procedure for Esterification of Aryloxyacetic Acid and Arylthioacetic Acid Catalyzed by Silica Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    LI,Hong-Ya; LI,Ji-Tai; LI,Hui-Zhang

    2004-01-01

    @@ Aryloxyacetate and arylthioacetate are wildly used in herbicides, plant regulator and insecticides. Recently, Wille et al. have reported that methyl aryloxyacetate is an efficient agent to prevent and treat allergic contact dermatitis.[1] The most popular synthesis is by heating sodium phenoxide (mercaptide) with ethyl chloroacetate in DMF,[2] or by the esterification of acid with alcohol using concentrated H2SO4 as catalyst.[3] In this paper, synthesis of aryloxyacetate and aryl thioacetate from aryloxyacetic acid and arylthioacetic acid respectively in ether catalyzed by silica sulfuric acid in 83%~94% yields is described. The catalyst is reused for 3 times without significant loss of activity (Entry 4). Compared with common procedures, the present procedure possesses the advantages of the operational simplicity, short reaction time,less-corrosion, high yield and reusable catalyst.

  5. Maleic acid and succinic acid in fermented alcoholic beverages are the stimulants of gastric acid secretion

    OpenAIRE

    Teyssen, Stephan; González-Calero, Gloria; Schimiczek, Michael; Singer, Manfred V.

    1999-01-01

    Alcoholic beverages produced by fermentation (e.g., beer and wine) are powerful stimulants of gastric acid output and gastrin release in humans. The aim of this study was to separate and specify the gastric acid stimulatory ingredients in alcoholic beverages produced by fermentation. Yeast-fermented glucose was used as a simple model of fermented alcoholic beverages; it was stepwise separated by different methods of liquid chromatography, and each separated solution was tested in human volunt...

  6. Thermal Stability of Acetohydroxamic Acid/Nitric Acid Solutions

    International Nuclear Information System (INIS)

    The transmutation of transuranic actinides and long-lived fission products in spent commercial nuclear reactor fuel has been proposed as one element of the Advanced Accelerator Applications Program. Preparation of targets for irradiation in an accelerator-driven subcritical reactor would involve dissolution of the fuel and separation of uranium, technetium, and iodine from the transuranic actinides and other fission products. The UREX solvent extraction process is being developed to reject and isolate the transuranic actinides in the acid waste stream by scrubbing with acetohydroxamic acid (AHA). To ensure that a runaway reaction will not occur between nitric acid and AHA, an analogue of hydroxyl amine, thermal stability tests were performed to identify if any processing conditions could lead to a runaway reaction

  7. Structural features of lignohumic acids

    Science.gov (United States)

    Novák, František; Šestauberová, Martina; Hrabal, Richard

    2015-08-01

    The composition and structure of humic acids isolated from lignohumate, which is produced by hydrolytic-oxidative conversion of technical lignosulfonates, were characterized by chemical and spectral methods (UV/VIS, FTIR, and 13C NMR spectroscopy). As comparative samples, humic acids (HA) were isolated also from lignite and organic horizon of mountain spruce forest soil. When compared with other HA studied, the lignohumate humic acids (LHHA) contained relatively few carboxyl groups, whose role is partly fulfilled by sulfonic acid groups. Distinctive 13C NMR signal of methoxyl group carbons, typical for lignin and related humic substances, was found at the shift of 55.9 ppm. Other alkoxy carbons were present in limited quantity, like the aliphatic carbons. Due to the low content of these carbon types, the LHHA has high aromaticity of 60.6%. Comparison with the natural HA has shown that lignohumate obtained by thermal processing of technical lignosulfonate can be regarded as an industrially produced analog of natural humic substances. Based on the chemical and spectral data evaluation, structural features of lignohumate humic acids were clarified and their hypothetical chemical structure proposed, which described typical "average" properties of the isolated fraction.

  8. Branched-Chain Amino Acids

    Directory of Open Access Journals (Sweden)

    Matteo Ghiringhelli

    2015-07-01

    Full Text Available Our study is focused on evaluation and use of the most effective and correct nutrients. In particular, our attention is directed to the role of certain amino acids in cachectic patients.During parenteral nutrition in humans, physician already associates in the PN-bags different formulations including amino acids, lipids and glucose solutions or essential amino acids solution alone or exclusively branched-chain amino acids (BCAA. Studies investigated the effects of dietary BCAA ingestion on different diseases and conditions such as obesity and metabolic disorders, liver disease, muscle atrophy, cancer, impaired immunity or injuries (surgery, trauma, burns, and sepsis. BCAAs have been shown to affect gene expression, protein metabolism, apoptosis and regeneration of hepatocytes, and insulin resistance. They have also been shown to inhibit the proliferation of liver cancer cells in vitro, and are essential for lymphocyte proliferation and dendritic cell maturation. Oral or parenteral administration of these three amino acids will allow us to evaluate the real efficacy of these compounds during a therapy to treat malnutrition in subjects unable to feed themselves.

  9. Fixation Status of Acid Soils

    International Nuclear Information System (INIS)

    Six acid soil series from different benchmark sites; Rangsit soil (Sulfic Tropaquepts) (two acid sulfate soils), Pakchong soil (Oxic Paleustults) Korat soil (Oxic Paleustults), Warin soil (Oxic Paleustults), Mae Taeng soil (Typic paleustults) and Boundary grey soil and two Thai phosphate rocks (P R) (Lampun P R and Ratchabuie P R) had been characterized in the laboratory by isotope techniques (E, value Part 1). Triple superphosphate (TSP) was used as a standard fertilizer. R P and TSP with 50 mg P Kg-1 soil were incubated for 30 days to examine the fixing capacity of the acid soils. The results showed that Rangsit Soil which is acid sulfate had high fixing capacity. Pakchong soil retained higher P fixation ability than Korat and Warin soil series. The highest fixation capacity among 7 acid soils were Grey Soil and Mae Taeng soil series. The solubility of TSP was decreased when incorporated with soil after incubation for 30 days. P R from Ratchaburi showed higher effectiveness than Lamphun P R

  10. Conjugated Linoleic Acid Accumulation via 10-Hydroxy-12-Octadecaenoic Acid during Microaerobic Transformation of Linoleic Acid by Lactobacillus acidophilus

    OpenAIRE

    Ogawa, Jun; Matsumura, Kenji; Kishino, Shigenobu; Omura, Yoriko; Shimizu, Sakayu

    2001-01-01

    Specific isomers of conjugated linoleic acid (CLA), a fatty acid with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from linoleic acid by washed cells of Lactobacillus acidophilus AKU 1137 under microaerobic conditions, and the metabolic pathway of CLA production from linoleic acid is explained for the first time. The CLA isomers produced were identified as cis-9, trans-11- or trans-9, cis-11-octadecadienoic acid and trans-9, trans-11-octadecadie...

  11. New nalidixic acid resistance mutations related to deoxyribonucleic acid gyrase activity.

    OpenAIRE

    Yamagishi, J; Furutani, Y; Inoue, S.; Ohue, T; Nakamura, S; Shimizu, M

    1981-01-01

    In Escherichia coli K-12 mutants which had a new nalidixic acid resistance mutation at about 82 min on the chromosome map, cell growth was resistant to or hypersusceptible to nalidixic acid, oxolinic acid, piromidic acid, pipemidic acid, and novobiocin. Deoxyribonucleic acid gyrase activity as tested by supercoiling of lambda phage deoxyribonucleic acid inside the mutants was similarly resistant or hypersusceptible to the compounds. The drug concentrations required for gyrase inhibition were ...

  12. 49 CFR 173.158 - Nitric acid.

    Science.gov (United States)

    2010-10-01

    ... 2.5 L (0.66 gallon) capacity each. (f) Nitric acid of 70 percent or less concentration, when offered... 49 Transportation 2 2010-10-01 2010-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any...

  13. Veal fatty acid composition of different breeds

    OpenAIRE

    Ivica Kos; Jelena Ramljak; Ante Ivanković; Miljenko Konjačić; Nikolina Kelava

    2010-01-01

    Veal fatty acid composition in M. Longissimus thoracis was investigated in different calf breeds (Simmental, Holstein, Simmental x Holstein). Calves were reared on the same farm under identical feeding and handling conditions. Simmental calves had higher polyunsaturated fatty acid (PUFA) but lower saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) values than Holstein and crossbreed calves (P

  14. How does Listeria monocytogenes combat acid conditions?

    Science.gov (United States)

    Listeria monocytogenes, a major foodborne pathogen, possesses a number of mechanisms which enable it to combat the challenges posed by acidic environments such as acidic foods and the acidity in the gastrointestinal tract. These mechanisms include the acid tolerance response, a two-component regula...

  15. 21 CFR 184.1061 - Lactic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactic acid. 184.1061 Section 184.1061 Food and... Substances Affirmed as GRAS § 184.1061 Lactic acid. (a) Lactic acid (C3H6O3, CAS Reg. Nos.: dl mixture, 598... hydrogen cyanide and subsequent hydrolysis to lactic acid. (b) The ingredient meets the specifications...

  16. Influence of acidified acidity to uranium bioleaching

    International Nuclear Information System (INIS)

    The relationship between the acidified acidity and the acid consumption and uranium leaching rate in the process of uranium bioleaching is investigated. Results indicate that higher uranium leaching rate is obtained when the relatively high acidity was applied at beginning. For different minerals, although the original acidity should be different, lower original acidity was not better for shortening leaching period and improving uranium leaching rate. It confirms 30-40 g/L sulfuric acid as the original acidity was more suitable and more than 30 g/ L should be applied if the mineral particle sizes were larger. (authors)

  17. Uranium extraction in phosphoric acid

    International Nuclear Information System (INIS)

    Uranium is recovered from the phosphoric liquor produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). The proposed process consists of two extraction cycles. In the first one, uranium is reduced to its tetravalent state and then extracted by dioctylpyrophosphoric acid, diluted in Kerosene. Re-extraction is carried out with concentrated phosphoric acid containing an oxidising agent to convert uranium to its hexavalent state. This extract (from the first cycle) is submitted to the second cycle where uranium is extracted with DEPA-TOPO (di-2-hexylphosphoric acid/tri-n-octyl phosphine oxide) in Kerosene. The extract is then washed and uranium is backextracted and precipitated as commercial concentrate. The organic phase is recovered. Results from discontinuous tests were satisfactory, enabling to establish operational conditions for the performance of a continuous test in a micro-pilot plant. (Author)

  18. Nitric Acid Poisoning: Case Report

    International Nuclear Information System (INIS)

    Nitric acid (HNO3) is a corrosive fluid that, when in contact with reducing agents, generates nitrogen oxides that are responsible for inhalation poisoning. We present two cases of poisoning from nitric acid gas inhalation resulting from occupational exposure. Imaging findings were similar in both cases, consistent with adult respiratory distress syndrome (ARDS): bilaterally diffuse alveolar opacities on the chest X-ray and a cobblestone pattern on computed tomography (CT).one of the patients died while the other evolved satisfactorily after treatment with n-acetyl cysteine and mechanical ventilation. The diagnosis of nitric acid poisoning was made on the basis of the history of exposure and the way in which the radiological findings evolved.

  19. Toxicologic Study of Monochloroacetic Acid

    Institute of Scientific and Technical Information of China (English)

    Lu Bo; Zhan Ping

    2006-01-01

    @@ Monochloroacetic Acid (MCA) is a chlorinated analog of acetic acids. MCA and its sodium salt (SMCA) are widely used as a chemical intermediate (primarily in the manufacture of chlorophenoxy herbicides,carboxymethylcelluose, glycine and indigoid dyes).Moreover, MCA has been found as a common by-product of the chlorination of drinking water. Chloroacetates are ubiquitous in the environment, and MCA is the most abundant among chloroacetates. A background level of 0.1 - 1μg/L is expected to occur in precipitation[1]. Total world wide annual production of MCA reported was about 400 000 tons[2]. Many studies have showed that MCA not only caused acute or chronic damage to the skin , liver, kidney, heart, brain and other organs, but also caused acute death systemically under high concentration[2,3]. So this article will discuss the toxic effect of Monochloroacetic Acid in Toxicology.

