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1

Hippuric acid and methyl hippuric acid in rat hair: possible monitoring of xylene and toluene exposure.  

PubMed

Thinner is mainly composed of toluene and xylenes, and we studied the incorporation of the main metabolites of toluene and xylenes, hippuric acid (HA) and o-, m-, and p-methyl hippuric acids (o-, m-, p-MHA), in dark agouti rats' hair. Rat black hair was shaved before any exposure with an electric shaver designed for animals. Studies were performed in vivo with exposures of 30 min per day at three different concentrations (100, 300, and 1000 ppm) of toluene and o-, m-, and p-xylene for a total of 10 times over 2 weeks. Newly grown hair was tweezed out from the root with tweezers at seventh of the last exposure. Hair samples were then washed, extracted, derivatized, and analyzed by gas chromatography-mass spectrometry (GC-MS). HA and o-, m-, and p-MHA were not detected (ND) in the unexposed rat hair. After exposure, the metabolite concentration in the hair changed depending on the exposure concentration. Mean concentrations ranged from ND to 7.6 ng/mg, from ND to 13.8 ng/mg, from ND to 10.1 ng/mg, and from ND to 9.2 ng/ml hair for HA, o-, m-, and p-MHA, respectively. These results indicate that the metabolites concentrations in hair are effective indices of thinner exposure. PMID:12742703

Saito, Takeshi; Kusakabe, Takahiko; Takeichi, Sanae

2003-04-23

2

Hippuric acid as a modifier of calcium oxalate crystallisation.  

PubMed

Hippuric acid (HA) originating from the conjugation of benzoic acid with glycine is a physiological component of human urine. Findings suggest that HA inhibits calcium oxalate (CaOx) growth and considerably enhances the CaOx solubility in artificial urine. Thus, it is assumed that HA is a major modifier of CaOx formation. However, only a slight CaOx growth inhibition of 1-8% was also reported. These values were also derived from artificial urine. The key mechanism, which led HA to be of interest in urolithiasis research is the fact that in presence of Ca2+ ions HA can form a hippurate complex. By forming such a complex, Ca2+ concentration in urine decreases, and as a consequence, CaOx formation is inhibited. This study was performed in order to clarify the role of HA in native and artificial urine. Biochemical analyses to calculate the relative CaOx supersaturations and crystallisation experiments using an in-line laser probe were examined. BONN Risk Indices indicating the risk of CaOx crystallisation were calculated from the results of the crystallisation experiments. The results obtained from artificial as well as from native urines showed that HA has no significant effects on CaOx formation. We suggest that HA plays only a minor role as a crystallisation modifier in human urine. PMID:11350018

Laube, N; Jansen, B; Schneider, A; Steffes, H J; Hesse, A

2001-03-01

3

High-performance liquid chromatographic analysis of hippuric acid in human blood plasma.  

PubMed

A method has been developed for the isocratic high-performance liquid chromatographic analysis of hippuric acid in human blood plasma. After the addition of an internal standard (3-methoxysalicylic acid), plasma samples (1 ml) were made alkaline and extracted stepwise with methylene chloride and ethyl acetate. The detection limit was 50 pmol of hippuric acid per ml of plasma. The concentrations of hippuric acid in plasma from house painters (n = 8), with long-term exposure to solvent vapours from alkyd paints, were in the range 1-21 nmol/mol (median 11 nmol/ml). These values were statistically significantly higher than those for controls (n = 9): 2-8 nmol/ml (median 3 nmol/ml). PMID:2079538

Beving, H; Olsson, U; Bemgård, A; Kristensson, J; Palmborg, J; Sollenberg, J

1990-10-26

4

Determination of hippuric acid in human urine by ion chromatography with conductivity detection.  

PubMed

A simple, rapid, precise and eco-friendly ion chromatography (IC) method for the determination of hippuric acid (HA) in human urine was proposed in this paper. The separation was carried out an anion exchange column with 2.0 mmol L?¹ Na?CO? + 2.0 mmol L?¹ NaHCO? as mobile phase at the flow-rate 0.7 mL min?¹. A suppressed conductivity detector was used and the detection limit was 1.0 ?g L?¹ (S/N=3) for hippuric acid. The analysis time for one run was 30 min under the optimized IC condition. The recovery of hippuric acid was 93.2-98.0% while the relative standard deviation (RSD) was 1.4-2.3% by seven measurements. PMID:21236740

Zhao, Fuyong; Wang, Zonghua; Wang, Hui; Ding, Mingyu

2010-12-28

5

Differentiation of organic goat's milk based on its hippuric acid content as determined by capillary electrophoresis.  

PubMed

Organic foods have lately aroused interest by virtue of their quality and their essential, exclusive characteristics. In this study, we assessed the potential of CE to detect a marker that is able to identify the particular food given to the goats and develop an effective method to determine directly the most abundant organic acid in goat's milk (viz. hippuric acid). In addition, we examined the use of the hippuric acid content of goat's milk as a general marker for authenticating organic goat's milk. The feeding of these goats can be influenced by the time of the year. For this reason, we have collected samples from 20 conventionally fed goats and 20 organically fed goats over a period of 2 months. A threshold value dependent on the hippuric acid content was thus established for the first time with a view to discriminating between conventional and organic goat's milk. Organic acids in goat's milk were separated in a running buffer consisting of 120 mM sodium tetraborate decahydrate and 0.5 mM CTAB set to pH 8. The precision of the ensuing method is acceptable for hippuric acid; thus, the RSD for peak area and migration time was less than 10 and 4%, respectively. Also, calibration curves were linear throughout the studied concentration range. PMID:20593395

Carpio, Azahara; Rodríguez-Estévez, Vicente; Sánchez-Rodríguez, Manuel; Arce, Lourdes; Valcárcel, Miguel

2010-07-01

6

The mitigation potential of hippuric acid on N 2O emissions from urine patches: An in situ determination of its effect  

Microsoft Academic Search

Previous laboratory studies have demonstrated that hippuric acid, a ruminant urine constituent, can mitigate nitrous oxide (N2O) emissions from simulated urine patches. Hippuric acid has the potential to be a N2O mitigation tool because animal diets can be manipulated to adjust its concentration in the urine. This study was conducted to determine if the effect observed in previous laboratory studies

Tim J. Clough; Jessica L. Ray; Laura E. Buckthought; Joanne Calder; David Baird; Maureen O'Callaghan; Robert R. Sherlock; Leo M. Condron

2009-01-01

7

Effect of urea and thiourea on nonlinear optical hippuric acid crystals  

NASA Astrophysics Data System (ADS)

Pure, urea and thiourea doped hippuric acid (HA) single crystals have been grown in acetone using slow evaporation technique at a constant temperature, with the vision to improve the properties of the crystals. The crystal systems and the unit cell parameters of the grown crystals were identified from single crystal X-ray diffraction. The crystalline nature of the grown crystals was confirmed by powder X-ray diffraction and the diffraction peaks were indexed. The variations in composition due to the addition of dopants were identified by CHNS analysis. FT-IR studies reveal the presence of different vibrational bands. The optical characteristics were assessed by UV-vis analysis and it indicates the transmission in the visible region. TGA and DSC studies indicate the thermal behavior of pure and doped crystals. The Second Harmonic Generation (SHG) has been tested using Kurtz Powder Technique for the pure and doped crystals. It is found that the thiourea doped hippuric acid crystals have SHG efficiency of 2.08 times higher than that of potassium dihydrogen phosphate (KDP) single crystal. The dielectric studies were carried out, and the variations of dielectric constant and dielectric loss with temperature have been studied.

Krishna Mohan, M.; Jagannathan, K.; Ponnusamy, S.; Muthamizhchelvan, C.

2011-11-01

8

[Improved high performance liquid chromatography determination of hippuric acid and methylhippuric acid isomers in urine].  

PubMed

A study was made on the effect of detection wavelength and separation mode of HPLC on determination of urinary hippuric acid (HA) and three isomers of methylhippuric acid (MHA). The interference of other constituents of urine in the determination was effectively decreased by detection at a short wavelength of 227.6 nm. Meta and para MHAs were separated by the addition of beta-cyclodextrine to the mobile phase. Four metabolites were successfully separated from other components of urine by the combination of ODS-silica packed-column and mobile phase (method F). The detection limits were found to be 50 and 5 mg/l for HA and MHAs, respectively. MHAs could not be detected in the non-exposed subjects. Average levels (+/- SD) of HA in non-exposed males and females were 272.2 (+/- 210.8) and 393.0 (+/- 269.8) mg/l, respectively. The urinary levels of HA in females were significantly higher than those in males. PMID:3586389

Takeuchi, Y; Sakai, T; Ikeya, Y; Araki, T; Ushio, K; Yanagihara, S

1986-11-01

9

Evaluation of hippuric acid content in goat milk as a marker of feeding regimen.  

PubMed

Organic producers, traders, and consumers must address 2 issues related to milk: authentication of the production system and nutritional differentiation. The presence of hippuric acid (HA) in goat milk samples has been proposed as a possible marker to differentiate the feeding regimen of goats. The objective of this work is to check the hypothesis that HA could be a marker for the type of feeding regimen of goats by studying the influence of production system (conventional or organic) and feeding regimen (with or without grazing fodder). With this purpose, commercial cow and goat milk samples (n=27) and raw goat milk samples (n=185; collected from different breeds, localizations, and dates) were analyzed. Samples were grouped according to breed, feeding regimen, production system, and origin to compare HA content by ANOVA and honestly significant difference Tukey test at a confidence level of ?95%. Hippuric acid content was obtained by analyzing milk samples with capillary electrophoresis. This method was validated by analyzing part of the samples with HPLC as a reference technique. Sixty-nine raw goat milk samples (of the total 158 samples analyzed in this work) were quantified by capillary electrophoresis. In these samples, the lowest average content for HA was 7±3 mg/L. This value corresponds to a group of conventional raw milk samples from goats fed with compound feed. The highest value of this group was 28±10 mg/L, corresponding to goats fed compound feed plus grass. Conversely, for organic raw goat milk samples, the highest concentration was 67±14 mg/L, which corresponds to goats fed grass. By contrast, the lowest value of this organic group was 26±10 mg/L, which belongs to goats fed organic compounds. Notice that the highest HA average content was found in samples from grazing animals corresponding to the organic group. This result suggests that HA is a good marker to determine the type of goats feeding regimen; a high content of HA represents a diet based mainly or exclusively on eating green grass (grazing), independently of the production system. Hence, this marker would not be useful for the actual organic policies to distinguish organic milk under the current regulations, because organic dairy ruminants can be fed organic compound feed and conserved fodder without grazing at all. PMID:23849634

Carpio, A; Bonilla-Valverde, D; Arce, C; Rodríguez-Estévez, V; Sánchez-Rodríguez, M; Arce, L; Valcárcel, M

2013-07-10

10

Quantitative determination of hippuric and benzoic acids in urine by LC-MS/MS using surrogate standards.  

PubMed

An LC-MS/MS method for simultaneous determination of hippuric acid (HA) and benzoic acid (BA) in monkey urine after direct injection was developed. Since HA and BA are endogenous compounds in urine, surrogate standards ((13)C(6)-hippuric and (13)C(6)-benzoic acid) were employed to generate calibration curves. l-Phenylalanine-ring-D5 served as an internal standard. Multiple reaction monitoring in the negative ionization mode with an APCI source was used for detection of all components in the assay. The developed method is intended for determination of HA and BA in the range of 0.25-250 and 0.1-100microg/ml, respectively. Weighted (1/x) quadratic regression (r(2)>0.99) was used to generate calibration curves. Precision and accuracy of the method were assessed by analyzing 3 quality control samples (concentrations at low, medium, and high range of calibration curve) prepared in monkey urine. Stability for 48h at room temperature and after 3 freeze-thaw cycles was also evaluated. The proposed method was successfully utilized for analysis of urine samples from female monkeys following the administration of everninomicin alone and in combination with gentamicin. The concentrations of endogenous HA and BA were calculated based on the peak area ratio of the analyte to the internal standard using a regression equation for corresponding surrogate standard. PMID:20149566

Penner, Natalia; Ramanathan, Ragu; Zgoda-Pols, Joanna; Chowdhury, Swapan

2010-01-18

11

Effects of dietary benzoic acid and sodium-benzoate on performance, nitrogen and mineral balance and hippuric acid excretion of piglets  

Microsoft Academic Search

The objective of this study was to compare the effects of sodium-benzoate (NaB) with those of benzoic acid (BAc) on growth performance of piglets as well as nutrient digestibility, nitrogen and mineral balance, urinary pH, and the urinary excretion of BAc and hippuric acid (HAc). The study was conducted with 120 weaning piglets (6.5 kg body weight), divided in four groups

Tobias Gräber; Holger Kluge; Frank Hirche; Ji?í Brož; Gabriele I. Stangl

2012-01-01

12

Growth, structural and optical characterization of a new nonlinear optical crystal--hippuric acid doped potassium di hydrogen phosphate.  

PubMed

Potassium di hydrogen phosphate (KDP) is an efficient nonlinear optical crystal employed in frequency conversion applications. 1mol% hippuric acid doped potassium di hydrogen phosphate (HAKDP) crystals with the dimensions 35×8×4 mm(3) were grown using the slow evaporation technique. The grown HAKDP crystal is iso-structural with pure KDP, but a variation in the crystallographic parameters was observed. The UV-VIS-NIR study suggests that the crystal is highly transparent in the region 340-1200 nm. The functional groups present in the grown crystal were observed in the FTIR analysis. The powder SHG test performed on the grown crystal revealed the NLO efficiency of the crystal has increased due to doping when compared with pure KDP crystal. PMID:23648967

Kumaresh, A; Arun Kumar, R

2013-04-11

13

Growth, structural and optical characterization of a new nonlinear optical crystal - hippuric acid doped potassium di hydrogen phosphate  

NASA Astrophysics Data System (ADS)

Potassium di hydrogen phosphate (KDP) is an efficient nonlinear optical crystal employed in frequency conversion applications. 1 mol% hippuric acid doped potassium di hydrogen phosphate (HAKDP) crystals with the dimensions 35 × 8 × 4 mm3 were grown using the slow evaporation technique. The grown HAKDP crystal is iso-structural with pure KDP, but a variation in the crystallographic parameters was observed. The UV-VIS-NIR study suggests that the crystal is highly transparent in the region 340-1200 nm. The functional groups present in the grown crystal were observed in the FTIR analysis. The powder SHG test performed on the grown crystal revealed the NLO efficiency of the crystal has increased due to doping when compared with pure KDP crystal.

Kumaresh, A.; Arun Kumar, R.

2013-07-01

14

Urinary excretion of hippuric acid and m- or p-methylhippuric acid in the urine of persons exposed to vapours of toluene and m- or p-xylene as a test of exposure  

Microsoft Academic Search

Ogata, M., Tomokuni, K., and Takatsuka, Y. (1970).Brit. J. industr. Med.,27, 43-50. Urinary excretion of hippuric acid and m- or p-methylhippuric acid in the urine of persons exposed to vapours of toluene and m- or p-xylene as a test of exposure. Twenty-three male volunteers were exposed in groups of four or five to toluene and m- and p-xylene vapour for

Masana Ogata; Katsumaro Tomokuni; Yohiko Takatsuka

1970-01-01

15

Biomarkers of toluene exposure in rats: mercapturic acids versus traditional indicators (urinary hippuric acid and o-cresol and blood toluene).  

PubMed

1. Toluene (TOL) is a neurotoxic, ototoxic and reprotoxic solvent which is metabolized via the glutathione pathway, producing benzylmercapturic, o-, m- and p-toluylmercapturic acids (MAs). These metabolites could be useful as biomarkers of TOL exposure. 2. The aims of this study were (1) to provide data on MAs excretion in rat urine following TOL exposure by inhalation, (2) to compare them to data from traditional TOL biomarkers, i.e. TOL in blood (Tol-B), and urinary hippuric acid (HA) and o-cresol (oCre) and (3) to establish a relationship between these different indicators and the airborne TOL concentration (Tol-A). 3. Sprague-Dawley rats were exposed to a range of TOL concentrations. Blood and urine were collected and analyzed to determine biomarker levels. 4. Levels of the four MAs correlate strongly with Tol-A (comparable to the correlation with Tol-B). 5. MAs are thus clearly superior to oCre and HA as potential markers of exposure to TOL. PMID:23278281

Cosnier, Frédéric; Cossec, Benoît; Burgart, Manuella; Nunge, Hervé; Brochard, Céline; Décret, Marie-Josèphe; Rémy, Aurélie

2013-01-02

16

Hippurate: The Natural History of a Mammalian-Microbial Cometabolite.  

PubMed

Hippurate, the glycine conjugate of benzoic acid, is a normal constituent of the endogenous urinary metabolite profile and has long been associated with the microbial degradation of certain dietary components, hepatic function and toluene exposure, and is also commonly used as a measure of renal clearance. Here we discuss the potential relevance of hippurate excretion with regard to normal endogenous metabolism and trends in excretion relating to gender, age, and the intestinal microbiota. Additionally, the significance of hippurate excretion with respect to disease states including obesity, diabetes, gastrointestinal diseases, impaired renal function, psychological disorders and autism, as well as toxicity and parasitic infection, are considered. PMID:23342949

Lees, Hannah J; Swann, Jonathan R; Wilson, Ian D; Nicholson, Jeremy K; Holmes, Elaine

2013-03-01

17

Validation of urine density correction in cases of hippuric acid and un-metabolized toluene in urine of workers exposed to toluene.  

PubMed

To investigate if it is appropriate to apply urine density correction when a urine sample is dense or dilute. Data on hippuric acid (HA-U), toluene (Tol-U), creatinine (CR) and specific gravity (SG) in end-of-shift urine samples and exposure to air-borne toluene were cited from previous publications. In practice, 837 cases were available, and they were classified into dense, intermediate and dilute groups taking 0.3 and 3.0 g/l of CR and 1.010 and 1.030 of SG as cut-off points. Lines of regression of HA-U and Tol-U (as observed, CR-corrected or SG-corrected) with air-borne toluene were calculated for each density groups, and correlation coefficients (CCs) were compared. The dense groups gave CCs similar to those of the intermediate groups. Dilute versus intermediate group comparison also gave promising results. These conclusions were however based primarily on the findings with observed values, because the numbers of cases in the dilute or dense group were limited when CR- or SG-correction was applied. Literature survey showed that urine density correction does not always improve the correlation between solvents in air and exposure makers in urine. It was concluded that no correction for urine density may be necessary in evaluating HA-U and Tol-U in dense (and probably also dilute) urine samples as markers of occupational toluene exposure. Just in case when correction for urine density is desired for any reason, SG-correction may be recommended. PMID:20424345

Kawai, Toshio; Eitaki, Yoko; Ukai, Hirohiko; Inoue, Osamu; Maeshima, Yuki; Ueda, Naohiro; Ohashi, Fumiko; Sakurai, Haruhiko; Ikeda, Masayuki

2010-01-01

18

Differences in gut microbial metabolism are responsible for reduced hippurate synthesis in Crohn's disease  

PubMed Central

Background Certain urinary metabolites are the product of gut microbial or mammalian metabolism; others, such as hippurate, are mammalian-microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut microbial metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal conjugation of benzoate with glycine, forming hippurate. Differences in such urinary co-metabolites may therefore reflect systemic consequences of altered gut microbial metabolism, though altered host metabolic pathways may also be involved. Methods It was hypothesised that reduced hippurate excretion in CD patients was due to alterations in the gut microbiota, and not differences in dietary benzoate, nor defective host enzymatic conjugation of benzoate. 5 mg/kg sodium benzoate were administered orally to 16 CD patients and 16 healthy controls on a low-benzoate diet. Baseline and peak urinary hippurate excretion were measured. Results Baseline hippurate levels were significantly lower in the CD patients (p = 0.0009). After benzoate ingestion, peak urinary levels of hippurate did not differ significantly between the cohorts. Consequently the relative increase in excretion was significantly greater in CD (p = 0.0007). Conclusions Lower urinary hippurate levels in CD are not due to differences in dietary benzoate. A defect in the enzymatic conjugation of benzoate in CD has been excluded, strongly implicating altered gut microbial metabolism as the cause of decreased hippurate levels in CD.

2010-01-01

19

Differences in gut microbial metabolism are responsible for reduced hippurate synthesis in Crohn's disease  

Microsoft Academic Search

BACKGROUND: Certain urinary metabolites are the product of gut microbial or mammalian metabolism; others, such as hippurate, are mammalian-microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut microbial metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal

Horace RT Williams; I Jane Cox; David G Walker; Jeremy FL Cobbold; Simon D Taylor-Robinson; Sara E Marshall; Timothy R Orchard

2010-01-01

20

Long-term treatment with methenamine hippurate in recurrent urinary tract infection.  

PubMed

Twenty-four patients with a history of recurrent urinary tract infection and in whom residual urine was considered to be a factor of importance for chronicity, have been treated for an average of 16 months with 1 g methenamine hippurate morning and evening. No patient had urinary calculus at the commencement of treatment and neither did any patient have an indwelling catheter. In patients without urinary tract infection or in whom abacteriuria was achieved with methenamine hippurate, the number of reinfections was reduced by approximately two thirds compared to periods prior to treatment. No patient was completely free from infection throughout the whole treatment period. However, in no case did bacteria with extensive resistance appear. When urinary tract infection was treated with methenamine hippurate, abacteriuria was achieved in only 6 of 14 patients. It would therefore seem that this agent is only of limited value for treatment of established infection. In the event of manifest infection it would appear appropriate to treat the infection primarily with antibiotics and to use methenamine hippurate for prophylaxis when abacteriuria has been achieved. No patient developed urinary calculus during treatment with methenamine hippurate and no deterioration of renal function or haematological change was observed. PMID:1166827

Nilsson, S

21

Glycine conjugation of para-aminobenzoic acid (PABA): A quantitative test of liver function  

Microsoft Academic Search

To evaluate glycine conjugation of para-aminobenzoic acid (PABA) to the hippurated metabolites, para-aminohippuric acid (PAHA), and para-acetamidohippuric acid (PAAHA) as a quantitative liver function test in patients with liver disease.Serum concentrations of PABA and metabolites were measured by high pressure liquid chromatography in 24 controls and 50 patients with hepatobiliary disease.Hippurate formation was significantly decreased in all patient groups with

Katryn N. Furuya; Peter R. Durie; Eve A. Roberts; Steven J. Soldin; Zul Verjee; Linda Yung-Jato; Esther Giesbrecht; Lynda Ellis

1995-01-01

22

Simultaneous LC-MS/MS determination of phenylbutyrate, phenylacetate benzoate and their corresponding metabolites phenylacetylglutamine and hippurate in blood and urine.  

PubMed

Inborn errors of urea metabolism result in hyperammonemia. Treatment of urea cycle disorders can effectively lower plasma ammonium levels and results in survival in the majority of patients. Available medications for treating urea cycle disorders include sodium benzoate (BA), sodium phenylacetate (PAA), and sodium phenylbutyrate (PBA) and are given to provide alternate routes for disposition of waste nitrogen excretion. In this study, we develop and validate a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of benzoic acid, phenylacetic acid, phenylbutyric acid, phenylacetylglutamine, and hippuric acid in plasma and urine from children with inborn errors of urea synthesis. Plasma extracts and diluted urine samples were injected on a reverse-phase column and identified and quantified by selected reaction monitoring (SRM) in negative ion mode. Deuterated analogues served as internal standards. Analysis time was 7 min. Assay precision, accuracy, and linearity and sample stability were determined using enriched samples. Quantification limits of the method were 100 ng/ml (0.3-0.8 ?mol/L) for all analytes, and recoveries were >90%. Inter- and intraday relative standard deviations were <10%. Our newly developed LC-MS/MS represents a robust, sensitive, and rapid method that allows simultaneous determination of the five compounds in plasma and urine. PMID:20694517

Laryea, Maurice D; Herebian, Diran; Meissner, Thomas; Mayatepek, Ertan

2010-08-07

23

Benzoic acid as a natural compound in cultured dairy products and cheese  

Microsoft Academic Search

This review deals with the ‘state of the art’ of benzoic acid in cultured dairy products and cheese. During fermentation, benzoic acid is produced from hippuric acid, a component of milk naturally present at concentrations of up to 50 mg\\/kg. In smearripened cheese, however, higher benzoic acid concentrations have often been measured on the surface or even inside such cheeses.

R Sieber; U Bütikofer; J. O Bosset

1995-01-01

24

The detection of hip O gene by real-time PCR in thermophilic Campylobacter spp. with very weak and negative reaction of hippurate hydrolysis  

Microsoft Academic Search

A total of 190 Campylobacter spp. isolates, of which 34 gave the result of very weak activity, and 156 gave the negative activity in the test for hippurate\\u000a hydrolysis were characterized. The genomic DNA was isolated from a fresh culture of each isolate and the real-time PCR, targeting\\u000a the hipO gene, was used to confirm the species distribution of Campylobacter

Vildan Caner; Yavuz Cokal; Cengiz Cetin; Aysin Sen; Nedim Karagenc

2008-01-01

25

Organic Acids and Volatile Flavor Components Evolved During Refrigerated Storage of Kefir1  

Microsoft Academic Search

Kefir samples were prepared and transferred to ster- ile jars for storage at 4°C. After 0, 7, 14, and 21 d of storage, the pH, organic acid, and volatile flavor compo- nent content were determined to monitor possible flavor changes during storage. Stored samples were analyzed for organic acid (orotic, citric, pyruvic, lactic, uric, ace- tic, propionic, butyric, and hippuric)

Z. Guzel-Seydim; A. C. Seydim; A. K. Greene

2000-01-01

26

Species differences in the aromatization of quinic acid in vivo and the role of gut bacteria  

PubMed Central

1. The fate of (?)-quinic acid has been investigated in 22 species of animals including man. 2. In man and three species of Old World monkeys, i.e. rhesus monkey, baboon and green monkey, oral quinic acid was extensively aromatized (20–60%) and excreted in the urine as hippuric acid, which was determined fluorimetrically. 3. In three species of New World monkeys, i.e. squirrel monkey, spider monkey and capuchin, in three species of lemurs, i.e. bushbaby, slow loris and tree shrew, in the dog, cat, ferret, rabbit, rat, mouse, guinea pig, hamster, lemming, fruit bat, hedgehog and pigeon, oral quinic acid was not extensively aromatized (0–5%). 4. In the rhesus monkey, injected quinic acid was not aromatized, but largely excreted unchanged. 5. In rhesus monkeys pretreated with neomycin to suppress gut flora, the aromatization of oral quinic acid was considerably suppressed. 6. In rats and rhesus monkeys [14C]quinic acid was used and this confirmed its low aromatization in rats and its high aromatization in the monkeys. 7. Shikimic acid given orally was excreted as hippuric acid (26–56%) in rhesus monkeys, but not in rats. 8. The results support the view that quinic acid and shikimic acid are aromatized by the gut flora in man and the Old World monkeys.

Adamson, R. H.; Bridges, J. W.; Evans, M. E.; Williams, R. T.

1970-01-01

27

Effect of milk on the urinary excretion of microbial phenolic acids after cocoa powder consumption in humans.  

PubMed

Health effects of cocoa flavonols depend on their bioavailability, which is strongly influenced by the food matrix and the degree of flavanol polymerization. The effect of milk on the bioavailability of cocoa flavanoids considering phase II metabolites of epicatechin has been the subject of considerable debate. This work studies the effect of milk at the colonic microbial metabolism level of the nonabsorbed flavanol fraction that reaches the colon and is metabolized by the colonic microbiota into various phenolic acids. Twenty-one human volunteers followed a diet low in polyphenols for at least 48 h before taking, in a random order, 40 g of cocoa powder dissolved either in 250 mL of whole milk or in 250 mL of water. Urine samples were collected before the intake and during three different periods (0-6, 6-12, and 12-24 h). Phenolic acids were analyzed by LC-MS/MS after solid-phase extraction. Of the 15 metabolites assessed, the excretion of 9 phenolic acids was affected by the intake of milk. The urinary concentration of 3,4-dihydroxyphenylacetic, protocatechuic, 4-hydroxybenzoic, 4-hydroxyhippuric, hippuric, caffeic, and ferulic acids diminished after the intake of cocoa with milk, whereas urinary concentrations of vanillic and phenylacetic acids increased. In conclusion, milk partially affects the formation of microbial phenolic acids derived from the colonic degradation of procyanidins and other compounds present in cocoa powder. PMID:20222713

Urpi-Sarda, Mireia; Llorach, Rafael; Khan, Nasiruddin; Monagas, Maria; Rotches-Ribalta, Maria; Lamuela-Raventos, Rosa; Estruch, Ramon; Tinahones, Francisco J; Andres-Lacueva, Cristina

2010-04-28

28

Quantitation of urinary metabolites of toluene, xylene, styrene, ethylbenzene, benzene and phenol by automated high performance liquid chromatography  

Microsoft Academic Search

An automated high performance liquid chromatographic method (HPLC) for the direct determination of urinary concentrations of hippuric acid (HA), and o-, m- and p-methyl hippuric acids (MHAs), metabolites of toluene and o-, m-, and p-xylenes, and of urinary phenyl glyoxylic acid (PGA) and mandelic acid (MA), metabolites of styrene or ethylbenzene, is described. Methanol was added to urine, the mixture

Masana Ogata; Toyohiro Taguchi

1987-01-01

29

Metabolic profiling of phenolic acids and oxidative stress markers after consumption of Lonicera caerulea L. fruit.  

PubMed

This study investigated the effect of one-week consumption of 165 g/day fresh blue honeysuckle berries (208 mg/day anthocyanins) in 10 healthy volunteers. At the end of intervention, levels of benzoic (median 1782 vs 4156), protocatechuic (709 vs 2417), vanillic (2779 vs 4753), 3-hydroxycinnamic (143 vs 351), p-coumaric (182 vs 271), isoferulic (805 vs 1570), ferulic (1086 vs 2395), and hippuric (194833 vs 398711 ?g/mg creatinine) acids by LC/MS were significantly increased in the urine. Clinical chemistry safety markers were not altered. Oxidative stress markers, erythrocyte glutathione peroxidase (0.73 vs 0.88 U/g Hb) and catalase (2.5 vs 2.8 ?kat/g Hb) activities, and erythrocyte/plasma thiobarbituric acid reactive substance (522 vs 612/33 vs 38 ?mol/g Hb/protein) levels were significantly increased, without change in plasma antioxidant status. Nonsignificant changes of advanced oxidation protein products and oxidized LDL were observed. The results provide a solid base for further study of metabolite excretion and antioxidant parameters after ingestion of anthocyanins. PMID:23581742

Heinrich, Jan; Valentová, Kate?ina; Vacek, Jan; Palíková, Irena; Zatloukalová, Martina; Kosina, Pavel; Ulrichová, Jitka; Vrbková, Jana; Šimánek, Vilím

2013-05-06

30

Mycophenolic Acid  

Center for Drug Evaluation (CDER)

... Publications on Genomics. -. Mycophenolic Acid. Pharmacogenomic Information. ... Mycophenolic Acid, Transplantation, HGPRT, Precautions. ... More results from www.fda.gov/drugs/scienceresearch/researchareas

31

Acid rain  

Microsoft Academic Search

Acid precipitation is a global problem. The effects were first seen in Europe; it affects the Great Lakes and the Midwest because higher-than-normal levels of acidity in rain are found in these areas. Several bays of the Great Lakes are now known to receive substantial runoff from freshwater streams that have been made acidic by acid rains. These areas may

1979-01-01

32

Acid rain  

SciTech Connect

A series of definitions for the field of acid rain studies are presented. Protocols for acid rain sampling and monitoring are also presented. A procedure for calculatory precipitation pH is discussed. 11 references, 1 table.