  20. Tumor Acidity as Evolutionary Spite

    International Nuclear Information System (INIS)

    Most cancer cells shift their metabolic pathway from a metabolism reflecting the Pasteur-effect into one reflecting the Warburg-effect. This shift creates an acidic microenvironment around the tumor and becomes the driving force for a positive carcinogenesis feedback loop. As a consequence of tumor acidity, the tumor microenvironment encourages a selection of certain cell phenotypes that are able to survive in this caustic environment to the detriment of other cell types. This selection can be described by a process which can be modeled upon spite: the tumor cells reduce their own fitness by making an acidic environment, but this reduces the fitness of their competitors to an even greater extent. Moreover, the environment is an important dimension that further drives this spite process. Thus, diminishing the selective environment most probably interferes with the spite process. Such interference has been recently utilized in cancer treatment

  1. The acid rain differential game

    International Nuclear Information System (INIS)

    Countries emit sulphur which is partly transferred to other countries. Depositions above critical loads ultimately destroy the soil. Countries face a trade-off between the costs of emission reductions and the damage to the soil due to the depletion of the acid buffers. Because of the transboundary externalities the outcome will depend on whether the countries cooperate or not. This paper presents the cooperative outcome and the open-loop and Markov-perfect Nash equilibria of the acid rain differential game. It will be shown that the depositions always converge to the critical loads but the steady-state levels of the buffer stocks differ. The theory is used to analyse the acid rain differential game for sulphur between Great Britain and Ireland. Finally, some results are given for the whole of Europe. 20 refs

  2. Fusidic acid betamethasone lipid cream.

    Science.gov (United States)

    Girolomoni, G; Mattina, R; Manfredini, S; Vertuani, S; Fabrizi, G

    2016-05-01

    Bacterial infections of the skin and soft tissues are frequent disorders. They can be primitive infections (e.g. impetigo, folliculitis) or secondary infections complicating other diseases, particularly atopic dermatitis. The most common aetiologic agent is Staphylococcus aureus. Topical antibiotic therapy may be sufficient in many instances to control these infections. Fusidic acid is an antibiotic used topically on the skin which is very active against S. aureus, including methicillin-resistant strains, and other Gram-positive bacteria. Resistance rates to fusidic acid are stably low. A fusidic acid and betamethasone formulation in a lipid-enriched cream (lipid cream) has been recently developed in order to provide effective antibacterial and anti-inflammatory activities in conjunction with a powerful emollient and moisturising effect. This preparation may be especially useful in patients with atopic-infected eczema. PMID:27121235

  3. Solid–liquid equilibria measurements for binary systems comprising (butyric acid + propionic or pentanoic acid) and (heptanoic acid + propionic or butyric or pentanoic or hexanoic acid)

    International Nuclear Information System (INIS)

    Highlights: ► Binary SLE measurement for butyric acid + {propionic or pentanoic acid}. ► Binary SLE measurements for heptanoic acid + {propionic or butyric or pentanoic or hexanoic acid}. ► Measurements undertaken using a synthetic method using two new apparati. - Abstract: Solid–liquid equilibria (SLE) measurements have been undertaken for carboxylic acid systems comprising (butyric acid + propionic or pentanoic acid) and (heptanoic acid + propionic or butyric or pentanoic or hexanoic acid) via a synthetic method using two complementary pieces of equipment. The measurements have been obtained at atmospheric pressure and over the temperature range of (225.6 to 270.7) K. All the acid mixtures exhibit a eutectic point in their respective phase diagrams, which have been determined experimentally. The estimated maximum uncertainties in the reported temperatures and compositions are ±1 K and ±0.0006 mole fraction, respectively. The experimental data have been satisfactorily correlated with the Wilson and NRTL activity coefficient models.

  4. Hydroxamic acids in asymmetric synthesis.

    Science.gov (United States)

    Li, Zhi; Yamamoto, Hisashi

    2013-02-19

    Metal-catalyzed stereoselective reactions are a central theme in organic chemistry research. In these reactions, the stereoselection is achieved predominantly by introducing chiral ligands at the metal catalyst's center. For decades, researchers have sought better chiral ligands for asymmetric catalysis and have made great progress. Nevertheless, to achieve optimal stereoselectivity and to catalyze new reactions, new chiral ligands are needed. Because of their high metal affinity, hydroxamic acids play major roles across a broad spectrum of fields from biochemistry to metal extraction. Dr. K. Barry Sharpless first revealed their potential as chiral ligands for asymmetric synthesis in 1977: He published the chiral vanadium-hydroxamic-acid-catalyzed, enantioselective epoxidation of allylic alcohols before his discovery of Sharpless asymmetric epoxidation, which uses the titanium-tartrate complex as the chiral reagent. However, researchers have reported few highly enantioselective reactions using metal-hydroxamic acid as catalysts since then. This Account summarizes our research on metal-catalyzed asymmetric epoxidation using hydroxamic acids as chiral ligands. We designed and synthesized a series of new hydroxamic acids, most notably the C2-symmetric bis-hydroxamic acid (BHA) family. V-BHA-catalyzed epoxidation of allylic and homoallylic alcohols achieved higher activity and stereoselectivity than Sharpless asymmetric epoxidation in many cases. Changing the metal species led to a series of unprecedented asymmetric epoxidation reactions, such as (i) single olefins and sulfides with Mo-BHA, (ii) homoallylic and bishomoallylic alcohols with Zr- and Hf-BHA, and (iii) N-alkenyl sulfonamides and N-sulfonyl imines with Hf-BHA. These reactions produce uniquely functionalized chiral epoxides with good yields and enantioselectivities. PMID:23157425

  5. Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

    DEFF Research Database (Denmark)

    Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben;

    2010-01-01

    Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic materials. In the present study, hyaluronic...

  6. Solubilities of Isophthalic Acid in Acetic Acid + Water Solvent Mixtures

    Institute of Scientific and Technical Information of China (English)

    CHENG Youwei; HUO Lei; LI Xi

    2013-01-01

    The solubilities of isophthalic acid (1) in binary acetic acid (2) + water (3) solvent mixtures were determined in a pressurized vessel.The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x2 =0 to 1.A new method to measure the solubility was developed,which solved the problem of sampling at high temperature.The experimental results indicated that within the temperature range studied,the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature.The experimental solubilities were correlated by the Buchowski equation,and the calculate results showed good agreement with the experimental solubilities.Furthermore,the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility,which may be attributed to the intermolecular association between the solute and the solvent mixture.The maximum solubility effect was well modeled by the modified Wilson equation.

  7. Enrichment of decanoic acid in cuphea fatty acids via distillation

    Science.gov (United States)

    The introduction of a new crop often requires the development of new products and purification techniques of either the oil or fatty acids. Most new crops enter the cosmetic market first due to their high rates of returns. However, the cosmetic market often demands high purity and colorless materi...

  8. Acidity of carboxylic acids: a rebuttal and redefinition

    Czech Academy of Sciences Publication Activity Database

    Exner, Otto; Čársky, Petr

    2001-01-01

    Roč. 123, č. 39 (2001), s. 9564-9570. ISSN 0002-7863 R&D Projects: GA ČR GA203/99/1454 Institutional research plan: CEZ:AV0Z4055905 Keywords : carboxylic acids Subject RIV: CC - Organic Chemistry Impact factor: 6.079, year: 2001

  9. Acid Sulfate Alteration on Mars

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.

    2016-01-01

    A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

  10. Acid-functionalized polyolefin materials and their use in acid-promoted chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Oyola, Yatsandra; Tian, Chengcheng; Bauer, John Christopher; Dai, Sheng

    2016-06-07

    An acid-functionalized polyolefin material that can be used as an acid catalyst in a wide range of acid-promoted chemical reactions, wherein the acid-functionalized polyolefin material includes a polyolefin backbone on which acid groups are appended. Also described is a method for the preparation of the acid catalyst in which a precursor polyolefin is subjected to ionizing radiation (e.g., electron beam irradiation) of sufficient power and the irradiated precursor polyolefin reacted with at least one vinyl monomer having an acid group thereon. Further described is a method for conducting an acid-promoted chemical reaction, wherein an acid-reactive organic precursor is contacted in liquid form with a solid heterogeneous acid catalyst comprising a polyolefin backbone of at least 1 micron in one dimension and having carboxylic acid groups and either sulfonic acid or phosphoric acid groups appended thereto.

  11. Risk and Health Effect of Boric Acid

    Directory of Open Access Journals (Sweden)

    Ang S. See

    2010-01-01

    Full Text Available Problem statement: Boric acid is a pesticide usually used to kill mites, fungi, plants and insect including fleas, termites, cockroaches and wood decay fungi. Besides, it was also used in many fields such as food preservative, in newborn baby’s nurseries and antiseptic. Many reports indicated that boric acid poisoning occurred due to the misuse of household product and illegal use of boric acid in food product. In this study, the concern issue was the usage of boric acid that may lead to boric acid poisoning. Approach: This review had shown some information for boric acid such as its usage, the existent method for detection of boric acid in food. Besides, this review also discussed about the toxicology and pharmacokinetic of boric acid and the health impact of boric acid on human and animal. Result: Previous studies showed that food products such as yellow noodles contain boric acid. The boric acid level in most foods was different among the factory and the production period. It is due to the lack of standard measurement during the processing. Conclusion: Since boric acid was harmful to human health and may cause poisoning, hence, the control and the awareness of the usage of boric acid especially in food should be increased. There are numerous methods available for quantification of boric acid such as mannitol titration technique, colorimetric method. Accordingly, the analysis of boric acid is essential.

  12. Citric Acid Passivation of Stainless Steel

    Science.gov (United States)

    Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

    2009-01-01

    Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

  13. [Alpha-linolenic acid and cardiovascular diseases].

    Science.gov (United States)

    Ristić-Medić, Danijela; Ristić, Gordana; Tepsić, Vesna

    2003-01-01

    IMPORTANCE AND METABOLISM OF ALPHA-LINOLENIC ACID: Alpha-linolenic acid is an essential fatty acid which cannot be produced in the body and must be taken by food. Both in animals and humans, alpha-linolenic acid is desaturated and elongated into eicosapentaenoic and docosahexaenoic acid. It is also incorporated into plasma and tissue lipids and its conversion is affected by levels of linoleic acid. POTENTIAL ROLE IN PATHOGENESIS OF CARDIOVASCULAR DISEASES: Diet enriched in n-3 fatty acids, especially alpha-linolenic acid, reduces the incidence of cardiac death. Studies have shown that alpha linolenic acid prevents ventricular fibrillation which is the main cause of cardiac death. Studies in rats suggest that alpha-linolenic acid may be more effective in preventing ventricular fibrillations than eicosapentaenoic and docosahexaenoic acid. Furthermore, alpha-linolenic acid is the main fatty acid decreasing platalet aggregation which is an important step in thrombosis i.e. non-fatal myocardial infarction and stroke. DIETARY SOURCES AND NUTRITION RECOMMENDATIONS: Dietary sources include flaxseed and flaxseed oil, canola oil, soybean and soybean oil, pumpkin seed and pumpkin oil, walnuts and walnut oil. Strong evidence supports beneficial effects of alpha-linolenic acid and its dietary sources should be incorporated into balanced diet for prevention of cardiovascular diseases. The recommended daily intake is 2 g with a ratio of 5/1 for linoleic/alpha-linolenic acid. PMID:15510909

  14. Acid Rain: What It Is -- How You Can Help!

    Science.gov (United States)

    National Wildlife Federation, Washington, DC.

    This publication discusses the nature and consequences of acid precipitation (commonly called acid rain). Topic areas include: (1) the chemical nature of acid rain; (2) sources of acid rain; (3) geographic areas where acid rain is a problem; (4) effects of acid rain on lakes; (5) effect of acid rain on vegetation; (6) possible effects of acid rain…

  15. Peptide Nucleic Acids Complexes of Two Peptide Nucleic Acid Strands and One

    DEFF Research Database (Denmark)

    1999-01-01

    Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest...

  16. 40 CFR 721.2086 - Coco acid triamine condensate, polycarboxylic acid salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Coco acid triamine condensate... Specific Chemical Substances § 721.2086 Coco acid triamine condensate, polycarboxylic acid salts. (a... coco acid triamine condensate, poly-car-box-ylic acid salts. (PMN P-92-446) is subject to...

  17. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  18. Acid evaporation property in chemically amplified resists

    Science.gov (United States)

    Hashimoto, Shuichi; Itani, Toshiro; Yoshino, Hiroshi; Yamana, Mitsuharu; Samoto, Norihiko; Kasama, Kunihiko

    1997-07-01

    The lithographic performance of a chemically amplified resist system very much depends on the photo-generated acid structure. In a previous paper, we reported the molecular structure dependence of two typical photo-generated acids (aromatic sulfonic acid and alkyl sulfonic acid) from the viewpoints of lithographic performance and acid characteristics such as acid generation efficiency, acid diffusion behavior and acid evaporation property. In this paper, we evaluate the effect of the remaining solvent in a resist film on the acid evaporation property. Four types of two-component chemically amplified positive KrF resists were prepared consisting of tert-butoxycarbonyl (t-BOC) protected polyhydroxystyrene and sulfonic acid derivative photo-acid generator (PAG). Here, a different combination of two types of PAGs [2,4-dimethylbenzenesulfonic acid (aromatic sulfonic acid) derivative PAG and cyclohexanesulfonic acid (alkyl sulfonic acid) derivative PAG] and two types of solvents (propylene glycol monomethyl ether acetate; PGMEA and ethyl lactate; EL) were evaluated. The aromatic sulfonic acid was able to evaporate easily during post exposure bake (PEB) treatment, but the alkyl sulfonic acid was not. The higher evaporation property of aromatic sulfonic acid might be due to the higher vapor pressure and the longer acid diffusion length. Furthermore, the amount of aromatic sulfonic acid in the PGMEA resist was reduced by more than that in the EL resist. The amount of acid loss also became smaller at a higher prebake temperature. The concentration of the remaining solvent in the resist film decreased with the increasing prebake temperature. We think that the acid evaporation property was affected by the remaining solvent in the resist, film; the large amount of remaining solvent promoted the acid diffusion and eventually accelerated the acid evaporation from the resist film surface in the PGMEA resist. In summary, the acid evaporation property depends on both the acid

  19. 2-(3-Hydroxybenzylaminoacetic acid

    Directory of Open Access Journals (Sweden)

    Li-Hua Zhi

    2011-07-01

    Full Text Available There are two independent 2-(3-hydroxybenzylaminoacetic acid molecules, C9H11NO3, in the asymmetric unit of the title compound. The dihedral angle between the benzene rings of the two independent molecules is 58.12 (4°. The crystal packing is stablized by intermolecular O—H...O and N—H...O hydrogen bonds.