Stensland, G.J.

1983-11-01

33

Oleanolic acid.  

PubMed

Oleanolic acid (3?-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpenoid compound with a widespread occurrence throughout the plant kingdom. In nature, the compound exists either as a free acid or as an aglycone precursor for triterpenoid saponins, in which it can be linked to one or more sugar chains. Oleanolic acid and its derivatives possess several promising pharmacological activities, such as hepatoprotective effects, and anti-inflammatory, antioxidant, or anticancer activities. With the recent elucidation of its biosynthesis and the imminent commercialization of the first oleanolic acid-derived drug, the compound promises to remain important for various studies. In this review, the recent progress in understanding the oleanolic acid biosynthesis and its pharmacology are discussed. Furthermore, the importance and potential application of synthetic oleanolic acid derivatives are highlighted, and research perspectives on oleanolic acid are given. PMID:22377690

Pollier, Jacob; Goossens, Alain

2012-02-28

34

Aminocaproic Acid  

MedlinePLUS

Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

35

Ethacrynic Acid  

MedlinePLUS

Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

36

Acid Reflux  

MedlinePLUS

... end of the esophagus called the lower esophageal sphincter or “LES” — keeps the acid in the stomach ... moderately symptomatic GERD. These drugs increase lower esophageal sphincter pressure, which helps prevent acid reflux, and improves ...

37

Acidizing method  

SciTech Connect

A method is described for acidizing a subterranean formation, comprising the steps of: (a) forming an acidizing composition by mixing an aqueous acid component with at least one water-soluble organosilicon compound; and (b) injecting the composition into the formation.

Watkins, D.R.; Kalfayan, L.J.; Hewgill, G.S.

1987-03-03

38

Calcium acetate catalyzed synthesis of 4-arylidene-2-phenyl-5(4 H)-oxazolones under solvent-free conditions  

Microsoft Academic Search

Eight 4-arylidene-2-phenyl-5(4H)-oxazolones (azlactones) have been prepared via Erlenmeyer synthesis from aromatic aldehydes and hippuric acid using calcium acetate under solvent-free conditions with microwave irradiation.

Satya Paul; Puja Nanda; Rajive Gupta; André Loupy

2004-01-01

39

Clinical Review - Agalsidase beta (Fabrazyme), Genzyme ...  

Center for Drug Evaluation (CDER)

Text Version... Ophthalmic examination • 24-hour urine GL-3 • Glomerular filtration rate by para amino hippuric acid (PAH) and inulin clearance • Dispensing of ... More results from www.fda.gov/downloads/drugs/developmentapprovalprocess

40

Sequential and Functional Renal Scintiscanning in Diabetic and Hypertensive Patients.  

National Technical Information Service (NTIS)

47 diabetics (94 kidneys), 30 diabetics with concurrent hypertension (60 kidneys), and 23 hypertensives (46 kidneys) were examined by renal serial functional scintiscanning with exp 131 I-ortho-iodo-hippuric acid. For evaluation, camera nephrographs of th...

M. Wagner

1978-01-01

41

Basically Acids  

NSDL National Science Digital Library

Students learn the basics of acid/base chemistry in a fun, interactive way by studying instances of acid/base chemistry found in popular films such as Harry Potter and the Prisoner of Azkaban and National Treasure. Students learn what acids, bases and indicators are and how they can be used, including invisible ink. They also learn how engineers use acids and bases every day to better our quality of life. Students' interest is piqued by the use of popular culture in the classroom.

University Of Houston

42

Mefenamic Acid  

MedlinePLUS

... any of the following symptoms, stop taking mefenamic acid and call your doctor: stomach pain, heartburn, vomit that is bloody or looks ... Mefenamic acid may cause side effects. Tell your doctor if any of these ... nervousness ringing in the ears Some side effects can be serious. If you ...

43

Acid test  

NSDL National Science Digital Library

Baking soda can be used as an indicator of how much acid a substance contains. Lemons and limes have more acid in them than grapefruits and oranges. Indophenol can be used as an indicator of how much vitamin C is in a substance.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-06

44

Acid Rain  

Microsoft Academic Search

Measurements of the acidity of rain and snow reveal that in parts of the eastern U.S. and of western Europe precipitation has changed from a nearly neutral solution 200 years ago to a dilute solution of sulfuric and nitric acids today. The trend is a result of the emission of sulfur and nitrogen oxides to the atmosphere accompanying the rise

Gene E. Likens; Richard F. Wright; James N. Galloway; Thomas J. Butler

1979-01-01

45

Acid rain  

SciTech Connect

This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

Elsworth, S.

1985-01-01

46

Acid rain  

SciTech Connect

This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

White, J.C. (Cornell University, Ithaca, NY (US))

1988-01-01

47

Hydrochloric acid  

Microsoft Academic Search

The effect of a single instillation of acid and pepsin on the cell proliferation in the distal esophageal mucosa was investigated in four dogs. The doses of acid and pepsin used were lower than those provoking acute esophagitis and erosions. Usingin vitro labeling with [3H]thymidine and autoradiography, the epithelial mitotic and DNA synthesis indices were determined at 0, 4, 8,

A. De Backer; P. Haentjens; G. Willems

1985-01-01

48

Acids (GCMP)  

NSDL National Science Digital Library

Acids: this is a resource in the collection "General Chemistry Multimedia Problems". We will observe the reaction of sodium bicarbonate with three acid solutions. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

49

Domoic Acid  

NSDL National Science Digital Library

This online student report discusses the chemistry of domoic acid, a biotoxin that is produced by the diatom Psuedo-nitzschia and associated with Amnesiac Shellfish Poisoning (ASP). In addition to a descriptive summary and images, the report links to other areas of interest related to domoic acid poisoning including signs and symptoms, modes of action, and treatment.

Kohlen, Corinne; Bailey, Christina

2010-02-10

50

Acid Precipitation  

NSDL National Science Digital Library

Acid precipitation will be defined. At different points in the lesson students will write balanced reactions for the formation acid precipitation from atmospheric sulfur and nitrogen oxides and the neutralization of acids by limestone. Students will determine which states are most at risk from acid precipitation and assess how that risk has changed from 1996 to 2006. Sources of atmospheric sulfur (burning of high-sulfur coal) and nitrogen oxides (automobile exhaust) will be listed. The buffering effect of limestone soils and its mitigating effect on acid precipitation will be discussed. Students will correlate these areas with sulfur and nitrogen oxide production, population, composition of coal fields, and soil composition. This resource includes both a teaching guide and student worksheets.

Tyser, Jim

2011-09-15

51

Acid rain  

SciTech Connect

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 different aspects of acid precipitation. Despite some unknowns, the preponderance of our evidence to date points to the need to control the emissions of acid-forming sulfur and nitrogen compounds. Given the potential for damage from acid precipitation, prudence dictates that we act soon to avoid far more serious problems in the future. EPA's regulatory standards for new power plants and motor vehicles are a major step in the right direction. Further steps may be required in the near future. This background document tells what we know - and don't know - about acid precipitation.

Not Available

1980-07-01

52

Acid Rain  

NSDL National Science Digital Library

Due to the presence of dissolved gases such as carbon dioxide, rainfall is naturally acidic. The release of other gases and chemicals such as sulfur dioxide during the combustion of coal and oil can cause rainfall to become even more acidic, sometimes to the point of toxicity. In this activity, students will measure the pH of local rainfall to see what effect these gases have in their region. They will also check an online resource to see how the releases of acid rain-causing chemicals have varied over the past 20 years, and answer questions about the information they uncover.

Fox, Chris

53

Tranexamic Acid  

MedlinePLUS

... or lower legs hoarseness changes in vision, including color vision chest pain shortness of breath leg pain, swelling, tenderness, redness, or warmth Tranexamic acid may cause other side effects. Call your doctor if you have any unusual ...

54

Valproic Acid  

MedlinePLUS

... with other medications to treat certain types of seizures. Valproic acid is also used to treat mania ( ... a severe, long-lasting and possibly life-threatening seizure. Your doctor will probably decrease your dose gradually.

55

?-Amino acids  

Microsoft Academic Search

Summary 1.It has been established that by the decarboxylation of the glycidic acid, obtained by Darzens' method from cis-decahydro-2-naphthol of m.p. 105°, a mixture of stereoisomeric decahydro-2-naphthaldehydes is formed; these have not been investigated further.2.The synthesis has been affected, by Rodionov's method, of ß-(2-decalyl)-ß-alanine (ß-aminodecahydro-2-naphthalenepropionic acid), which also appeared to be a mixture of isomers, the separation of which was

V. M. Rodionov; L. V. Antik

1953-01-01

56

Acidizing with chemically heated weak acid  

SciTech Connect

Materials in and around a well are acidized with chemically heated, hot acid by injecting a solution of both nitrogen and heat generating reactants and a mixture of weak acid and weak acid salt that both buffers the relation and provides a weak acid acidizing solution.

Richardson, E. A.

1984-11-13

57

Stearic Acid  

ERIC Educational Resources Information Center

|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.|

Young, Jay A.

2004-01-01

58

Acid rain  

SciTech Connect

An overview is presented of acid rain and the problems it causes to the environment worldwide. The acidification of lakes and streams is having a dramatic effect on aquatic life. Aluminum, present in virtually all forest soils, leaches out readily under acid conditions and interferes with the gills of all fish, some more seriously than others. There is evidence of major damage to forests in European countries. In the US, the most severe forest damage appears to be in New England, New York's Adirondacks, and the central Appalachians. This small region is part of a larger area of the Northeast and Canada that appears to have more acid rainfall than the rest of the country. It is downwind from major coal burning states, which produce about one quarter of US SO/sub 2/ emissions and one sixth of nitrogen oxide emissions. Uncertainties exist over the causes of forest damage and more research is needed before advocating expensive programs to reduce rain acidity. The President's current budget seeks an expansion of research funds from the current $30 million per year to $120 million.

Not Available

1984-06-01

59

Carbonate acidizing  

SciTech Connect

The authors present the first quantitative study and complete model of the wormholing phenomenon, leading to a means of predicting and optimizing carbonate acidizing treatments. Laboratory experiments on a gypsum model system and computer simulations show that for a given geometry, wormholes can be quantified by a unique parameter, their equivalent hydraulic length. The behavior of this quantifying parameter vs. all the system parameters is studied and allows the quantitative prediction of the efficiency of an acidizing treatment. This study highlights the fractal nature of the phenomenon, which is accounted for in the equations, and the strong effect of the sample geometry. Three types of etching can be obtained: compact, wormhole type, or homogeneous. The optimum conditions for achieving the best skin decrease correspond to the creation of wormholes and can then be defined in terms of fluid reactivity and injection rate.

Daccord, G.; Touboul, E.; Lenormand, R.

1989-02-01

60

Acidizing sandstone formations with fluoboric acid  

SciTech Connect

The continuing search for an effective deep-penetrating sandstone acidizing system recently has focused on fluoboric acid (HBF/sub 4/). Because this acid first must hydrolyze in water to produce HF, it was believed that deeper radial penetration of live acid could be achieved during matrix acidizing operations. However, a thorough experimental study has shown that typical formation temperatures will cause fluoboric acid to spend at a rapid rate similar to that of conventional hydrofluoric acid (HF), thereby severly limiting its usefulness in most sandstone formations. Furthermore, the same silica reprecipitation potential associated with HF acidizing is also inherent in the HBF/sub 4/ system.

Kunze, K.R.; Shaughnessy, C.M.

1983-02-01

61

Simultaneous determination by gas chromatography of the major metabolites in urine of toluene, xylenes and styrene.  

PubMed Central

A gas chromatographic method has been developed to determine the following metabolites in urine simultaneously if necessary: hippuric acid from toluene or styrene; 3- and 4-methyl hippuric acids from xylenes; phenylglyoxylic acid and mandelic acid from styrene. Heptadecanoic acid is added to the urine as an internal standard and after ethyl acetate extraction from acidic solution, the trimethylsilyl (TMS) derivatives of the metabolites are formed and simultaneously analysed by gas chromatography on 3% OV-1 on 80/100 gas chrom Q (flame ionisation detector).

Van Roosmalen, P B; Drummond, I

1978-01-01

62

Understanding Acid Rain  

ERIC Educational Resources Information Center

|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…

Damonte, Kathleen

2004-01-01

63

Acidizing concepts - Matrix vs. fracture acidizing  

SciTech Connect

Acidizing involves a wide range of stimulation treatments that can yield impressive production increases in many wells if properly applied. Acidizing treatments are divided into two categories: matrix acidizing and fracture acidizing. To use either treatment properly, an understanding is required of what the treatments do and what is necessary to stimulate the well.

King, G.E.

1986-05-01

64

New method of acidizing or acid fracturing: crosslinked acid gels  

SciTech Connect

Acid polymer gels having pH less than one have been crosslinked for retarding the chemical and physical activity of hydrochloric acid on calcareous formations. Hydrochloric acid concentrations from .0025 to 28% have been successfully crosslinked. This stimulation fluid offers high viscosity with adequate shear stability, perfect support for proppants, and clay stabilization. Additionally, the fluid provides effective fluid loss control and retardation of acid reaction enabling live acid to penetrate deeper into the formation for better formation conductivity and practically a residue-free break for rapid clean-up of the well after the job. Results of lab and field tests show the acid crosslinked system to be an effective stimulation fluid for acidizing and acid fracturing in calcareous and sandstone formations having low formation permeability.

Pabley, A.S.; Holcomb, D.L.

1980-01-01

65

Acid rain  

SciTech Connect

Deposition of acidic substances from the atmosphere is considered by many to be, along with increasing CO/sub 2/ concentrations in the atmosphere, one of the most serious environmental problems of this generation. Despite the limited title of this small book, it touches, in a nontechnical and elementary way, on all of the important aspects of this subject: definitions, history, suspected causes and harmful effects, proposed remedial actions, the case for additional research, and political and economic impacts. The material is presented largely as statements and opinions of scientists and governmental officials. The book is reportorial in style and reasonably balanced in its presentation of contrasting and opposing opinions about causes, effects, and remedies, although the final chapter, What Citizens Can Do, includes the names and addresses of organizations involved in efforts to protect clean air, forestry and wilderness areas. Also included are school projects and examples of what individuals and groups have done to help us understand the problem and/or to promote action.

Gay, K.

1983-01-01

66

NPN-Komponenten der Milch als analytische Indikatoren in Lebensmitteln  

Microsoft Academic Search

Summary Non-protein-nitrogen (NPN) components of milk, namely orotic acid, total creatinine, uric acid and hippuric acid, were examined for their importance in the analysis and quantification of the portion of milk in foodstuffs. Over a period of 1 year the average biological variations were recorded in dried skimmed milk. The results were 64±5 mg for orotic acid, 82 ± 8

Anton J. Plasser; Henning Klostermeyer

1988-01-01

67

[Correlation of psychological and neurological changes with indicators of exposure of workers in a shoe factory to glue solvents].  

PubMed

In the group of 349 women exposed to organic solvents, chiefly extraction naphtha, n-hexane and toluene, medical examinations were carried out. Among them the 100 persons without signs of chronic intoxication were selected. In this group the following examinations were performed: Graham-Kendall's and Bender's psychologic tests, electroencephalograms, testing motor conduction of peripheral nerves. In the exposed and control groups urinary phenol and hippuric acid content was determined. Air solvents concentration at work environment was also measured. Within the examined group, psychologic tests score was as follows: 37 persons without organic changes, 28 on the border-1 and of the norm, 35 with cortical organic changes. No significant difference in average urinary phenol and hippuric acid content was found in 3 groups mentioned above. The hippuric acid excretion in the exposed group was significantly higher than in the control one. Hippuric acid in workers with normal and abnormal electrocardiograms was at the same level. No difference in the hippuric acid concentration in groups with normal and slowed nerve conduction velocity was noticed. The urinary phenol content in the exposed and control groups was at the same level. At some work posts extraction naphtha and toluene concentration exceeded MAC. Cortical organic changes and subclinical neuropathy were significantly more frequent in workers exposed to high concentrations of extraction naphtha and toluene. The authors suppose that subclinical signs, detectable by means of psychologic and neurophysiologic methods, may be considered as early symptoms of individual reaction to organic solvents. PMID:6672527

Langauer-Lewowicka, H; Wocka-Marek, T; Braszczy?ska, Z; Witecki, K; Kozera, G; Zygan, U

1983-01-01

68

Uric acid test (image)  

MedlinePLUS

Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

69

Bioavailability of phenolic acids  

Microsoft Academic Search

Two large classes of phenolic acids were comprised in this review: benzoic acid derivatives and cinnamic acid derivatives.\\u000a They have been found to be very extended in fruits and vegetables at different concentrations. For example, hydroxycinnamic\\u000a acids concentration was higher than that found for hydroxybenzoic acids. Concerning their consumption, hydroxycinnamic acids\\u000a provide larger contributions to the total polyphenol intake than

Sophie Lafay; Angel Gil-Izquierdo

2008-01-01

70

BBB - Domoic Acid Structure  

Center for Food Safety and Applied Nutrition (CFSAN)

... BBB - Domoic Acid Structure. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook Domoic Acid. ... More results from www.fda.gov/food/foodborneillnesscontaminants/causesofillnessbadbugbook

71

BBB - Okadaic Acid Structure  

Center for Food Safety and Applied Nutrition (CFSAN)

... BBB - Okadaic Acid Structure. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook Okadaic Acid. ... More results from www.fda.gov/food/foodborneillnesscontaminants/causesofillnessbadbugbook

72

Refining Lurgi tar acids  

Microsoft Academic Search

There is disclosed a process for removing tar bases and neutral oils from the Lurgi tar acids by treating the tar acids with aqueous sodium bisulfate to change the tar bases to salts and to hydrolyze the neutral oils to hydrolysis products and distilling the tar acids to obtain refined tar acid as the distillate while the tar base salts

Greco

1984-01-01

73

Acid-Base Equilibria  

NSDL National Science Digital Library

This 9-page PDF document is part of an environmental geochemistry course taught by Dr. David Sherman at the University of Bristol. Topics include acid-base theories, aqueous systems, strong and weak acids and bases, acid-base properties of minerals, the pH of weak acid and buffered systems, and the calculation of titration curves.

Sherman, David W.; Bristol, University O.

74

21 CFR 172.860 - Fatty acids.  

Code of Federal Regulations, 2013 CFR

...acids and their associated fatty acids manufactured from fats and oils derived from edible sources: Capric acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The food additive meets the...

2013-04-01

75

21 CFR 172.860 - Fatty acids.  

Code of Federal Regulations, 2010 CFR

...acids and their associated fatty acids manufactured from fats and oils derived from edible sources: Capric acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The food additive meets the...

2009-04-01

76

21 CFR 172.860 - Fatty acids.  

Code of Federal Regulations, 2010 CFR

...acids and their associated fatty acids manufactured from fats and oils derived from edible sources: Capric acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The food additive meets the...

2010-01-01

77

Uric acid nephrolithiasis.  

PubMed

Uric acid nephrolithiasis may be the final manifestation of various pathophysiological processes. Recent advances in renal urate transport have elucidated mechanisms by which hyperuricosuria occurs. However, in most uric acid stone formers the primary pathophysiologic defect is an excessively acidic urine pH rather than hyperuricosuria. Insulin resistance may contribute to the development of acidic urine by augmenting endogenous acid production and decreasing renal ammonium excretion. Medical management strategies focus primarily on alkali treatment or decreasing hyperuricosuria. PMID:17678984

Cameron, Mary Ann; Sakhaee, Khashayar

2007-08-01

78

Acids and Bases (Netorials)  

NSDL National Science Digital Library

Acids and Bases: this is a resource in the collection "Netorials". In this module there is an introduction to the chemical properties of acids and bases. Afterwards, the sections include topics such as Molecular Structures of Acids and Bases, Ionization constants, properties of salts, buffers and Lewis theory of Acids and Bases. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

79

Simultaneous determination of urinary creatinine and metabolites of toluene, xylene, styrene, ethylbenzene and phenol by automated high performance liquid chromatography  

Microsoft Academic Search

Summary An attempt was made to establish a method for the direct determination of urinary concentrations of creatinine, hippuric acid, methylhippuric acid and mandelic acid by automated high performance liquid chromatography (HPLC). Urine was diluted with distilled water or mobile phase, then the mixture was centrifuged and the supernatant was injected into HPLC. A stainless-steel column packed with octadecyl silanized

Masana Ogata; Toyohiro Taguchi

1988-01-01

80

Detection of bound phenolic acids: prevention by ascorbic acid and ethylenediaminetetraacetic acid of degradation of phenolic acids during alkaline hydrolysis  

Microsoft Academic Search

The experimental conditions commonly used to detect bound phenolic acids by alkaline hydrolysis result in loss of several phenolic acids, particularly dihydroxy-derivatives (caffeic acid, dihydrocaffeic acid, homogentisic acid). In this study we show that the addition of ascorbic acid, a strong antioxidant, and ethylenediaminetetraacetic acid, a metal chelator, totally prevent the loss of phenolic acids during alkaline hydrolysis. In these

M Nardini; E Cirillo; F Natella; D Mencarelli; A Comisso; C Scaccini

2002-01-01

81

Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.  

SciTech Connect

Gas-phase acidities (GA or ?Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage’s importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3–4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2? group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

Li, Zhong; Matus, Myrna H.; Velazquez, Hector A.; Dixon, David A.; Cassady, Carolyn J.

2007-02-14

82

Acid Inhibition and the Acid Rebound Effect  

Microsoft Academic Search

Acid secretion from gastric parietal cells is a result of a complex interaction between different stimulatory and inhibitory mediators. One of the most important mediators is gastrin, which stimulates gastric acid secretion from parietal cells mostly indirectly, by the release of histamine from enterochromaffin-like (ECL) cells. Therapy with antisecretory agents leads to hypergastrinemia, mucosal hyperplasia and increased ECL cell mass,

Marko Duvnjak

2011-01-01

83

Acid Thunder: Acid Rain and Ancient Mesoamerica  

ERIC Educational Resources Information Center

|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…

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

2006-01-01

84

Purification of oleic acid and linoleic acid  

SciTech Connect

To permit kinetic studies of the reactivity of unsaturated fatty acids towards oxygen radicals, it is essential to remove traces of hydroperoxides and other conjugated lipid impurities commonly present in commercial samples. Removal of these impurities has been satisfactorily achieved for oleic and linoleic acids by anaerobic low temperature recrystallization from acetonitrile. The uv spectra of commercial and purified samples are compared.

Arudi, R.L.; Sutherland, M.W.; Bielski, B.H.J.

1983-01-01

85

New bioactive fatty acids.  

PubMed

Many oxygenated fatty acids are bioactive compounds. Nocardia cholesterolicum and Flavobacterium DS5 convert oleic acid to 10 hydroxy stearic acid and linoleic acid to 10-hydroxy-12(Z)-octadecanoic acid. Pseudomonas aeruginosa PR3 converts oleic acid to the new compounds, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) through 10-hydroxy-8-octadecenoic acid, and racinoleic acid to 7,10,12-trihydroxy-8-octadecenoic acid. DOD showed antibacterial activity including against food-borne pathogens. Bacillus megaterium ALA2 converted n-6 and n-3 PUFAs to many new oxygenated fatty acids. For example: linoleic acid was converted to12,13-epoxy-9-octadecenoic acid and then to 12,13-dihydroxy-9-octadecenoic acid (12,13-DHOA). From here, there are two bioconversion pathways. The major pathway is: 12,13-DHOA --> 12,13,17-trihydroxy-9(S)-octadecenoic acid (THOA) --> 12,17;13,17-diepoxy-16-hydroxy-9(Z)-octadecenoic acid (DEOA) --> 7-hydroxy-DEOA. The minor pathway is: 12,13-DHOA --> 12,13,16-THOA --> 12-hydroxy-13,16-epoxy-9(Z)-octadecenoic acid. 12,13,17-THOA has anti-plant pathogenic fungal activity. The tetrahydrofuranyl moiety is known in anti cancer drugs. Strain ALA2 also converts other n-3 and n-6 PUFAs such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) to many new oxygenated unsaturated fatty acid products. All of these new products have high potential for antimicrobial agents or biomedical applications. We also screened 12 Mortierella fungal strains from the ARS Culture Collection for the production of bioactive fatty acids such as dihomo-gama-linolenic acid (DGLA) and arachidonic acid. All of the strains tested produced AA and DGLA from glucose or glycerol. The top five AA producers (mg AA/g CDW) were in the following order: M. alpina > M. zychae > M. hygrophila > M. minutissima > M. parvispora. Both AA and DGLA are important natural precursors of a large family of prostaglandin and thromboxane groups. PMID:18296335

Hou, Ching T

2008-01-01

86

Zoledronic Acid Injection  

MedlinePLUS

... acid (Reclast) is used to prevent or treat osteoporosis (condition in which the bones become thin and ... Zoledronic acid (Reclast) is also used to treat osteoporosis in men, and to prevent or treat osteoporosis ...

87

Mixed Acid Oxidation  

SciTech Connect

Several non-thermal processes have been developed to destroy organic waste compounds using chemicals with high oxidation potentials. These efforts have focused on developing technologies that work at low temperatures, relative to incineration, to overcome many of the regulatory issues associated with obtaining permits for waste incinerators. One such technique with great flexibility is mixed acid oxidation. Mixed acid oxidation, developed at the Savannah River Site, uses a mixture of an oxidant (nitric acid) and a carrier acid (phosphoric acid). The carrier acid acts as a non-volatile holding medium for the somewhat volatile oxidant. The combination of acids allows appreciable amounts of the concentrated oxidant to remain in the carrier acid well above the oxidant''s normal boiling point.

Pierce, R.A.

1999-10-26

88

Hydrochloric acid poisoning  

MedlinePLUS

Hydrocholoric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe damage, such ... poisoning due to swallowing or breathing in hydrochloric acid. This is for information only and not for ...

89

Acid-fast stain  

MedlinePLUS

The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body ... lab team member washes the slide with an acid solution and applies a different stain. The bacteria ...

90

Carbolic acid poisoning  

MedlinePLUS

Phenol poisoning; Phenylic acid poisoning; Hydroxybenzene poisoning; Phenic acid poisoning; Benzenol poisoning ... Phenol ... and Disease Registry (ATSDR). 2008. Toxicological profile for Phenol. Atlanta, GA: U.S. Department of Health and Human ...

91

Lactic acid test  

MedlinePLUS

Lactate test ... test. Exercise can cause a temporary increase in lactic acid levels. ... oxygen. See: Oxygen deprivation Conditions that can increase lactic acid levels include: Heart failure Liver problems Lung disease ...

92

Aminocaproic Acid Injection  

MedlinePLUS

Aminocaproic acid injection is used to control bleeding that occurs when blood clots are broken down too quickly. This ... the baby is ready to be born). Aminocaproic acid injection is also used to control bleeding in ...

93

Polymerization of Itaconic Acid.  

National Technical Information Service (NTIS)

Itaconic acid has various uses in chain copolymerization reactions, because of its two carboxylic groups and relatively good reactivity with different comonomers. As an unsaturated dicarboxylic acid it also has applications in grafting reactions and polyc...

J. Ahlgren

1990-01-01

94

Acid inhibition and the acid rebound effect.  

PubMed

Acid secretion from gastric parietal cells is a result of a complex interaction between different stimulatory and inhibitory mediators. One of the most important mediators is gastrin, which stimulates gastric acid secretion from parietal cells mostly indirectly, by the release of histamine from enterochromaffin-like (ECL) cells. Therapy with antisecretory agents leads to hypergastrinemia, mucosal hyperplasia and increased ECL cell mass, which results in increase of gastric acid secretion capacity. This increased secretion capacity has been shown to manifest itself after antisecretory therapy withdrawal as rebound acid hypersecretion (RAH). Various studies have quantified acid hypersecretion after the cessation of therapy with H(2) antagonists and proton-pump inhibitors (PPIs). While most of those studies had small patient numbers, the findings generally demonstrate that RAH after H(2) antagonist therapy is of low magnitude, short duration, and has questionable clinical significance. On the contrary, acid hypersecretion after PPI therapy is more pronounced, lasts longer, and could possibly be the cause of acid-related symptoms. Potential for causing symptoms has recently been confirmed in two randomized placebo-controlled studies, and while we witness the increasing use of PPIs, RAH could become a proven cause of failure to withdraw therapy in a proportion of patients with reflux or dyspeptic symptoms. PMID:22095014

Leroti?, Ivan; Barši?, Neven; Stojsavljevi?, Sanja; Duvnjak, Marko

2011-11-16

95

Nucleic acid molecule  

US Patent & Trademark Office Database

The invention relates to an isolated nucleic acid molecule encoding a polypeptide capable of producing a triterpenoid hydrocarbon. The invention also relates to the encoded polypeptide, a vector comprising the nucleic acid molecule, a recombinant non-human organism comprising the nucleic acid molecule, and to methods of producing a triterpenoid hydrocarbon or an intermediate of biofuel using the nucleic acid molecule, polypeptide or recombinant organism.

Ball; Andrew (Bedford Park, AU); Moore; Robert (Bedford Park, AU); Knowles; Gregory (Bedford Park, AU); Qin; Jian (Bedford Park, AU)

2011-10-11

96

Plant fatty acid hydroxylases  

DOEpatents

This invention relates to plant fatty acyl hydroxylases. Methods to use conserved amino acid or nucleotide sequences to obtain plant fatty acyl hydroxylases are described. Also described is the use of cDNA clones encoding a plant hydroxylase to produce a family of hydroxylated fatty acids in transgenic plants. In addition, the use of genes encoding fatty acid hydroxylases or desaturases to alter the level of lipid fatty acid unsaturation in transgenic plants is described.

Somerville, Chris (Portola Valley, CA); Broun, Pierre (Burlingame, CA); van de Loo, Frank (Lexington, KY)

2001-01-01

97

Quinolinic acid, ?-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhance the Fenton reaction in phosphate buffer  

Microsoft Academic Search

Quinolinic acid, ?-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhanced the Fenton reaction in phosphate buffer, respectively. The enhancement by quinolinic acid, ?-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid of the Fenton reaction may be partly related to their respective actions in the biological systems such as a neurotoxic effect (quinolinic acid), a marked growth-inhibitory action on rice seeding (?-picolinic

Hideo Iwahashi; Hiroyuki Kawamori; Kazuaki Fukushima

1999-01-01

98

The Acid Rain Reader.  

ERIC Educational Resources Information Center

|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)…

Stubbs, Harriett S.; And Others

99

What Is Acid Rain?  

ERIC Educational Resources Information Center

|Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

Likens, Gene E.

2004-01-01

100

Bile acid diarrhea.  

PubMed

Bile acids normally undergo enterohepatic circulation. When this circulation is interrupted, bile acids enter the colon in increased concentrations. Here, they produce Cl- secretion by a calcium- and cyclic AMP-dependent mechanism, resulting in diarrhea. Cholestasis may lead to serum bile acid concentrations high enough to produce colonic secretion by serosal surface effects. When resection or disease interferes with ileal function, the resulting diarrhea can be clearly attributed to bile acid malabsorption. In other states, such as postcholecystectomy diarrhea and idiopathic bile acid diarrhea, the role of bile acids is less well defined. 23-75Selena-25-homotaurocholic acid provides a way of tracing the metabolism of bile acids and their enterohepatic circulation in vivo. Metabolized similarly to natural bile acids, its circulation is easily traced by scintigraphy. Barium x-rays, serum concentrations of bile acids or bile acid intermediates, and tests of vitamin B12 absorption provide indirect measures of ileal function. Careful history and examination combined with one of many the available tests of ileal function allow a diagnosis. A therapeutic trial with a bile acid binding resin confirms the impression and treats the diarrhea. PMID:9571377

Potter, G D

101

Acid (and Base) Rainbows  

NSDL National Science Digital Library

Learners use red cabbage juice and pH indicator paper to test the acidity and basicity of household materials. The activity links this concept of acids and bases to acid rain and other pollutants. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.

Kolenbrander, Amy; Yowell, Janet; Mach, Natalie; Zarske, Malinda S.; Carlson, Denise; Perez, Sharon

2004-01-01

102

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

|Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

103

Uric acid nephrolithiasis.  

PubMed

Uric acid is the end-product of purine nucleotide metabolism in man. The renal handling of urate is a complicated process, resulting in a fractional clearance of 8.2-10.3%. The anhydrous form is thermodynamically the most stable uric acid crystal. Uric acid is a weak acid that ionizes with a Pka at pH 5.75. At the normal acidic region, uric acid solubility is strongly increased by urinary pH. The prevalence of uric acid stones varies between countries, reflecting climatic, dietary, and ethnical differences, ranging from 2.1% (in Texas) to 37.7% (in Iran). The risk for uric acid stone formation correlates with the degree of uric acid supersaturation in the urine, depending on uric acid concentration and urinary pH. Hyperuricosuria is the major risk factor, the most common cause being increased purine intake in the diet. Acquired and hereditary diseases accompanied by hyperuricosuria and stone disease include: gout, in strong correlation with the amount of uric acid excreted, myelo- and lymphoproliferative disorders, multiple myeloma, secondary polycythemia, pernicious anemia and hemolytic disorders, hemoglobinopathies and thalassemia, the complete or partial deficiency of HGPRT, superactivity of PRPP synthetase, and hereditary renal hypouricemia. A common denominator in patients with idiopathic and gouty stone formers is a low urinary pH. Uric acid nephrolithiasis is indicated in the presence of a radiolucent stone, a persistent undue urine acidity and uric acid crystals in fresh urine samples. A radiolucent stone in combination with normal or acidic pH should raise the possibility of urate stones.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7783706

Halabe, A; Sperling, O

1994-01-01

104

Acid Strengths of Some Substituted Picric Acids.  

National Technical Information Service (NTIS)

The aqueous dissociation constants for a number of substituted picric acids and related compounds were determined spectrophotometrically, and the values obtained correlated with the mid-equivalence potentials obtained by half-neutralization in acetone sol...

P. J. Pearce R. J. J. Simkins

1968-01-01

105

Editorial: Acid precipitation  

SciTech Connect

This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

NONE

1995-09-01

106

Equilibrium fracture acidizing  

SciTech Connect

This patent describes a method for acidizing a formation penetrated by a well comprising: injecting acid into the formation at a pressure sufficient to initiate and propagate a fracture in the formation; reducing the injection rate of the acid into the fracture to a rate sufficient to hold the fracture open without significant further extension, such that the acid contacts and etches the fracture; and reducing the injection rate of the acid into the fracture to a rate that is sufficient to hold the fracture open.

Tinker, S.J.

1989-06-06

107

[Uric acid nephrolithiasis].  

PubMed

Uric acid nephrolithiasis is frequent accounting for 10% of urinary stones in industrialized countries. Its frequency will increase in the next decades because of the ageing and the increasing prevalence of obesity and type 2 diabetes mellitus. The pathophysiologic defect is an excessively acidic urine pH rather than hyperuricosuria. Undissociated uric acid is poorly soluble in acidic urines (pH < 5.5) but solubility increases when sodium urate forms at higher pH. Insulin resistance may contribute to the development of acidic urine because of higher net acid excretion. Because uric acid kidney stones are radiolucent, diagnosis is based on echography and tomodensitometry. Medical management strategies focus primarily on alkali treatment and/or decreasing hyper-uricosuria. PMID:21563421

Dussol, Bertrand

2011-03-01

108

Process for the preparation of lactic acid and glyceric acid  

DOEpatents

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02

109

The Enzymic Conversion of the Tartaric Acids to Oxaloacetic Acid  

Microsoft Academic Search

SUMMARY: Certain bacteria of the genus Pseudomonas attack the tartaric acids by means of inducible stereospecific dehydrases. Each dehydrase converts its specific isomeric substrate to oxaloacetic acid ; in crude cell-free extracts the oxaloacetic acid is in turn converted to pyruvic acid, which accumulates. By treatment of the crude extracts with ethylenediaminetetraacetic acid (EDTA), substantial accumulations of oxaloacetic acid can

M. SHILO

1957-01-01

110

Isoprenoid Acids in Recent Sediments.  

National Technical Information Service (NTIS)

Phytanic acid, pristanic acid, and 4,8,12-trimethyltridecanoic acid have been isolated from three recent marine sediments. The ratio of palmitic to pristanic acid is similar to that encountered in typical marine lipids. This suggests a biochemical origin ...

M. Blumer W. J. Cooper

1968-01-01

111

Fatty acids and neurodevelopment.  

PubMed

Knowledge of the importance of docosahexaenoic acid (DHA), arachidonic acid (AA), and long-chain polyunsaturated fatty acids (LCPUFAs) in neurodevelopment was originally obtained from animal studies. These fatty acids are rapidly accreted in brain during the first postnatal year in animal and human infants, and they are found in high concentrations in breast milk. Reports of enhanced intellectual development in breast-fed children, and reports linking LCPUFA deficiency with neurodevelopmental disorders have stressed the physiological importance of DHA in visual and neural systems. In addition to high concentrations of fatty acids in breast milk, they are also present in fish and algae oil and have recently been added to infant formulas. Esterified poplyunsaturated fatty acids act in cellular membranes, in signal transduction, in neurotransmission, and in the formation of lipid rafts. Nonesterified polyunsaturated fatty acids can modulate gene expression and ion channel activities, thus becoming neuroprotective agents. The conversion of linoleic acid and alpha-linolenic acid into ARA and DHA have led to randomized clinical trials that have studied whether infant formulas supplemented with DHA or both DHA and ARA would enhance visual and cognitive development. This review gives an overview of fatty acids and neurodevelopment, focusing on the findings from these studies. PMID:18667917

Belkind-Gerson, J; Carreón-Rodríguez, A; Contreras-Ochoa, C O; Estrada-Mondaca, S; Parra-Cabrera, M S

2008-08-01

112

Lewis Acid Organocatalysts  

NASA Astrophysics Data System (ADS)

The term Lewis acid catalysts generally refers to metal salts like aluminium chloride, titanium chloride and zinc chloride. Their application in asymmetric catalysis can be achieved by the addition of enantiopure ligands to these salts. However, not only metal centers can function as Lewis acids. Compounds containing carbenium, silyl or phosphonium cations display Lewis acid catalytic activity. In addition, hypervalent compounds based on phosphorus and silicon, inherit Lewis acidity. Furthermore, ionic liquids, organic salts with a melting point below 100 °C, have revealed the ability to catalyze a range of reactions either in substoichiometric amount or, if used as the reaction medium, in stoichiometric or even larger quantities. The ionic liquids can often be efficiently recovered. The catalytic activity of the ionic liquid is explained by the Lewis acidic nature of their cations. This review covers the survey of known classes of metal-free Lewis acids and their application in catalysis.

Sereda, Oksana; Tabassum, Sobia; Wilhelm, René

113

Acid rain reports  

NASA Astrophysics Data System (ADS)

Three independent reports on acid precipitation issued in June reinforce each other and, taken together, support those seeking immediate action to curb man-generated acid deposition in northeastern North America by reducing emissions of sulfur and nitrogen oxides. The Interagency Task Force on Acid Precipitation report concluded that manmade pollution is to blame for acid precipitation problems in the northeastern United States. A National Research Council (NRC) committee stated that reducing the manmade emissions of sulfur and nitrogen oxides will result in a proportional reduction in the deposition of acid precipitation. And an acid rain panel assembled by the White House Office of Science and Technology Policy (OSTP) called for immediate action to curb the emissions despite incomplete scientific data.

Richman, Barbara T.

114

Kidney amino acid transport  

Microsoft Academic Search

Near complete reabsorption of filtered amino acids is a main specialized transport function of the kidney proximal tubule.\\u000a This evolutionary conserved task is carried out by a subset of luminal and basolateral transporters that together form the\\u000a transcellular amino acid transport machinery similar to that of small intestine. A number of other amino acid transporters\\u000a expressed in the basolateral membrane

François Verrey; Dustin Singer; Tamara Ramadan; Raphael N. Vuille-dit-Bille; Luca Mariotta; Simone M. R. Camargo

2009-01-01

115

Chronic valproic acid intoxication.  

PubMed

Valproic acid intoxication may be associated with cerebral, cardiovascular, respiratory, gastrointestinal, and hematologic complications. We report a case of a 7-year-old girl, epilepsy-treated chronically with valproic acid, sulthiame, and clonazepam, who presented to the emergency room because of a global deterioration during the preceding 2 months, including poorer feeding and worsened general responsiveness. The girl was later diagnosed to have chronic valproic acid intoxication. PMID:23736073

Weiner, Dror; Nir, Vered; Klein-Kremer, Adi; Kassem, Eiass

2013-06-01

116

Acid rain on Bermuda  

Microsoft Academic Search

Increased acidity of precipitation due to combustion of fossil fuels has been well documented for both the eastern USA1 and Canada2. The SO2 and NOxemitted by the burning of coal, natural gas, fuel oil and petrol are oxidized in the atmosphere to sulphuric and nitric acids which subsequently give rise to acid precipitation1. However, the SO2 and NOx emitted, and

Timothy Jickells; Anthony Knap; Thomas Church; James Galloway; John Miller

1982-01-01

117

Preparation of petroselinic acid  

Microsoft Academic Search

Petroselinic acid of a grade which is suitable for most laboratory applications has been prepared by a single crystallization\\u000a of the mixed fatty acids of parsley seed oil from 90% ethanol. A product of higher purity has been prepared from this acid\\u000a by application of urea segregation techniques for the removal of saturated materials. No evidence of the presence of

Sara P. Fore; Raiford L. Holmes; W. G. Bickford

1960-01-01

118

Well acidization with alpha-hydroxysulfonic acid  

SciTech Connect

This patent describes a well treating process in which fluid is injected into a well and flowed into contact with acidifiable material in and around a portion of the well within a subterranean earth formation in order to contact the acidifiable material with at least one strong acid. An improved process for controlling the rate of the acidification reaction comprises: flowing fluid inclusive of water, SO/sub 2/ and carbonyl compound into the well and into and out of contact with the acidifiable material with the composition of the fluid arranged so that, in contact with the acidifiable material, the fluid consists essentially of an acidic solution of water, SO/sub 2/ and carbonyl compound in equilibrium with at least one reactively formed alpha-hydroxysulfonic acid.

Slaugh, L.H.

1987-06-02

119

Aristolochic Acid: Safety Alert  

Center for Food Safety and Applied Nutrition (CFSAN)

... Section Contents Menu. Recalls, Outbreaks & Emergencies. Safety Alerts & Advisories. -. Aristolochic Acid: Safety Alert. FDA ... More results from www.fda.gov/food/recallsoutbreaksemergencies/safetyalertsadvisories

120

Recovery of organic acids  

SciTech Connect

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Menlo Park, CA); Eggeman, Timothy J. (Lakewood, CO)

2011-11-01

121

Recovery of organic acids  

DOEpatents

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Golden, CO); Eggeman, Timothy J. (Lakewood, CO)

2009-10-13

122

Acidizing concentrates for oil well acidizing systems  

SciTech Connect

An acidizing composition is described for treating oil-bearing formations comprising: (a) from about 90 to about 99.99 percent by volume of an aqueous acid solution; and (b) from about 0.01 to about 10 percent by weight of an acidizing concentrate consisting of: a mixture of a branched-aliphatic C/sub 3/-C/sub 6/ alcohol and a branched aliphatic C/sub 7/-C/sub 10/ alcohol; and an effective amount of a non-ionic polyether surfactant to render the alcohols soluble in the acid. The surfactant has the formula: R is the oxyalkylation residue of a C/sub 2/-C/sub 10/ diol or triol; n is an integer of 2 or 3, X and Y are numbers such that the ratio of X to Y is from 8:1 to 0.3:1; and the total molecular weight of the molecule is from 1,000 to 15,000. The weight ratio of the mixture of alcohols to the nonionic surfactant is from 10:1 to 1:10. The composition is capable of dissolving sludge deposits in the oil-bearing formations.

Crema, S.C.

1987-06-30

123

Strong Acids (GCMP)  

NSDL National Science Digital Library

Strong Acids: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore the properties of common strong acids. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

124

Acids and Salts (GCMP)  

NSDL National Science Digital Library

Acids and Salts: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore a few properties of common acids and their salts. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

125

Facts about Folic Acid  

MedlinePLUS

... INFO (800-232-4636) TTY: (888) 232-6348 Contact CDC-INFO flo@cdc.gov Folic Acid Homepage Facts Quiz Questions & Answers Cereals with Folic Acid Data and Statistics Research Global Initiative Articles & Key Findings Recommendations Free Materials Links ...

126

Folic Acid Quiz  

MedlinePLUS

... INFO (800-232-4636) TTY: (888) 232-6348 Contact CDC-INFO flo@cdc.gov Folic Acid Homepage Facts Quiz Questions & Answers Cereals with Folic Acid Data and Statistics Research Global Initiative Articles & Key Findings Recommendations Free Materials Links ...

127

Acid rain options  

SciTech Connect

A number of contributions made to a series of seminars on acid rain options held by the Air Pollution Control Association are presented. They include statements on US and Canadian policy and legislation, and views from coal producers, electric utilities and motor vehicle manufacturers on measures to counteract or prevent the effects of acid rain.

Perhac, R.M.

1985-03-01

128

Azelaic Acid Topical  

MedlinePLUS

Finacea® Gel ... Azelaic acid gel is used to clear the bumps, lesions, and swelling caused by rosacea (a skin disease that causes redness, ... Azelaic acid comes as a gel and a cream to apply to the skin. It is usually applied twice a day, in the morning and the evening. ...

129

EFFECTS OF ACID PRECIPITATION  

EPA Science Inventory

Recent reviews of available data indicate that precipitation in a large region of North America is highly acidic when its pH is compared with the expected pH value of 5.65 for pure rain water in equilibrium with CO2. A growing body of evidence suggests that acid rain is responsib...

130

(Acid rain workshop)  

Microsoft Academic Search

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment

1990-01-01

131

Acid in water  

NSDL National Science Digital Library

Plants and animals that live in water create some amount of acid in the water. The carbon dioxide that plants and animals release into the water makes the water acidic and unsafe for living organisms. This is why the water of captive aquatic animals and plants must be changed often.

Laszlo Ilyes (None;)

2007-05-16

132

Amino acids: Analytical aspects  

Microsoft Academic Search

This workshop was organized as a direct response to concerns and queries raised by laboratory personnel, both in Europe and in the United States, about the imminent withdrawal of Beckman Coulter from the amino acid analysis market. The topics covered included external quality control schemes, standard operating procedures for amino acid analysis and instrumentation, both from a user's perspective and

P. D. Mayne; G. Roche; D. Deverell

2001-01-01

133

EXPOSURES TO ACIDIC AEROSOLS  

EPA Science Inventory

Ambient monitoring of acid aerosol in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. easurements made in Kingston, TN, and Stuebenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 ti...

134

Toxicology of Perfluoroalkyl acids  

EPA Science Inventory

The Perfluoroalkyl acids(PFAAs) area a family of organic chemicals consisting of a perflurinated carbon backbone (4-12in length) and a acidic functional moiety (Carboxylate or sulfonate). These compounds have excellent surface-tension reducing properties and have numerous industr...

135

Toxicology of Perfluoroalkyl Acids*  

EPA Science Inventory

The perfluoroalkyl acids (PFAAs) are a family of organic chemicals consisting of a perfluorinated carbon backbone (4-12 in length) and an acidic functional moiety (carboxylate or sulfonate). These compounds are chemically stable, have excellent surface-tension reducing properties...

136

Fats and fatty acids  

Technology Transfer Automated Retrieval System (TEKTRAN)

The absolute fat requirement of the human species is the amount of essential fatty acids needed to maintain optimal fatty acid composition of all tissues and normal eicosanoid synthesis. At most, this requirement is no more than about 5% of an adequate energy intake. However, fat accounts for appro...

137

Metabolism of Acid Mucopolysaccharides  

PubMed Central

The biosynthesis of the acid mucopolysaccharides, hyaluronic acid and chondroitin sulfuric acid, occurs by way of uridine nucleotides which contain the monosaccharide units of the respective polysaccharides. The mechanism of alternation of groups is as yet unknown. Certain of the acid mucopolysaccharides are covalently bound to protein by way of serine. In the case of the protein-polysaccharide complex of cartilage, there is evidence to suggest that the polysaccharide may be linked to the serine by way of galactose. Chondroitin sulfuric acid B may be isolated almost free of amino acids from the tissues and urine of patients with the Hurler syndrome without the use of proteolytic enzymes, acid, or alkali. This contrasts markedly with the tight binding of this compound to protein in normal tissue. It is suggested that the metabolic defect in this disease may reside in a defect of the peptide or linkage of the peptide to polysaccharide resulting in failure of the acid mucopolysaccharide to be fixed normally in connective tissue. Such a defect may result in interference with normal regulation of polysaccharide synthesis with a resultant increased synthesis. It is proposed that such a mechanism may obtain in other heritable connective tissue diseases as well as other storage diseases.

Dorfman, Albert

1964-01-01

138

Amino Acid Crossword Puzzle  

ERIC Educational Resources Information Center

|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;…

Sims, Paul A.

2011-01-01

139

Gelatinization with formic acid.  

PubMed

1. A study has been made of the gelatins obtained by treating a number of fresh and fossil collagens with dilute formic acid. 2. Compositions of their peptides separated by filtration through polyacrylamide gels has been established. 3. Solubilization results in the freeing of much aspartic acid and less glycine, the amounts being determined for the collagens investigated. PMID:318457

Wyckoff, R W; Davidson, F D

1979-01-01

140

Silicic acid: boric acid complexes as wood preservatives  

Microsoft Academic Search

Wood was treated with a low molecular-weight silicic acid: boric acid agent and examined for increased resistance to termites and combustion. Wood treated with silicic acid only exhibited increased termite resistance, but not to the marked extent observed after treatment with a mixture of silicic and boric acids. Increasing the quantity of boric acid also increased the termite mortality rate

Haruhiko Yamaguchi

2003-01-01

141

Docosahexaenoic acid and arachidonic acid in infant development  

Microsoft Academic Search

Docosahaxaenoic acid and arachidonic acid are highly concentrated in the central nervous system. The amount of these fatty acids in the central nervous system increases dramatically during the last intrauterine trimester and the first year of life. A central question of research conducted during the past 20 years is if the essential fatty acid precursor of docosahexaenoic acid is sufficient

Susan E. Carlson

2001-01-01

142

Acid rain trends summarized  

NASA Astrophysics Data System (ADS)

In the northeastern United States, the acidity of precipitation has changed little in recent years, although the acidity is increasing in other regions. That's the latest word from a comprehensive review by the U.S. Geological Survey (USGS) of more than 200 published reports of acid rain research from the past 30 years. The report contributes to the controversy over whether increased sulfur emissions from Midwest powerplants increase the acidity of precipitation in the Northeast.“When the results of the many individual studies are combined, they show that acidification of precipitation in the Northeast, which has the most damaging level of acidity on a regional basis, occurred primarily before the mid-1950's and has been largely stabilized since the mid-1960s,” said John T. Turk, a research hydrologist at the USGS Denver office and author of the 18-page summary report.

143

Energy and acid rain  

SciTech Connect

Acid rain is one of the foremost environmental issues of the 1980s and will be of continuining importance to energy policy for several reasons. First, the pollutants that cause acid rain are projected to increase through the end of the century as the demand for energy grows and as coal replaces oil. Second, many of the effects of acid rain are cumulative, so that even at current levels of emissions the problem is expected to intensify and to spread geographically. Third, the transport of air pollutants across state and national boundaries has raised fundamental issues of equity that are likely to be disputed for some time. Finally, any serious program for reducing acid rain will exert a profound influence on the future development of energy supplies. This review summarizes the causes, effects, and transport of acid rain, and discusses possible strategies for mitigating the problem.

Gould, R.R.

1984-01-01

144

Acid Rain Revisited  

NSDL National Science Digital Library

The results of a long term study of the effects of acidic deposition in the Northeast were published in Bioscience this week, and they suggest that forests, lakes, and streams of the Northeastern US are not recovering from the toxic effects of acid rain despite significant cuts in the power plant emissions of sulfur dioxide and nitrogen oxide -- two major contributors to the problem. "Acid rain," more accurately called acidic deposition, causes toxic forms of aluminum to concentrate in soil and water, vital calcium and magnesium to be leached from trees, and surface waters to become inhospitable to aquatic biota. The study showed that, after 30 years of federally mandated air emission reductions, sulfur dioxide emissions have decreased while nitrogen oxide emissions have remained the same and that acidic deposition-related problems continue to plague New York and New England.

Sanders, Hilary C.

2001-01-01

145

Fatty Acid Production from Amino Acids and ?-Keto Acids by Brevibacterium linens BL2†  

PubMed Central

Low concentrations of branched-chain fatty acids, such as isobutyric and isovaleric acids, develop during the ripening of hard cheeses and contribute to the beneficial flavor profile. Catabolism of amino acids, such as branched-chain amino acids, by bacteria via aminotransferase reactions and ?-keto acids is one mechanism to generate these flavorful compounds; however, metabolism of ?-keto acids to flavor-associated compounds is controversial. The objective of this study was to determine the ability of Brevibacterium linens BL2 to produce fatty acids from amino acids and ?-keto acids and determine the occurrence of the likely genes in the draft genome sequence. BL2 catabolized amino acids to fatty acids only under carbohydrate starvation conditions. The primary fatty acid end products from leucine were isovaleric acid, acetic acid, and propionic acid. In contrast, logarithmic-phase cells of BL2 produced fatty acids from ?-keto acids only. BL2 also converted ?-keto acids to branched-chain fatty acids after carbohydrate starvation was achieved. At least 100 genes are potentially involved in five different metabolic pathways. The genome of B. linens ATCC 9174 contained these genes for production and degradation of fatty acids. These data indicate that brevibacteria have the ability to produce fatty acids from amino and ?-keto acids and that carbon metabolism is important in regulating this event.

Ganesan, Balasubramanian; Seefeldt, Kimberly; Weimer, Bart C.

2004-01-01

146

Airborne haloacetic acids.  

PubMed

Haloacetic acid (HAA) concentrations were measured in air samples from a semi-rural and a highly urbanized site in southern Ontario throughout 2000 to investigate their sources and gas-particle partitioning behavior. Denuders were efficient for collection of gaseous HAAs, and the particle phase was collected on a downstream quartz filter with negligible breakthrough. Total HAA concentrations (i.e., gas + particles) ranged between <0.025 and 19 ng m(-3) for individual HAAs at both sites. The dominant airborne HAA was monochloroacetic acid (MCA), followed in decreasing order by dichloroacetic acid (DCA), trifluoroacetic acid (TFA), and trichloroacetic acid (TCA). Difluoroacetic acid (DFA), monofluoroacetic acid (MFA), and chlorodifluoroacetic acid (CDFA) were also frequently detected at lower concentrations. Between sites, TFA, DFA, MFA, and TCA concentrations were significantly higher in Toronto, while CDFA concentrations were higher in Guelph. HAAs were primarily in the gas phase all year; however, during colder months, particle-phase HAA concentrations increased relative to the gas phase. Trichloroacetic acid had the highest particle fraction (phi) for all detected HAAs, with a mean phi of 0.51 and 0.56 for Guelph and Toronto, respectively, and both vapor pressure and acid strength appeared to influence gas-particle partitioning. Temporal trends at both sites were partially explained by temperature, short-wave radiation, and particle mass (PM10), leading to indications of the respective sources. A simple deposition model indicated that dry deposition of TFA and TCA should not be neglected in temperate mid-latitude environments and that precipitation concentrations can be successfully predicted by the Henry's law constant. PMID:12875391

Martin, Jonathan W; Mabury, Scott A; Wong, Charles S; Noventa, Francis; Solomon, Keith R; Alaee, Mehran; Muir, Derek C G

2003-07-01

147

Glycidyl Esters of Aromatic Acids  

Microsoft Academic Search

The reaction of substituted benzoic acids, dicarboxylic acids such as phthalic, terephthalic, and isophthalic acids, and the sodium or potassium salts of these acids with equimolar or excess epichlorohydrin in the presence of benzyltrimethylammonium chloride has been studied using various solvents such as toluene, dioxane, monochlorobenzene, and tetrachloroethylene. Use of the free carboxylic acids gave only fair to low yields

Yoshio Tanaka; Hiroshi Kakiuchi

1967-01-01

148

Strongly Acidic Auxin Indole-3-Methanesulfonic Acid  

PubMed Central

A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles.

Cohen, Jerry D.; Baldi, Bruce G.; Bialek, Krystyna

1985-01-01

149

Antioxidant activity of caffeic acid (3,4-dihydroxycinnamic acid)  

Microsoft Academic Search

Caffeic acid (3,4-dihydroxycinnamic acid) is among the major hydroxycinnamic acids present in wine; sinapic acid, which is a potent antioxidant. It has also been identified as one of the active antioxidant. In the present study, the antioxidant properties of the caffeic acid were evaluated by using different in vitro antioxidant assays such as 2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picryl-hydrazyl free

?lhami Gülçin

2006-01-01

150

Ceric acid decontamination of nuclear reactors  

SciTech Connect

This patent describes a composition, it consists of water; about 0.5 to about 3% by weight of a ceric acid selected from the group consisting of tetrasulfato ceric acid, hexasulfamato ceric acid, hexaperchlorato ceric acid, and mixtures thereof; and about 1 to about 5% by weight of an inorganic acid. The inorganic acid is sulfuric acid when the ceric acid is tetrasulfato ceric acid, sulfamic acid when the ceric acid is hexasulfamato ceric acid, perchloric acid when the ceric acid is a mixture selected from the group consisting of tetrasulfato ceric acid, hexasulfamato ceric acid, and hexaperchlorato ceric acid.

Murray, A.P; Slater, C.G.; White, R.W.

1989-11-14

151

Acid rain agreement  

SciTech Connect

Scientific working groups from Canada and the US have been established to prepare for acid rain negotiations scheduled for June 1981. The groups will take air samples and estimate impact of acid rain on the environment, determine the precise origin of acid rain, and develop a strategy for abatement. Some constraints on the negotiations are costs (potentially $400-500 million for Canada and 5 to 8 times that for the US between now and 2000), the relative independence of Canada's provinces, and the US utility lobby.

Smith, R.J.

1980-08-22

152

Citric acid production.  

PubMed

Citric acid is a commodity chemical produced and consumed throughout The World. It is used mainly in the food and beverage industry, primarily as an acidulant. Although it is one of the oldest industrial fermentations, its World production is still in rapid increasing. Global production of citric acid in 2007 was over 1.6 million tones. Biochemistry of citric acid fermentation, various microbial strains, as well as various substrates, technological processes and product recovery are presented. World production and economics aspects of this strategically product of bulk biotechnology are discussed. PMID:17875481

Berovic, Marin; Legisa, Matic

2007-01-01

153

WASTE ACID DETOXIFICATION AND RECLAMATION  

EPA Science Inventory

This Environmental Security Technology Certification Program (ESTCP) project demonstrated the Waste Acid Detoxification and Reclamation (WADR) systems ability to recover waste electropolish acid solutions generated during the manufacturing of gun-tubes, and reuse the clean acid. ...

154

Atmospheric chemistry: Natural atmospheric acidity  

NASA Astrophysics Data System (ADS)

Formic acid exerts a significant influence on atmospheric chemistry and rainwater acidity. Satellite observations and model simulations suggest that terrestrial vegetation accounts for around 90% of the formic acid produced annually.

Millet, Dylan B.

2012-01-01

155

Hydroxy-Conjugated Fatty Acids.  

National Technical Information Service (NTIS)

This invention relates to a method of producing hydroxy-conjugated octadecadienoic acid from linoleic acid contained in vegetable oils and soap stocks from alkali-refined vegetable oils. Linoleic acid soaps are dispersed in an aqueous medium containing di...

E. A. Emkeu

1973-01-01

156

High-performance liquid chromatography for the quantitative determination of the urinary metabolites of toluene, xylene, and styrene  

Microsoft Academic Search

A new high-pressure liquid chromatography (HPLC) method for simultaneous quantitative determination of the urinary metabolites of toluene, m-xylene, and styrene (hippuric acid, m-methylhippuric acid, phenylglyoxylic acid, mandelic acid) is described. The extraction procedure was performed on acidified urines, after addition of 4-hydroxybenzoic acid as internal standard, using a butylchloride\\/isopropanol mixture and drying 0.5 ml of the organic layer under nitrogen

G. Poggi; M. Giusiani; U. Palagi; P. L. Paggiaro; A. M. Loi; F. Dazzi; C. Siclari; L. Baschieri

1982-01-01

157

Acid Hydrolysis of Wood.  