  20. Hyaluronic acid and tendon lesions

    Science.gov (United States)

    Kaux, Jean-François; Samson, Antoine; Crielaard, Jean-Michel

    2015-01-01

    Summary Introduction recently, the viscoelastic properties of hyaluronic acid (HA) on liquid connective tissue have been proposed for the treatment of tendinopathies. Some fundamental studies show encouraging results on hyaluronic acid’s ability to promote tendon gliding and reduce adhesion as well as to improve tendon architectural organisation. Some observations also support its use in a clinical setting to improve pain and function. This literature review analyses studies relating to the use of hyaluronic acid in the treatment of tendinopathies. Methods this review was constructed using the Medline database via Pubmed, Scopus and Google Scholar. The key words hyaluronic acid, tendon and tendinopathy were used for the research. Results in total, 28 articles (in English and French) on the application of hyaluronic acid to tendons were selected for their relevance and scientific quality, including 13 for the in vitro part, 7 for the in vivo animal part and 8 for the human section. Conclusions preclinical studies demonstrate encouraging results: HA permits tendon gliding, reduces adhesions, creates better tendon architectural organisation and limits inflammation. These laboratory observations appear to be supported by limited but encouraging short-term clinical results on pain and function. However, controlled randomised studies are still needed. PMID:26958533

  1. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks. PMID:21120449

  2. Abscisic Acid Signaling in Plants

    Czech Academy of Sciences Publication Activity Database

    Vaňková, Radomíra

    NEW YORK : Springer, 2012 - (Ahmad, P.; Prasad, M.), s. 359-368 ISBN 978-1-4614-0633-4 R&D Projects: GA ČR GA522/09/2058 Institutional research plan: CEZ:AV0Z50380511 Keywords : PP2C * PYR/PYL/RCAR proteins * Abscisic acid Subject RIV: ED - Physiology

  3. Antibiofilm Properties of Acetic Acid

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup;

    2014-01-01

    infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram...

  4. An assessment of acid fog

    International Nuclear Information System (INIS)

    Airborne particles have long been associated with adverse effects on public health, begin with the notorious air pollution disasters of several decades ago. Although H2SO4 was identified early on as a potential causal factors during these episodes (in part because of concern for potential health effects of particle acidity per se has intensified only recently. Most of the recent aerometric research in the US on acid fog has focused on the ability of clouds and fog to deliver acidity to vegetation and ecosystems. Strong acids are characterized chemically by their pH or H+ concentration. For fog, concentrations are referred to the droplet liquid content; for other (i.e., ''clear air'') aerosols, to the volume of air sampled. A useful measure of the relationship between aerosol and fog is obtained by comparing their mass concentrations on the basis of the same volume of air, by multiplying fogwater concentrations by liquid water content (LWC). This paper reviews fog measurement capability, physical properties and chemistry, and presents a simple urban airshed model which is used to simulate the evolution of fog and aerosol concentrations under urban stagnation conditions

  5. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  6. Uric acid in multiple sclerosis

    NARCIS (Netherlands)

    Koch, M; De Keyser, J

    2006-01-01

    Peroxynitrite, a reactive oxidant formed by the reaction of nitric oxide with superoxide at sites of inflammation in multiple sclerosis (MS), is capable of damaging tissues and cells. Uric acid, a natural scavenger of peroxynitrite, reduces inflammatory demyelination in experimental allergic encepha

  7. Radiolabeled derivatives of folic acid

    International Nuclear Information System (INIS)

    Derivatives of folic acid are described, in which the α-carboxyl group is substituted with an amino compound having an aromatic or heterocyclic ring substituent which is capable of being radiolabelled. Particularly mentioned as a radiolabel is 125I. (author)

  8. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid

    OpenAIRE

    Tareq Irshaidat

    2014-01-01

    On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293) illustrated that beryllium ions are capable of significantly modulating (changing) the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+, AlF2(1+), AlF2+, and Al3+) were investigated. Several aspects were addressed: natural bond orbitals, including second order perturbation ana...

  9. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Science.gov (United States)

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

    2016-01-18

    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues. PMID:26572799

  10. Omega-3 Fatty Acids and Inflammatory Processes

    Directory of Open Access Journals (Sweden)

    Philip C. Calder

    2010-03-01

    Full Text Available Long chain fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or at least associated with, changes in fatty acid composition of cell membranes. Changes in these compositions can modify membrane fluidity, cell signaling leading to altered gene expression, and the pattern of lipid mediator production. Cell involved in the inflammatory response are typically rich in the n-6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the n-3 fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these often have differing properties from those of arachidonic acid-derived eicosanoids. EPA and DHA give rise to newly discovered resolvins which are anti-inflammatory and inflammation resolving. Increased membrane content of EPA and DHA (and decreased arachidonic acid content results in a changed pattern of production of eicosanoids and resolvins. Changing the fatty acid composition of cells involved in the inflammatory response also affects production of peptide mediators of inflammation (adhesion molecules, cytokines etc.. Thus, the fatty acid composition of cells involved in the inflammatory response influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti-inflammatory effects of marine n-3 PUFAs suggest that they may be useful as therapeutic agents in disorders with an inflammatory component.

  11. The β-lactamase inhibitor avibactam (NXL104) does not induce ampC β-lactamase in Enterobacter cloacae

    OpenAIRE

    Miossec, Christine; Claudon, Monique; Levasseur, Premavathy; Black, Michael T.

    2013-01-01

    Induction of ampC β-lactamase expression can often compromise antibiotic treatment and is triggered by several β-lactams (such as cefoxitin and imipenem) and by the β-lactamase inhibitor clavulanic acid. The novel β-lactamase inhibitor avibactam (NXL104) is a potent inhibitor of both class A and class C enzymes. The potential of avibactam for induction of ampC expression in Enterobacter cloacae was investigated by ampC messenger ribonucleic acid quantitation. Cefoxitin and clavulanic acid wer...

  12. Digestion and absorption of lipids and bile acids in sheep fed stearic acid, oleic acid, or tristearin

    International Nuclear Information System (INIS)

    Sheep were fed diets containing 7.5% added stearic acid, oleic acid, or tristearin for 21 days. In addition, 50 microCi/kg cerium-141 was included for the last 10 days on experimental diets as an unabsorbed reference substance. In the rumen dietary triglycerides were approximately 50% hydrolyzed, and hydrogenation resulted in saturation of the free fatty acid fraction. Some net synthesis of phospholipids, presumably microbial phospholipids, occurred in the rumen. In the intestine immediately distal to the pylorus, extensive secretion of bile acids, cholesterol, phospholipids, triglycerides, free fatty acids, and lipase occurred. This resulted in doubling of fatty acid fluxes through the duodenum. These endogenous secretions were reabsorbed rapidly however, with the major site of lipid and bile acid absorption in the region .6 to 4 m distal to the pylorus. Additional but less absorption occurred in the more distal segments of the small intestine. Overall absorption of stearic acid, oleic acid, and tristearin supplements was in the range 60 to 70%, and no differences were apparent between fats. Unsaturated fatty acids were over 90% absorbed as compared with 55 to 65% for saturated fatty acids. No significant effect of any of the supplements was observed on ruminal total volatile fatty acids, ratios of volatile fatty acids, or on overall cellulose or caloric digestion

  13. Crystal growth and physical characterization of picolinic acid cocrystallized with dicarboxylic acids

    Science.gov (United States)

    Somphon, Weenawan; Haller, Kenneth J.

    2013-01-01

    Pharmaceutical cocrystals are multicomponent materials containing an active pharmaceutical ingredient with another component in well-defined stoichiometry within the same unit cell. Such cocrystals are important in drug design, particularly for improving physicochemical properties such as solubility, bioavailability, or chemical stability. Picolinic acid is an endogenous metabolite of tryptophan and is widely used for neuroprotective, immunological, and anti-proliferative effects within the body. In this paper we present cocrystallization experiments of a series of dicarboxylic acids, oxalic acid, succinic acid, DL-tartaric acid, pimelic acid, and phthalic acid, with picolinic acid. Characterization by FT-IR and Raman spectroscopy, DSC and TG/DTG analysis, and X-ray powder diffraction show that new compounds are formed, including a 1:1 picolinium tartrate monohydrate, a 2:1 monohydrate adduct of picolinic acid and oxalic acid, and a 2:1 picolinic acid-succinic acid monohydrate cocrystal.

  14. Acidic lakes and streams in the United States: The role of acidic deposition

    International Nuclear Information System (INIS)

    A statistically designed survey of lakes and streams in acid-sensitive areas of the United States, the National Surface Water Survey (NSWS), was used to identify the role of acidic deposition, relative to other factors, in causing acidic conditions in 1,181 lakes and 4,668 streams. Atmospheric deposition is the dominant source of acid anions in 75% of the acidic lakes and 47% of the acidic streams. Organic anions are dominant in one-fourth of the acidic lakes and streams; acidic mine drainage is the dominant acid source in 25% of the acidic streams. Other causes of acidic conditions are relatively unimportant on a regional scale. Nearly all the deposition-dominated acidic systems were found in six well-delineated subpopulations that represent about one-fourth of the NSWS lake population and one-third of the NSWS stream population

  15. Chemical peeling - Glycolic acid versus trichloroacetic acid in melasma

    Directory of Open Access Journals (Sweden)

    Kalla G

    2001-01-01

    Full Text Available Melasma continues to be a therapeutic challenge. 100 patients of melasma not responding to conventional depigmenting agents were divided into 2 groups, one treated with 55 - 75% glycolic acid (68 patients and the other with 10-15% trichloroacetic acid (32 patients. Applications were made after every 15 days and response assessed clinically along with relapse or hyperpigmentation after 3 month follow up period. More than 75% improvement was seen in 30%, and 50-75% improvement in 24% patients. Response with TCA was more rapid as compared to GA. Chronic pigmentation responded more favourably to TCA. Relapse and hyperpigmentation was more-25% in TCA as compared to 5.9% GA. Sun exposure was the most important precipitating factor followed by pregnancy and drugs.

  16. Uric Acid Inhibits Placental System A Amino Acid Uptake☆

    OpenAIRE

    Bainbridge, S.A.; von Versen-Höynck, F.; Roberts, J M

    2008-01-01

    Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasi...

  17. Endocrine and paracrine role of bile acids

    Directory of Open Access Journals (Sweden)

    Verena Keitel, Ralf Kubitz, Dieter Häussinger

    2008-10-01

    Full Text Available Bile acids are not only important for the absorption of dietary lipids and fat soluble vitamins but are signalling molecules with diverse endocrine and paracrine functions. Bile acids regulate bile acid, lipid and glucose metabolism and modulate temperature and energy homeostasis. Furthermore, bile acids can not only promote cell proliferation and liver regeneration but can also induce programmed cell death. Bile acid functions are mediated through different pathways which comprise the activation of nuclear hormone receptors, of intracellular kinases and of the plasma membrane-bound, G-protein coupled bile acid receptor TGR5/Gpbar-1.

  18. Bile acid metabolism in tupaias (lemurs)

    International Nuclear Information System (INIS)

    The goal of this work is to study biliary elimination and the metabolism of the most important primary bile acids, cholic acid and chenodesoxycholic acid, and the toxic secondary bile acid, lithocholic acid, which is formed in the intestine as a result of chenodesoxycholate therapy for the dissolving of gall stones. This work herewith offers a contribution to the answering of the question whether tupaias are a relevant animal model for the study of gall stone formation and their medicamentous dissolution by means of bile acids. (orig./MG)

  19. Determination of titratable acidity in white wine

    OpenAIRE

    Rajković Miloš B.; Novaković Ivana D.; Petrović Aleksandar

    2007-01-01

    The amount of titration acid in must is in the largest number of cases with in the range 5.0-8.0 g/dm3. Wines, as a rule, contain less acids than must, and according to Regulations, titratable acidity is in the range of 4.0-8.0 g/dm3 expressed in tartaric acid, because a part of tartaric acid is deposited in the form of salts (tartar or argol) during alcohol fermentation. For wines that contain less than 4 g/dm3 of titratable acids there arises a suspicion about their origin, that is, that du...

  20. Uncarilic Acid and Secouncarilic Acid, Two New Triterpenoids from Uucaria sessilifructus

    OpenAIRE

    Yan Li; De-Qiang Feng; You-Kai Xu; Shang-Gao Liao; Mao-Juan Zhang; Bing Liu; Kai-Long Ji

    2013-01-01

    Two new compounds, the 6-oxo oleanane-type triterpenoid uncarilic acid, and its 5,6-secotriterpenoid derivative, secouncarilic acid, were isolated from the hooks and stems of Uucaria sessilifructus together with seven known ursane-type triterpenoids. Uncarilic acid is the second 6-oxo oleanane-type triterpenoid ever reported, while secouncarilic acid is the first oleanane-type 5,6-secotriterpenoid. A plausible biosynthetic pathway from uncarilic acid to secouncarilic acid was also postulated....

  1. Oxidation-reduction reactions of simple hydroxamic acids and plutonium(IV) ions in nitric acid

    OpenAIRE

    Carrott, M. J.; Fox, O. D.; LeGurun, G.; Jones, C J; Mason, C; Taylor, Robin; Andrieux, Fabrice; Boxall, Colin

    2008-01-01

    Simple hydroxamic acids such as formo- and aceto-hydroxamic acids have been proposed as suitable reagents for the separation of either Pu and/or Np from U in modified or single cycle Purex based solvent extraction processes designed to meet the emerging requirements of advanced fuel cycles. The stability of these hydroxamic acids is dominated by their decomposition through acid hydrolysis. Kinetic studies of the acid hydrolysis of formo- and acetohydroxamic acids are reported in the absence a...

  2. Spontaneous curvature of phosphatidic acid and lysophosphatidic acid.

    Science.gov (United States)

    Kooijman, Edgar E; Chupin, Vladimir; Fuller, Nola L; Kozlov, Michael M; de Kruijff, Ben; Burger, Koert N J; Rand, Peter R

    2005-02-15

    The formation of phosphatidic acid (PA) from lysophosphatidic acid (LPA), diacylglycerol, or phosphatidylcholine plays a key role in the regulation of intracellular membrane fission events, but the underlying molecular mechanism has not been resolved. A likely possibility is that PA affects local membrane curvature facilitating membrane bending and fission. To examine this possibility, we determined the spontaneous radius of curvature (R(0p)) of PA and LPA, carrying oleoyl fatty acids, using well-established X-ray diffraction methods. We found that, under physiological conditions of pH and salt concentration (pH 7.0, 150 mM NaCl), the R(0p) values of PA and LPA were -46 A and +20 A, respectively. Thus PA has considerable negative spontaneous curvature while LPA has the most positive spontaneous curvature of any membrane lipid measured to date. The further addition of Ca(2+) did not significantly affect lipid spontaneous curvature; however, omitting NaCl from the hydration buffer greatly reduced the spontaneous curvature of PA, turning it into a cylindrically shaped lipid molecule (R(0p) of -1.3 x 10(2) A). Our quantitative data on the spontaneous radius of curvature of PA and LPA at a physiological pH and salt concentration will be instrumental in developing future models of biomembrane fission. PMID:15697235

  3. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    Science.gov (United States)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  4. Complex formation of calcium with humic acid and polyacrylic acid

    International Nuclear Information System (INIS)

    In order to understand the migration behavior of radionuclides in the underground, it is also important to estimate the effect of the competing cations originally present in the groundwater. In this connection, the complexation of Ca(II) with Aldrich humic acid has been examined. For the study at trace concentrations (∝ 10-10 M) of Ca(II), the solvent extraction of 45Ca with TTA and TOPO in cyclohexane has been used. At macro concentrations (10-4 M) of Ca(II), the measurement of the free Ca2+ ion concentration with a calcium selective electrode has been conducted. To estimate the polyelectrolyte effect of humic acid separately from its heterogeneous composition effect, polyacrylic acid ([-CH2CH(COOH)-]n) has been selected as a representative of the homogeneous polymeric weak acids and its complexation with Ca(II) has also been examined. The values of log βα have been obtained at pH 5 ∝ 7 in 0.1, 0.4 and 1.0 M NaCl, where βα is the apparent formation constants defined by βα = [ML]/([M][R]). In this definition, [ML] and [M] are the concentrations of bound and free Ca2+ respectively, [R] is the concentration of dissociated proton exchanging sites. log βα of humate decreases from 2.19 ∝ 2.92 (depending on pH and ionic strength 1.0 α of polyacrylate (1.36 ∝ 3.24 for I = 0.1 ∝ 1.0). For both humate and polyacrylate, log βα decreases linearly with log[Na+], where [Na+] is the bulk concentration of sodium ion. Their dependences of log βα on ionic strength are stronger than those of log β of monomeric carboxylates such as oxalate and EDTA, indicating the large electrostatic effect of crowded negative charges on the macromolecules of humic or polyacrylic acid. (orig.)

  5. Thermochemistry of aqueous pyridine-3-carboxylic acid (nicotinic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Elsa M. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto Politecnico de Setubal, ESTBarreiro, Rua Americo da Silva Marinho, 2839-001 Lavradio (Portugal); Rego, Talita S. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Minas da Piedade, Manuel E., E-mail: memp@fc.ul.p [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2011-06-15

    Research highlights: {yields} We determined the {Delta}{sub sol}H{sub m} of solid nicotinic acid (NA) in water by solution calorimetry. {yields} We determined {Delta}{sub dil}H{sub m} of an aqueous nicotinic acid solution by flow calorimetry. {yields} We determined (aq, {infinity}) for the 3 NA species involved in acid/base equilibria. {yields} We determined the enthalpy of formation of NA(aq) under saturation conditions.. - Abstract: The molar enthalpy of solution of solid nicotinic acid (NA) at T = 298.15 K, to give an aqueous solution of molality m = 3.748 . 10{sup -3} mol {center_dot} kg{sup -1}, was determined as {Delta}{sub sol}H{sub m} = (19,927 {+-} 48) J {center_dot} mol{sup -1}, by solution calorimetry. Enthalpies of dilution, {Delta}{sub dil}H{sub m}, of 0.1005 mol {center_dot} kg{sup -1} aqueous nicotinic acid to yield final solutions with molality in the approximate range (0.03 to 0.09) mol {center_dot} kg{sup -1} were also measured by flow calorimetry. Combining the two sets of data and the results of pH measurements, with values of proton dissociation enthalpies and {Delta}{sub f}H{sub m}{sup 0}(NA, cr) selected from the literature, it was possible to derive the standard molar enthalpies of formation of the three nicotinic acid species involved in protonation/deprotonation equilibria, at infinite dilution: {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COOH.{infinity}H{sub 2}O,aq) = (328.2 {+-} 1.2) kJ {center_dot} mol{sup -1}, {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (325.0 {+-} 1.2) kJ {center_dot} mol{sup -1}, and {Delta}{sub f}H{sub m}{sup 0}(NC{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (313.7 {+-} 1.2) kJ {center_dot} mol{sup -1}. Finally, the enthalpy of solution of nicotinic acid at T = 298.15 K, under saturation conditions (m = 0.138 mol {center_dot} kg{sup -1}), and the standard molar enthalpy of formation of the corresponding solution could also be obtained as {Delta

  6. Increase of betulinic acid production in Saccharomyces cerevisiae by balancing fatty acids and betulinic acid forming pathways.

    Science.gov (United States)

    Li, Jing; Zhang, Yansheng

    2014-04-01

    Betulinic acid is a plant-based triterpenoid that has been recognized for its antitumor and anti-HIV activities. The level of betulinic acid in its natural hosts is extremely low. In the present study, we constructed betulinic acid biosynthetic pathway in Saccharomyces cerevisiae by metabolic engineering. Given the betulinic acid forming pathways sharing the common substrate acetyl-CoA with fatty acid synthesis, the metabolic fluxes between the two pathways were varied by changing gene expressions, and their effects on betulinic acid production were investigated. We constructed nine S. cerevisiae strains representing nine combinations of the flux distributions between betulinic acid and fatty acid pathways. Our results demonstrated that it was possible to improve the betulinic acid production in S. cerevisiae while keeping a desirable growth phenotype by optimally balancing the carbon fluxes of the two pathways. Through modulating the expressions of the key genes on betulinic acid and fatty acid pathways, the difference in betulinic acid yield varied largely in the range of 0.01-1.92 mg L(-1) OD(-1). The metabolic engineering approach used in this study could be extended for synthesizing other triterpenoids in S. cerevisiae. PMID:24389702

  7. Effect of supplementation of arachidonic acid (AA) or a combination of AA plus docosahexaenoic acid on breastmilk fatty acid composition

    NARCIS (Netherlands)

    Smit, EN; Koopmann, M; Boersma, ER; Muskiet, FAJ

    2000-01-01

    We investigated whether supplementation with arachidonic acid (20:4 omega 6; AA), ora combination of AA and docosahexaenoic acid (22:6 omega 3; DHA) would affect human milk polyunsaturated fatty acid (PUFA) composition. Ten women were daily supplemented with 300 mg AA, eight with 300 mg AA, 110 mg e

  8. Palmitic Acid and Health: Introduction.

    Science.gov (United States)

    Agostoni, Carlo; Moreno, Luis; Shamir, Raanan

    2016-09-01

    Interest in the dietary role and metabolic effect of saturated fatty acids has been recently renewed on the basis of epidemiologic observations and economical approach to health and well-being. Saturated fats may favorably increase blood HDL-Cholesterol levels without significant changes of the total cholesterol/HDL-Cholesterol ratio. Also, the negative effect of saturated fat on cardiovascular diseases risk has recently been challenged. Palmitic acid, among all, may have special structural and functional roles in utero and in infancy, and indeed is it is being delivered in a unique form in human milk. Future research should include objective cost-benefit analyses when disentangling the role of saturated fats in dietary recommendations. PMID:25764181

  9. [Inherited amino acid transport disorders].

    Science.gov (United States)

    Igarashi, Y; Tada, K

    1992-07-01

    Disorders due to inherited amino acids transport defect are reviewed. The disorders were categorized into three types of transport defects, namely, brush-border membrane of epithelial cells of small intestine and kidney tubules (Hartnup disease, blue diaper syndrome, cystinuria, iminoglycinuria and lysine malabsorption syndrome), basolateral membrane (lysinuric protein intolerance) and membrane of intracellular organelles (cystinosis and hyperornitinemia-hyperammonemia-homocitrullinuria syndrome). Pathogenesis, clinical feature, laboratory findings, diagnosis, genetics and treatment of these disorders are described, briefly. There is not much data for the transport systems themselves, so that further investigation in molecular and gene levels for transport systems is necessary to clarify the characteristics of the transport and heterogeneity of phenotypes in inherited amino acids transport disorders. PMID:1404888

  10. Europium complexes with trifluoroacetic acid

    International Nuclear Information System (INIS)

    Synthesis conditions and spectra-luminescent properties of different-ligand europium complexes of the composition Eu (TFA)2x2D, where TFA = anion of trifluoroacetic acid, D = 1,10-phenanthroline, 2,2-dipyridyl, triphenylphosphinoxide, hexamethyl-phosphotriamide, were studied. The compounds prepared have been characterized by the methods of elementary chemical analysis, IR and luminescence spectroscopy. It is shown that in the complex compounds two methods of coordination of the acid residue functional groups are realized, i.e. monodentate and bridge functions. The compounds were tested for resistance to UV light effect and to heating in the air. Complex with 2,2-dipyridyl proved the most thermally stable complex in the series studied, its decomposition temperature being 240 deg C

  11. Ursodeoxycholic acid and superoxide anion

    Institute of Scientific and Technical Information of China (English)

    Predrag Ljubuncic; Omar Abu-Salach; Arieh Bomzon

    2005-01-01

    AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.

  12. Nucleic Acid Aptamers Against Proteases

    OpenAIRE

    Dupont, D M; Andersen, L M; Bøtkjær, Kenneth Alrø; Andreasen, P A

    2011-01-01

    Proteases are potential or realized therapeutic targets in a wide variety of pathological conditions. Moreover, proteases are classical subjects for studies of enzymatic and regulatory mechanisms. We here review the literature on nucleic acid aptamers selected with proteases as targets. Designing small molecule protease inhibitors of sufficient specificity has proved a daunting task. Aptamers seem to represent a promising alternative. In our review, we concentrate on biochemical mechanisms of...

  13. Ions in hyaluronic acid solutions

    OpenAIRE

    Horkay, Ferenc; Basser, Peter J.; Londono, David J.; Hecht, Anne-Marie; Geissler, Erik

    2009-01-01

    Hyaluronic acid (HA) is an anionic biopolymer that is almost ubiquitous in biological tissues. An attempt is made to determine the dominant features that account for both its abundance and its multifunctional role, and which set it apart from other types of biopolymers. A combination of osmotic and scattering techniques is employed to quantify its dynamic and static properties in near-physiological solution conditions, where it is exposed both to mono- and divalent counterions. An equation of...

  14. Rechargeable lead-acid batteries.

    Science.gov (United States)

    1990-09-01

    Batteries used in medical equipment, like their counterparts in consumer products, attract little attention until they fail to function effectively. In some applications, such as in emergency medical devices, battery failure can have fatal consequences. While modern batteries are usually quite reliable, ECRI has received 53 written problem reports and countless verbal reports or questions related to battery problems in hospitals during the past five years. This large number of reports is due, at least in part, to the enormous quality of batteries used to operate or provide backup power in contemporary hospital equipment. As part of an ongoing evaluation of rehabilitation assistive equipment, ECRI has been studying the performance of 12 V rechargeable deep-cycle lead-acid batteries used in powered wheelchairs. During the course of this evaluation, it has become apparent that many professionals, both clinical and industrial, regard batteries as "black box" devices and know little about proper care and maintenance--and even less about battery selection and purchase. Because equipment performance and reliability can be strongly influenced by different battery models, an understanding of battery characteristics and how they affect performance is essential when selecting and purchasing batteries. The types of rechargeable batteries used most commonly in hospitals are lead-acid and nickel-cadmium (nicad), which we compare below; however, the guidance we provide in this article focuses on lead-acid batteries. While the examples given are for high-capacity 12 V deep-cycle batteries, similar analyses can be applied to smaller lead-acid batteries of different voltages. PMID:2211174

  15. Perfluorooctanoic Acid for Shotgun Proteomics

    OpenAIRE

    Kadiyala, Chandra Sekhar Rao; Tomechko, Sara E.; Miyagi, Masaru

    2010-01-01

    Here, we describe the novel use of a volatile surfactant, perfluorooctanoic acid (PFOA), for shotgun proteomics. PFOA was found to solubilize membrane proteins as effectively as sodium dodecyl sulfate (SDS). PFOA concentrations up to 0.5% (w/v) did not significantly inhibit trypsin activity. The unique features of PFOA allowed us to develop a single-tube shotgun proteomics method that used all volatile chemicals that could easily be removed by evaporation prior to mass spectrometry analysis. ...