National Technical Information Service (NTIS)

A series of investigations into the acid hydrolysis of pinus radiata (Monterey pine) and the results therefrom are described. Main objectives of the investigation were to establish, using the most promising routes, the conditions of hydrolysis that would ...

A. L. Titchener B. K. Guha

1981-01-01

158

Aristolochic Acid: Safety Alert  

Center for Food Safety and Applied Nutrition (CFSAN)

... Section Contents Menu. Recalls, Outbreaks & Emergencies. Safety Alerts & Advisories. -. Aristolochic Acid: Safety Alert. FDA ... More results from www.fda.gov/food/recalls,%20outbreaks%20&%20emergencies/safetyalertsadvisories

159

Uric acid - blood  

MedlinePLUS

... blood. High levels of uric acid can cause gout or kidney disease. Your doctor may also order ... hyperuricemia) may be due to: Acidosis Alcoholism Diabetes Gout Hypoparathyroidism Lead poisoning Leukemia Nephrolithiasis Polycythemia vera Renal ...

160

Trans fatty acids (image)  

MedlinePLUS

Trans fatty acids are manufactured fats created during a process called hydrogenation, which is aimed at stabilizing polyunsaturated oils to prevent them from becoming rancid and to keep them solid at room temperature. They may ...

161

Nucleic Acids for Computation  

NASA Astrophysics Data System (ADS)

Nucleic acids have many features that are ideal for molecular computation. Using nucleic acids, we have constructed a full set of molecular logic gates, with modular stem-loop-controlled deoxyribozymes as switches and single-stranded oligonucleotides as inputs and outputs. These gates have been combined to form basic computational circuits, including a half- and a full-adder, and can also be assembled into automata to perform complex computational tasks such as game playing. Our most advanced automaton to-date integrates more than 100 nucleic acid logic gates to play a complete game of tic-tac-toe encompassing 76 possible game plays. Inputs and outputs can also be coupled with upstream and downstream components, such as aptamers, sensors, secondary gate activation, and small-molecule release, indicating the potential for nucleic acid computation in the engineering of autonomous therapeutic and diagnostic molecular devices.

MacDonald, Joanne; Stojanovic, Milan N.

162

Zoledronic Acid Written Request  

Center for Drug Evaluation (CDER)

Text Version... dated April 18, 2006, requesting changes to FDA's August 19, 2002, Written Request for pediatric studies for zoledronic acid, as amended ... More results from www.fda.gov/downloads/drugs/developmentapprovalprocess

163

Polymers for acid thickening  

SciTech Connect

Acids, thickened with branched emulsion or suspension polymers of diallyldimethylammonium chloride are useful as oil well drilling and fracturing fluids for stimulating well production and in other applications, such as thickeners for cosmetics, paints, adhesives, textiles and printing inks.

Dixon, K.W.

1980-09-30

164

(Acid rain workshop)  

SciTech Connect

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment Program, the United Nations Economic and Social Commission for Asia and the Pacific, and the World Bank. Papers presented on the first day discussed how the experience gained with acid rain in North America and Europe might be applied to the Asian situation. Papers describing energy use projections, sulfur emissions, and effects of acid rain in several Asian countries were presented on the second day. The remaining time was allotted to discussion, planning, and writing plans for a future research program.

Turner, R.S.

1990-12-05

165

Acid Precipitation: A Bibliography.  

National Technical Information Service (NTIS)

This bibliography contains 3197 references to information on various aspects of acid precipitation that have been included in the Department of Energy's Energy Data Base through February 1983. The references cover research reports, journal articles, books...

P. S. Blackburn

1983-01-01

166

Valproic Acid and Pregnancy  

MedlinePLUS

... valproic acid and then had a relapse of bipolar disorder during my pregnancy? Recurrence of depression or mania ... 7. Yonkers KA et al. 2004. Management of bipolar disorders during pregnancy and the postpartum period. Am J ...

167

Acid Mine Drainage Treatment.  

National Technical Information Service (NTIS)

Contaminated water flowing from abandoned coal mines is one of the most significant contributors to water pollution in former and current coal- producing areas. Acid mine drainage (AMD) can have severe impacts to aquatic resources, can stunt terrestrial p...

J. Fripp P. F. Ziemkiewicz H. Charkavorki

2000-01-01

168

Acid prehydrolysis of wood  

Treesearch

Acid pretreatment of wood provides significant energy savings during refining ... reduction in specific refiner energy consumption, with a minor sacrifice in brightness. ... The similarity in behavior of these two pretreatments suggests a common ...

169

Acid Lipase Disease  

MedlinePLUS

... Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, Wolman’s Disease Table of Contents (click to ... include waxes, oils, and cholesterol. Two rare lipid storage diseases are caused by the deficiency of the ...

170

Acid-Base Tutorial  

NSDL National Science Digital Library

Website for anyone wanting to become more familiar with the physiology of acid-base balance in clinical medicine. Several pages are interactive. Numerical results are accompanied by text interpretations to facilitate recognition and understanding.

MD Alan W. Grogono (Tulane University School of Medicine Dept. of Anesthesiology)

2002-06-01

171

Salicylic Acid Topical  

MedlinePLUS

... skin dryness and scaling), dandruff, corns, calluses, and warts on the hands or feet. Topical salicylic acid should not be used to treat genital warts, warts on the face, warts with hair growing ...

172

Folic acid in diet  

MedlinePLUS

... certain types of anemias . Folate works along with vitamin B12 and vitamin C to help the body break ... Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academy Press, ...

173

Nucleic Acids for Computation  

Microsoft Academic Search

\\u000a Nucleic acids have many features that are ideal for molecular computation. Using nucleic acids, we have constructed a full\\u000a set of molecular logic gates, with modular stem-loop-controlled deoxyribozymes as switches and single-stranded oligonucleotides\\u000a as inputs and outputs. These gates have been combined to form basic computational circuits, including a half- and a full-adder,\\u000a and can also be assembled into automata

Joanne MacDonald; Milan N. Stojanovic

2009-01-01

174

Biodegradation of polyhydroxyalkanoic acids  

Microsoft Academic Search

Stimulated by the commercial availability of bacteriologically produced polyesters such as poly[(R)-3-hydroxybutyric acid], and encouraged by the discovery of new constituents of polyhydroxyalkanoic acids (PHA), a considerable\\u000a body of knowledge on the metabolism of PHA in microorganisms has accumulated. The objective of this essay is to give an overview\\u000a on the biodegradation of PHA. The following topics are discussed: (i)

D. Jendrossek; A. Schirmer; H. G. Schlegel

1996-01-01

175

Acids of pomegranate peel  

Microsoft Academic Search

the substance were identical with those of ellagic acid. On the basis of the results of a determination of the maximum intensities of the spots (SF-4a at 440 nm) revealed with a 1% solution of iron ammonium alum, it was established that the peel contains0.55% of ellagic acid on the air-dry raw material. The ethereal extract was evaporated to dryness

E. P. Nosacheva; Yu. B. Kerimov; T. N. Bikbulatova

1973-01-01

176

Nucleic acid detection method  

US Patent & Trademark Office Database

A method of detecting a target nucleotide sequence in a nucleic acid molecule, which comprises: (a) binding of an oligonucleotide probe to said nucleic acid molecule; (b) selective labelling of the bound oligonucleotide probe in the presence of said target nucleotide sequence; (c) hybridization of the labelled oligonucleotide to a complementary sequence; and (d) subsequent detection of the label; such methods being suitable for qualitative and quantitative assays of microbiological populations.

Rudi; Knut (Oslo, NO); Jakobsen; Kjetill Sigurd (Olso, NO)

2003-09-09

177

Acid Rain Lesson Plan  

NSDL National Science Digital Library

Five articulated lessons focus on air quality using classroom and field data collection activities. Case study in Great Smoky Mountains has broader application. Background and data for lessons on: the pH scale, understanding acid vs. base, collecting data, mapping relationship of weather events to acid rain. Links to NPS data on air quality, current values, atlas and reports, packaged datasets on ozone, meteorological conditions and other parameters. Also available: teacher resources; educator workshops.

178

Molecular Structure of Gallic acid  

NSDL National Science Digital Library

Gallic acid is found in its free state and combined with the tannin molecule, from which it can be extracted by the hydrolysis of tannic acid with sulfuric acid. Since one molecule of gallic acid has a carboxylic acid group and hydroxyl groups, it can react with another molecule of gallic acid to form an ester, digallic acid. When heated above 200 degrees C, gallic acid loses carbon dioxide to form pyrogallol (1,2,3-trihydroxybenzene, C6H3(OH)3), which is used in the production of azo dyes, photographic developers, and in laboratories for absorbing oxygen.

2003-05-08

179

Portable nucleic acid thermocyclers.  

PubMed

A nucleic acid thermal cycler is considered to be portable if it is under ten pounds, easily carried by one individual, and battery powered. Nucleic acid amplification includes both polymerase chain reaction (e.g. PCR, RT-PCR) and isothermal amplification (e.g. RPA, HDA, LAMP, NASBA, RCA, ICAN, SMART, SDA). There are valuable applications for portable nucleic acid thermocyclers in fields that include clinical diagnostics, biothreat detection, and veterinary testing. A system that is portable allows for the distributed detection of targets at the point of care and a reduction of the time from sample to answer. The designer of a portable nucleic acid thermocycler must carefully consider both thermal control and the detection of amplification. In addition to thermal control and detection, the designer may consider the integration of a sample preparation subsystem with the nucleic acid thermocycler. There are a variety of technologies that can achieve accurate thermal control and the detection of nucleic acid amplification. Important evaluation criteria for each technology include maturity, power requirements, cost, sensitivity, speed, and manufacturability. Ultimately the needs of a particular market will lead to user requirements that drive the decision between available technologies. PMID:24030680

Almassian, David R; Cockrell, Lisa M; Nelson, William M

2013-10-21

180

Estimating amounts of toluene inhaled by workers with protective mask using biological indicators of toluene  

Microsoft Academic Search

Personal air samplers were attached to workers wearing protective masks to determine the levels of toluene vapor in the breathing zone. Concentrations of toluene in exhaled air, blood and urine; and hippuric acid and o-cresol concentrations in the urine of the workers were determined. Subsequently, toluene concentrations in the air inhaled by workers with and without gas masks were estimated

Masana Ogata; Hiromi Michitsuji; Yukio Fujiki

1999-01-01

181

Synthesis of 4-Arylidene-2-Phenyloxazol-5-Ones Using 1:1 Mixture of Al2O3 -H3BO3  

Microsoft Academic Search

Cyclodehydration-condensation of hippuric acid and arylaldehydes have been carried out using a 1:1 mixture of Al2O3-H3BO3 in the presence of stoichiometric quantity of acetic anhydride to give the target compound in good yield. This procedure can be used to synthesize the 4-alkylidene analogs also.

Jyotimoni Kashyap; A. B. Chetry; Pranab J. Das

1998-01-01

182

Monitoring of workers exposed to a mixture of toluene, styrene and methanol vapours by means of diffusive air sampling, blood analysis and urinalysis  

Microsoft Academic Search

Summary Exposure of 34 male workers to combined toluene, styrene and methanol was monitored by personal diffusive sampling of solvent vapours in breathing zone air, analysis of shift-end blood for the 3 solvents and analysis of shift-end urine for hippuric, mandelic and phenylglyoxylic acids and methanol. The exposure of most of the workers was below current occupational exposure limits. Regression

Toshio Kawai; Tomojiro Yasugi; Kazunori Mizunuma; Shun'ichi Horiguchi; Ikuharu Morioka; Kazuhisa Miyashita; Yoko Uchida; Masayuki Ikeda

1992-01-01

183

Helicobacter rodentium sp. nov., a Urease-Negative Helicobacter Species Isolated from Laboratory Mice  

Microsoft Academic Search

A spiral-shaped bacterium with bipolar, single, nonsheathed flagella was isolated from the intestines of laboratory mice. The organism grew at 37 and 42°C under microaerobic and anaerobic conditions, did not hydrolyze urea, was weakly positive for catalase and oxidase, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and was resistant to cephalothin and nalidixic acid. This is

Z. SHEN; J. G. FOX; F. E. DEWHIRST; B. J. PASTER; C. J. FOLTZ; L. YAN; B. SHAMES

184

Acidification and Acid Rain  

NASA Astrophysics Data System (ADS)

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 endangers the existing biota. Concerns about acid (or acidic) rain in its modern sense were publicized by the Swedish soil scientist Svante Odén (1968). He argued, initially in the Swedish press, that long-term increases in the atmospheric deposition of acid could lower the pH of surface waters, cause a decline in fish stocks, deplete soils of nutrients, and accelerate damage to materials. By the 1970s, acidification of surface waters was reported in many countries in Europe as well as in North America. The late twentieth-century rush to understand the impact of acid rain was driven by: (i) reports of damaged or threatened freshwater fisheries and (ii) damaged forests. Perhaps the earliest linkage between acidic surface water and damage to fish was made by Dahl (1921) in southern Norway. There, spring runoff was sufficiently acidic to kill trout. It was not until the 1970s that a strong link was established between depressed pH, mobilization of aluminum from soil, and fish status ( Schofield and Trojnar,1980). The relationship between acidification of soils and forest health started with hypotheses in the 1960s and has slowly developed. Acid rain enhances the availability of some nutrients (e.g., nitrogen), and may either enhance or diminish the availability of others (e.g., calcium, magnesium, potassium, and phosphorus). Damage to anthropogenic structures, human health, and visibility have also raised concerns. The history of these early developments was summarized by Cowling (1982). Since the 1970s, sulfur and nitrogen emissions to the atmosphere have been reduced by 50-85% and 0-30%, respectively, both in North America and Europe. The emission reductions have occurred as a consequence of knowledge gained and economic factors. While recovery of water quality is underway in some areas, problems of acidification persist, and are now complicated by the effects of climate change ( Schindler, 1997).

Norton, S. A.; Veselã½, J.

2003-12-01

185

Nitric acid-formic acid compatibility in DWPF  

SciTech Connect

The addition of the Nitric Acid Flowsheet to the DWPF feed preparation process introduces nitric acid into a vessel which will subsequently receive a formic acid solution. The combination of these two acids suggests that a denitration reaction might occur. This memorandum reviews the conditions under which a denitration reaction is possible and compares these conditions to DWPF operating conditions.

Eibling, R.E.

1992-10-20

186

Export of Acidity in Drainage Water from Acid Sulphate Soils  

Microsoft Academic Search

Disturbed acid sulphate soils are potent sources of acidity in coastal waterways. Monitoring studies of the drainage water for sites at East Trinity, Cairns and Pimpama, south-east Queensland indicate that considerable acidity is found in the drainage water from these sites. Hydrogen (H+), ferrous (Fe2+) and aluminium (Al) ions are the dominant acid cations involved. When drainage water is mixed

F. J Cook; W Hicks; E. A Gardner; G. D Carlin; D. W Froggatt

2000-01-01

187

CONVERSION OF OLEIC ACID TO BRANCHED-CHAIN FATTY ACIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Oleic acid and linoleic acid are the most abundant fatty acids of cottonseed oil. As part of a project to develop new value-added industrial applications for cottonseed oil (such as biodiesel, fuel additives, and lubricants), studies were conducted in the synthetic conversion of oleic acid to branc...

188

Kidney amino acid transport.  

PubMed

Near complete reabsorption of filtered amino acids is a main specialized transport function of the kidney proximal tubule. This evolutionary conserved task is carried out by a subset of luminal and basolateral transporters that together form the transcellular amino acid transport machinery similar to that of small intestine. A number of other amino acid transporters expressed in the basolateral membrane of proximal kidney tubule cells subserve either specialized metabolic functions, such as the production of ammonium, or are part of the cellular housekeeping equipment. A new finding is that the luminal Na(+)-dependent neutral amino acid transporters of the SLC6 family require an associated protein for their surface expression as shown for the Hartnup transporter B(0)AT1 (SLC6A19) and suggested for the L: -proline transporter SIT1 (IMINO(B), SLC6A20) and for B(0)AT3 (XT2, SLC6A18). This accessory subunit called collectrin (TMEM27) is homologous to the transmembrane anchor region of the renin-angiotensin system enzyme ACE2 that we have shown to function in small intestine as associated subunit of the luminal SLC6 transporters B(0)AT1 and SIT1. Some mutations of B(0)AT1 differentially interact with these accessory subunits, providing an explanation for differential intestinal phenotypes among Hartnup patients. The basolateral efflux of numerous amino acids from kidney tubular cells is mediated by heteromeric amino acid transporters that function as obligatory exchangers. Thus, other transporters within the same membrane need to mediate the net efflux of exchange substrates, controlling thereby the net basolateral amino transport and thus the intracellular amino acid concentration. PMID:19184091

Verrey, François; Singer, Dustin; Ramadan, Tamara; Vuille-dit-Bille, Raphael N; Mariotta, Luca; Camargo, Simone M R

2009-01-28

189

Transformation of some hydroxy amino acids to other amino acids.  

PubMed

It has been observed that beta-hydroxy-alpha-amino acids are transformed into other amino acids, when heated in dilute solutions with phosphorous acid, phosphoric acid or their ammonium salts. It has been shown that as in the case of previously reported glycine-aldehyde reactions, glycine also reacts with acetone to give beta-hydroxyvaline under prebiologically feasible conditions. It is suggested, therefore, that the formation of beta-hydroxy-alpha-amino acids and their transformation to other amino acids may have been a pathway for the synthesis of amino acids under primitive earth conditions. PMID:1208100

Choughuley, A S; Subbaraman, A S; Kazi, Z A; Chadha, M S

1975-10-01

190

Adsorption of humic acid on acid-activated Greek bentonite  

Microsoft Academic Search

The adsorption of humic acid on bentonite from Milos Island (Greece) acid-treated with dilute H2SO4 solutions over a concentration range between 0.25 and 13M has been studied. Bentonite activated with 3M sulfuric acid (AAS) showed a higher efficiency in removing humic acid from aqueous solutions and was selected for further investigation. The specific surface area of acid-activated bentonite was estimated

Danae Doulia; Ch. Leodopoulos; K. Gimouhopoulos; F. Rigas

2009-01-01

191

Analysis of Bile Acids  

NASA Astrophysics Data System (ADS)

Bile acids constitute a large family of steroids in vertebrates, normally formed from cholesterol and carrying a carboxyl group in a side-chain of variable length. Bile alcohols, also formed from cholesterol, have similar structures as bile acids, except for the absence of a carboxyl group in the steroid skeleton. The conversion of cholesterol to bile acids and/or bile alcohols is of major importance for maintenance of cholesterol homeostasis, both from quantitative and regulatory points of view (Chiang, 2004; Kalaany and Mangelsdorf, 2006; Moore, Kato, Xie, et al., 2006; Scotti, Gilardi, Godio, et al., 2007). Appropriately conjugated bile acids and bile alcohols (also referred to as bile salts) are secreted in bile and serve vital functions in the absorption of lipids and lipid-soluble compounds (Hofmann, 2007). Reliable analytical methods are required for studies of the functions and pathophysiological importance of the variety of bile acids and bile alcohols present in living organisms. When combined with genetic and proteomic studies, analysis of these small molecules (in today's terminology: metabolomics, steroidomics, sterolomics, cholanoidomics, etc.) will lead to a deeper understanding of the integrated metabolic processes in lipid metabolism.

Sjövall, Jan; Griffiths, William J.; Setchell, Kenneth D. R.; Mano, Nariyasu; Goto, Junichi

192

Optical high acidity sensor  

DOEpatents

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber. 10 figs.

Jorgensen, B.S.; Nekimken, H.L.; Carey, W.P.; O`Rourke, P.E.

1997-07-22

193

78 FR 20029 - Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance...  

Federal Register 2010, 2011, 2012, 2013

...EPA-HQ-OPP-2013-0057; FRL-9381-2] Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic...tolerance for residues of castor oil, polymer with adipic acid, linoleic acid, oleic...ingredient in a pesticide formulation. Advance Polymer Technology submitted a petition to...

2013-04-03

194

Oleanane acid from Myrica cerifera.  

PubMed

From the twigs of Myrica cerifera L. (Myricaceae), a new oleanane triterpenic acid named myrica acid was isolated along with myricalactone and several other known constituents. The structure of the acid was determined as 3beta-hydroxy-1-oxoolean-11,13(18)-dien-28-oic acid on the basis of chemical and spectral evidence. PMID:11045444

Nagai, M; Sakurai, N; Yumoto, N; Nagumo, S; Seo, S

2000-10-01

195

Ursodeoxycholic acid, 7-ketolithocholic acid, and chenodeoxycholic acid are primary bile acids of the nutria (Myocastor coypus).  

PubMed

Because ursodeoxycholic and chenodeoxycholic acids are interconverted in humans via 7-ketolithocholic acid, bile acid metabolism was studied in the nutria (Myocastor coypus), the bile of which is known to contain these three bile acids. Relative concentrations of ursodeoxycholic (37% +/- 20%), 7-ketolithocholic (33% +/- 17%), and chenodeoxycholic (17% +/- 9%) acids in gallbladder bile were unchanged by 5-20 h of complete biliary diversion (n = 7). Injection of either [14C]cholesterol, [14C]ursodeoxycholic, [14C]7-ketolithocholic acid, or a mixture of [7 beta-3H]chenodeoxycholic acid and [14C]chenodeoxycholic acid into bile fistula nutria demonstrated that all three bile acids can be synthesized hepatically from cholesterol, that they are interconverted sparingly (2%-5%) by the liver, but that 7-ketolithocholic acid is an intermediate in the hepatic transformation of chenodeoxycholic acid to ursodeoxycholic acid. An animal that had been fed antibiotics showed an unusually elevated concentration of ursodeoxycholic acid in gallbladder and hepatic bile, suggesting that bacterial transformation of ursodeoxycholic acid in the intestine may be a source of some biliary chenodeoxycholic acid and 7-ketolithocholic acid. PMID:3943698

Tint, G S; Bullock, J; Batta, A K; Shefer, S; Salen, G

1986-03-01

196

Atmospheric Dust and Acid Rain  

Microsoft Academic Search

Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid

Lars O. Hedin; Gene E. Likens

1996-01-01

197

BIOSYNTHESIS OF TETRAHYDROFURANYL FATTY ACIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Clavibacter sp. ALA2 converts linoleic acid into many novel oxygenated products including hydroxy fatty acids and tetrahydrofuranyl unsaturated fatty acids (THFAs). One of them was tentatively identified by GC/MS as 12,13,16-trihydroxy-9(z)-octadecenoic acid (12,13,16-THOA, Hou et al. J Am. Oil Che...

198

Acid rain: a background report  

Microsoft Academic Search

This Staff Brief was prepared for the Wisconsin Legislative Council's Special Committee on Acid Rain to provide an introduction to the issue of acid rain. It is divided into four parts. Part I provides an overview on the controversies surrounding the measurement, formation and effects of acid rain. As described in Part I, the term acid rain is used to

L. Glustrom; J. Stolzenberg

1982-01-01

199

Diversity of bacterial polyhydroxyalkanoic acids  

Microsoft Academic Search

An overview is provided on the diversity of biosynthetic polyhydroxyalkanoic acids, and all hitherto known constituents of these microbial storage compounds are listed. The occurrence of 91 different hydroxyalkanoic acids reflects the low substrate specificity of polyhydroxyalkanoic acid synthases which are the key enzymes of polyhydroxyalkanoic acid biosynthesis. In addition, the importance of bacterial anabolism and catabolism, which provide the

Alexander Steinbüchel; Henry E. Valentin

1995-01-01

200

Method for acidizing siliceous formations  

SciTech Connect

A method is described for treating a subterranean formation surrounding a wellbore which comprises injecting into the formation an aqueous acidizing solution. The aqueous acidizing solution contains hydrofluoric acid and excess fluoride. The excess fluoride is present in an amount greater than the amount of fluoride stoichiometrically required to form hydrofluoric acid, and thereafter fluids are produced from the wellbore.

Lamb, W.J.; Kunze, K.R.

1987-03-10

201

Corrosion inhibitors used in acidizing  

Microsoft Academic Search

The history of the development of oil well acidizing and acid corrosion inhibitors used by this industry is reviewed. As deeper and hotter wells were drilled, stimulation acids were exposed to hotter conditions and the organic inhibitors required intensifiers. High-temperature acid corrosion inhibitors are also discussed.

Cizek

1994-01-01

202

Thiol modified mycolic acids.  

PubMed

Patient serum antibodies to mycolic acids have the potential to be surrogate markers of active tuberculosis (TB) when they can be distinguished from the ubiquitously present cross-reactive antibodies to cholesterol. Mycolic acids are known to interact more strongly with antibodies present in the serum of patients with active TB than in patients with latent TB or no TB. Examples of single stereoisomers of mycolic acids with chain lengths corresponding to major homologues of those present in Mycobacterium tuberculosis have now been synthesised with a sulfur substituent on the terminal position of the ?-chain; initial studies have established that one of these binds to a gold electrode surface, offering the potential to develop second generation sensors for diagnostic patient antibody detection. PMID:23603063

Balogun, Mohammed O; Huws, Enlli H; Sirhan, Muthana M; Saleh, Ahmed D; Al Dulayymi, Juma'a R; Pilcher, Lynne; Verschoor, Jan A; Baird, Mark S

2013-04-18

203

Acid rain in Asia  

NASA Astrophysics Data System (ADS)

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in the developing world, particularly in Asia, is much bleaker. Given the policies of many Asian nations to achieve levels of development comparable with the industrialized world—which necessitate a significant expansion of energy consumption (most derived from indigenous coal reserves)—the potential for the formation of, and damage from, acid deposition in these developing countries is very high. This article delineates and assesses the emissions patterns, meteorology, physical geology, and biological and cultural resources present in various Asian nations. Based on this analysis and the risk factors to acidification, it is concluded that a number of areas in Asia are currently vulnerable to acid rain. These regions include Japan, North and South Korea, southern China, and the mountainous portions of Southeast Asia and southwestern India. Furthermore, with accelerated development (and its attendant increase in energy use and production of emissions of acid deposition precursors) in many nations of Asia, it is likely that other regions will also be affected by acidification in the near future. Based on the results of this overview, it is clear that acid deposition has significant potential to impact the Asian region. However, empirical evidence is urgently needed to confirm this and to provide early warning of increases in the magnitude and spread of acid deposition and its effects throughout this part of the world.

Bhatti, Neeloo; Streets, David G.; Foell, Wesley K.

1992-07-01

204

Molecular Structure of Citric Acid  

NSDL National Science Digital Library

Citric Acid was first isolated in 1734 by Carl Wilhelm Scheele. Citric acid is found in many fruits, in particular lemons, grapefruit, and oranges. Several types of bacteria and fungi are also known to produce citric acid. In fact, the fungus Aspergillus niger produces the vast majority of citric acid, which is used in almost all carbonated sodas. Additionally, citric acid is also used to clean stainless steel.

2002-08-13

205

Eucomic acid methanol monosolvate  

PubMed Central

In the crystal structure of the title compound [systematic name: 2-hy­droxy-2-(4-hy­droxy­benz­yl)butane­dioic acid methanol monosolvate], C11H12O6·CH3OH, the dihedral angles between the planes of the carboxyl groups and the benzene ring are 51.23?(9) and 87.97?(9)°. Inter­molecular O—H?O hydrogen-bonding inter­actions involving the hy­droxy and carb­oxy­lic acid groups and the methanol solvent mol­ecule give a three-dimensional structure.

Li, Guo-Qiang; Li, Yao-Lan; Wang, Guo-Cai; Liang, Zhi-Hong; Jiang, Ren-Wang

2011-01-01

206

Polyvalent Nucleic Acid Nanostructures  

PubMed Central

Polyvalent oligonucleotide-nanoparticle conjugates possess several unique emergent properties including enhanced cellular uptake, high antisense bioactivity, and nuclease resistance, which hypothetically originate from the dense packing and orientation of oligonucleotides on the surface of the nanoparticle. In this communication, we describe a new class of polyvalent nucleic acid nanostructures (PNANs), which comprise only crosslinked and oriented nucleic acids. We demonstrate that these particles are capable of effecting high cellular uptake and gene regulation without the need of a cationic polymer co-carrier. The PNANs also exhibit cooperative binding behavior and nuclease resistance properties.

Cutler, Joshua I.; Zhang, Ke; Zheng, Dan; Auyeung, Evelyn; Prigodich, Andrew E.

2011-01-01

207

Acid rain information clearinghouse  

SciTech Connect

Twenty-one research institutions, environmental organizations, trade associations and government agencies from the United States and Canada are co-sponsoring Acid Rain: The Relationship Between Sources and Receptors, a conference to be held December 3-4, 1986 at the Sheraton National Hotel in Arlington, Virginia. The conference, designed for a nontechnical audience as well as specialists in acid rain research, will cover the nature and scope of scientific understanding and research programs, identify areas of consensus and disagreement, and assess policy options in the light of current understanding. A special session on December 3 will address the legal aspects of source-receptor relationships.

Not Available

1986-11-01

208

Acid rain revisited  

SciTech Connect

This article reviews calculations of the estimates reported in this Newletter in 1983 on the contributions of nitric and sulfuric acids to deposition that may originate with motor vehicles. Previous estimates can now be updated, based on the recently released 1985 emissions inventory that was compiled by the National Acid Precipitation Assessment Program (NAPAP). This inventory relied in turn on the US Environmental Protection Agency's National emissions Data System (NEDS), the 1985 version of which is the latest containing both point source and area source information in sufficient detail to be useful for this purpose.

Not Available

1990-06-01

209

The second acidic constant of salicylic acid.  

PubMed

The second dissociation constant of salicylic acid (H2L) has been determined, at 25 degrees C, in NaCl ionic media by UV spectrophotometric measurements. The investigated ionic strength values were 0.16, 0.25, 0.50, 1.0, 2.0 and 3.0 M. The protolysis constants calculated at the different ionic strengths yielded, with the Specific Interaction Theory, the infinite dilution constant, log beta1(0) = 13.62 +/- 0.03, for the equilibrium L2- + H+ <==> HL-. The interaction coefficient between Na+ and L2-, b(Na+, L2-) = 0.02 +/- 0.07, has been also calculated. PMID:16235788

Porto, Raffaella; De Tommaso, Gaetano; Furia, Emilia

210

The Acid-Base Titration of a Very Weak Acid: Boric Acid  

ERIC Educational Resources Information Center

|A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

2012-01-01

211

Acid neutralizing capacity, alkalinity, and acid-base status of natural waters containing organic acids  

Microsoft Academic Search

The terms acid neutralizing capacity (ANC) and alkalinity (Alk) are extensively employed in the characterization of natural waters, including soft circumneutral or acidic waters. However, in the presence of organic acids, ANC measurements are inconsistent with many conceptual definitions of ANC or Alk and do not provide an adequate characterization of the acid-base chemistry of water. Knowledge of Gran ANC

Harold F. Hemond

1990-01-01

212

Oxalic acid excretion after intravenous ascorbic acid administration  

PubMed Central

Ascorbic acid is frequently administered intravenously by alternative health practitioners and, occasionally, by mainstream physicians. Intravenous administration can greatly increase the amount of ascorbic acid that reaches the circulation, potentially increasing the risk of oxalate crystallization in the urinary space. To investigate this possibility, we developed gas chromatography mass spectrometry methodology and sampling and storage procedures for oxalic acid analysis without interference from ascorbic acid and measured urinary oxalic acid excretion in people administered intravenous ascorbic acid in doses ranging from 0.2 to 1.5 g/kg body weight. In vitro oxidation of ascorbic acid to oxalic acid did not occur when urine samples were brought immediately to pH less than 2 and stored at –30°C within 6 hours. Even very high ascorbic acid concentrations did not interfere with the analysis when oxalic acid extraction was carried out at pH 1. As measured during and over the 6 hours after ascorbic acid infusions, urinary oxalic acid excretion increased with increasing doses, reaching approximately 80 mg at a dose of approximately 100 g. We conclude that, when studied using correct procedures for sample handling, storage, and analysis, less than 0.5% of a very large intravenous dose of ascorbic acid is recovered as urinary oxalic acid in people with normal renal function.

Robitaille, Line; Mamer, Orval A.; Miller, Wilson H.; Levine, Mark; Assouline, Sarit; Melnychuk, David; Rousseau, Caroline; Hoffer, L. John

2012-01-01

213

Prediction of effective acid penetration and acid volume for matrix acidizing treatments in naturally fractured carbonates  

SciTech Connect

This paper discusses a new method and a corresponding computer model developed to investigate matrix acidizing in naturally fractured carbonates. With this method, the effective acid penetration distance and acid volume needed for acid treatments in naturally fractured carbonates can be predicted. The new model simulates acid flowing in the natural fracture network and the acid/rock reaction. During the simulation, the model considers the influence of formation temperature, reaction heat, and common ion effect on acid penetration. A set of graphs showing the relationship between acid penetration and the acid volume needed in different formations was developed from numerical simulation results. From these plots, the acid volume that should be used to remove the formation damage can be determined easily when the formation temperature and the damage radius are known or can be estimated.

Xiong, H. (S.A. Holditch and Associates, Inc., College Station, TX (United States))

1994-08-01

214

[Studies on interaction of acid-treated nanotube titanic acid and amino acids].  

PubMed

Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination. PMID:20649031

Zhang, Huqin; Chen, Xuemei; Jin, Zhensheng; Liao, Guangxi; Wu, Xiaoming; Du, Jianqiang; Cao, Xiang

2010-06-01

215

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite  

NASA Astrophysics Data System (ADS)

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

1992-11-01

216

Lysergic Acid Diethylamide: Radioimmunoassay  

Microsoft Academic Search

A radioimmunoassay for d-lysergic acid diethylamide (LSD) is described. Antibodies to LSD were obtained by immunizing rabbits with a conjugate of LSD and human serum albumin. The specificity of the antibody was shown by competitive binding studies. The method has been used to detect the presence of LSD in human urines. Picogram amounts can be measured by this assay.

Alison Taunton-Rigby; Stephanie E. Sher; Paul R. Kelley

1973-01-01

217

Acidification and Acid Rain  

Microsoft Academic Search

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

S. A. Norton

2003-01-01

218

Basically Acidic Ink  

NSDL National Science Digital Library

Students hypothesize whether vinegar and ammonia-based glass cleaner are acids or bases. They create designs on index cards using these substances as invisible inks. After the index cards have dried, they apply red cabbage juice as an indicator to reveal the designs.

University Of Houston

219

Beyond acid rain  

Microsoft Academic Search

This paper discussed the effects of the interactions of soluble oxidants and organic toxins with sulfur dioxide and nitrogen dioxide. It suggested that these chemical reactions in the atmosphere produced a more potent acid rain which was harmful not only because it had a low pH but because it contained oxidants and organic toxins which were harmful to surface vegetation

J. S. Gaffney; G. E. Streit; W. D. Spall; J. H. Hall

1987-01-01

220

Gallic acid pyridine monosolvate  

PubMed Central

In the title compound (systenatic name: 3,4,5-trihy­droxy­benzoic acid pyridine monosolvate), C5H5N·C7H6O5, the gallic acid mol­ecule is essentially planar (r.m.s deviation = 0.0766?Å for non-H atoms) and is linked to the pyridine mol­ecule by an O—H?N hydrogen bond. An intra­molecular O—H?O hydrogen bond occurs in the gallic acid mol­ecule. The gallic acid and pyridine mean planes make a dihedral angle 12.6?(3)°. Inter­molecular O—H?O and O—H?N hydrogen bonding involving the hy­droxy and carboxyl groups and the pyridine mol­ecule, and ?–? inter­actions between inversion-related pyridines [centroid–centroid distance = 3.459?(6)?Å] and between pyridine and benzene rings [centroid–centroid distance = 3.548?(6)?Å], lead to a three-dimensional network in the crystal.

Dong, Fu-Yue; Wu, Jie; Tian, Hai-Yan; Ye, Qing-Mei; Jiang, Ren-Wang

2011-01-01

221

Federal Acid Rain Games  

Microsoft Academic Search

Federal environmental policy, designed to control acid rain, is shaped after the hierarchy of the system, and is controlled simultaneously by regional and central governments. Each governmental level controls one of two policy instruments: pollution abatement production and pollution tax. In a two-stage game where regional governments are Stackelberg leaders and control pollution taxes, the subgame perfect equilibrium is socially

Arthur J. Caplan; Emilson C. D. Silva

1999-01-01

222

Acid rain bibliography  

SciTech Connect

This bibliography identifies 900 citations on various aspects of Acid Rain, covering published bibliographies, books, reports, conference and symposium proceedings, audio visual materials, pamphlets and newsletters. It includes five sections: citations index (complete record of author, title, source, order number); KWIC index; title index; author index; and source index. 900 references.

Sayers, C.S.

1983-09-01

223

Acid rain in Asia  

Microsoft Academic Search

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging perception that the problem in these Western nations is nearing solution. The situation in

N. Bhatti; D. G. Streets; W. K. Foell

2009-01-01

224

Acid rain in Asia  

Microsoft Academic Search

Acid rain has been an issue of widespread concern in North America and Europe for more than fifteen years. However, there is an emerging feeling that the problem in Europe and North America is nearing solution, largely as a result of existing and newly enacted legislation, decreased energy use due to conservation and efficiency improvements, and\\/or trends in energy policy

N. Bhatti; D. G. Streets; W. K. Foell

1991-01-01

225

Immunostimulatory Nucleic Acid Molecules.  

National Technical Information Service (NTIS)

Nucleic acids containing unmethylated CpG dinucleotides and therapeutic utilities based on their ability to stimulate an immune response and to redirect a Th2 response to a Th1 response in a subject are disclosed. Methods for treating atopic diseases, inc...

A. D. Steinberg A. M. Krieg D. Klinman J. Kline

2005-01-01

226

Optimize acid gas removal  

Microsoft Academic Search

Innovative design of physical solvent plants for acid gas removal can materially reduce both installation and operating costs. A review of the design considerations for one physical solvent process (Selexol) points to numerous arrangements for potential improvement. These are evaluated for a specific case in four combinations that identify an optimum for the case in question but, more importantly, illustrate

D. M. Nicholas; J. T. Wilkins

1983-01-01

227

Fumaric acid esters  

Microsoft Academic Search

Several clinical studies have shown that systemic therapy with fumaric acid esters (FAEs) in patients with moderate to severe psoriasis is effective and has a good long-term safety profile. For therapeutic use, tablets with a defined mixture of FAEs (dimethylfumarate [DMF] and three different salts of monoethylfumarate) are registered in Germany. There is evidence that DMF is the most essential

Martin Rostami Yazdi; Ulrich Mrowietz

2008-01-01

228

Water surface is acidic  

PubMed Central

Water autoionization reaction 2H2O ? H3O? + OH? is a textbook process of basic importance, resulting in pH = 7 for pure water. However, pH of pure water surface is shown to be significantly lower, the reduction being caused by proton stabilization at the surface. The evidence presented here includes ab initio and classical molecular dynamics simulations of water slabs with solvated H3O+ and OH? ions, density functional studies of (H2O)48H+ clusters, and spectroscopic isotopic-exchange data for D2O substitutional impurities at the surface and in the interior of ice nanocrystals. Because H3O+ does, but OH? does not, display preference for surface sites, the H2O surface is predicted to be acidic with pH < 4.8. For similar reasons, the strength of some weak acids, such as carbonic acid, is expected to increase at the surface. Enhanced surface acidity can have a significant impact on aqueous surface chemistry, e.g., in the atmosphere.

Buch, Victoria; Milet, Anne; Vacha, Robert; Jungwirth, Pavel; Devlin, J. Paul

2007-01-01

229

Acid Mine Drainage Remediation  

NSDL National Science Digital Library

In this video, an environmental technologist visits an abandoned coal mine in Kentucky to talk about how a remediation system (a series of settling ponds and treatment cells) is neutralizing the acid drainage flowing from the mine and keeping it from damaging a creek downstream.

Ket

2011-01-11

230

Spermatotoxicity of dichloroacetic acid  

EPA Science Inventory

The testicular toxicity of dichloroacetic acid (DCA), a disinfection byproduct of drinking water, was evaluated in adult male rats given both single and multiple (up to 14 d) oral doses. Delayed spermiation and altered resorption of residual bodies were observed in rats given sin...

231

Bile acid coenzyme A: amino acid N-acyltransferase in the amino acid conjugation of bile acids.  

PubMed

Bile acids are converted to their glycine and taurine N-acyl amidates by enzymes in the liver in a two-step process. This increases their aqueous solubility, particularly in the acidic environment of the upper part of the small intestine. Bile acid coenzyme A (CoA) thioesters synthesized by bile acid CoA ligase (see Shonsey et al., 2005) are substrates of bile acid CoA:amino acid N-acyltransferases (BAT) in the formation of bile acid N-acyl amidates. This chapter describes the methods used to purify BAT from human liver, to isolate and clone cDNAs encoding BAT from human, mouse, and rat liver cDNA libraries, the expression of BAT, the assays used to measure BAT activity, and the chemical syntheses of bile acid N-acylamidates. In addition, an enzyme that catalyzes further metabolism of glycine-conjugated bile acids is described. PMID:16399361

Shonsey, Erin M; Sfakianos, Mindan; Johnson, Michelle; He, Dongning; Falany, Charles N; Falany, Josie; Merkler, David J; Barnes, Stephen

2005-01-01

232

Tranexamic acid and thrombosis.  

PubMed

Tranexamic acid is an antifibrinolytic drug. It therefore reduces bleeding but, in certain situations, it may expose patients to a risk of thrombosis. It is used for the treatment of various types of bleeding, including menorrhagia, haematuria, certain surgical procedures and trauma. Its harm-benefit balance is favourable in certain situations associated with serious bleeding.The harm-benefit balance is different in minor bleeding: the expected benefits are smaller because the condition is not serious, and the risk of thromboembolism may be higher without the haemodilution associated with severe bleeding. Various drug regulatory agencies have received reports of thrombotic events attributed to tranexamic acid. In a case-control study using data from the British General Practice Research Database, women taking tranexamic acid had a 3-fold higher risk of developing deep vein thrombosis. There was a wide 95% confidence interval, ranging from 0.7 to 15.8; thus, a major increase in the risk of thrombosis cannot be ruled out. Only one comparative randomised trial assessed thrombotic events in 53 women receiving tranexamic acid for menorrhagia; too few patients were studied to determine the risk. Clinical trials conducted in serious haemorrhage or in patients undergoing surgery with a high risk of bleeding have not shown an increased risk of thrombosis with tranexamic acid. In practice, as of early 2013, the harm-benefit balance of tranexamic acidis favourable in severe traumatic bleeding. But when bleeding is not life-threatening, the thrombotic risk is too poorly documented to justify exposing patients to a plausible and inadequately evaluated risk. PMID:23951593

2013-07-01

233

Specific bile acids inhibit hepatic fatty acid uptake  

PubMed Central

Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. Here we tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. In summary, the data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease.

Nie, Biao; Park, Hyo Min; Kazantzis, Melissa; Lin, Min; Henkin, Amy; Ng, Stephanie; Song, Sujin; Chen, Yuli; Tran, Heather; Lai, Robin; Her, Chris; Maher, Jacquelyn J.; Forman, Barry M.; Stahl, Andreas

2012-01-01

234

Effects of acidic precipitation and acidity on soil microbial processes  

SciTech Connect

Effects of oil acidity on microbial decomposition of organic matter and transformation of nitrogen in an acid forest soil were investigated. In the oak-leaf-amended pH-adjusted acid soils, CO/sub 2/ production in 14- and 150-day preincubated samples decreased by about 6 and 37%, respectively. In the control (unamended) acidified soils, reductions in CO/sub 2/ production of 14% in 14-day preincubated samples and 52% in 150-day samples were observed. Ammonia formation in the pH-adjusted acid soil was about 50% less than in the naturally acid soil. Increased rates of ammonification and nitrification were observed in the pH-adjusted neutral soil. Little autotrophic and heterotrophic nitrifying activity was detected in naturally acid and acidified forest soils. The rate of denitrification was rather slow in acid soils, and at greater acidities N/sub 2/O was the predominant end product. The abundance of nitrogen-fixing free-living bacteria was very low in acidic and acidified forest soils, and nitrogen gains by asymbiotic bacterial fixation in an acid forest ecosystem may be insignificant. These results suggest that further acidification of acid forest soils by addition of sulfuric acid or by acid precipitation may lead to significant reductions in the leaf litter decomposition, ammonification, nitrification, and denitrification and thus reduce nutrient recycling in the forest ecosystem.

Francis, A.J.

1981-01-01

235

Measurement of ascorbic acid and dehydroascorbic acid in biological samples.  

PubMed

Ascorbic acid and dehydroascorbic acid are commonly used biomarkers of oxidative stress in a variety of experimental models. However, the accurate measurement of these labile compounds remains a challenge both in terms of sample collection and analysis. Determination of dehydroascorbic acid most commonly involves indirect measurement. The concentration is calculated by subtraction of the measured ascorbic acid concentration from that of total ascorbic acid analyzed after reduction of the dehydroascorbic acid present; a method referred to as the subtraction method. Consequently, successful determination of dehydroascorbic acid is dependent upon proper sample handling, quantitative reduction of the compound, and accurate quantification of both ascorbic acid and total ascorbic acid. The unit presents a detailed introduction to ascorbate analysis in biological samples and discusses common problems and pitfalls. The analytical method described is based on reversed-phase HPLC with coloumetric detection. This method includes co-analysis of isoascorbic acid and uric acid. Where applicable, uric acid can conveniently be used as an endogenous intrasample standard that significantly improves the accuracy of the subsequent dehydroascorbic acid calculation. PMID:20954159

Lykkesfeldt, Jens

2002-08-01

236

Radioenzymatic assay for quinolinic acid  

SciTech Connect

A new and rapid method for the determination of the excitotoxic tryptophan metabolite quinolinic acid is based on its enzymatic conversion to nicotinic acid mononucleotide and, in a second step utilizing (/sup 3/H)ATP, further to (/sup 3/H) deamido-NAD. Specificity of the assay is assured by using a highly purified preparation of the specific quinolinic acid-catabolizing enzyme, quinolinic acid phosphoribosyltransferase, in the initial step. The limit of sensitivity was found to be 2.5 pmol of quinolinic acid, sufficient to conveniently determine quinolinic acid levels in small volumes of human urine and blood plasma.

Foster, A.C.; Okuno, E.; Brougher, D.S.; Schwarcz, R.

1986-10-01

237

Linoleic acid requirement of rats fed trans fatty acids  

Microsoft Academic Search

The amount of linoleic acid required to prevent undesirable effects of C18trans fatty acids was investigated. In a first experiment, six groups of rats were fed diets with a high content oftrans fatty acids (20% of energy [en%]), and increasing amounts of linoleic acid (0.4 to 7.1 en%). In a second experiment, four\\u000a groups of rats were fed diets designed

J. L. Zevenbergen; U. M. T. Houtsmuller; J. J. Gottenbos

1988-01-01

238

Do trans Fatty Acids Impair Linoleic Acid Metabolism in Children?  

Microsoft Academic Search

Trans isomeric fatty acids disturb themetabolism of essential polyunsaturated fatty acids in animals and in premature infants. We assessed whether similar effects may also occur in healthy children. Plasma phospholipid fatty acid composition was analysed in 53 apparently healthy children aged 1-15 years (mean 7.5 years). Trans fatty acids were found in all samples and contributed 1.78 ± 0.10% (w\\/w,

Tamås Decsi; Berthold Koletzko

1995-01-01

239

Thiobarbituric Acid Spray Reagent for Deoxy Sugars and Sialic Acids  

Microsoft Academic Search

RECENTLY, new sensitive assays have been reported for deoxy sugars1, 2-keto,3-deoxy sugar acids2-4, and sialic acids5,6. In these assays, the products of periodate oxidation, malonaldehyde from deoxy sugars and beta-formylpyruvic acid from the latter two groups of compounds, are coupled with 2-thiobarbituric acid to produce a bright red chromophore. I wish to report an adaptation of these methods for spraying

Leonard Warren

1960-01-01

240

Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine.  

PubMed

The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain. PMID:19376463

Campos, Francisco M; Figueiredo, Ana R; Hogg, Tim A; Couto, José A

2009-02-07

241

A Variation in Acid-Catalyzed Isomerization of Abietadienoic Acids  

Microsoft Academic Search

Heating the individual common abietadienoic acid methyl esters with p-toluene sulfonic acid in chloroform led to the formation of methyl abietadienoates other than the equilibrium mixture of methyl abietate, palustrate, and neoabietate that is usually formed by acid-catalyzed isomerization. Of these other methyl abietadienoates, the three principal constituents comprised 10%, 4% and 2% of the monomers; these compounds were isolated

Duane F. Zinkel

1991-01-01

242

College Chemistry Students' Mental Models of Acids and Acid Strength  

ERIC Educational Resources Information Center

|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…

McClary, LaKeisha; Talanquer, Vicente

2011-01-01

243

NAPAP (National Acid Precipitation Assessment Program) results on acid rain  

SciTech Connect

The National Acid Precipitation Assessment Program (NAPAP) was mandated by Congress in 1980 to study the effects of acid rain. The results of 10 years of research on the effect of acid deposition and ozone on forests, particularly high elevation spruce and fir, southern pines, eastern hardwoods and western conifers, will be published this year.

Not Available

1990-06-01

244

Acid Earth--The Global Threat of Acid Pollution.  

ERIC Educational Resources Information Center

|Acid pollution is a major international problem, but the debate it has elicited has often clouded the distinction between myth and facts. This publication attempts to concerning the acid pollution situation. This publication attempts to identify available facts. It is the first global review of the problem of acid pollution and the first to…

McCormick, John

245

College Chemistry Students' Mental Models of Acids and Acid Strength  

ERIC Educational Resources Information Center

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…

McClary, LaKeisha; Talanquer, Vicente

2011-01-01

246

Acid Earth--The Global Threat of Acid Pollution.  

ERIC Educational Resources Information Center

Acid pollution is a major international problem, but the debate it has elicited has often clouded the distinction between myth and facts. This publication attempts to concerning the acid pollution situation. This publication attempts to identify available facts. It is the first global review of the problem of acid pollution and the first to…

McCormick, John

247

Acid rain abatement  

SciTech Connect

This patent describes a method of obtaining acid rain abatement from a flue gas containing nitrogen oxides (NOX) and sulfur oxides (SOX). It comprises the steps of treating the flue gas with a reducing agent to remove the remaining oxygen and produce an effluent, the reducing agent being selected from group consisting of natural gas, methane, a mixture of CO and hydrogen derived from steam, hydrocarbon, and hydrogen, passing effluent over a catalyst to simultaneously reduce the NOX to water and elemental nitrogen and the SOX to H{sub 2}S or elemental sulfur, the catalyst being selected from the group consisting of heteropoly acids and their salts, the reduction of the NOX and SOX taking place in a temperature range of 200{degrees} - 900{degrees} C., and removing the sulfur or sulfur compounds from the reduced flue gas to thereby remove essentially all of the NOX and SOX.

Stiles, A.B.

1991-06-11

248

Weak Acid Equilibrium  

NSDL National Science Digital Library

Students are asked to calculate the pH of a weak acid aqueous solution. The problems involve a series of generic acids with assigned equilibrium constants (Ka) and total concentrations (Ct). Initially, students are required to hand calculate all problems by algebraic manipulation of the mathematical relationships of the system. The solution is a cubic equation. Through a series of assumptions, the solution is simplified. The assumptions are based on the chemistry of the system given the Ka and Ct for the problem. The problems are then graphically solved. Ultimately, the students develop an Excel worksheet to solve the problems and a Bjerrum plot to display the speciation as a function of pH.

Stapleton, Michael

249

(Radioiodinated free fatty acids)  

SciTech Connect

The traveler participated in the Second International Workshop on Radioiodinated Free Fatty Acids in Amsterdam, The Netherlands where he presented an invited paper describing the pioneering work at the Oak Ridge National Laboratory (ORNL) involving the design, development and testing of new radioiodinated methyl-branched fatty acids for evaluation of heart disease. He also chaired a technical session on the testing of new agents in various in vitro and in vivo systems. He also visited the Institute for Clinical and Experimental Nuclear Medicine in Bonn, West Germany, to review, discuss, plan and coordinate collaborative investigations with that institution. In addition, he visited the Cyclotron Research Center in Liege, Belgium, to discuss continuing collaborative studies with the Osmium-191/Iridium-191m radionuclide generator system, and to complete manuscripts and plan future studies.

Knapp, Jr., F. F.

1987-12-11

250

Molecular Structure of Glutaric acid  

NSDL National Science Digital Library

Glutaric acid is a colorless liquid and white crystals as a solid occurring in plants and animal tissues. It is used in organic synthesis and as an intermediate for the manufacture of polymers such as polyamides and polyesters, ester plasticizers and corrosion inhibitors. It is also useful in the application of decreasing polymer elasticity and in a variety of industrial applications. In addition glutaric acid plays an important role as an intermediary in the Krebs cycle and is used in medication against a large number of viruses and in animal diabetes. Glutaric acid can be prepared from cyclopentanone by oxidative ring fission with nitric acid and in the presence of a catalyst. Glutaric acid has the lowest melting point among dicarboxylic acids (98 C); it is very soluble in water and the solution in water is a medium strong acid. Short-term exposure to glutaric acid may cause irritation to the eyes, skin and the respiratory tract.

2004-11-10

251

Mycolic Acids of Mycobacterium porcinum  

Microsoft Academic Search

The type strain of Mycobacterium porcinum had a characteristic pattern of a-, a'-, and epoxymycolic acids. This pattern of mycolic acids has been found previously only in representatives of M. farcinogenes, M. fortuitum, \\

M. LUQUIN; L. MARGARIT; M. J. CONDOM; V. AUSINA

1987-01-01

252

Omega-3 fatty acids (image)  

MedlinePLUS

Omega-3 fatty acids are a form of polyunsaturated fat that the body derives from food. Omega-3s (and omega-6s) are known as essential fatty acids (EFAs) because they are important for good health. ...

253

Crosslinked acid gels offer advantages  

SciTech Connect

Acid polymer gels having a pH less than one have been crosslinked for retarding the chemical and physical activity of hydrochloric acid on calcareous formations. Hydrochloric acid concentrations from /one quarter/% to 28% have been successfully crosslinked. This unique stimulation fluid offers high viscosity with adequate shear stability, perfect support for propants, and clay stabilization. Additionally, the fluid provided effective fluid loss control and retardation of acid reaction enabling live acid to penetrate deeper into the formation for better conductivity; furthermore, there is practically a residue free break for rapid cleanup of the well after the job. Results of lab and field tests show this new acid crosslinked system to be an effective stimulation fluid for acidizing and acid fracturing in calcareous and sandstone formations having low permeability. 5 refs.

Pabley, A.S.; Holcomb, D.L.

1981-09-28

254

Boric Acid Reclamation System (BARS).  

National Technical Information Service (NTIS)

KLM Technologies' personnel have identified a Boric Acid Reclamation System (BARS) utilizing reverse osmosis and ultrafiltration to produce a recyclable grade of otherwise waste boric acid at PWRs, thus reducing a major source of low-level radwaste. The d...

B. G. Kniazewycz J. Markind

1986-01-01

255

Ideas about Acids and Alkalis.  

ERIC Educational Resources Information Center

|Investigates students' ideas, conceptions, and misconceptions about acids and alkalis before and after a teaching sequence in a small-scale research project. Concludes that student understanding of acids and alkalis is lacking. (DDR)|

Toplis, Rob

1998-01-01

256

Biopolymers: Protein and Nucleic Acids.  

National Technical Information Service (NTIS)

The work focuses on learning the principles that govern interactions between proteins and nucleic acids. With these principles as guides we are synthesizing peptides (of about 50 amino acids) that bind to specific regions of DNA. Various reactive function...

J. H. Richards J. N. Abelson L. E. Hood M. I. Simon J. L. Campbell

1987-01-01

257

Acid rain options modeled  

NASA Astrophysics Data System (ADS)

Results from new computer models that could allow policymakers to compare different strategies for controlling acid rain will be presented at the AGU Spring Meeting in Baltimore, Md., May 18-21, 1987. The optimization models, developed by scientists from the Johns Hopkins University (Baltimore, Md.), are set up so that competing goals—for instance, reducing the deposition of sulfur without wiping out the high-sulfur coal industry— can be taken into account.

Katzoff, Judith A.

258

Acid rain in Asia  

Microsoft Academic Search

Acid rain has been an issue of great concern in North America and Europe during the past several decades. However, due to\\u000a the passage of a number of recent regulations, most notably the Clean Air Act in the United States in 1990, there is an emerging\\u000a perception that the problem in these Western nations is nearing solution. The situation in

Neeloo Bhatti; David G. Streets; Wesley K. Foell

1992-01-01

259

Lna (Locked Nucleic Acid)  

Microsoft Academic Search

LNA (Locked Nucleic Acid) forms duplexes with complementary DNA, RNA or LNA with unprecedented thermal affinities. CD spectra show that duplexes involving fully modified LNA (especially LNA:RNA) structurally resemble an A-form RNA:RNA duplex. NMR examination of an LNA:DNA duplex confirm the 3?-endo conformation of an LNA monomer. Recognition of double-stranded DNA is demonstrated suggesting strand invasion by LNA. Lipofectin-mediated efficient

Jesper Wengel; Alexei Koshkin; Sanjay K. Singh; Poul Nielsen; Michael Meldgaard; Vivek K. Rajwanshi; Ravindra Kumar; Jan Skouv; Christina B. Nielsen; Jens Peter Jacobsen; Nana Jacobsen; Carl E. Olsen

1999-01-01

260

Acid Rain Effects  

NSDL National Science Digital Library

Learners conduct a simple experiment to model and explore the harmful effects of acid rain (vinegar) on living (green leaf and eggshell) and non-living (paper clip) objects. Learners observe the effects over a period of days. This activity has links to other activities which can be combined to make a larger lesson. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.

Kolenbrander, Amy; Yowell, Janet; Mach, Natalie; Zarske, Malinda S.; Carlson, Denise

2004-01-01

261

Optimize acid gas removal  

SciTech Connect

Innovative design of physical solvent plants for acid gas removal can materially reduce both installation and operating costs. A review of the design considerations for one physical solvent process (Selexol) points to numerous arrangements for potential improvement. These are evaluated for a specific case in four combinations that identify an optimum for the case in question but, more importantly, illustrate the mechanism for use for such optimization elsewhere.

Nicholas, D.M.; Wilkins, J.T.

1983-09-01

262

Grading acid rain research  

NASA Astrophysics Data System (ADS)

The growing concern with the environmental effects of acid rain has spawned a number of study groups in recent years, and now the Office of Science and Technology Policy (OSTP) has released what is essentially a study of a study. In January 1982, White House Science Advisor George Keyworth asked William Nierenberg, Director of the Scripps Institution of Oceanography, and a panel of nine scientists to conduct a peer review of three separate reports on acid deposition in eastern North America that had been turned in by U.S.-Canadian scientific working groups.Those studies had been requisitioned by a 1980 Memorandum of Intent between the United States and Canada regarding transboundary air pollution. Overall, the Nierenberg peer review panel was “impressed with the efforts of the United States-Canadian Working Groups,” (labeled Groups 1, 2, and 3B), but it also found problems. While applauding the work groups' exhaustive search through the acid rain literature, the Nierenberg panel cited what they call an “overdependence on ‘soft’ literature,” or writings such as in-house reports and personal communications, which are outside the publicly available (and carefully scrutinized) body of scientific literature.

263

Acid rain in Asia  

SciTech Connect

In Asia, fossil fuels are used in large quantities, such that local air pollution is becoming a serious problem and high deposition levels are being measured. Emission regulations in most countries (with the exception of Japan) are not very stringent. Energy plans in many countries call for very large increases in coal combustion in the future. Finally, there is not presently a strong constituency for action to mitigate the potential effects of acid deposition. These factors imply potentially serious problems in the future for long-range transport and deposition of sulfur and nitrogen species and consequent damage to ecosystems and materials. The political ramifications of transboundary environmental pollution in this region are also potentially serious. A predictive tool could be built to help decision makers project future trends in emissions, estimate the regional consequences for acid deposition levels, evaluate the vulnerability of natural and man-made systems, and determine the costs and effectiveness of alternative mitigative actions that might be taken. Such a policy analysis exercise can start to raise environmental awareness in the region and begin a dialogue that could help ameliorate an environmental problem in its early stages. The purpose of this paper is to provide background information on the acid deposition situation in Asia, with the intention of laying the foundation for the design of a possible research program for this region. 41 refs., 10 figs., 9 tabs.

Bhatti, N.; Streets, D.G. (Argonne National Lab., IL (USA)); Foell, W.K. (Resource Management Associates, Madison, WI (USA) Wisconsin Univ., Madison, WI (USA))

1989-01-01

264

Acid rain in Asia  

SciTech Connect

Acid rain has been an issue of widespread concern in North America and Europe for more than fifteen years. However, there is an emerging feeling that the problem in Europe and North America is nearing solution, largely as a result of existing and newly enacted legislation, decreased energy use due to conservation and efficiency improvements, and/or trends in energy policy away from fossil fuels. The situation in Asia appears much bleaker. Fossil fuels are already used in large quantities, such that local air pollution is becoming a serious problem and high deposition levels are being measured. Emission regulations in most countries (with the notable exception of Japan) are not very stringent. Energy plans in many countries (particularly PRC, India, Thailand, and South Korea) call for very large increases in coal combustion in the future. Finally, there is not presently a strong scientific or public constituency for action to mitigate the potential effects of acid deposition. These factors imply potentially serious problems in the future for long-range transport and deposition of sulfur and nitrogen species and consequent damage to ecosystems and materials. The political ramifications of transboundary environmental pollution in this region are also potentially serious. The purpose of this paper is to provide background information on the acid deposition situation in Asia, with the intention of laying the foundation for the development of a possible research program for this region. 36 refs., 8 figs., 8 tabs.