  16. Electrochemical analysis of nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Paleček, Emil; Fojta, Miroslav; Jelen, František; Vetterl, Vladimír

    Weinheim : WileyVCH, 2002 - (Bard, A.; Stratmann, M.; Wilson, G.), s. 365-429 ISBN 3-527-30401-0 R&D Projects: GA ČR GV204/97/K084; GA AV ČR IBS5004107; GA AV ČR IAA4004901; GA AV ČR IAA4004002 Institutional research plan: CEZ:AV0Z5004920 Keywords : nucleic acid s * electrochemical analysis * DNA biosensors Subject RIV: BO - Biophysics

  17. Diabetes and alpha lipoic acid

    OpenAIRE

    IssyLaher

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complicatio...

  18. Diabetes and Alpha Lipoic Acid

    OpenAIRE

    Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complicatio...

  19. Acid Rain: The Silent Environmental Threat.

    Science.gov (United States)

    Zmud, Mia

    1992-01-01

    Describes the silent environmental threat posed by acid rain. Caused mainly by manmade pollutants, acid rain damages water and trees, decreases visibility, corrodes monuments, and threatens public health. The article includes guidelines for action. (SM)

  20. Nature in the Classroom: Acid Rain.

    Science.gov (United States)

    Doyle, Charles

    1982-01-01

    As a lesson topic, acid rain is defined, its chemistry given, and its development since the 1950s described. The worldwide effects of acid rain are discussed along with the available technology for controlling the problem. (CM)

  1. How Acid Reflux Disease Damages Teeth

    Science.gov (United States)

    ... more Seniors' Oral Health How to Keep Your Teeth for a Lifetime Tooth loss is simply the ... your desktop! more... How Acid Reflux Disease Damages Teeth Article Chapters How Acid Reflux Disease Damages Teeth ...

  2. Recovery of mercury from acid waste residues

    Science.gov (United States)

    Greenhalgh, Wilbur O.

    1989-01-01

    Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

  3. Histidine-Containing Peptide Nucleic Acids

    DEFF Research Database (Denmark)

    2000-01-01

    Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....

  4. RETINOIC ACID ALTERS EPITHELIAL DIFFERENTIATION DURING PALATOGENESIS

    Science.gov (United States)

    Retinoids are teratogenic in humans and animals, producing a syndrome of craniofacial malformations which includes cleft palate. his study investigates the mechanism through which retinoic acid induces cleft palate. urine palatogenesis after exposure to retinoic acid in utero is ...

  5. Role of succinic acid in chemical evolution

    Science.gov (United States)

    Negron-Mendoza, A.; Ponnamperuma, C.

    1982-01-01

    Succinic acid is converted into other carboxylic acids by ionizing radiation. The results obtained have been correlated with the ready formation of this compound in prebiotic experiments. Its role in biological systems may be related to its prebiotic occurrence.

  6. Acid rain information book. Second edition

    International Nuclear Information System (INIS)

    Potential consequences of widespread acid precipitation are reviewed through an extensive literature search. Major aspects of the acid rain phenomena are discussed, areas of uncertainty identified, and current research summarized

  7. Stereochemistry of a Rhododaurichromanic Acid Derivative.

    Science.gov (United States)

    Swamy, Mahadeva M M; Mándi, Attila; Anetai, Masaki; Monde, Kenji

    2016-02-01

    A rhododaurichromanic acid A derivative was synthesized from the naturally occurring daurichromenic acid in enantiomeric pure form. Its absolute configuration was elucidated by applying VCD, ECD and DFT calculations. PMID:27032199

  8. Antimicrobial susceptibility of clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Shi, Z Y; Liu, P Y; Lau, Y; Lin, Y; Hu, B S; Shir J-M

    1996-02-01

    The in-vitro activity of 18 antimicrobial agents alone or in combination against 248 clinical isolates of Acinetobacter baumannii from Taiwan were tested by agar dilution. The MIC90S of ampicillin, amoxicillin, piperacillin, cefuroxime, cefotaxime, ceftriaxone, gentamicin, and amikacin were at least 128 mu g/ml. Ceftazidime, cefepime, sulbactam, clavulanic acid, and tazobactam presented moderate activity with MIC90S of 32, 16, 16, 32, and 32 mu g/ml, respectively. The increased activity of ampicillin/sulbactam, amoxicillin/clavulanic acid, and piperacillin/tazobactam was due to the intrinsic effect of sulbactam, clavulanic acid, and tazobactam, respectively. Imipenem, meropenem, and ciprofloxacin were the most active antimicrobial agents with MIC90S of 1, 1, and 0.5 mu g/ml, respectively. Nineteen isolates (7.7%) were resistant to all aminoglycosides and beta-lactam antibiotics, except carbapenems and ciprofloxacin. We are concerned about the multidrug resistance of A. baumannii in this study. PMID:9147913

  9. Thermal Stability Of Formohydroxamic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F. F.; Rudisill, T. S.

    2011-10-21

    The thermal stability of formohydroxamic acid (FHA) was evaluated to address the potential for exothermic decomposition during storage and its use in the uranium extraction process. Accelerating rate calorimetry showed rapid decomposition at a temperature above 65 {degree}C; although, the rate of pressure rise was greater than two orders of magnitude less than the lower bound for materials which have no explosive properties with respect to transportation. FHA solutions in water and nitric acid did not reach runaway conditions until 150 {degree}C. Analysis by differential scanning calorimetry showed that FHA melted at 67 {degree}C and thermally decomposed at 90 {degree}C with an enthalpy of -1924 J/g. The energics of the FHA thermal decomposition are comparable to those measured for aqueous solutions of hydroxylamine nitrate. Solid FHA should be stored in a location where the temperature does not exceed 20-25 {degree}C. As a best practice, the solid material should be stored in a climate-controlled environment such as a refrigerator or freezer. FHA solutions in water are not susceptible to degradation by acid hydrolysis and are the preferred way to handle FHA prior to use.

  10. Oleic acid biosynthesis in cyanobacteria

    International Nuclear Information System (INIS)

    The biosynthesis of fatty acids in cyanobacteria is very similar to the well characterized system found in green plants. However, the initial desaturation of stearic acid in cyanobacteria appears to represent a significant departure from plant systems in which stearoyl-ACP is the exclusive substrate for desaturation. In Anabaena variabilis, the substrate appears to be monoglucosyldiacylglycerol, a lipid not found in plants. The authors examined five different cyanobacteria to determine if the pathway in A. variabilis was generally present in other cyanobacteria. The cyanobacteria studied were A. variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis marina, and Anacystis nidulans. Each were grown in liquid culture, harvested, and examined for stearoyl-ACP desaturase activity or incubated with 14CO2. None of the cyanobacteria contained any stearoyl-ACP desaturase activity in whole homogenates or 105,000g supernatants. All were capable of incorporating 14CO2 into monoglucosyldiacylglycerol and results from incubations of 20 min, 1 hr, 1 hr + 10 hr chase were consistent with monoglucosyldiacylglycerol serving as precursor for monogalctosyldiacylglycerol. Thus, initial evidence is consistent with oleic acid biosynthesis occurring by desaturation of stearoyl-monoglucosyldiacylglycerol in all cyanobacteria

  11. Incorporation of conjugated linoleic acid (CLA and α-linolenic acid (LNA in pacu fillets

    Directory of Open Access Journals (Sweden)

    Deoclécio José Barilli

    2014-03-01

    Full Text Available The objective of this study was to evaluate the incorporation of conjugated linoleic acid and α-linolenic acid in fillets of pacu fish raised in net cages and fed diets enriched with these acids. The fish were fed for 49 days, and at the end of this period the fatty acid content in the fillets was determined by gas chromatography. Concentrations of α-linolenic acid, eicosapentaenoic acid, and the total omega-3 (n-3 fatty acid in the fillets increased, improving the n-6/n-3 ratio. In addition, the incorporation of conjugated linoleic acid in the fish fillets proved well established. This study showed that the use of diets enriched with conjugated linoleic acid and α-linolenic acid results in the incorporation of these acids in the of pacu fish fillets, improving their nutritional quality.

  12. Capture and release of acid-gasses with acid-gas binding organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Heldebrant, David J; Yonker, Clement R; Koech, Phillip K

    2015-03-17

    A system and method for acid-gas capture wherein organic acid-gas capture materials form hetero-atom analogs of alkyl-carbonate when contacted with an acid gas. These organic-acid gas capture materials include combinations of a weak acid and a base, or zwitterionic liquids. This invention allows for reversible acid-gas binding to these organic binding materials thus allowing for the capture and release of one or more acid gases. These acid-gas binding organic compounds can be regenerated to release the captured acid gasses and enable these organic acid-gas binding materials to be reused. This enables transport of the liquid capture compounds and the release of the acid gases from the organic liquid with significant energy savings compared to current aqueous systems.

  13. Analysis of the apple fruit acid/low-acid trait by SSR markers

    Institute of Scientific and Technical Information of China (English)

    Yuxin YAO; Heng ZHAI; Lingling ZHAO; Kai YI; Zhi LIU; Ye SONG

    2008-01-01

    It is necessary to find out the genetic character-istics of malic acid in the course of apple genomic research and breeding. In this study, the SSR marker linked to the acid/low-acid trait in apple fruit was identified from 140 SSR primer pairs, using 91 F1 population hybrids from the intra-specific cross between apple cultivar 'Dongguang' and 'Fuji' as the experimental materials. Of 140 SSR primer pairs, only primer SDY085 produced a polymorphic band linked to acid trait, and the linkage distance was 8.89 cM. Also, the titrated acid and malic acid in different developmental stages were determined. The SSR marker analysis, coupled with the change of the total acid and malic acid contents, revealed that the acid/low-acid trait was governed by a major gene and acid trait was completely dominant.

  14. Transformation of chenodeoxycholic acid to ursodeoxycholic acid in patients with Crohn's disease

    International Nuclear Information System (INIS)

    In vivo 7 beta-epimerization of chenodeoxycholic acid to ursodeoxycholic acid and the role of 7-ketolithocholic acid as an intermediate in this biotransformation were studied in 11 patients with Crohn's disease and in 5 healthy volunteers. The incorporation of deuterium into biliary ursodeoxycholic acid and 7-ketolithocholic acid was determined by computed gas chromatography-mass fragmentography after ingestion of a dideuterated chenodeoxycholic acid, chenodeoxycholic-11,12-d2 acid. The incorporation of deuterium into ursodeoxycholic acid increased to a peak level at 48 h in the patients with Crohn's disease, but was delayed in healthy volunteers. In 8 patients and 2 healthy controls there were small amounts of 7-ketolithocholic acid in bile. The incorporation of deuterium into 7-ketolithocholic acid was confirmed in only 2 patients and the peak level was noted at 48 h. These observations suggest that 7-ketolithocholic acid is an intermediate of this biotransformation in patients with Crohn's disease

  15. Profile of Fatty Acids, Amino Acids, Carotenoid Total, and α-Tocopherol from Flying Fish Eggs

    Directory of Open Access Journals (Sweden)

    Aulia Azka

    2015-12-01

    Full Text Available Flying fish are found in waters of eastern Indonesia, which until now is still limited information about nutritional content. The purpose of this research was determine the composition of fatty acids, amino acids, total carotenoids, α-tocopherol flying fish eggs (Hyrundicthys sp.. The composition of fatty acid was measured by gas chromatography (GC, while amino acids, total carotenoids, α-tocopherol was measured by High performanced Liquid Chromatography (HPLC. Egg contained 22 fatty acids such as saturated fatty acid 29.71%, monounsaturated fatty acid 7.86%, and polysaturated fatty acid 13.64%. The result showed that eggs flying fish contained 17 amino acids, such as essential amino acid 14.96% and non-essential amino acids 20.27%. Eggs contained a total carotenoid of 245.37 ppm. α-tocopherol content of flying fish eggs by 1.06 ppm.

  16. Study of americium sorption by humic acids

    International Nuclear Information System (INIS)

    The results of investigation of influence of the cation content and acidity of soil solution on americium sorption by the humic acids have been shown. The most influence on the interphase distribution coefficient in the system 'humic acid - model soil solution' is caused by the presence of the iron (III), calcium ions and acidity of the solution. The increase of the sodium ions concentration in the solution makes an insignificant impact on the americium sorption. (Authors)

  17. Recovery of boric acid from ion exchangers

    International Nuclear Information System (INIS)

    The recovery of boric acid from an anion exchange resin is improved by eluting the boric acid with an aqueous solution of ammonium bicarbonate. The boric acid can be readily purified and concentrated by distilling off the water and ammonium bicarbonate. This process is especially useful for the recovery of boric acid containing a high percentage of 10B which may be found in some nuclear reactor coolant solutions. 10 claims

  18. CLIMATE CHANGE ADAPTATION IN ACID SULFATE LANDSCAPES

    OpenAIRE

    Chuxia Lin

    2012-01-01

    Oxidation of sulfide minerals produces sulfuric acid and consequently creates Acid Sulfate Landscapes (ASLs), which represent one of the most degraded types of land-surface environments. Although acid sulfate-producing weathering is a naturally occurring process, it is markedly facilitated by human intervention. Mining is by far the dominant anthropogenic cause for the creation of inland acid sulfate footprints while land reclamation in coastal lowlands is the driver for the formation of coas...