Bhatti, N.; Streets, D.G. (Argonne National Lab., IL (USA)); Foell, W.K. (Resource Management Associates, Madison, WI (USA))

1991-01-01

265

An amino acid transporter involved in gastric acid secretion.  

PubMed

Gastric acid secretion is regulated by a variety of stimuli, in particular histamine and acetyl choline. In addition, dietary factors such as the acute intake of a protein-rich diet and the subsequent increase in serum amino acids can stimulate gastric acid secretion only through partially characterized pathways. Recently, we described in mouse stomach parietal cells the expression of the system L heteromeric amino acid transporter comprised of the LAT2-4F2hc dimer. Here we address the potential role of the system L amino acid transporter in gastric acid secretion by parietal cells in freshly isolated rat gastric glands. RT-PCR, western blotting and immunohistochemistry confirmed the expression of 4F2-LAT2 amino acid transporters in rat parietal cells. In addition, mRNA was detected for the B(0)AT1, ASCT2, and ATB(0+) amino acid transporters. Intracellular pH measurements in parietal cells showed histamine-induced and omeprazole-sensitive H+-extrusion which was enhanced by about 50% in the presence of glutamine or cysteine (1 mM), two substrates of system L amino acid transporters. BCH, a non-metabolizable substrate and a competitive inhibitor of system L amino acid transport, abolished the stimulation of acid secretion by glutamine or cysteine suggesting that this stimulation required the uptake of amino acids by system L. In the absence of histamine glutamine also stimulated H+-extrusion, whereas glutamate did not. Also, phenylalanine was effective in stimulating H+/K+-ATPase activity. Glutamine did not increase intracellular Ca2+ levels indicating that it did not act via the recently described amino acid modulated Ca2+-sensing receptor. These data suggest a novel role for heterodimeric amino acid transporters and may elucidate a pathway by which protein-rich diets stimulate gastric acid secretion. PMID:16308696

Kirchhoff, Philipp; Dave, Mital H; Remy, Christine; Kosiek, Ortrud; Busque, Stephanie M; Dufner, Matthias; Geibel, John P; Verrey, Francois; Wagner, Carsten A

2005-11-25

266

Molecular Structure of Acetic acid  

NSDL National Science Digital Library

Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

2003-06-02

267

Fatty acid signaling in Arabidopsis  

Microsoft Academic Search

.   Many organisms use fatty acid derivatives as biological regulators. In plants, for example, fatty acid-derived signals have\\u000a established roles in the regulation of developmental and defense gene expression. Growing numbers of these compounds, mostly\\u000a derived from fatty acid hydroperoxides, are being characterized. The model plant Arabidopsis thaliana is serving a vital role in the discovery of fatty acid-derived signal

Edward E. Farmer; Hans Weber; Sabine Vollenweider

1998-01-01

268

Molecular Structure of Octanoic acid  

NSDL National Science Digital Library

Caprylic acid is a colorless oil manufactured from 1-heptene or 1-octanol. Octanoic acid has an unpleasant rancid taste. When converted from the carboxlic acid to an ester, it has a pleasant taste. In addition, esters of caprylic acid are used in the preparation of dyes, perfumes, and food preservatives. This compound has also been found to have antifungal activity and is used to treat yeast infections.

2002-10-11

269

Acid rain: Reign of controversy  

SciTech Connect

Acid Rain is a primer on the science and politics of acid rain. Several introductory chapters describe in simple terms the relevant principles of water chemistry, soil chemistry, and plant physiology and discuss the demonstrated or postulated effects of acid rain on fresh waters and forests as well as on statuary and other exposed objects. There follow discussions on the economic and social implications of acid rain (for example, possible health effects) and on the sources, transport, and distribution of air pollutants.

Kahan, A.M.

1986-01-01

270

A radioimmunoassay for abscisic acid  

Microsoft Academic Search

We have developed a radioimmunoassay (RIA) for abscisic acid (ABA) in the 0.1 ng to 2.5 ng range. Antibodies were obtained from rabbits immunized with ABA bound via its carboxyl group to bovine serum albumin. Cross-reactivity studies indicate that ABA esters are completely cross-reactive with ABA, while trans, trans abscisic acid (t-ABA) phaseic acid (PA) and dihydrophaseic acid (DPA) have

Daniel Walton; William Dashek; Eva Galson

1979-01-01

271

Molecular Structure of Trimesic acid  

NSDL National Science Digital Library

Trimesic Acid is made up of a benzene ring with three carboxylic groups at the 1, 3, and 5 positions, and it can be synthesized from the oxidation of 1,3,5-trimethyl benzene. The acid is an important building block in crystal engineering which is used to form honeycomb structures, but it has the ability to form diverse supramolecular structures. Also, trimesic acid salt and the free trimesic acid are useful as a plasticizer.

2003-05-08

272

Radioenzymatic assay for quinolinic acid  

Microsoft Academic Search

A new and rapid method for the determination of the excitotoxic tryptophan metabolite quinolinic acid is based on its enzymatic conversion to nicotinic acid mononucleotide and, in a second step utilizing (³H)ATP, further to (³H) deamido-NAD. Specificity of the assay is assured by using a highly purified preparation of the specific quinolinic acid-catabolizing enzyme, quinolinic acid phosphoribosyltransferase, in the initial

A. C. Foster; E. Okuno; D. S. Brougher; R. Schwarcz

1986-01-01

273

Levulinic acid in organic synthesis  

NASA Astrophysics Data System (ADS)

Data concerning the methods of synthesis, chemical transformations and application of levulinic acid are analysed and generalised. The wide synthetic potential of levulinic acid, particularly as a key compound in the synthesis of various heterocyclic systems, saturated and unsaturated ketones and diketones, difficultly accessible acids and other compounds is demonstrated. The accessibility of levulinic acid from hexose-containing wood-processing and agricultural wastes is noted. The bibliography includes 260 references.

Timokhin, Boris V.; Baransky, V. A.; Eliseeva, G. D.

1999-01-01

274

Determination of Mine Waste Acidity.  

National Technical Information Service (NTIS)

Pollution from acid mine drainage is a chronic problem. The current vigorous interest has led to a re-examination of the methods of measuring total acidity, which are clearly based on the limited laboratory capabilities of prior years. Defined acid-metal ...

B. V. Salotto E. F. Barth M. B. Ettinger W. E. Tolliver

1967-01-01

275

Carboxylic acid sorption regeneration process  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine.

King, C. Judson (Kensington, CA); Poole, Loree J. (Baton Rouge, LA)

1995-01-01

276

Acidic compounds in biodegraded petroleum  

Microsoft Academic Search

Twelve oil samples have been characterised by titration, FT-IR and chromatographic analysis to determine the differences between the organic acid composition of biodegraded and non-biodegraded oils. The biodegraded oils have higher total acid and total base contents, both by titration and extraction. The molecular weight ranges of the extracted acids are lowest in the biodegraded oils, and the equivalent weight

Tanja Barth; Sylvi Høiland; Per Fotland; Kjell Magne Askvik; Bent Skaare Pedersen; Anna Elisabet Borgund

2004-01-01

277

New politics of acid rain  

SciTech Connect

The acid rain problem is not nationwide across the USA but the politicians want to spread the cost of emission reductions. An overview of acid rain and its environmental impacts is given, and a cost-benefit analysis of acid rain control is outlined. USA policies are discussed. 6 references.

Trisko, E.M.

1983-07-01

278

Synthesis of Acetylsalicylic Acid (Aspirin)  

Microsoft Academic Search

The purpose of this experiment was to synthesize acetylsalicylic acid via an esterification reaction between salicylic acid and acetic anhydride. The product was recrystallized using 95% ethanol. This percent yield of this synthesized product was 68.4%. Using ethanol again as a recrystallizing solvent, acetylsalicylic acid was also extracted from commercial aspirin tablets. This commercial product did not have a percent

Jamie Yeadon; Leah Monroe

279

Serum Uric Acid in Smokers  

PubMed Central

Objectives To demonstrate the possible effect of smoking on serum uric acid. Methods Subjects enrolled in study were divided into two groups; nonsmokers and smokers, each with 60 male volunteers of the same social class and dietary habit without history of alcohol consumption, diabetes mellitus, hyperuricemia and gout, renal, joint, lung or heart diseases. Fasting blood and random urine samples were obtained from both groups for measurement of uric acid and creatinine. Calculation of both urine uric acid/urine creatinine ratio and fraction excretion of uric acid were done. The results were statistically evaluated by standard statistical methods. Results No significant differences in the age, serum creatinine, spot urine uric acid/urine creatinine ratio and fraction excretion of uric acid between the two groups, serum uric acid was significantly lower in smokers. In smokers there was significant negative correlation of smoking status (average number of cigarette smoked/day, duration of smoking and cumulative amount of smoking) with serum uric acid. Conclusion After exclusion of other factors affecting uric acid level, the significant low serum uric acid level in smokers was attributed to reduce endogenous production as a result of chronic exposure to cigarette smoke that is a significant source of oxidative stress. As this reduction is proportionate with smoking status and predisposes to cardiovascular disease, it is, therefore, recommended for smokers to stop or reduce smoking and introduce serum uric acid estimation as routine test since its cheap and simple to reflect their antioxidant level. Keywords Smokers; Uric acid; CVD.

Hanna, Bassam E.; Hamed, Jamal M.; Touhala, Luma M.

2008-01-01

280

Stimulation with inhibited acidizing fluids  

Microsoft Academic Search

Production and injection wells are stimulated with an inhibited acidizing microemulsion containing hydrocarbon (external phase), surfactant, and acid. The acid is inhibited from reacting with the reservoir rock until it has penetrated the rock face. About 5 to 500 gal of the microemulsion per vertical foot of formation are useful to stimulate the wells. Carbonate reservoirs are particulary suited for

C. T. Presley; R. E. Smith

1974-01-01

281

Bacterial Degradation of Nicotinic Acid  

Microsoft Academic Search

A BACTERIUM utilizing nicotinic acid was isolated from culture media made up of a solution of nicotinic acid and dilute sodium sulphide and inoculated with a small amount of Potomac mud. After allowing the bacteria to grow anaerobically, several successive transfers were made into a medium containing nicotinic acid, peptone, yeast extract, metals, phosphate and sodium sulphide. The mixed bacterial

Isaac Harary

1956-01-01

282

An Umbrella for Acid Rain.  

ERIC Educational Resources Information Center

|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)|

Randal, Judith

1979-01-01

283

Scientists Puzzle Over Acid Rain  

ERIC Educational Resources Information Center

|Reports on a growing concern over increased acidity in atmospheric percipitation. Explores possible causes of the increased acidity, identifies chemical components of precipitation in various parts of the world, and presents environmental changes that might be attributed to the acidity. (GS)|

Chemical and Engineering News, 1975

1975-01-01

284

Acid-hydrolysis of fish wastes for lactic acid fermentation.  

PubMed

In this study, two acid-hydrolysis processes, process A and process B, were proposed to produce low-cost nutrients for the production of lactic acid. Process A was a direct way to hydrolyze protein with diluted acid while process B was process A plus fish wastes pretreatment (an extraction by water). The two methods could both treat fish wastes to be suitable nutrient sources for promoting lactic acid production. As the pretreatment indicated some favorable effect on fish waste hydrolyzate (FWH), process B increased lactic acid productivity by 22%. Compared with 20 g/L yeast extract (YE), 6.8% FWH hydrolyzed by process B had more efficiency in lactic acid production, indicating that process B was suitable to produce high performance nutrients for lactic acid production and FWH hydrolyzed by process B would be an substitute for YE. PMID:16293413

Gao, Min-Tian; Hirata, Makoto; Toorisaka, Eiichi; Hano, Tadashi

2005-11-15

285

Caffeic acid derivatives from Eupatorium perfoliatum L.  

PubMed

From the ethyl acetate soluble fraction of a methanol/water extract of the herb Eupatorium perfoliatum L. (Asteraceae) six caffeic acid derivatives have been isolated and identified by 1D- and 2D-NMR spectroscopic data. Besides the common quinic acid derivatives 5-caffeoylquinic acid (chlorogenic acid), 3-caffeoylquinic acid (neochlorogenic acid) and 3,5-dicaffeoylquinic acid, three up to now unknown depsides of caffeic acid with glucaric acid have been isolated: 2,5-dicaffeoylglucaric acid, 3,4-dicaffeoylglucaric acid, and 2,4- or 3,5-dicaffeoylglucaric acid. PMID:19104484

Maas, Mareike; Petereit, Frank; Hensel, Andreas

2008-12-23

286

Composition for nucleic acid sequencing  

DOEpatents

The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

Korlach, Jonas (Ithaca, NY); Webb, Watt W. (Ithaca, NY); Levene, Michael (Ithaca, NY); Turner, Stephen (Ithaca, NY); Craighead, Harold G. (Ithaca, NY); Foquet, Mathieu (Ithaca, NY)

2008-08-26

287

Degradation of Phthalic Acids and Benzoic Acid from Terephthalic Acid Wastewater by Advanced Oxidation Processes  

Microsoft Academic Search

Terephthalic acid (TPA) wastewater is traditionally being treated by biological method. This study investigates the degradation of three major toxic target organic species, namely terephthalic acid (TPA), isophthalic acid (IPA), benzoic acid (BA), present in the TPA wastewater, by several advanced oxidation processes. The performance of three main oxidation processes such as photofenton oxidation (UV-H2O2-Fe), photocatalytic ozonation (UV-O3-Fe) and photofenton

Ramesh Thiruvenkatachari; Tae Ouk Kwon; Il Shik Moon

2006-01-01

288

The politics of acid rain  

SciTech Connect

This work examines and compares the acid rain policies through the different political systems of Canada, Great Britain and the United States. Because the flow of acid rain can transcend national boundaries, acid rain has become a crucial international problem. According to the author, because of differences in governmental institutions and structure, the extent of governmental intervention in the industrial economy, the degree of reliance on coal for power generation, and the extent of acid rain damage, national responses to the acid rain problem have varied.

Wilcher, M.E. (Pennsylvania State Univ., New Kensington, PA (US))

1989-01-01

289

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

ERIC Educational Resources Information Center

|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)|

Raw, C. J. G.; And Others

1983-01-01

290

Some Physical Properties of Binary Liquid Systems: (Ethanoic Acid or Propanoic Acid or Butanoic Acid + Ethanenitrile)  

Microsoft Academic Search

Density, viscosity and surface tension of three binary liquid systems: ethanoic acid + ethanenitrile, propanoic acid + ethanenitrile, butanoic acid + ethanenitrile have been determined at 25, 35 and 45°C, over the whole compositional range. The excess values of molar volume, viscosity, Gibbs free energy for the activation of flow and surface tension were evaluated. The excess values were fitted

R. Ahluwalia; R. K. Wanchoo; J. L. Vashisht

1995-01-01

291

Amino acids in Arctic aerosols  

NASA Astrophysics Data System (ADS)

Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs) in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS) to analyze 20 amino acids and quantify compounds at fmol m-3 levels. Mean total FAA concentration was 1070 fmol m-3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45-60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m-3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (< 0.49 ?m) and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanic emissions.

Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

2012-11-01

292

Allelopathic interactions involving phenolic acids.  

PubMed

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 exceptions, single phenolic acids have been tested. Studies of mixtures of phenolic acids and other toxic (e.g., methionine) and nontoxic (e.g., glucose) organic compounds in laboratory bioassays indicate that the action of a single phenolic acid is not representative of the actions of such mixtures. Specifically, as the number of phenolic acids added to soil increased, concentrations of the individual phenolic acids required to bring about a growth inhibition declined. The addition of other organic compounds (e.g., glucose, methionine) to the soil also reduced the concentration of a phenolic acid (e.g., p-coumaric acid) required for growth inhibition. These results support the hypothesis that in the field mixtures of phenolic acids and other organic compounds can cause inhibitory effects even though the concentrations of individual compounds are well below their inhibitory levels. PMID:19277143

Blum, U

1996-09-01

293

Do we need gastric acid?  

PubMed

Evidence from comparative anatomy and physiology studies indicates that gastric acid secretion developed during the evolution of vertebrates approximately 350 million years ago. The cellular mechanisms that produce gastric acid have been conserved over the millennia and therefore proton pump inhibitors have pharmacological effects in almost all relevant species. These observations suggest that gastric acid provides an important selective advantage; however, in modern-day humans the need for gastric acid can be questioned in light of the widespread use of safe and effective pharmacologic acid suppression. The Kandahar Working Group addressed questions concerning the need, production and effects of gastric acid, specifically: (1) motility in the upper gastrointestinal (GI) tract; (2) neuroendocrine factors; (3) digestive and mucosal processes; (4) microbiology, and (5) central processes and psychological involvement. We addressed each topic with the individual models available to answer our questions including animal versus human studies, pharmacologic, surgical as well as pathophysiologic states of acid suppression. PMID:18594142

Pohl, D; Fox, M; Fried, M; Göke, B; Prinz, C; Mönnikes, H; Rogler, G; Dauer, M; Keller, J; Lippl, F; Schiefke, I; Seidler, U; Allescher, H D

2008-07-02

294

Molecular Structure of Picric acid  

NSDL National Science Digital Library

Picric Acid was first discovered in 1771 by a British Chemist named Peter Woulfe by treatment of indigo with nitric acid. It is most commonly seen in its yellow, water-soluble, crystalline form. For this reason, picric acid first saw use as a dyeing agent in textiles. However, around 1849 it was discovered (for obvious reasons) that picric acid is a shock, heat, and friction-sensitive explosive. Its first use as an explosive material came in military weaponry: torpedoes in particular due to its shock-sensitive nature not requiring a detonator to explode on contact with a target. However, picric acid was found to be highly corrosive to metals, making the weapons very difficult to handle and the acid itself difficult to store. Today, picric acid is used more widely as an ingredient in the manufacture of inert dyes and stable explosives such as dynamite.

2002-09-23

295

Pathophysiology of uric acid nephrolithiasis.  

PubMed

Humans although a predominantly ureotylic organism, has preserved the ability to excrete nitrogen as uric acid and ammonia. An imbalance between these two secondary modes of nitrogen excretion has resulted in uric acid precipitation in human urine. Uric acid nephrolithiasis can arise from diverse etiologies all with distinct underlying defects converging to one or more of three defects of hyperuricosuria, acidic urine pH, and low urinary volume, originating from secondary, genetic or heretofore undefined (idiopathic) causes. A subset of idiopathic uric acid nephrolithiasis (gouty diathesis) may be the "tip of the icebergp" of a broader systemic illness characterized by insulin resistance. A novel renal manifestation of insulin resistance is a mild defect in ammonium excretion, which is not severe enough to disturb acid-base homeostasis, but is sufficient to set up the chemical milieu for uric acid nephrolithiasis. PMID:12474637

Moe, Orson W; Abate, Nicola; Sakhaee, Khashayar

2002-12-01

296

Molecular Structure of Sorbic acid  

NSDL National Science Digital Library

Sorbic acid is a colorless or white crystalline powder, with a weak characteristic odor and slightly acidic taste. It may be obtained from berries of the mountain ash or prepared synthetically by condensing crotonaldehyde and malonic acid in pyridine solution. Sorbic acid is a polyunsaturated fat used to inhibit molds and yeast, is a fungistatic agent for foods (especially cheeses, wine and baked goods). The main use of sorbic acid is as a preservative in foods, animal feeds, tobacco, cosmetics and pharmaceuticals, as well in packing materials for these substances and in other products that come in contact with human or animal skin in some way. Sorbic acid is also used as an intermediate for plasticizers and lubricants. Sorbic acid reacts with potassium to make potassium sorbate and with calcium to make calcium sorbate.

2004-11-11

297

Mycophenolic Acid in Silage  

PubMed Central

We examined 233 silage samples and found that molds were present in 206 samples with counts between 1 × 103 and 8.9 × 107 (mean, 4.7 × 106) CFU/g. Mycophenolic acid, a metabolite of Penicillium roqueforti, was detected by liquid chromatography-mass spectrometry in 74 (32%) of these samples at levels ranging from 20 to 35,000 (mean, 1,400) ?g/kg. This compound has well-known immunosuppressive properties, so feeding with contaminated silage may promote the development of infectious diseases in livestock.

Schneweis, Isabell; Meyer, Karsten; Hormansdorfer, Stefan; Bauer, Johann

2000-01-01

298

Cytenamide acetic acid solvate  

PubMed Central

In the crystal structure of the title compound (systematic name: 5H-dibenzo[a,d]cyclo­hepta­triene-5-carboxamide ethanoic acid solvate), C16H13NO·C2H4O2, the cytenamide and solvent mol­ecules form a hydrogen-bonded R 2 2(8) dimer motif, which is further connected to form a centrosymmetric double ring motif arrangement. The cycloheptene ring adopts a boat conformation and the dihedral angle between the least-squares planes through the two aromatic rings is 54.7?(2)°.

Johnston, Andrea; Florence, Alastair J.; Fabianni, Francesca J. A.; Shankland, Kenneth; Bedford, Colin T.

2008-01-01

299

Cytenamide acetic acid solvate.  

PubMed

IN THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND (SYSTEMATIC NAME: 5H-dibenzo[a,d]cyclo-hepta-triene-5-carboxamide ethanoic acid solvate), C(16)H(13)NO·C(2)H(4)O(2), the cytenamide and solvent mol-ecules form a hydrogen-bonded R(2) (2)(8) dimer motif, which is further connected to form a centrosymmetric double ring motif arrangement. The cycloheptene ring adopts a boat conformation and the dihedral angle between the least-squares planes through the two aromatic rings is 54.7?(2)°. PMID:21202682

Johnston, Andrea; Florence, Alastair J; Fabianni, Francesca J A; Shankland, Kenneth; Bedford, Colin T

2008-05-30

300

Synthesis of amino acids  

DOEpatents

A method is described for synthesizing amino acids preceding through novel intermediates of the formulas: R/sub 1/R/sub 2/C(OSOC1)CN, R/sub 1/R/sub 2/C(C1)CN and (R/sub 1/R/sub 2/C(CN)O)/sub 2/SO wherein R/sub 1/ and R/sub 2/ are each selected from hydrogen and monovalent hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

Davis, J.W. Jr.

1979-09-21

301

Beyond acid rain  

SciTech Connect

This paper discussed the effects of the interactions of soluble oxidants and organic toxins with sulfur dioxide and nitrogen dioxide. It suggested that these chemical reactions in the atmosphere produced a more potent acid rain which was harmful not only because it had a low pH but because it contained oxidants and organic toxins which were harmful to surface vegetation and the organisms found in surface waters. It was stressed that air pollution is a global problem and that is is necessary to develop a better fundamental understanding of how air pollution is causing damage to the streams and forests of the world. 50 references.

Gaffney, J.S.; Streit, G.E.; Spall, W.D.; Hall, J.H.

1987-06-01

302

Conformational studies of hydantoin-5-acetic acid and orotic acid.  

PubMed

Hydantoin-5-acetic acid [2-(2,5-dioxoimidazolidin-4-yl)acetic acid] and orotic acid (2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid) each contain one rigid acceptor-donor-acceptor hydrogen-bonding site and a flexible side chain, which can adopt different conformations. Since both compounds may be used as coformers for supramolecular complexes, they have been crystallized in order to examine their conformational preferences, giving solvent-free hydantoin-5-acetic acid, C(5)H(6)N(2)O(4), (I), and three crystals containing orotic acid, namely, orotic acid dimethyl sulfoxide monosolvate, C(5)H(4)N(2)O(4)·C(2)H(6)OS, (IIa), dimethylammonium orotate-orotic acid (1/1), C(2)H(8)N(+)·C(5)H(3)N(2)O(4)(-)·C(5)H(4)N(2)O(4), (IIb), and dimethylammonium orotate-orotic acid (3/1), 3C(2)H(8)N(+)·3C(5)H(3)N(2)O(4)(-)·C(5)H(4)N(2)O(4), (IIc). The crystal structure of (I) shows a three-dimensional network, with the acid function located perpendicular to the ring. Interestingly, the hydroxy O atom acts as an acceptor, even though the carbonyl O atom is not involved in any hydrogen bonds. However, in (IIa), (IIb) and (IIc), the acid functions are only slightly twisted out of the ring planes. All H atoms of the acidic functions are directed away from the rings and, with respect to the carbonyl O atoms, they show an antiperiplanar conformation in (I) and synperiplanar conformations in (IIa), (IIb) and (IIc). Furthermore, in (IIa), (IIb) and (IIc), different conformations of the acid O=C-C-N torsion angle are observed, leading to different hydrogen-bonding arrangements depending on their conformation and composition. PMID:22307261

Gerhardt, Valeska; Tutughamiarso, Maya; Bolte, Michael

2012-01-18

303

Circulating folic acid in plasma: relation to folic acid fortification  

PubMed Central

Background The implementation of folic acid fortification in the United States has resulted in unprecedented amounts of this synthetic form of folate in the American diet. Folic acid in circulation may be a useful measure of physiologic exposure to synthetic folic acid, and there is a potential for elevated concentrations after fortification and the possibility of adverse effects. Objective We assessed the effect of folic acid fortification on circulating concentrations of folic acid and 5-methyltetrahydrofolate in the Framingham Offspring Cohort. Design This is a cross-sectional study that used plasma samples from fasting subjects before and after fortification. Samples were measured for folate distribution with the use of an affinity-HPLC method with electrochemical detection. Results Among nonsupplement users, the median concentration of folic acid in plasma increased from 0.25 to 0.50 nmol/L (P < 0.001) after fortification, and among supplement users the median increased from 0.54 to 0.68 nmol/L (P = 0.001). Among nonsupplement users, the prevalence of high circulating folic acid (?85th percentile) increased from 9.4% to 19.1% (P = 0.002) after fortification. Among supplement users, the prevalence of high circulating folic acid increased from 15.9% to 24.3% (P = 0.02). Folic acid intake and total plasma folate were positively and significantly related to high circulating folic acid after adjustment for potential confounding factors (P for trend < 0.001). Conclusions Folic acid fortification has resulted in increased exposure to circulating folic acid. The biochemical and physiologic consequences of this are unknown, but these findings highlight the need to understand the effects of chronic exposure to circulating folic acid.

Kalmbach, Renee D; Choumenkovitch, Silvina F; Troen, Aron M; D'Agostino, Ralph; Jacques, Paul F; Selhub, Jacob

2013-01-01

304

Lipid metabolism in the perfused chicken liver. The uptake and metabolism of oleic acid, elaidic acid, cis-vaccenic acid, trans-vaccenic acid and stearic acid  

PubMed Central

Comparative studies were made of the uptake and metabolism of cis- and trans-octadecenoic acids by the perfused chicken liver. No differences were observed in the rates of uptake of the isomers. There was considerable incorporation of radioactivity into triglycerides and phospholipids, and some release of labelled lipid into the perfusate was observed. The cis-fatty acids were more readily incorporated into triglycerides than phospholipids, the reverse being true of the trans-fatty acids. Examination of the intramolecular distribution of fatty acids in triglycerides showed that the trans-fatty acid and stearate mainly occupied the 1- and 3-positions, and cis-fatty acids the 2-position. In the phospholipids phosphatidylcholine and phosphatidylethanolamine the trans-fatty acids again behaved like stearic acid and favoured the 1-position. No evidence was obtained of atypical patterns of uptake or metabolism of the trans-fatty acids.

Bickerstaffe, R.; Annison, E. F.

1970-01-01

305

Preparation of the 3-monosulphates of cholic acid, chenodeoxycholic acid and deoxycholic acid.  

PubMed Central

1. The 3-sulphates of cholic, chenodeoxycholic and deoxycholic acids were prepared as crystalline disodium salts. 2. The method described shows that it is possible to prepare specific sulphate esters of polyhydroxy bile acids and to remove protecting acyl groups without removing the sulphate. 3. A study of bile acid sulphate solvolysis showed that none of the usual methods give the original bile acid in major yield in a single step. 4. An understanding of the preparation, properties and methods of solvolysis of bile acid sulphates is basic for investigations of cholestasis and liver disease.

Haslewood, E S; Haslewood, G A

1976-01-01

306

Action of picolinic acid and structurally related pyridine carboxylic acids on quinolinic acid-induced cortical cholinergic damage  

Microsoft Academic Search

Picolinic acid, a pyridine monocarboxylic acid derived from tryptophan metabolism by the kynurenine pathway, was shown to block cortical cholinergic neurotoxicity induced by quinolinic acid (QUIN), a pyridine dicarboxylic acid yielded by the same pathway. This study examined the specificity of the anti-toxic effect of picolinic acid by comparing its effect with several structurally related mono- and dicarboxylic acids, and

J. Cockhill; K. Jhamandas; R. J. Boegman; R. J. Beninger

1992-01-01

307

21 CFR 184.1069 - Malic acid.  

Code of Federal Regulations, 2010 CFR

...referred to as L-malic acid, occurs naturally in...foods. Racemic DL-malic acid does not occur naturally...commercially by hydration of fumaric acid or maleic acid...percent for nonalcoholic beverages as defined in §...

2009-04-01

308

21 CFR 184.1069 - Malic acid.  

Code of Federal Regulations, 2010 CFR

...referred to as L-malic acid, occurs naturally in...foods. Racemic DL-malic acid does not occur naturally...commercially by hydration of fumaric acid or maleic acid...percent for nonalcoholic beverages as defined in §...

2010-01-01

309

An orsellinic acid glucoside from syzygium aromatica  

Microsoft Academic Search

The buds of Syzygium aromatica yielded two triterpenoid acids, oleanolic acid and crategolic acid, and a new phenolic glucoside, orsellinic-2-O-?-d-glucopyranoside, from its methanolic extract. The structure was elucidated by spectroscopic methods and acid hydrolysis.

Reena Charles; Shri Niwas Garg; Sushil Kumar

1998-01-01

310

Solid-phase extraction of acidic herbicides.  

PubMed

A discussion of solid-phase extraction method development for acidic herbicides is presented that reviews sample matrix modification, extraction sorbent selection, derivatization procedures for gas chromatographic analysis, and clean-up procedures for high-performance liquid chromatographic analysis. Acidic herbicides are families of compounds that include derivatives of phenol (dinoseb, dinoterb and pentachlorophenol), benzoic acid (acifluorfen, chloramben, dicamba, 3,5-dichlorobenzoic acid and dacthal--a dibenzoic acid derivative), acetic acid [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)], propanoic acid [dichlorprop, fluazifop, haloxyfop, 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and silvex], butanoic acid [4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB) and 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB)], and other miscellaneous acids such as pyridinecarboxylic acid (picloram) and thiadiazine dioxide (bentazon). PMID:10941675

Wells, M J; Yu, L Z

2000-07-14

311

21 CFR 184.1091 - Succinic acid.  

Code of Federal Regulations, 2010 CFR

...acid, is the chemical 1,4-butanedioic acid. It is commercially prepared by hydrogenation of maleic or fumaric acid. It can also be produced by aqueous alkali or acid hydrolysis of succinonitrile....

2010-01-01

312

Cryoprotection from lipoteichoic acid  

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

313

Nucleic acid detection methods  

DOEpatents

The invention relates to methods for rapidly determining the sequence and/or length a target sequence. The target sequence may be a series of known or unknown repeat sequences which are hybridized to an array of probes. The hybridized array is digested with a single-strand nuclease and free 3{prime}-hydroxyl groups extended with a nucleic acid polymerase. Nuclease cleaved heteroduplexes can be easily distinguish from nuclease uncleaved heteroduplexes by differential labeling. Probes and target can be differentially labeled with detectable labels. Matched target can be detected by cleaving resulting loops from the hybridized target and creating free 3-hydroxyl groups. These groups are recognized and extended by polymerases added into the reaction system which also adds or releases one label into solution. Analysis of the resulting products using either solid phase or solution. These methods can be used to detect characteristic nucleic acid sequences, to determine target sequence and to screen for genetic defects and disorders. Assays can be conducted on solid surfaces allowing for multiple reactions to be conducted in parallel and, if desired, automated. 18 figs.

Smith, C.L.; Yaar, R.; Szafranski, P.; Cantor, C.R.

1998-05-19

314

Ozone and acid rain  

SciTech Connect

The roles of ozone and other oxidizing agents are discussed. The major polluting emissions are SO/sub 2/, NO, and volatile organic chemicals. In the usual ambient concentrations, these substances are relatively harmless. However, when SO/sub 2/ and NO are oxidized, they are converted into more acid, more toxic, substances. Oxidants, including OH, H/sub 2/O/sub 2/, HO/sub 2/, and organic peroxides, arise out of complex photochemistry that involves the ozone, the nitrogen oxides, and volatile organic chemicals. Were SO/sub 2/ the only pollutant, most of it would escape unchanged to the western Atlantic Ocean where it would be so diluted as to have no effect. At present about 35 percent of the SO/sub 2/ produced in the United States leaves the continent. In contrast, because of higher rates of reaction with oxidants, most of the NO is converted into nitric acid and deposited on land. The nitrogen oxides are involved in the production of ozone, some of which is naturally present. But particularly in urban settings where concentrations of NO/sub x/ are elevated and volatile organic chemicals such as those in gasoline are present, ozone concentrations may rise to levels deleterious to health. The Environmental Protection Agency has set standards for levels not to be exceeded, but nearly half of urban communities are not in compliance. The NO/sub x/ involved in the formation of urban ozone comes mostly from vehicular emissions.

Not Available

1987-10-09

315

46 CFR 151.50-77 - Fluorosilicic acid (30% or less) (hydrofluorosilicic acid).  

Code of Federal Regulations, 2010 CFR

...Fluorosilicic acid (30% or less) (hydrofluorosilicic acid). 151.50-77 Section 151...Fluorosilicic acid (30% or less) (hydrofluorosilicic acid). (a) Hydrofluorosilicic acid must be carried in gravity or...

2009-10-01

316

46 CFR 151.50-77 - Fluorosilicic acid (30% or less) (hydrofluorosilicic acid).  

Code of Federal Regulations, 2010 CFR

...Fluorosilicic acid (30% or less) (hydrofluorosilicic acid). 151.50-77 Section 151...Fluorosilicic acid (30% or less) (hydrofluorosilicic acid). (a) Hydrofluorosilicic acid must be carried in gravity or...

2010-10-01

317

Growth of nitric acid hydrates on thin sulfuric acid films  

NASA Astrophysics Data System (ADS)

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.

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

1994-05-01

318

Determination of benzoic acid, chlorobenzoic acids and chlorendic acid in water  

SciTech Connect

To characterize and conduct treatment studies of a landfill leachate an analysis procedure was required to determine concentrations of benzoic acid, the three isomers of chlorobenzoic acid and chlorendic acid. The title compounds were isolated from acidified (pH 1) water by extraction with methyl t-butyl ether. Analytes were concentrated by back-extracting the ether with 0.1 N sodium hydroxide which was separated and acidified. This solution was analyzed by C[sub 18] reversed-phase HPLC with water/acetonitrile/acetic acid eluent and UV detection at 222 nm. The method has detection limits of 200 [mu]g/L for chlorendic acid and 100 [mu]g/L for benzoic acid and each isomer of chlorobenzoic acid. Validation studies with water which was fortified with the analytes at concentrations ranging from one to ten times detection limits resulted in average recoveries of >95%.

Dietz, E.A.; Cortellucci, N.J.; Singley, K.F. (Occidental Chemical Corp., Grand Island, NY (United States))

1993-01-01

319

Acidizing: A well completion reference  

SciTech Connect

Acidizing removes near-wellbore formation damage by dissolving or bypassing drilling mud, completion fluid or other restrictions. These treatments include matrix pump rate jobs, washes and chemical injection. Matrix stimulation techniques are performed without fracturing reservoir rock. Acid is used to remove drilling, completion, workover or production damage. Solvents and surfactants like crude, condensate, diesel or mutual solvents are used to change pore fluid or formation wettability characteristics. Washes remove scale and other dispersible or soluble material from formations, perforations and casing. The purpose of the above methods is to improve well productivity by removing or mitigating formation damage. Hydrofluoric (HF) acid dissolves clay and fine particles in sandstones. Hydrochloric (HCl) acid etches wormholes that bypass damage in carbonates. Products are subdivided into groups that have similar function and performance. Where applicable, groups have been subdivided to reflect significant differences in additive chemical nature to emphasize uniqueness in the product lines of each company. Products and additives are grouped in 28 categories: water-base completion fluids; water-base polymers; friction reducers; fluid loss; diverting agents; polymer plugs; acid inhibitors; acid retarders; emulsifiers; clay stabilizers; surfactants; non-emulsifiers; fines suspender; anti-sludge agent; foamers; scale inhibitors; iron (Fe) control; oxygen scavenger; mutual solvents; corrosion inhibitors; paraffin control; miscellaneous products; acid systems; retarded acid system; mud acid plus surfactants; mud acid plus alcohol; SGMA; and retarded HF.

NONE

1997-11-01

320

Acid rain: Rhetoric and reality  

SciTech Connect

Acid rain is now one of the most serious environmental problems in developed countries. Emissions and fallout were previously extremely localized, but since the introduction of tall stacks policies in both Britain and the US - pardoxically to disperse particulate pollutants and hence reduce local damage - emissions are now lifted into the upper air currents and carried long distances downwind. The acid rain debate now embraces many western countries - including Canada, the US, England, Scotland, Wales, Sweden, Norway, Denmark, West Germany, the Netherlands, Austria, Switzerland - and a growing number of eastern countries - including the Soviet Union, Poland, East Germany, and Czechoslovakia. The problem of acid rain arises, strictly speaking, not so much from the rainfall itself as from its effects on the environment. Runoff affects surface water and groundwater, as well as soils and vegetation. Consequently changes in rainfall acidity can trigger off a range of impacts on the chemistry and ecology of lakes and rivers, soil chemistry and processes, the health and productivity of plants, and building materials, and metallic structures. The most suitable solutions to the problems of acid rain require prevention rather than cure, and there is broad agreement in both the political scientific communities on the need to reduce emissions of sulfur and nitrogen oxides to the atmosphere. Book divisions discuss: the problem of acid rain, the science of acid rain, the technology of acid rain, and the politics of acid rain, in an effort to evaluate this growing global problem of acid rain.

Park, C.C.

1987-01-01

321

Ultraviolet photodegradation of folic acid.  

PubMed

The vitamin folate is vital for all living creatures. Scientists have suggested that ultraviolet degradation of folate in vivo played a role in the evolution of mankind. In order to better understand the photodegradation of folate, we have provided a spectroscopic study of the ultraviolet photodegradation of aqueous folic acid under aerobic conditions. We found strong indications that the folic acid molecule is cleaved into p-aminobenzoyl-L-glutamic acid and 6-formyl pterin when exposed to ultraviolet radiation. When the irradiation continues, 6-formyl pterin is degraded to pterin-6-carboxylic acid. The photodegradation of folic acid is divided into three phases. In the first phase, the formation of photoproducts follows a zero order rate law. In the second phase the presence of photoproducts sensitizes the degradation of folic acid and the degradation process is accelerated. In the third phase the degradation of 6-formyl pterin to pterin-6-carboxylic acid is the dominating process. This reaction follows a first order rate law. We show that both 6-formyl pterin and pterin-6-carboxylic acid sensitize the photodegradation of folic acid. However, experiments performed in heavy water indicate that generation of singlet oxygen is probably not the explanation for the photosensitizing of folic acid. PMID:15963436

Off, Morten Kristian; Steindal, Arnfinn Engeset; Porojnicu, Alina Carmen; Juzeniene, Asta; Vorobey, Alexander; Johnsson, Anders; Moan, Johan

2005-04-13

322

Conversion of phenolics to lignans: Sinapic acid to thomasidioic acid  

Microsoft Academic Search

Changes in sinapic acid when exposed to aqueous alkaline conditions were elucidated. Sinapic acid was exposed to a volatile\\u000a buffer (pH 8.5) for 24 h, lyophilized, acidified, extracted, and characterized using nuclear magnetic resonance and mass spectroscopy.\\u000a The product obtained was identified as the lignan thomasidioic acid. This identification was confirmed by comparison with\\u000a a synthesized authentic sample of thomasidioic

M. I. Rubino; S. D. Arntfield; J. L. Charlton

1995-01-01

323

Preparation of dodecylamine and 6-aminohexanoic acid from petroselinic acid  

Microsoft Academic Search

A procedure is given for the ozonization of petroselinic acid, chemical reduction of the ozonides to aldehydes, formation\\u000a of oximes, and catalytic hydrogenation of the oximes using Raney nickel in the presence of ammonia, to yield 48% dodecylamine\\u000a and 44% 6-aminohexanoic acid calculated on the amounts theoretically available from the wt of petroselinic acid. The ultimate\\u000a analyses, melting points, and

R. L. Holmes; J. P. Moreau; R. T. O'Connor

1962-01-01

324

Growth of nitric acid hydrates on thin sulfuric acid films  

Microsoft Academic Search

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

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

1994-01-01

325

Ethane to acetic acid oxidation over supported heteropoly acids  

Microsoft Academic Search

Molybdo(vanado)phosphoric heteropoly acids of Keggin structure supported on oxide supports (SiO2, TiO2, Al2O3) were used as catalysts for ethane to acetic acid oxidation in the range of reaction temperature from 250 to 400°C. Vanadium atoms introduced into Keggin structure enhanced oxidative activity of catalytic system, while vanadyl groups exchanged into cationic position diminished ethane conversion. Nature of support (acidic or

M. Sopa; A. W?c?aw-Held; M. Grossy; J. Pijanka; K. Nowi?ska

2005-01-01

326

Clerodendranoic acid, a new phenolic acid from Clerodendranthus spicatus.  

PubMed

Phenolic acid derivatives are typical constituents of Clerodendranthus spicatus which were considered to the active principles of this medicinal plant. These chemical constituents with their interesting frameworks and biological significance attracted our attention. As part of our ongoing chemical investigation of C. spicatus using various column chromatography techniques, a new phenolic compound, named clerodendranoic acid (1), was isolated from the aerial parts of C. spicatus together with five known ones, including rosmarinic acid (2), methyl rosmarinate (3), caffeic acid (4), methyl caffeate (5), ethyl caffeate (6). Their structures, including stereochemical configurations, were completely established by extensive spectroscopic methods, mainly inclvolving 1D, 2D NMR, as well as HRESIMS. PMID:23165309

Zheng, Qingxia; Sun, Zhaocui; Zhang, Xiaopo; Yuan, Jinquan; Wu, Haifeng; Yang, Junshan; Xu, Xudong

2012-11-19

327

Acid-Base Balance in Lake Water.  

National Technical Information Service (NTIS)

As expected, the acid-base content of lake water is composed of strong base or acid, weak acids (mainly fulvic acid) and carbonic acid. All of these may be determined by using a simple titration method. The concentration of undissociated carbonic acid som...

C. Brosset

1980-01-01

328

Molecular Structure of Salicylic acid  

NSDL National Science Digital Library

Salicylic acid is a colorless to white crystalline powder with a sweetish acrid taste that occurs naturally in many microorganisms and plants in very small amounts. It is also made synthetically and used as preservative of food products in some countries and as an antiseptic in mouthwashes and toothpastes. This chemical is also used in the manufacture of methyl salicylates, acetylasalicylic acid (aspirin) and other salicylates. Salicylic acid is a chemical intermediate in the synthesis of dyestuff, salicylate esters and salts. It is prepared commercially by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure to form sodium salicylate, which is treated with sulfuric acid to liberate salicylic acid. Salicylic acid is quite irritating to skin and mucosa and it destroys epithelial cells. Absorption of large amounts can cause vomiting, abdominal pain, acidosis and mental disturbances.

2004-11-11

329

Organic Acids by Ion Chromatography  

NASA Astrophysics Data System (ADS)

The presence of increased levels of various organic acids in physiological fluids such as serum, plasma, and urine has been correlated with a variety of diseases (1). Although some are rare, others such as lactic acidosis and hyperoxaluria are more widespread (2, 3). The estimation of organic acids in biological fluids has long been an analytical problem owing to the nature of the samples and the hydrophilic behavior of the various acids.

Rich, William E.; Johnson, Edward; Lois, Louis; Stafford, Brian E.; Kabra, Pokar M.; Marton, Laurence J.

330

Acid rain and dry deposition  

SciTech Connect

This book provides information on the formation of acid rain and the long-range transport of air pollutants. The effects of acid precipitation on both terrestrial and aquatic ecosystems are highlighted and technical and policy issues associated with the delineation and implementation of control strategies for acid rain and dry deposition are covered. Dry deposition is addressed, with emphasis given to precipitation metals and organics.

Canter, L.W.

1985-01-01

331

Intestinal metabolism of fatty acids  

PubMed Central

1. The effect of concentration on the oxidation and incorporation into lipids of lauric acid and linoleic acid by rings of rat small intestine has been studied in vitro. 2. In the absence of glucose, the oxidation of lauric acid in the range 0·01–5·0mm showed a maximum at 0·1mm. In the presence of glucose the maximum was at 0·5mm. The oxidation of linoleic acid in the presence of glucose increased throughout the concentration range 0·01–5·0mm. 3. The incorporation of lauric acid into lipids was maximal at 0·5–0·6mm in the presence of glucose, but at 10mm in the absence of glucose. At 0·8mm-lauric acid, in the presence of glucose, over 75% of the incorporated lauric acid was in triglycerides, but at 10mm they only contained 30%. The incorporation of glucose carbon into glycerides paralleled the incorporation of lauric acid. 4. In the range 0·01–2·5mm-linoleic acid the quantity incorporated into lipids increased. In the range 0·01–0·4mm linoleic acid was incorporated predominantly into triglycerides, but between 0·4 and 1·0mm most was in diglycerides, and between 2·5 and 5·0mm most was in monoglycerides. 5. The relationship of fatty acid concentration to the mechanism of absorption is discussed, together with the correlation between the distribution of the absorbed fatty acids within the tissue lipids and the lipase activity of intestinal mucosa.

Enser, M.

1965-01-01

332

Absorption spectra of humic acids  

Microsoft Academic Search

For the purpose of explaining the forming process of soil humic acids, the author determined the absorption spectra of various humic acids. From soils and peats which were pretreated with 5% HCl at 70°C for 30 minutes or from those which were not, humic acids were extracted by treating with 0.5% NaOH at boiling temperature for 30 minutes. In these

Kyoichi Kumada

1955-01-01

333

trans Fatty acids in milkfat  

Microsoft Academic Search

Milkfat is extremely complex, with ca. 500 different fatty acids reported in the triglycerides. Seasonal feed variation results\\u000a in higher unsaturated fatty acid levels in summer than in winter. Rumen microbes hydrogenate unsaturated feed lipids to yield\\u000a a mixture of geometrical and positional isomers which are transmitted to the milk. Total isolatedtrans fatty acids in milkfat reported in the literature

L. Deman; J. M. Deman

1983-01-01

334

[Hydrofluoric acid poisoning: case report].  

PubMed

Hydrofluoric acid is a highly dangerous substance with industrial and domestically appliances. Clinical manifestations of poisoning depend on exposure mechanism, acid concentration and exposed tissue penetrability. Gastrointestinal tract symptoms do not correlate with injury severity. Patients with history of hydrofluoric acid ingestion should undergo an endoscopy of the upper gastrointestinal tract. Intoxication requires immediate intervention because systemic toxicity can take place. We present a 5 year old girl who accidentally swallowed 5 ml of 20% hydrofluoric acid. We performed gastrointestinal tract endoscopy post ingestion, which revealed erythematous esophagus and stomach with erosive lesions. Two months later, same study was performed and revealed esophagus and stomach normal mucous membrane. PMID:23381711

Cortina, Tatiana Judith; Ferrero, Hilario Andrés

335

Acid rain: the Canada connection  

SciTech Connect

A review of a controversial new book called The Silent Alliance is presented. The book deals with very sensitive issues: acid rain, electricity imports from Canada, and Canada's alleged role in US acid rain legislation. Canadian officials are accused of lobbying strenuously for acid rain legislation in the US so Canada can increase its already large electricity exports to the US. It is concluded that the wide divergence between Canada's statements and practice on acid rain, and the numerous incentives to export additional electricity, should cause the US to examine Canada's lobbying efforts critically.

Not Available

1984-10-01

336

Molecular Structure of Propionic acid  

NSDL National Science Digital Library

Propanoic acid was named after the Greek word "Pro" for first and "pion" for fat, because it is the first fatty acid. It is a liquid and has a slightly pungent odor that can be characterized as rancid. Sweat, milk, and fermentation products all contain small amounts of this chemical. It can be synthesized from ethanol or ethylene and carbon monoxide. The calcium salt of propanoic acid is used as an antimolding agent and is an additive in breads. Esters of this carboxylic acid have a pleasant smell and taste and are used in the manufacture of fruit flavors and perfume bases. This compound is also found in a herbicide, called Silverado.

2002-10-11

337

Acidic gas capture by diamines  

DOEpatents

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

Rochelle, Gary (Austin, TX); Hilliard, Marcus (Missouri City, TX)

2011-05-10

338

[Acid-base equilibrium in experimental acid indigestion in cattle].  

PubMed

Blood and urine acid-base parameters were investigated in 4 heifers with acid indigestion produced by intraruminal infusion of sugar in a dose of 12 g/kg b.wt. Observations were carried out for 9 days after sugar administration. It was found that rumen acidosis was accompanied by disturbances in blood acid-base balance characteristic of partially compensated metabolic acidosis. The most pronounced changes in acid-base parameters were observed within the first 24 hours after sugar infusion, i.e. during rapid increase of lactic acid levels in blood. These changes were reflected by a decrease of blood pH values to 7.138-7.275 reduction in standard bicarbonate to 12.2-17.0 mmol/l and deficiency in base excess ranging from 9.3 to 16.7 mmol/l. The maximum reduction in partial pressure of CO2 to 4.35-4.79 kPa occurred during the second day of the experiment. The duration of acid-base disturbances depended on their intensity in individual animals and oscillated between 4 and 9 days after sugar administration. When acidosis subsided, acid-base balance returned to normal or showed a tendency toward blood alkalization. The observed decrease of pH values in urine to 5.42-5.74 and renal acid excretion from 170 to 299 mmol/l indicate a significant role of kidney function in the correction of metabolic acidosis. PMID:3822857

Albrycht, A; Bieniek, K; Caka?a, S

1986-01-01

339

Acid rain on acid soil: a new perspective  

Microsoft Academic Search

Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has

E. C. Krug; C. R. Frink

1983-01-01

340

No Potassium, No Acid: K+ Channels and Gastric Acid Secretion  

NSDL National Science Digital Library

The gastric H+-K+-ATPase pumps H+ into the lumen and takes up K+ in parallel. In the acid-producing parietal cells, luminal KCNE2/KCNQ1 K+ channels play a pivotal role in replenishing K+ in the luminal fluid. Inactivation of KCNE2/KCNQ1 channels abrogates gastric acid secretion and dramatically modifies the architecture of gastric mucosa.

2007-10-01

341

Minimizing Amino Acid Catabolism Decreases Amino Acid Requirements1  

Microsoft Academic Search

The processes of natural selection shape the efficiency of nutrient use by animals, with some being especially thrifty while others are wasteful. An examination of the widely divergent amino acid economies of different species vividly illustrates this basic nutritional principle. The domestic cat evolved as a carnivore and has a very high maintenance requirement for dietary amino acids.The cat's veryhigh

Kirk C. Klasing

342

Capturing a sulfenic Acid with arylboronic acids and benzoxaborole.  

PubMed

Post-translational redox generation of cysteine-sulfenic acids (Cys-SOH) functions as an important reversible regulatory mechanism for many biological functions, such as signal transduction, balancing cellular redox states, catalysis, and gene transcription. Herein we show that arylboronic acids and cyclic benzoxaboroles can form adducts with sulfenic acids in aqueous medium and that these boron-based compounds can potentially be used to trap biologically significant sulfenic acids. As proof of principle we demonstrate that a benzoxaborole can inhibit the enzyme activity of an iron-containing nitrile hydratase, which requires a catalytic ?Cys114-SOH in the active site. The nature of the adduct and the effect of the boronic acid's pKa(B) on the stability constant of the adduct are discussed within. PMID:24050501

Liu, C Tony; Benkovic, Stephen J

2013-09-19

343

Acid rain on acid soil: a new perspective  

SciTech Connect

Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and Northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

Krug, E.C.; Frink, C.R.

1983-08-05

344

Carbonic Acid Pretreatment of Biomass  

SciTech Connect

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 acid compared to water alone. 6) Determine optimal conditions for carbonic acid pretreatment of aspen wood. Optimal severities appeared to be in the mid range tested. ASPEN-Plus modeling and economic analysis of the process indicate that the process could be cost competitive with sulfuric acid if the concentration of solids in the pretreatment is maintained very high (~50%). Lower solids concentrations result in larger reactors that become expensive to construct for high pressure applications.

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

2003-05-31

345

Carbonic Acid Retreatment of Biomass  

SciTech Connect

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 the use of carbonic acid compared to water alone. (6) Determine optimal conditions for carbonic acid pretreatment of aspen wood. Optimal severities appeared to be in the mid range tested. ASPEN-Plus modeling and economic analysis of the process indicate that the process could be cost competitive with sulfuric acid if the concentration of solids in the pretreatment is maintained very high ({approx}50%). Lower solids concentrations result in larger reactors that become expensive to construct for high pressure applications.

Baylor university

2003-06-01

346

Structures of chloralide, d-lactic acid chloralide, malic acid chloralide and citric acid chloralide  

Microsoft Academic Search

The crystal and molecular structures of chloralide (1), d-lactic acid chloralide (2), malic acid chloralide (3) and citric acid chloralide (4) have been determined by X-ray diffraction methods. Compound 1 crystallizes in the monoclinic space group, P21c, a = 6.201(2), b = 17.11(2), c = 10.357(6) A?, ? = 95.21(4)°, Z = 4; compound 2 in the monoclinic space group

L. L. Koh; H. H. Huang; L. H. L. Chia; E. P. Liang

1995-01-01

347

Acids of Surakhany crude oil  

SciTech Connect

Carboxylic acids are the principal oxygen-containing components of crude oil. Studies of the composition of petroleum acids (particularly high MW acids contained in the higher boiling distillates and petroleum residues) are of interest in relation to problems concerning the origin of petroleum hydrocarbons. In addition to the theoretical aspect, additional information on the composition and structure of individual petroleum acids is also of practical value, since these compounds have many valuable properties and are widely used in many fields of the national economy. Carboxylic acid concentrates were isolated from Surakhany crude oil heavy residue (b.p. > 350/sup 0/C) by extraction with a dilute solution of potassium carbonate in methanol and subsequent thin layer and column chromatography on silica gel. GC/MS was used to identify normal acids C/sub 11/H/sub 23/COOH - C/sub 20/H/sub 41/COOH, 3,7,11,15-tetramethylhexadecanoic (phytanoic) acid, a homologous series of ..beta..-methylsubstituted acids containing C/sub 9/H/sub 19/CH/CH/sub 3//CH/sub 2/COOH - C/sub 17/H/sub 25/CH/CH/sub 3//CH/sub 2/COOH. Pentacyclic acids of the hopane series, C/sub 27/H/sub 45/COOH - C/sub 31/H/sub 53/COOH were identified. On the basis of MS fragmentation the stereochemistry of hopane acids was established: (17..cap alpha.., 21..beta..)H, (17..beta..,21..beta..)H isomers were detected. It was shown that (17..cap alpha.., 21..beta..)H, C/sub 30/H/sub 51/COOH and C/sub 31/H/sub 53/COOH hopane acids are present as isomers with non-regrouped configuration of the C/sub 22/ chiral atom.

Frolov, E.B.; Vanyukova, N.A.; Mikaya, A.I.; Sanin, P.I.

1985-01-01

348

Catalyzed oxidation reactions. IV. Picolinic acid catalysis of chromic acid oxidations  

Microsoft Academic Search

Picolinic acid and several closely related acids are effective catalysts in the chromic acid oxidation of primary and secondary alcohols; the oxidation of other substrates is accelerated only moderately. The reaction is first order in chromium-(VI), alcohol, and picolinic acid; it is second order in hydrogen ions at low acidity and approaches acidity independence at high perchloric acid concentrations. A

Jan Rocek; T. Y. Peng

1977-01-01

349

Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains  

PubMed Central

A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, ?-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli.

Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

1988-01-01

350

Production of succinic Acid from citric Acid and related acids by lactobacillus strains.  

PubMed

A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, alpha-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

Kaneuchi, C; Seki, M; Komagata, K

1988-12-01

351

Acid rain: effects on fish and wildlife  

SciTech Connect

The following questions concerning acid rain are discussed: what is acid rain; what causes acid rain; where do sulfur and nitrogen oxides originate; what areas in the U.S. are susceptible to acid rain; are there early warning signals of acidification to aquatic resources; how does acid rain affect fishery resources; does acid rain affect wildlife; and how can effects of acid rain be reduced.

Mayer, K.S.; Multer, E.P.; Schreiber, R.K.

1984-01-01

352

Amino Acid Concentrations in Rumen Fluid  

PubMed Central

Methods using dialysis or ultrafiltration are described for the collection of extracellular fluid in rumen contents for analysis of amino acids. Marked differences in the concentration of aspartic acid, glutamic acid, and alanine were found in samples of either diffusate or ultrafiltrate and in clarified acidified rumen liquor. Concentrations are given for aspartic acid, glutamic acid, alanine, glycine, ?-aminobutyric acid, valine, ?-aminovaleric acid, and leucine.

Wright, D. E.; Hungate, R. E.

1967-01-01

353

Formation of formic acid, acetic acid and lactic acid from decomposition of citric acid by coal ash particles at room temperature  

Microsoft Academic Search

It was found for the first time that citric acid was decomposed to formic acid, acetic acid and lactic acid in the presence of coal ash particles at pH 3 at 20°C, while it was not decomposed at more than pH 5. The yield of organic acid at stirring time of 60min is in the order of formic acid>acetic acid>lactic

Hiroyuki Nakui; Kenji Okitsu; Yasuaki Maeda; Rokuro Nishimura

2009-01-01

354

Molecular Structure of Isophthalic acid  

NSDL National Science Digital Library

Isophthalic acid is one of the three simple aromatic dicarboxylic acids with the carboxyl groups in the meta postions. It is used to produce isophthalic polyester that together with other components is used in resin systems for flame retardants and in corrosion prevention.

2008-01-10

355

Acid Precipitation: Causes and Consequences.  

ERIC Educational Resources Information Center

|This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)|

Babich, Harvey; And Others

1980-01-01

356

Glyoxylic Acid: A Key Chemical.  

National Technical Information Service (NTIS)

The principal aim of the dissertation is to gain insight into the reactions concerning glyoxylic acid in reaction with phenol in aqueous medium in order to obtain improved methods for the preparation of 2- and 4-hydroxymandelic acid and products derived o...

A. J. Hoefnagel

1993-01-01

357

Cinnamic Acid Hydroxylase in Spinach.  

National Technical Information Service (NTIS)

An acetone precipitate from an extract of spinach leaves catalysed the hydroxylation of trans-cinnamic acid to p-coumaric acid. The enzyme was unstable and could not be purified. Crude preparations had a pH optimum of 4.6 and showed an absolute requiremen...

P. M. Nair L. C. Vining

1964-01-01

358

Dicarboxylic Acid-Urea Complexes.  

National Technical Information Service (NTIS)

A study of the reaction of several acids with urea resulted in a series of compounds of varying stoichiometry and structure. The acids having the structure HO2C(CH2)nCO2H produced saltlike compounds with urea when n = 0 and 1 and H-bonded complexes for n ...

J. Radell B. W. Brodman J. J. Domanski

1966-01-01

359

Folic Acid Questions and Answers  

MedlinePLUS

... INFO (800-232-4636) TTY: (888) 232-6348 Contact CDC-INFO flo@cdc.gov Folic Acid Homepage Facts Quiz Questions & Answers Cereals with Folic Acid Data and Statistics Research Global Initiative Articles & Key Findings Recommendations Free Materials Links ...

360

SOIL REACTION AND ACIDIC DEPOSITION  

EPA Science Inventory

This chapter discusses the major chemical processes by which acidic deposition interacts with soils. he focus is on forest soils, as the effects of acidic deposition on soils used for production of food and fiber are generally small compared to effects of agricultural practices s...

361

The Acid Rain Differential Game  

Microsoft Academic Search

This paper considers an acid rain differential game. 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

Karl-Göran Mäler; Aart De Zeeuw

1998-01-01

362

Acid Rain: A Background Report.  

National Technical Information Service (NTIS)

This Staff Brief was prepared for the Wisconsin Legislative Council's Special Committee on Acid Rain to provide an introduction to the issue of acid rain. It is divided into four parts. Part I provides an overview on the controversies surrounding the meas...

L. Glustrom J. Stolzenberg

1982-01-01

363

Acid rain & electric utilities II  

SciTech Connect

This document presents reports which were presented at the Acid Rain and Electric Utilities Conference. Topics include environmental issues and electric utilities; acid rain program overview; global climate change and carbon dioxide; emissions data management; compliance; emissions control; allowance and trading; nitrogen oxides; and assessment. Individual reports have been processed separately for the United States Department of Energy databases.