  19. Direct Channeling of Retinoic Acid between Cellular Retinoic Acid-Binding Protein II and Retinoic Acid Receptor Sensitizes Mammary Carcinoma Cells to Retinoic Acid-Induced Growth Arrest

    OpenAIRE

    Budhu, Anuradha S.; Noy, Noa

    2002-01-01

    Cellular retinoic acid-binding protein II (CRABP-II) is an intracellular lipid-binding protein that associates with retinoic acid with a subnanomolar affinity. We previously showed that CRABP-II enhances the transcriptional activity of the nuclear receptor with which it shares a common ligand, namely, the retinoic acid receptor (RAR), and we suggested that it may act by delivering retinoic acid to this receptor. Here, the mechanisms underlying the effects of CRABP-II on the transcriptional ac...

  20. Folic acid derivatives for use in radioimmunoassay

    International Nuclear Information System (INIS)

    The chemical preparation of two folic acid derivatives, labelled with 125I or 131I, is described for use in radioimmunoassay of folic acid and its metabolites in biological fluids such as blood serum. Labelled compounds of the present invention more closely resemble folic acid in that they have glutamic acid in the terminal position. Examples of the use of these compounds in three different assays are given. (U.K.)

  1. Microbial production of natural poly amino acid

    Institute of Scientific and Technical Information of China (English)

    SHI Feng; XU ZhiNan; CEN PeiLin

    2007-01-01

    Three kinds of poly amino acids, poly-γ-glutamic acid, poly(ε-L-lysine) and multi-L-arginyl-poly (L-aspartic acid) can be synthesized by enzymatic process independently from ribosomal protein biosynthesis pathways in microorganism. These biosynthesized polymers have attracted more and more attentions because of their unique properties and various applications. In this review, the current knowledge on the biosynthesis, biodegradations and applications of these three poly amino acids are summarized.

  2. Enhancement of colposcopic image by sulphosalicylic acid.

    Directory of Open Access Journals (Sweden)

    Khilnani P

    1993-01-01

    Full Text Available Acetic acid is used conventionally for enhancement of the colposcopic image. We used sulphosalicylic acid instead of acetic acid in 50 normal cases. The normal appearance was enhanced in all cases. The image was also enhanced in 70% cases of cervical intraepithelial neoplasia and 90% cases of cervical condyloma accuminata. The image was not inferior to that with acetic acid in any of the cases.

  3. Complicated Composting: Persistent Pyridine Carboxylic Acid Herbicides

    OpenAIRE

    Reimer, Julie

    2013-01-01

    This paper reviews pyridine carboxylic acid herbicide impacts on compost. Pyridine carboxylic acid herbicides are not completely broken down during grass growth, harvest and drying of hay, in the digestive tract of livestock, or during composting. These herbicides are a popular choice for broadleaf weed control because of this persistence: they remain effective for months or years. Pyridine carboxylic acids are also more effective than the common herbicide 2, 4-dichlorophenoxyacetic acid and ...

  4. 21 CFR 172.320 - Amino acids.

    Science.gov (United States)

    2010-04-01

    ...-Cysteine L-Cystine L-Glutamic acid L-Glutamine Aminoacetic acid (glycine) L-Histidine L-Isoleucine L... following: L-Asparagine L-Aspartic acid L-Glutamine L-Histidine (c) The additive(s) is used or intended for....4 Aminoacetic acid (glycine) 3.5 L-Histidine 2.4 L-Isoleucine 6.6 L-Leucine 8.8 L-Lysine 6.4 L-...

  5. Removal of lactobionic acid by electrodialysis

    OpenAIRE

    J. B. Severo Júnior; ALVES T. L. M.; H. C. Ferraz

    2014-01-01

    Lactobionic acid has a number of applications, such as in cosmetic formulations and detergents, as well as in the medical field, where it is used for the preservation of organs destined for transplantation. Previous studies have reported that a promising alternative procedure for the production of lactobionic acid is the biotechnological route, using permeabilized cells of Zymomonas mobilis to produce sorbitol and lactobionic acid from fructose and lactose. However, the acid produced during t...

  6. Drug Nanoparticle Formulation Using Ascorbic Acid Derivatives

    OpenAIRE

    Kunikazu Moribe; Waree Limwikrant; Kenjirou Higashi; Keiji Yamamoto

    2011-01-01

    Drug nanoparticle formulation using ascorbic acid derivatives and its therapeutic uses have recently been introduced. Hydrophilic ascorbic acid derivatives such as ascorbyl glycoside have been used not only as antioxidants but also as food and pharmaceutical excipients. In addition to drug solubilization, drug nanoparticle formation was observed using ascorbyl glycoside. Hydrophobic ascorbic acid derivatives such as ascorbyl mono- and di-n-alkyl fatty acid derivatives are used either as drugs...

  7. Fatty Acid Composition of Agaricus bisporus (Lange) Sing.

    OpenAIRE

    Aktümsek, Abdurrahman; ÖZTÜRK, Celâleddin; KAŞIK, Giyasettin

    1998-01-01

    Fatty acid compositions of fruit body, stem, lamellae and total of Agaricus bisporus were seperately analysed by GLC. In the all fatty acid compositions of A. bisporus, linoleic acid were predominant. Percentages of linoleic acid were varied between 53.45 - 68.78%. It was showed that the other major fatty acids were palmitic, oleic and stearic acid in the fatty acid compositions.

  8. Acid Rain: What We Must Do.

    Science.gov (United States)

    Gorham, Eville

    1983-01-01

    Addresses questions about the nature, source, and history of acid rain. In addition, discusses the questions: Why is acid rain a problem? Is acid rain getting worse? What is the threat of further problems? Concludes that it is time to act on the problem and recommends an appropriate course of action. (JN)

  9. Acid Rain. LC Science Tracer Bullet.

    Science.gov (United States)

    Hollmann, Pauline, Comp.

    The term "acid rain," also called "acid precipitation," generally refers to any precipitation having a pH value of less than 5.6. This guide to the literature on acid rain in the collections of the Library of Congress is not necessarily intended to be a comprehensive bibliography. It is designed to provide the reader with a set of resources that…

  10. Acid Rain Students Do Original Research.

    Science.gov (United States)

    Outdoor Communicator, 1984

    1984-01-01

    At Park Senior High School (Cottage Grove, Minnesota), 46 juniors and seniors planted 384 red pine seedlings in connection with their original research on acid rain, with advice from Dr. Harriet Stubbs, director of the Acid Precipitation Awareness Program (West Saint Paul), which has been developing acid rain teaching materials. (MH)

  11. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    1988-01-01

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  12. Allelochemical phenolic acids from Gypsophila paniculata

    Science.gov (United States)

    Bioassay-guided fractionation of Gypsophila paniculata L. (Caryophyllaceae) resulted in the isolation of the phenolics p-coumaric acid (1), dihydroferulic acid (2), and syringic acid (3). In addition to their noted weak antimicrobial activity, compounds 1 and 3 are known to be potent exuded alleloc...

  13. Acrylic Acid and Esters Will Be Oversupply

    Institute of Scientific and Technical Information of China (English)

    Zheng Chengwang

    2007-01-01

    @@ Drastic capacity growth The production capacity of acrylic acid in China has grown drastically in recent years. With the completion of the 80 thousand t/a acrylic acid and 130 thous and t/a acrylic ester project in Shenyang Paraffin Chemical Industrial Co., Ltd., (CCR2006,No. 31) the capacity of acrylic acid in China has reached 882 thousand t/a.

  14. Dietary arachidonic acid in perinatal nutrition

    DEFF Research Database (Denmark)

    Lauritzen, Lotte; Fewtrell, Mary; Agostoni, Carlo

    2015-01-01

    Arachidonic acid (AA) is supplied together with docosahexaenoic acid (DHA) in infant formulas, but we have limited knowledge about the effects of supplementation with either of these long-chain polyunsaturated fatty acids (LCPUFA) on growth and developmental outcomes. AA is present in similar lev...

  15. Lipoxygenase inhibitory activity of anacardic acids.

    Science.gov (United States)

    Ha, Tae Joung; Kubo, Isao

    2005-06-01

    6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor. PMID:15913294

  16. 21 CFR 582.1095 - Sulfuric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sulfuric acid. 582.1095 Section 582.1095 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1095 Sulfuric acid. (a) Product. Sulfuric acid. (b) Conditions of use. This substance is...

  17. Tranexamic acid for upper gastrointestinal bleeding

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Klingenberg, Sarah Louise; Langholz, Ebbe

    2012-01-01

    Tranexamic acid reduces haemorrhage through its antifibrinolytic effects. In a previous version of the present review, we found that tranexamic acid may reduce mortality. The present review includes updated searches of randomised trials on tranexamic acid versus placebo, cimetidine or lansoprazole....

  18. Unnatural reactive amino acid genetic code additions

    Energy Technology Data Exchange (ETDEWEB)

    Deiters, Alexander; Cropp, Ashton T; Chin, Jason W; Anderson, Christopher J; Schultz, Peter G

    2013-05-21

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  19. Unnatural reactive amino acid genetic code additions

    Energy Technology Data Exchange (ETDEWEB)

    Deiters, Alexander; Cropp, T. Ashton; Chin, Jason W.; Anderson, J. Christopher; Schultz, Peter G.

    2014-08-26

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  20. Acid rain and the NAPAP study

    International Nuclear Information System (INIS)

    This article reports on preliminary state of science and technology reports on acidic deposition released by the National Acid Precipitation Assessment Program. These are part of the integrated assessment of acidic deposition and related air pollutants to be released at a later date. SO2 and NOx emissions and effects are discussed

  1. More on Effects Controlling Carboxylic Acidity.

    Science.gov (United States)

    Schwartz, Lowell M.

    1981-01-01

    Gas phase acidity data shown are offered to writers of elementary organic chemistry texts for replacement of the aqueous phase data that are universally used. Relative acidities in the gas phase are controlled virtually exclusively by enthalpic factors. Structural-energetic explanations of acidic trends can therefore be used. (SK)

  2. 21 CFR 582.1061 - Lactic acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is...

  3. Solid-state actinide acid phosphites from phosphorous acid melts

    Energy Technology Data Exchange (ETDEWEB)

    Oh, George N. [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Burns, Peter C., E-mail: pburns@nd.edu [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-07-01

    The reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})]. This compound crystallizes in space group P2{sub 1}/n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O)·2(H{sub 2}O). α- and β-An(HPO{sub 2}OH){sub 4} crystallize in space groups C2/c and P2{sub 1}/n, respectively, and comprise a three-dimensional network of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO{sub 3})(HPO{sub 2}OH){sub 2}(H{sub 2}O){sub 2}·(H{sub 2}O) crystallizes in a layered structure in space group Pbca that is composed of An{sup 4+} cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO{sub 3} and H{sub 3}PO{sub 3} at 100 °C and subsequent reaction with DMF produces crystals of (NH{sub 2}(CH{sub 3}){sub 2})[UO{sub 2}(HPO{sub 2}OH)(HPO{sub 3})] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO{sub 2}OH){sub 4} (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite

  4. Structure of seven organic salts assembled from 2,6-diaminopyridine with monocarboxylic acids, dicarboxylic acids, and tetracarboxylic acids

    Science.gov (United States)

    Gao, Xingjun; Zhang, Huan; Wen, Xianhong; Liu, Bin; Jin, Shouwen; Wang, Daqi

    2015-08-01

    Studies concentrating on non-covalent interactions between the organic base of 2,6-diaminopyridine, and carboxylic acids have led to an increased understanding of the role 2,6-diaminopyridine in binding with carboxylic acid derivatives. Here anhydrous and hydrated multi-component organic acid-base salts of 2,6-diaminopyridine have been prepared with the carboxylic acids as nicotinic acid, o-chlorobenzoic acid, 1,3-benzodioxole-5-carboxylic acid, 3,5-dinitrosalicylic acid, 4-nitro-phthalic acid, 1,4-cyclohexanedicarboxylic acid, and butane-1,2,3,4-tetracarboxylic acid. The seven crystalline compounds were characterized by X-ray diffraction analysis, infrared (IR), melting point (mp), and elemental analysis. All structures adopted the hetero R22(8) supramolecular synthons. The supramolecular architectures bear extensive Nsbnd H⋯N, Osbnd H⋯N, Osbnd H⋯O, Nsbnd H⋯O, and CH⋯O associations as well as other nonbonding contacts as CHsbnd N, CH2sbnd O, π-π, C-π, O-π, Cl-π, Clsbnd O, and Osbnd O interactions. The role of weak and strong hydrogen bonding in the crystal packing is ascertained.

  5. SEM ANALYSIS OF THE ACID-ETCHED ENAMEL PATTERNS PROMOTED BY ACIDIC MONOMERS AND PHOSPHORIC ACIDS

    OpenAIRE

    Mirela Sanae Shinohara; Marcelo Tavares de Oliveira; Vinícius Di Hipólito; Marcelo Giannini; Mario Fernando de Goes

    2006-01-01

    ABSTRACT OBJECTIVE: Although self-etching bonding systems (SES) are indicated to prepare dental enamel for bonding, concerns have been expressed regarding their effectiveness. The aim of this study was to analyze the etching pattern (EP) of nine SES in comparison with 35% and 34% phosphoric acid etchants (FA) on intact (IN) and ground (GR) enamel surface. MATERIALS AND METHODS: Twenty-two human third molars were sectioned in mesial-distal and buccal-lingual directions, and four dental fragmen...

  6. Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and Its Relevance to Europa

    Science.gov (United States)

    Loeffler, M. J.; Hudson, R. L.; Moore, M. H.; Carlson, R. W.

    2011-01-01

    We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4 H2O), and sulfuric acid tetrahydrate (H2SO4 4H2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4(exp -), and SO4(exp 2-). At high radiation doses, we find that H2SO4 molecules are destroyed completely and that H2SO4 H2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H2SO4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H2SO4 or H2SO4 H2O, the loss of H2SO4 4H2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa s surface, we speculate that the variations in SO2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

  7. Simultaneous detection of ascorbic acid, uric acid and homovanillic acid at copper modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraju, T. [Centre for Photoelectrochemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021 (India); Ramaraj, R. [Centre for Photoelectrochemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021 (India)]. E-mail: ramarajr@yahoo.com

    2007-02-15

    The copper was deposited on glassy carbon (GC) and indium tin oxide (ITO) electrodes by electrochemical method. The copper structures on electrode were characterized by atomic force microscope, X-ray diffractometeric pattern and differential pulse voltammetric studies. Optimal conditions for uniform growth of copper structures on the electrode were established. Voltammetric sensor was fabricated using the copper deposited GC electrode for the simultaneous detection and determination of uric acid (UA) and homovanillic acid (HVA) in the presence of excess concentrations of ascorbic acid (AA). The voltammetric signals due to AA and UA oxidation were well separated with a potential difference of 400 mV and AA did not interfere with the measurement of UA and HVA at the GC/Cu electrode. Linear calibration curves were obtained in the concentration range 1-40 {mu}M for AA and 20-50 {mu}M for UA at physiological pH and a detection limit of 10 nM of UA in the presence of 10-fold excess concentrations of AA was achieved. The simultaneous detection of submicromolar concentrations of AA, UA and HVA was achieved at the GC/Cu electrode. The practical utility of the present GC/Cu modified electrode was demonstrated by measuring the AA content in Vitamin C tablet, UA content in human urine and blood serum samples with satisfactory results.

  8. Recombinant Streptomyces clavuligerus strain including cas2 gene production and analysis its antibiotic overproduction by bioassay

    Directory of Open Access Journals (Sweden)

    Zohreh Hojati

    2014-03-01

    Full Text Available Background: Streptomyces clavuligerus is one of the most important strain that produce clavulanic acid that wildly used in combination of strong but sensitive to β-lactamase antibiotics in clinics. The cas2 is one of the important genes in the biosynthesis pathway of clavulanic acid. Materials and Methods: The recombinant construct pMTcas2 which contain cas2 gene is obtained from Isfahan University. Recombinant plasmid extracts from streptomyces lividans and confirm by enzyme digestion. The streptomyces clavuligerus protoplast was prepared and transformation was done by using polyethylene glycol. Transformation was confirmed by plasmid extraction and PCR using cas2 specific primers. Finally, bioassay method was used to survey the effect of extra copy of cas2 on clavulanic acid production. Result: Plasmid extraction was initially carried out and the structure of plasmid was confirmed by digestion. The typical white colony was seen on protoplast recovery culture containing thiostrepton antibiotic and gray spores were detected after one week. Plasmid extraction was done from transformed strain and transformation was confirmed by PCR. The results of the bioassay show that amplification of the cas2 gene in multicopy plasmids resulted in a 4.1 fold increase in clavulanic acid production. Conclusion: The bioassay was done and the diameters of zone of inhibition in control and sample were compared. The results of the bioassay show that amplification of the cas2 gene in multicopy plasmids resulted in a 4.1 fold increase in clavulanic acid production. Overproduction of clavulanic acid decreases the cost of its dependent drug production.

  9. Desaturation of fatty acids in Trypanosoma cruzi

    International Nuclear Information System (INIS)

    Uptake and metabolism of saturated (16:0, 18:0) and unsaturated [18:1(n-9), 18:2(n-6), 18:3(n-3)] fatty acids by cultured epimastigotes of Trypanosoma cruzi were studied. Between 17.5 and 33.5% of the total radioactivity of [1-14C]labeled fatty acids initially added to the culture medium was incorporated into the lipids of T. cruzi and mostly choline and ethanolamine phospholipids. As demonstrated by argentation thin layer chromatography, gas liquid chromatography and ozonolysis of the fatty acids synthesized, exogenous palmitic acid was elongated to stearic acid, and the latter was desaturated to oleic acid and 18:2 fatty acid. The 18:2 fatty acid was tentatively identified as linoleic acid with the first bond in the delta 9 position and the second bond toward the terminal methyl end. Exogenous stearic acid was also desaturated to oleic and 18:2 fatty acid, while oleic acid was only converted into 18:2. All of the saturated and unsaturated fatty acids investigated were also converted to a small extent (2-4%) into polyunsaturated fatty acids. No radioactive aldehyde methyl ester fragments of less than nine carbon atoms were detected after ozonolysis of any of the fatty acids studied. These results demonstrate the existence of delta 9 and either delta 12 or delta 15 desaturases, or both, in T. cruzi and suggest that delta 6 desaturase or other desaturases of the animal type are likely absent in cultured forms of this organism

  10. Uptake of actinides by sulphonated phosphinic acid resin from acid medium

    International Nuclear Information System (INIS)

    The removal of uranium and americium from nitric acid solutions by sulphonated phosphinic acid resin has been investigated. The capacity of the sulphonated resin exceeds the capacities of phosphinic acid resin and commercial cation exchange resin. Other advantages of the sulphonated resin for uranium and americium removal include reduced sensitivity to acidity and inert salt concentration. (author)

  11. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  12. Molecular pharmacology of 4-substituted glutamic acid analogues at ionotropic and metabotropic excitatory amino acid receptors

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Nielsen, B; Stensbøl, T B; Johansen, T N; Skjaerbaek, N; Krogsgaard-Larsen, P

    The pharmacology of (2S,4R)-4-methylglutamic acid, (2S,4S)-4-methylglutamic acid and (S)- and (R)-4-methyleneglutamic acids (obtained in high chemical and enantiomeric purity from racemic 4-methyleneglutamic acid by chiral HPLC using a Crownpak CR(+) column), was examined in binding experiments u...

  13. Device for the detection of acid vapors and particularly hydrofluoric acid vapors

    International Nuclear Information System (INIS)

    This device concerns the detection of acid vapors contained in a gaseous environment which have to be controlled. It uses a detector with a calorimetric material. It can be used to detect acid vapors, but it detects particularly hydrofluoric acid vapors. In nuclear industry, this device can detect hydrofluoric acid from UF6, even at high temperature. (TEC)

  14. Kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid

    NARCIS (Netherlands)

    Girisuta, B.; Janssen, L. P. B. M.; Heeres, H. J.

    2007-01-01

    A variety of interesting bulk chemicals is accessible by the acid-catalyzed hydrolysis of cellulose. An interesting example is levulinic acid, a versatile precursor for fuel additives, polymers, and resins. A detailed kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid is r

  15. Interference effects from coexisting fatty acids on elaidic acid separation by fractionating crystallization: A model study

    DEFF Research Database (Denmark)

    Jala, Ram Chandra Reddy; Guo, Zheng; Bjerring, Thomas;

    2010-01-01

    A multi-stage temperature-programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating...

  16. Separation and identification of amino acids from lignite humic acids by thin layer chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Damian, L.; Marutoiu, C.; Niac, G.

    1985-07-01

    Thin layer chromatography with and without temperature gradient was used to identify ten amino acids in the humic acid hydrolysate of Rovinari lignite, using cellulose and volcanic tuff as stationary phases. The acids found were L-leucine, isoleucine, phenylalanine, L-valine, tyrosine, proline, L-alanine, glutamic acid, threonine and L-lysine. 8 references.

  17. Determination of bile acids by radioimmunoassays

    International Nuclear Information System (INIS)

    The present paper, based on the current literature, considers the practical aspects of bile acid radioimmunoassays. The problems assoziated with the raising of specific antisera and their characterization are discussed. Features of assay design for bile acids are considered. Solid-phase radioimmunoassays are described for separate determination of unconjugated cholic acid and conjugated cholic acid in serum. The clinical application of specific bile acid radioimmunoassays is shown by an 'oral cholate tolerance test' as a sensitive indicator of liver function and by an 'oral cholylglycine tolerance test' for characterization of intenstinal function in diarrheal states. (orig.)

  18. Formation constants of mixed ligand complexes of oxovanadium(IV) with salicylic acid/5-sulphosalicylic acid/8-hydroxyquinoline-5-sulphonic acid and hippuric acid

    International Nuclear Information System (INIS)

    Equilibrium studies are described on the interaction of oxovanadium(IV) with salicylic acid (SA)/5-sulphosalicylic acid (SSA)/8-hydroxyquinoline-5-sulphonic acid (HQSA) in presence of hippuric acid. The formation of 1:1:1 mixed ligand complexes and their hydroxo derivatives inferred from the pH-metric titration curves and formation constants of 1:1:1 ternary complexes have been evaluated at 30 +- 0.5deg (μ = 0.1 M KNO3). The order of stability of ternary complexes has been found to be the same as that of 1:1 binary complexes involving hydroxy acids. (author)

  19. Bile acids in regulation of intestinal physiology.

    LENUS (Irish Health Repository)

    Keating, Niamh

    2009-10-01

    In addition to their roles in facilitating lipid digestion and absorption, bile acids are recognized as important regulators of intestinal function. Exposure to bile acids can dramatically influence intestinal transport and barrier properties; in recent years, they have also become appreciated as important factors in regulating cell growth and survival. Indeed, few cells reside within the intestinal mucosa that are not altered to some degree by exposure to bile acids. The past decade saw great advances in the knowledge of how bile acids exert their actions at the cellular and molecular levels. In this review, we summarize the current understanding of the role of bile acids in regulation of intestinal physiology.

  20. Solvent extraction of metals with hydroxamic acids.

    Science.gov (United States)

    Vernon, F; Khorassani, J H

    1978-07-01

    Solvent extraction with hydroxamic acids has been investigated. with comparison of aliphatic and aromatic reagents for the extraction of iron, copper, cobalt and nickel. Caprylohydroxamic acid has been evaluated for use in extraction systems for titanium, vanadium, chromium, molybdenum and uranium, both in terms of acidity of aqueous phase and oxidation state of the metal. It has been established that caprylohydroxamic acid in 1-hexanol is a suitable extractant for the removal of titanium(IV), vanadium(V), chromium(VI), molybdenum(VI) and uranium(VI) from 6M hydrochloric acid. PMID:18962288

  1. Chicoric acid: chemistry, distribution, and production

    Directory of Open Access Journals (Sweden)

    Jungmin eLee

    2013-12-01

    Full Text Available Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike. Additionally, chicoric acid identification and quantification methods, biosynthesis, processing improvements to increase chicoric acid retention, and potential areas for future research are discussed.

  2. DOES JASMONIC ACID PREVENT THE GERMINATION

    OpenAIRE

    ÇAVUŞOĞLU, Kürşat

    2009-01-01

    Abstract: Effect of jasmonic acid on seed germination and seedling growth of barley (Hordeum vulgare L. cv. Bülbül 89) was investigated in the present study. Jasmonic acid concentrations less than 1500 µM have not inhibited the seed germination, while 1500 and 2000 µM jasmonic acid levels caused atypical germination. The germination was completely inhibited at 3000 µM level of jasmonic acid. However, the seedling growth clearly slowed down with increasing concentrations of jasmonic acid. Furt...

  3. The Specifications for Monitoring of Acid Rain

    Institute of Scientific and Technical Information of China (English)

    Tang Jie

    2011-01-01

    Background Since China is a country seriously affected by acid rain pollution,it is a long-term fundamental work for acid rain pollution prevention and control in China by getting well informed of the characteristics of spatial and temporal changes in acid rain and long-term trends of these changes.In order to reach the national demand for acid rain monitoring data,the China Meteorological Administration (CMA) began to construct the network of acid rain monitoring stations in 1992.By the end of 2010,the total number of monitoring stations has exceeded 340.

  4. Lactobionic and cellobionic acid production profiles of the resting cells of acetic acid bacteria.

    Science.gov (United States)

    Kiryu, Takaaki; Kiso, Taro; Nakano, Hirofumi; Murakami, Hiromi

    2015-01-01

    Lactobionic acid was produced by acetic acid bacteria to oxidize lactose. Gluconobacter spp. and Gluconacetobacter spp. showed higher lactose-oxidizing activities than Acetobacter spp. Gluconobacter frateurii NBRC3285 produced the highest amount of lactobionic acid per cell, among the strains tested. This bacterium assimilated neither lactose nor lactobionic acid. At high lactose concentration (30%), resting cells of the bacterium showed sufficient oxidizing activity for efficient production of lactobionic acid. These properties may contribute to industrial production of lactobionic acid by the bacterium. The bacterium showed higher oxidizing activity on cellobiose than that on lactose and produced cellobionic acid. PMID:25965080

  5. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    Institute of Scientific and Technical Information of China (English)

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao

    2005-01-01

    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  6. Evolution of retinoic acid receptors and retinoic acid signaling.

    Science.gov (United States)

    Gutierrez-Mazariegos, Juliana; Schubert, Michael; Laudet, Vincent

    2014-01-01

    Retinoic acid (RA) is a vitamin A-derived morphogen controlling important developmental processes in vertebrates, and more generally in chordates, including axial patterning and tissue formation and differentiation. In the embryo, endogenous RA levels are controlled by RA synthesizing and degrading enzymes and the RA signal is transduced by two retinoid receptors: the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). Both RAR and RXR are members of the nuclear receptor superfamily of ligand-activated transcription factors and mainly act as heterodimers to activate the transcription of target genes in the presence of their ligand, all-trans RA. This signaling pathway was long thought to be a chordate innovation, however, recent findings of gene homologs involved in RA signaling in the genomes of a wide variety of non-chordate animals, including ambulacrarians (sea urchins and acorn worms) and lophotrochozoans (annelids and mollusks), challenged this traditional view and suggested that the RA signaling pathway might have a more ancient evolutionary origin than previously thought. In this chapter, we discuss the evolutionary history of the RA signaling pathway, and more particularly of the RARs, which might have experienced independent gene losses and duplications in different animal lineages. In sum, the available data reveal novel insights into the origin of the RA signaling pathway as well as into the evolutionary history of the RARs. PMID:24962881

  7. Composition of acid tars from sulfuric acid treatment of petroleum oils

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, A.F.; Denisova, T.L.; Karpova, I.V.; Titova, T.S.

    1986-01-01

    This paper examines the composition of freshly produced acid tars and pond tars, gives an analysis of the acid part of the tars, and obtains data on the change in composition of the acid tar in the course of storage--data that are needed in developing methods for utilizing the tar. The acid-pond tars consist of a mixture of hydrocarbons with a very low content of acids, whereas the freshly produced acid tars consist mainly of sulfuric acid, sulfonic acids, and carboxylic acids. In the course of storage, hardening of acid tars in the volume proceeds through reactions of polymerization, condensation, and oxidation of the surface layer that is in contact with air.

  8. CLIMATE CHANGE ADAPTATION IN ACID SULFATE LANDSCAPES

    Directory of Open Access Journals (Sweden)

    Chuxia Lin

    2012-01-01

    Full Text Available Oxidation of sulfide minerals produces sulfuric acid and consequently creates Acid Sulfate Landscapes (ASLs, which represent one of the most degraded types of land-surface environments. Although acid sulfate-producing weathering is a naturally occurring process, it is markedly facilitated by human intervention. Mining is by far the dominant anthropogenic cause for the creation of inland acid sulfate footprints while land reclamation in coastal lowlands is the driver for the formation of coastal ASLs. The projected climate change highlights the possibility of an increase in the frequency and severity of extreme weather events such as droughts and heavy rains, which is likely to accelerate the acid generation in some circumstances and increase the frequency and magnitude of acid discharge. Sea level rise as a result of global warming will cause additional problems with the coastal ASLs. This is a review article. The following aspects are covered: (a the overriding biogeochemical processes leading to acid sulfate-producing weathering, (b a brief introduction to the inland acid sulfate landscapes, (c a brief introduction to the coastal acid sulfate landscapes, (d the likely impacts of climate change on ASLs and (e the possible measures to combat climate change-induced environmental degradation in the identified key acid sulfate footprints. The projected climate change is like to significantly affect the acid sulfate landscapes in different ways. Appropriate management strategies and cost-effective technologies need to be developed in order to minimize the climate change-induced ecological degradation.

  9. Amino acid properties conserved in molecular evolution.

    Directory of Open Access Journals (Sweden)

    Witold R Rudnicki

    Full Text Available That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts - one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications.

  10. Microbial production of citric acid

    Directory of Open Access Journals (Sweden)

    Luciana P. S Vandenberghe

    1999-01-01

    Full Text Available Citric acid is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch based media. However, other fermentation techniques, e.g. solid state fermentation and surface fermentation, and alternative sources of carbon such as agro-industrial residues have been intensively studied showing great perspective to its production. This paper reviews recent developments on citric acid production by presenting a brief summary of the subject, describing micro-organisms, production techniques, and substrates, etc.O ácido cítrico é o ácido mais produzido em termos de tonagem e é extensivamente utilizado pelas indústrias alimentícia e farmacêutica. É produzido principalmente por fermentação submersa utilizando o fungo Aspergillus niger e leveduras do gênero Candida sp. à partir de diferentes fontes de carbono, como a glicose e meios à base de amido. No entanto, outras técnicas de fermentação, e.g. fermentação no estado sólido e em superfície, e fontes alternativas de carbono tem sido intensamente estudadas mostrando grande perspectivas para o processo. O presente trabalho apresenta um resumo dos últimos avanços sobre a produção do ácido cítrico, descrevendo de maneira sucinta os trabalhos mais recentes, descrevendo microrganismos, técnicas de produção e substratos empregados, etc.

  11. Structure Property Relationships of Carboxylic Acid Isosteres.

    Science.gov (United States)

    Lassalas, Pierrik; Gay, Bryant; Lasfargeas, Caroline; James, Michael J; Tran, Van; Vijayendran, Krishna G; Brunden, Kurt R; Kozlowski, Marisa C; Thomas, Craig J; Smith, Amos B; Huryn, Donna M; Ballatore, Carlo

    2016-04-14

    The replacement of a carboxylic acid with a surrogate structure, or (bio)-isostere, is a classical strategy in medicinal chemistry. The general underlying principle is that by maintaining the features of the carboxylic acid critical for biological activity, but appropriately modifying the physicochemical properties, improved analogs may result. In this context, a systematic assessment of the physicochemical properties of carboxylic acid isosteres would be desirable to enable more informed decisions of potential replacements to be used for analog design. Herein we report the structure-property relationships (SPR) of 35 phenylpropionic acid derivatives, in which the carboxylic acid moiety is replaced with a series of known isosteres. The data set generated provides an assessment of the relative impact on the physicochemical properties that these replacements may have compared to the carboxylic acid analog. As such, this study presents a framework for how to rationally apply isosteric replacements of the carboxylic acid functional group. PMID:26967507

  12. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

    Directory of Open Access Journals (Sweden)

    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  13. Pairwise amino acid secondary structural propensities

    Science.gov (United States)

    Chemmama, Ilan E.; Chapagain, Prem P.; Gerstman, Bernard S.

    2015-04-01

    We investigate the propensities for amino acids to form a specific secondary structure when they are paired with other amino acids. Our investigations use molecular dynamics (MD) computer simulations, and we compare the results to those from the Protein Data Bank (PDB). Proper comparison requires weighting of the MD results in a manner consistent with the relative frequency of appearance in the PDB of each possible pair of amino acids. We find that the propensity for an amino acid to assume a secondary structure varies dramatically depending on the amino acid that is before or after it in the primary sequence. This cooperative effect means that when selecting amino acids to facilitate the formation of a secondary structure in peptide engineering experiments, the adjacent amino acids must be considered. We also examine the preference for a secondary structure in bacterial proteins and compare the results to those of human proteins.

  14. Nucleic acid delivery with microbubbles and ultrasound.

    Science.gov (United States)

    Rychak, Joshua J; Klibanov, Alexander L

    2014-06-01

    Nucleic acid-based therapy is a growing field of drug delivery research. Although ultrasound has been suggested to enhance transfection decades ago, it took a combination of ultrasound with nucleic acid carrier systems (microbubbles, liposomes, polyplexes, and viral carriers) to achieve reasonable nucleic acid delivery efficacy. Microbubbles serve as foci for local deposition of ultrasound energy near the target cell, and greatly enhance sonoporation. The major advantage of this approach is in the minimal transfection in the non-insonated non-target tissues. Microbubbles can be simply co-administered with the nucleic acid carrier or can be modified to carry nucleic acid themselves. Liposomes with embedded gas or gas precursor particles can also be used to carry nucleic acid, release and deliver it by the ultrasound trigger. Successful testing in a wide variety of animal models (myocardium, solid tumors, skeletal muscle, and pancreas) proves the potential usefulness of this technique for nucleic acid drug delivery. PMID:24486388

  15. The Strongest Acid: Protonation of Carbon Dioxide.

    Science.gov (United States)

    Cummings, Steven; Hratchian, Hrant P; Reed, Christopher A

    2016-01-22

    The strongest carborane acid, H(CHB11F11), protonates CO2 while traditional mixed Lewis/Brønsted superacids do not. The product is deduced from IR spectroscopy and calculation to be the proton disolvate, H(CO2)2(+). The carborane acid H(CHB11F11) is therefore the strongest known acid. The failure of traditional mixed superacids to protonate weak bases such as CO2 can be traced to a competition between the proton and the Lewis acid for the added base. The high protic acidity promised by large absolute values of the Hammett acidity function (H0) is not realized in practice because the basicity of an added base is suppressed by Lewis acid/base adduct formation. PMID:26663640

  16. Propylenated fatty acids as emulsifiers

    OpenAIRE

    El-Shattory, Y.; Aly, Saadia M.; Megahed, M. G.

    1999-01-01

    Hydroxy propylenyl stéarate, palmitate, laurate, oléate and linoleate were prepared by reaction of propylene oxide with fatty acid at 160 °C for five hours stirring in presence of potassium hydroxide as a catalyst. Physico-chemical properties of the five products, regarding their use as emulsifiers, were determined.

    Se prepararon estearato, palmitato, laurato, oleato y linoleato de hidroxipropilenilos mediante reacción de oxido de propileno con ácido graso a 160 °C durante ...

  17. Acid resistance in enteric bacteria.

    OpenAIRE

    Gorden, J; Small, P L

    1993-01-01

    Shigella species require a uniquely small inoculum for causing dysentery. One explanation for the low infective dose is that Shigella species are better able to survive the acidic conditions encountered in the stomach than are other enteric pathogens. We have tested Shigella species, Escherichia coli, and Salmonella species for the ability to survive at pH 2.5 for at least 2 h. Most isolates of Shigella and E. coli survived this treatment, whereas none of the Salmonella isolates were able to ...

  18. Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids

    Science.gov (United States)

    Helinck, Sandra; Le Bars, Dominique; Moreau, Daniel; Yvon, Mireille

    2004-01-01

    Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus to produce aroma compounds from three amino acids, leucine, phenylalanine, and methionine, under mid-pH conditions of cheese ripening (pH 5.5), and we investigated the catabolic pathways used by these bacteria. In the three lactic acid bacterial species, amino acid catabolism was initiated by a transamination step, which requires the presence of an α-keto acid such as α-ketoglutarate (α-KG) as the amino group acceptor, and produced α-keto acids. Only S. thermophilus exhibited glutamate dehydrogenase activity, which produces α-KG from glutamate, and consequently only S. thermophilus was capable of catabolizing amino acids in the reaction medium without α-KG addition. In the presence of α-KG, lactobacilli produced much more varied aroma compounds such as acids, aldehydes, and alcohols than S. thermophilus, which mainly produced α-keto acids and a small amount of hydroxy acids and acids. L. helveticus mainly produced acids from phenylalanine and leucine, while L. delbrueckii subsp. lactis produced larger amounts of alcohols and/or aldehydes. Formation of aldehydes, alcohols, and acids from α-keto acids by L. delbrueckii subsp. lactis mainly results from the action of an α-keto acid decarboxylase, which produces aldehydes that are then oxidized or reduced to acids or alcohols. In contrast, the enzyme involved in the α-keto acid conversion to acids in L. helveticus and S. thermophilus is an α-keto acid dehydrogenase that produces acyl coenzymes A. PMID:15240255

  19. Direct amidation of amino acid derivatives catalyzed by arylboronic acids : applications in dipeptide synthesis.

    OpenAIRE

    Liu, S.; Yang, Y.; Liu, X.; Ferdousi, F. K.; Batsanov, A.S.; Whiting, A

    2013-01-01

    The direct amidation of amino acid derivatives catalyzed by arylboronic acids has been examined. The reaction was generally slow relative to simple amine-carboxylic acid combinations though proceeded at 65–68 °C generally avoiding racemization. 3,4,5-Trifluorophenylboronic and o-nitrophenylboronic acids were found to be the best catalysts, though for slower dipeptide formations, high catalyst loadings were required and an interesting synergistic catalytic effect between two arylboronic acids ...

  20. Antimicrobial susceptibility and Ribosomal-RNA gene restriction patterns among Staphylococcus-intermedius from healthy dogs and from dogs sufferning from pyoderma or otitis-externa

    DEFF Research Database (Denmark)

    Pedersen, Karl; Wegener, Henrik Caspar

    1995-01-01

    10 strains from a previous study. Sixty per cent of the 50 strains tested for antibiotic susceptibility demonstrated resistance to penicillin, 24% to spiramycin, 20% to tetracycline, 16% to chloramphenicol, and 2% to fucidic acid, All isolates were susceptible to amoxycillin with clavulanic acid...