NONE

1997-12-31

364

Molecular Structure of Formic acid  

NSDL National Science Digital Library

Formic Acid, also known as methanoic acid and hydrogencarboxylic acid, is the simplest organic acid. It is a colorless, toxic, corrosive liquid with a pungent, penetrating odor. In nature, it is found in the stings and bites of many insects of the order hymenoptera, including bees and ants. The principal use of formic acid is as a preservative and antibacterial agent in livestock feed. The largest single use of formic acid is as a silage additive in Europe, but this market hardly exists in the United States. When sprayed on fresh hay or other silage, it arrests certain decay processes and causes the feed to retain its nutritive value longer. In the poultry industry, it is sometimes added to silage to kill salmonella bacteria. It is also used in textile dyeing, leather tanning, as a solvent, in electroplating processes, in the manufacturing of lacquers, glass, vinyl resin plasticizers, and formate esters (for flavor and fragrance) and in the manufacture of fumigants. Formic acid is a strong reducing agent, and may act both as an acid and as an aldehyde because the carboxyl is bound to a hydrogen rather than an alkyl group.

2003-05-08

365

Acid rain: a background report  

SciTech Connect

This Staff Brief was prepared for the Wisconsin Legislative Council's Special Committee on Acid Rain to provide an introduction to the issue of acid rain. It is divided into four parts. Part I provides an overview on the controversies surrounding the measurement, formation and effects of acid rain. As described in Part I, the term acid rain is used to describe the deposition of acidic components through both wet deposition (e.g., rain or snow) and dry deposition (e.g., direct contact between atmospheric constituents and the land, water or vegetation of the earth). Part II presents background information on state agency activities relating to acid rain in Wisconsin, describes what is known about the occurrence of, susceptibility to and effects of acid rain in Wisconsin, and provides information related to man-made sources of sulfur and nitrogen oxides in Wisconsin. Part III describes major policies and regulations relating to acid rain which have been or are being developed jointly by the United States and Canadian governments, by the United States government and by the State of Wisconsin. Part IV briefly discusses possible areas for Committee action.

Glustrom, L.; Stolzenberg, J.

1982-07-08

366

Perfectly Complementary Nucleic Acid Enzymes  

Microsoft Academic Search

The ability to maximize the use of available nucleic acid sequence space would have been crucial during the presumed RNA world and confers selective advantage in many contemporary organisms. One way to access sequence space at a higher density would be to make use of both strands of a duplex nucleic acid for the production of functional molecules. As a

Scott T. Kuhns; Gerald F. Joyce

2003-01-01

367

Acid Rain: An Educational Opportunity?  

ERIC Educational Resources Information Center

|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…

Marion, James I.

1984-01-01

368

Germany's Supplies of Nitric Acid  

Microsoft Academic Search

AN article in the Times of January 6 deals with the resources in Germany for producing nitric acid. Formerly, the major part of the world's supply of nitrates came from the caliche beds on the west of the Andes, but of recent years, as is well known, nitric acid and nitrates have been manufactured by the electric process of Birkeland

W. R

1916-01-01

369

Humic acid fouling during microfiltration  

Microsoft Academic Search

A major factor limiting the use of microfiltration for surface water treatment is membrane fouling by natural organic matter. The extent and mechanisms of humic acid fouling during microfiltration have been examined using stirred cell filtration experiments and scanning electron microscopy. The extent of fouling was strongly dependent on both the source and preparation of the humic acid solutions. The

Wei Yuan; Andrew L Zydney

1999-01-01

370

Learning About Acids and Bases  

NSDL National Science Digital Library

The chemistry of acids and bases is a fundamental area of study in the physical sciences. The following activity is really two exercises in one. First, students learn to distinguish between acids and bases using various color-changing indicator solutions.

Eichinger, John

2009-05-15

371

Getting Back to Basics (& Acidics)  

ERIC Educational Resources Information Center

|This article describes a few novel acid-base experiments intended to introduce students to the basic concepts of acid-base chemistry and provide practical examples that apply directly to the study of biology and the human body. Important concepts such as the reaction between carbon dioxide and water, buffers and protein denaturation, are covered.…

Rhodes, Sam

2006-01-01

372

Soil Reaction and Acidic Deposition.  

National Technical Information Service (NTIS)

The chapter discusses the major chemical processes by which acidic deposition interacts with soils. The focus is on forest soils, as the effects of acidic deposition on soils used for production of food and fiber are generally small compared to effects of...

J. O. Reuss P. M. Walthall

1990-01-01

373

Fatty Acids and Atherosclerotic Risk  

Microsoft Academic Search

Most research concerning the effects of dietary fatty acids on atherosclerotic risk has focused on their effects on lipid and lipoprotein metabolism. However, it is known that fatty acids also influence a number of other relevant mechanisms involved in atherosclerosis such as lipid peroxidation, inflammation and haemostasis. The most favourable distribution of cholesterol over the various lipoproteins is achieved when

M. A. Thijssen; R. P. Mensink

374

Metabolism of Lysergic Acid Diethylamide  

Microsoft Academic Search

ALTHOUGH the hallucinogenic agent, lysergic acid diethylamide, has been the subject of numerous investigations, little is known about its biological fate. The development of a specific and sensitive method for the estimation of lysergic acid diethylamide in biological materials has enabled us to study its physiological disposition and metabolism.

Julius Axelrod; Roscoe O. Brady; Bernhard Witkop; Edward V. Evarts

1956-01-01

375

Acid coal pile drainage prevention  

Microsoft Academic Search

The purpose of the present study was to evaluate different compounds or mixtures to prevent acid coal pile drainage. Acid coal pile drainage refers to the low pH drainage from the water leached through the high sulfur coal piles. Purdue University owns and operates a co-generating power plant that produces steam and electricity from the combustion of coal, gas, and

Sandra L Mansilla-Soto

1999-01-01

376

BOTANICAL ASPECTS OF ACIDIC PRECIPITATION  

EPA Science Inventory

Acidic precipitation can be characterized as wet or frozen atmospheric deposition with a hydrogen ion concentration greater than 2.5 microequivalents liter-1. Acidic precipitation is perceived as a significant air pollution problem derived chiefly from combustion of fossil fuels,...

377

ACID DEPOSITION AND FOREST DECLINE  

EPA Science Inventory

The location, topography and other characteristics of the high-elevation forests of eastern North America cause them to be receptors of high levels of acid deposition and airborn trace metals. No other major forested areas in the U.S. are subjected to such intensely acid cloud mo...

378

Biopolymers: Protein and Nucleic Acids.  

National Technical Information Service (NTIS)

The work focuses on learning the principles that govern interactions between proteins and nucleic acids both DNA and RNA (specifically tRNA). With these principles as guides we are synthesizing peptides (of about 50 amino acids) that bind to specific regi...

J. H. Richards J. N. Abelson L. H. Hood M. I. Simon P. B. Dervan

1988-01-01

379

Vibrational Spectra of ?-Aminobutyric Acid  

NASA Astrophysics Data System (ADS)

The NIR-FT Raman, FT-IR spectral analysis of ?-Aminobutyric acid (GABA) a simple amino acid is carried out by density functional computations. The vibrational spectra confirm the existence of NH3+ in GABA. Hydroxyl groups H-bonded to the different extents are analysed, supported by computed results.

Suresh, D. M.; Sajan, D.; Laladas, K. P.; Joe, I. Hubert; Jayakumar, V. S.

2008-11-01

380

Enantioselective oxidation of racemic lactic acid to d-lactic acid and pyruvic acid by Pseudomonas stutzeri SDM  

Microsoft Academic Search

d-Lactic acid and pyruvic acid are two important building block intermediates. Production of d-lactic acid and pyruvic acid from racemic lactic acid by biotransformation is economically interesting. Biocatalyst prepared from 9g dry cell wtl?1 of Pseudomonas stutzeri SDM could catalyze 45.00gl?1dl-lactic acid into 25.23gl?1d-lactic acid and 19.70gl?1 pyruvic acid in 10h. Using a simple ion exchange process, d-lactic acid and

Chao Gao; Jianhua Qiu; Jingchen Li; Cuiqing Ma; Hongzhi Tang; Ping Xu

2009-01-01

381

[On the phenolic acids of vegetables. III. Hydroxycinnamic acids and hydroxybenzoic acids of root vegetables (author's transl)].  

PubMed

In carrots, celeriac, scorzoneras, and horse radish caffeic acid, in small radishes p-coumaric acid, in beets ferulic acid and in radishes probably ferulic acid is dominating after hydrolysis. The contents of phenolic acids in the roots are much smaller than in the corresponding leaves. Carrots, small radishes, horse radish and partially scorzoneras show higher concentrations of phenolic acids in outer tissue layers. In contrary to hydroxycinnamic acid derivatives the contents of hydroxybenzoic acid derivatives (p-hydroxybenzoic, vanillic, salicylic and gentisic acid) mostly were small. Partially hydroxycoumarins (aesculetin and scopoletin) identified. PMID:1224796

Stöhr, H; Herrmann, K

1975-11-24

382

40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...  

Code of Federal Regulations, 2010 CFR

... Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle... Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle...as alkenedioic acid, dialkyl ester, reaction products with...

2009-07-01

383

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium  

NASA Astrophysics Data System (ADS)

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

Yamamoto, Hideki; Sumoge, Iwao

2011-03-01

384

Molecular Structure of Linoleic acid  

NSDL National Science Digital Library

Linoleic acid is a polyunsaturated fatty acid occurring widely in plant glycerides or fats. Common sources include many vegetable oils such as flax seed, safflower, soybean, peanut, and corn; some margarines; and dairy fats. It is a colorless to straw-colored liquid, insoluble in water, but soluble in alcohol and ether. Linoleic acid is easily oxidized by air and is combustible. It also appears as an aluminum salt, in the form of yellow lumps or powder, that is practically insoluble in water but soluble in oils and fixed alkalai hydroxides. Linoleic acid is essential in human nutrition and is used also for soaps, animal feeds, paints, drying protective coatings, emulsifying or smoothing and wetting agents, and in biochemical research. The conjugated form of linoleic acid or CLA has been associated with health benefits such as lowered risk of cancer and atherosclerosis. Prepared CLA is available as a supplement. However, foods high in CLA content could be used.

2003-05-08

385

Nucleic acid based molecular devices.  

PubMed

In biology, nucleic acids are carriers of molecular information: DNA's base sequence stores and imparts genetic instructions, while RNA's sequence plays the role of a messenger and a regulator of gene expression. As biopolymers, nucleic acids also have exciting physicochemical properties, which can be rationally influenced by the base sequence in myriad ways. Consequently, in recent years nucleic acids have also become important building blocks for bottom-up nanotechnology: as molecules for the self-assembly of molecular nanostructures and also as a material for building machinelike nanodevices. In this Review we will cover the most important developments in this growing field of nucleic acid nanodevices. We also provide an overview of the biochemical and biophysical background of this field and the major "historical" influences that shaped its development. Particular emphasis is laid on DNA molecular motors, molecular robotics, molecular information processing, and applications of nucleic acid nanodevices in biology. PMID:21432950

Krishnan, Yamuna; Simmel, Friedrich C

2011-03-28

386

Atmospheric dust and acid rain  

SciTech Connect

Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

Hedin, L.O.; Likens, G.E.

1996-12-01

387

Synthesis of higher monocarboxylic acids  

SciTech Connect

Brown-coal and peat waxes contain higher monocarboxylic acids, alcohols and esters of them as their main components. In view of this, considerable interest is presented by the preparation of individual compounds among those mentioned above, which is particularly important in the study of the composition and development of the optimum variants of the chemical processing of the waxes. In laboratory practice, to obtain higher monocarboxylic acids use is generally made of electrosynthesis according to Kolbe which permits unbranched higher aliphatic acids with given lengths of the hydrocarbon chain to be obtained. The aim of the present work was to synthesize higher monocarboxylic acids: arachidic, behenic, lignoceric, pentacosanoic, erotic, heptacosanoic, montanic, nonacosanoic, melissic, dotriacontanoic and tetratriacontanoic, which are present in waxes. Characteristics of synthesized acids are tabulated. 20 refs.

Taikov, B.F.; Novakovskii, E.M.; Zhelkovskaya, V.P.; Shadrova, V.N.; Shcherbik, P.K.

1981-01-01

388

Synthesis of l-(+)-Tartaric Acid from l-Ascorbic Acid via 5-Keto-d-Gluconic Acid in Grapes  

PubMed Central

5-Keto-l-idionic acid (?5-keto-d-gluconic acid, d-xylo-5-hexulosonic acid) was found as a metabolic product of l-ascorbic acid in slices of immature grapes, Vitis labrusca L. cv `Delaware'. Specifically labeled compounds, recognized as metabolic products of l-ascorbic acid in grapes, were fed to young grape tissues to investigate the metabolic pathway from l-ascorbic acid to l-(+)-tartaric acid. Label from dehydro-l-[1-14C]ascorbic acid, 2-keto-l-[1-14C]idonic acid (l-xylo-2-hexulosonic acid), l-[1-14C]idonic acid, or 5-keto-l-[1-14C] idonic acid was incorporated into l-(+)-tartaric acid in high yields as it was in the l-[1-14C]ascorbic acid experiment. In a double label experiment involving a mixture of l-[1-14C]idonic acid and l-[2-3H]idonic acid, the 3H/14C ratios of 5-keto-l-idonic acid and l-(+)-tartaric acid synthesized in young grape leaves were almost the same as the value of the l-idonic acid fed. Label from 5-keto-l-[6-14C]idonic acid was incorporated into sugars and insoluble residue in the same way as l-[6-14C]ascorbic acid was metabolized in grapes. These results provide strong evidence that in grapes l-(+)-tartaric acid is synthesized from the C4 fragment that corresponds to the C1 to C4 group of the 5-keto-l-idonic acid derived from l-ascorbic acid via 2-keto-l-idonic acid and l-idonic acid.

Saito, Kazumi; Kasai, Zenzaburo

1984-01-01

389

Docosahexaenoic acid and lactation.  

PubMed

Docosahexaenoic acid (DHA) is an important component of membrane phospholipids in the retina and brain and accumulates rapidly in these tissues during early infancy. DHA is present in human milk, but the amount varies considerably and is largely dependent on maternal diet. This article reviews data addressing the impact of different DHA intakes by lactating women on infant and maternal outcomes to determine if available data are sufficient to estimate optimal breast milk DHA content and estimate dietary reference intakes (DRIs) for DHA by breast-feeding mothers. Results of published observational studies and interventional trials assessing the impact of maternal DHA intake (or breast milk DHA content) on infant visual function, neurodevelopment, and immunologic status were reviewed. Studies related to the potential impact of DHA intake on depression or cognitive function of lactating women also were reviewed. Although only a limited number of studies are available in the current medical literature, and study results have not been consistent, better infant neurodevelopment and/or visual function have been reported with higher vs. lower levels of breast milk DHA. The effect of DHA intake on the incidence or severity of depression in lactating women is not clear. Increasing breast milk DHA content above that typically found in the US, by increasing maternal DHA intake, may confer neurodevelopmental benefits to the recipient breast-fed infant. However, current data are insufficient to permit determination of specific DRIs during this period. PMID:19632101

Jensen, Craig L; Lapillonne, Alexandre

2009-07-24

390

Hydrofluoric acid dermal exposure.  

PubMed

A retrospective review of 237 consecutive cases of dermal exposure to dilute (6-11%) hydrofluoric acid (HF)- containing rust stain remover consumer products reported to the Rocky Mountain Poison and Drug Center during 1986 was done to evaluate the toxicity of these agents and the efficacy of topical treatment with calcium gluconate gel. In 148 cases (62%), failure to follow manufacturers' recommended safety procedures was the likely cause of exposure. 219 patients developed the following symptoms: dermal swelling, redness, or both (131, 55%); blistering (12, 5%); black discoloration under fingernails (12, 5%); or pain without reported dermal changes (64, 27%). Local complications were noted in 7 cases (3%) (infection, 4 cases; fingertip dermal necrosis, 3 cases). No systemic toxicity was noted. 116 patients (49%) received treatment with topical calcium gluconate gel; 53 were followed until complete resolution of symptoms. There appeared to be a relationship between earlier initial gel application and more rapid resolution of signs and symptoms. Some degree of dermal injury may be quite common following exposure to dilute (6-11%) HF-containing rust stain remover consumer products. Failure to follow manufacturers' recommended safety procedures may be responsible for many exposures. Treatment with topical calcium gluconate gel may be effective, and more rapid resolution of signs and symptoms may occur with earlier initiation of this therapy. PMID:2741315

el Saadi, M S; Hall, A H; Hall, P K; Riggs, B S; Augenstein, W L; Rumack, B H

1989-06-01

391

Fumaric acid esters.  

PubMed

Several clinical studies have shown that systemic therapy with fumaric acid esters (FAEs) in patients with moderate to severe psoriasis is effective and has a good long-term safety profile. For therapeutic use, tablets with a defined mixture of FAEs (dimethylfumarate [DMF] and three different salts of monoethylfumarate) are registered in Germany. There is evidence that DMF is the most essential component in this formulation with an antipsoriatic effect. Currently, there are few data on the pharmacokinetics of fumarates in human beings. DMF seems to act as a prodrug for its main metabolite: monomethylfumarate. This hypothesis was supported by the observation that only monomethylfumarate was detected in the plasma of human beings after the oral administration of FAEs. FAEs have been tested in different biological assays, and effects such as inhibition of the nuclear factor kappa B pathway or induction of apoptosis by DMF have been described. For these data, the role of DMF as a modulator of intracellular glutathione plays an important role. PMID:18755371

Rostami Yazdi, Martin; Mrowietz, Ulrich

392

?-Oxidation of ?-Chlorinated Fatty Acids  

PubMed Central

Myeloperoxidase-derived HOCl targets tissue- and lipoprotein-associated plasmalogens to generate ?-chlorinated fatty aldehydes, including 2-chlorohexadecanal. Under physiological conditions, 2-chlorohexadecanal is oxidized to 2-chlorohexadecanoic acid (2-ClHA). This study demonstrates the catabolism of 2-ClHA by ?-oxidation and subsequent ?-oxidation from the ?-end. Mass spectrometric analyses revealed that 2-ClHA is ?-oxidized in the presence of liver microsomes with initial ?-hydroxylation of 2-ClHA. Subsequent oxidation steps were examined in a human hepatocellular cell line (HepG2). Three different ?-chlorinated dicarboxylic acids, 2-chlorohexadecane-(1,16)-dioic acid, 2-chlorotetradecane-(1,14)-dioic acid, and 2-chloroadipic acid (2-ClAdA), were identified. Levels of 2-chlorohexadecane-(1,16)-dioic acid, 2-chlorotetradecane-(1,14)-dioic acid, and 2-ClAdA produced by HepG2 cells were dependent on the concentration of 2-ClHA and the incubation time. Synthetic stable isotope-labeled 2-ClHA was used to demonstrate a precursor-product relationship between 2-ClHA and the ?-chlorinated dicarboxylic acids. We also report the identification of endogenous 2-ClAdA in human and rat urine and elevations in stable isotope-labeled urinary 2-ClAdA in rats subjected to intraperitoneal administration of stable isotope-labeled 2-ClHA. Furthermore, urinary 2-ClAdA and plasma 2-ClHA levels are increased in LPS-treated rats. Taken together, these data show that 2-ClHA is ?-oxidized to generate ?-chlorinated dicarboxylic acids, which include ?-chloroadipic acid that is excreted in the urine.

Brahmbhatt, Viral V.; Albert, Carolyn J.; Anbukumar, Dhanalakshmi S.; Cunningham, Bryce A.; Neumann, William L.; Ford, David A.

2010-01-01

393

Chicoric acid found in basil ( Ocimum basilicum L.) leaves  

Microsoft Academic Search

This is the first report to identify the presence of chicoric acid (cichoric acid; also known as dicaffeoyltartaric acid, which is a caffeic acid derivatized with tartaric acid) in basil leaves. Rosmarinic acid, chicoric acid and caftaric acid (in the order of most abundant to least; all derivatives of caffeic acid) were identified in fresh basil leaves. Rosmarinic acid was

Jungmin Lee; Carolyn F. Scagel

2009-01-01

394

Expression of sialic acids and other nonulosonic acids in Leptospira  

PubMed Central

Background Sialic acids are negatively charged nine carbon backbone sugars expressed on mammalian cell surfaces. Sialic acids are part of a larger family of nonulosonic acid (NulO) molecules that includes pseudaminic and legionaminic acids. Microbial expression of sialic acids and other nonulosonic acids has been shown to contribute to host-microbe interactions in a variety of contexts, including participation in colonization, immune subversion, and behaviors such as biofilm formation, autoagglutination and motility. Previous research has suggested that some spirochetes may also express these molecules. Results Here we use a combination of molecular tools to investigate the presence of NulO biosynthetic gene clusters among clinical and saprophytic isolates of the genus Leptospira. Polymerase chain reaction and Southern blotting suggested that a variety of leptospires encoded NulO biosynthetic pathways. High performance liquid chromatography and mass spectrometry analyses provided biochemical evidence that di-N-acetylated NulO molecules are expressed at relatively high levels by L. interrogans serovar Lai strain 55601, and at lower levels by L. alexanderi serovar Manhao and L. fainei serovar Hurstbridge. Endogenous expression of N-acetylneuraminic acid (Neu5Ac, the most common sialic acid) was documented in L. interrogans serovar Copenhageni strain L1-130. Neu5Ac biosynthesis is also supported by a unique gene fusion event resulting in an enzyme with an N-terminal N-acetylneuraminic acid synthase domain and a C-terminal phosphatase domain. This gene fusion suggests that L. interrogans uses a Neu5Ac biosynthetic pathway more similar to animals than to other bacteria. Analysis of the composition and phylogeny of putative NulO biosynthetic gene clusters in L. interrogans serovar Lai and serovar Copenhageni revealed that both strains have complete biosynthetic pathways for legionamimic acid synthesis, a molecule with the same stereochemistry as sialic acid. Lectin-based affinity purification of NulO-modified molecules, followed by mass spectrometric identification suggests post-translational modification of surface lipoproteins, including Loa22. Conclusions Leptospira species encode NulO biosynthetic pathways and synthesize multiple NulO molecules including sialic acid. Additional studies are needed to clarify the exact context and functional significance of NulO expression. These findings have implications for immune evasion during systemic leptospirosis.

2012-01-01

395

ACID RAIN DEGRADATION OF NYLON (POLYAMIDE, PHOTODEGRADATION)  

Microsoft Academic Search

Acid rain, precipitation with a ph less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid

KAREN E KYLLO

1984-01-01

396

Nucleic acid arrays and methods of synthesis  

Microsoft Academic Search

The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence

Chandran R. Sabanayagam; Takeshi Sano; John Misasi; Anson Hatch; Charles Cantor

2001-01-01

397

Quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhance the Fenton reaction in phosphate buffer.  

PubMed

Quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhanced the Fenton reaction in phosphate buffer, respectively. The enhancement by quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid of the Fenton reaction may be partly related to their respective actions in the biological systems such as a neurotoxic effect (quinolinic acid), a marked growth-inhibitory action on rice seeding (alpha-picolinic acid and fusaric acid), and an antiseptic (2,6-pyridinedicarboxylic acid). The ultraviolet-visible absorption spectrum of the mixture of alpha-picolinic acid with ferrous ion showed a characteristic visible absorbance band with a lambda(max) at 443 nm, suggesting that alpha-picolinic acid chelate of Fe2+ ion forms in the solution. Similar characteristic visible absorbance band was also observed for the mixture of Fe2+ ion with quinolinic acid (or fusaric acid, or 2,6-pyridinedicarboxylic acid). The chelation seems to be related to the enhancement by quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid of the Fenton reaction. alpha-Picolinic acid was reported to be a toxic substance isolated from the culture liquids of blast mould (Piricularia oryzae CAVARA). On the other hand, it has also been known that chlorogenic acid protects rice plants from the blast disease. The chlorogenic acid inhibited the formation of the hydroxyl radical in the reaction mixture of alpha-picolinic acid, FeSO4(NH4)2SO4, and H2O2. Thus the inhibition may be a possible mechanism of the protective action of the chlorogenic acid against the blast disease. PMID:10362227

Iwahashi, H; Kawamori, H; Fukushima, K

1999-04-15

398

Microbial oxidation of oleic acid.  

PubMed Central

Resting cells of Saccharomyces cerevisiae (baker's yeast, type II; Sigma) were used to convert oleic acid into 10-hydroxyoctadecanoic acid with a 45% yield. Nocardia aurantia (ATCC 12674), Nocardia sp. (NRRL 5646), and Mycobacterium fortuitum (UI 53378) all converted oleic acid into 10-oxo-octadecanoic acid with 65, 55, and 80% yields, respectively. Structures of all metabolites were suggested by 1H and 13C nuclear magnetic resonance and by infrared and mass spectrometry. Structures of isomeric hydroxystearate and oxostearate derivatives and the stereochemical purity of hydroxystearates are difficult to prove unambiguously unless authentic standard compounds are available for spectral comparison. We describe the use of the chemical Baeyer-Villiger oxidation technique with 10-oxo-octadecanoic acid followed by mass spectral analysis of neutral extracts as a simple method to confirm the position of oxo-functional groups in the structures of fatty acid ketones. We further introduce a simple method based on 1H nuclear magnetic resonance analysis of diastereomeric S-(+)-O-acetylmandelate esters of hydroxystearates as a means of ascertaining stereochemical purities of hydroxy fatty acids.

el-Sharkawy, S H; Yang, W; Dostal, L; Rosazza, J P

1992-01-01

399

Terahertz spectrum of gallic acid  

NASA Astrophysics Data System (ADS)

Gallic acid is natural polyphenol compound found in many green plants. More and more experiments have demonstrated that the gallic acid has comprehensive applications. In the field of medicine, the gallic acid plays an important role in antianaphylaxis, antineoplastic, antimycotic, anti-inflammatory, antivirotic, antiasthmatic and inhibiting the degradation of insulin. It also has a lot of applications in chemical industry, food industry and light industry. So it is important to study the terahertz time-domain spectroscopy of gallic acid. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technology based on the femtosecond laser. In this work, the spectral characteristics of gallic acid in the range of 0.4 THz to 2.6 THz have been measured by THz-TDS. We obtained its absorption and refraction spectra at room temperature. The vibration absorption spectrum of the single molecule between 0.4 THz and 2.6 THz is simulated based on the Density Functional Theory (DFT). It is found that the gallic acid has the spectral response to THz wave in this frequency range. The results show the abnormal dispersion at 1.51 THz and 2.05 THz. These results can be used in the qualitative analysis of gallic acid and the medicine and food inspection.

Wu, Meng; Zhao, Guozhong; Wang, Haiyan; Liang, Chengshen

2009-11-01

400

Diabetes and alpha lipoic Acid.  

PubMed

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 Nrf-2-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 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. PMID:22125537

Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

2011-11-17

401

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.  

PubMed

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ? Erie > Huron > Superior ? Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid. PMID:22722738

Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

2012-06-22

402

[Extraction and stripping of H acid and DSD acid wastewater].  

PubMed

H acid and DSD acid are two important substrate of dyes, which wastewater is treated more difficulty because of containing multi-component, with high chroma value and nonbiodegradability. A treatment way of this wastewater by extraction based on chemical association was carried out. Trialkylamine (Alamine 336) and chlorinated quaternary ammonium salt (Aliquat 336) were used as reacting agent with n-octanol, kerosene as modifier and diluent respectively. Results showed that the extraction efficiency depended on solution pH. Alamine 336 could be used to treat waste water with low pH while Aliquat 336 was high efficiency for waste water with pH > 6. Recovery yield of H acid and DSD acid was greater than 99% and the chroma value of wastewater was reduced effectively by simulating multi-stages cross-flow extraction. Back-extraction is quite easy and the solvent could be regenerated. PMID:11855182

Li, Z; Qin, W; Yang, Y; Dai, Y

2001-11-01

403

Amino acids attached to transfer ribonucleic acid in vivo.  

PubMed Central

1. tRNA was extracted from rabbit liver by both the phenol and diethyl pyrocarbonate methods under conditions preventing deacylation of the amino acids attached in vivo. 2. After deacylation 12 amino acids were determined by gas-liquid chromatography, by using the flame-ionization and nitrogen-sensitive thermionic detectors. 3. Comparison of the distribution of 12 amino acids attached to tRNA with those contained in total tissue protein and in the free pool showed little correlation. 4. Results for the enzymic charging assay for tRNA in vitro did not correlate satisfactorily with the analysis of amino acids attached to tRNA in vivo. Marked differences were ntoed in comparison made between our own and other published results.

Butler, M; Darbre, A; Arnstein, H R

1975-01-01

404

Metabolism of Cinnamic Acid in Plants: Chlorogenic Acid Formation.  

National Technical Information Service (NTIS)

Rapid, efficient synthesis of chlorogenic acid from cinnamate was observed in leaves of plants of several genera. Use of labelled cinnamate,p-coumarate and caffeate showed two pathways were operative in this synthesis in tobacco. Trapping experiments indi...

W. Steck

1968-01-01

405

17,21-Secohopanoic acids, 25-norhopanoic acids, and 28-norhopanoic acids in source rocks and crude oils  

Microsoft Academic Search

The presence of three families of hopanoic acids, 17,21-secohopanoic acids, 25-norhopanoic acids, and 28-norhopanoic acids, is discussed. Oils from West Siberia and tar balls from the Seychelles Islands were found to contain relatively high proportions of 17,21-secohopanoic acids. These acids have not been previously reported in any oils or source rocks. A heavily biodegraded West Siberian oil, was found to

Xueming Pan; R. Paul Philp

2006-01-01

406

Effects of the Teratogenic Folic Acid Antagonist, 9Methyl Pteroylglutamic Acid on Uronic Acid Levels in Fetal Rat Limbs  

Microsoft Academic Search

Experimental pregnant rats were placed on a transitory folic acid-deficient regimen, i.e. dietary restriction of folic acid plus the teratogen and folic acid antagonist, 9-methyl pteroylglutamic acid; a regimen resulting in multiple congenital skeletal malformations. Controls received a folic acid-supplemented regimen. Accumulation of a primary component of the extracellular matrix, glycosaminoglycans (GAG), was quantitatively evaluated by measuring uronic acid concentrations

B. V. Paynton; R. R. Schmidt; J. M. Cotler

1978-01-01

407

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Coco acid triamine condensate, polycarboxylic acid salts. 721.2086 Section 721.2086 Protection...Specific Chemical Substances § 721.2086 Coco acid triamine condensate, polycarboxylic acid...

2013-07-01

408

40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Fatty acid polyamine condensate, phosphoric acid ester salts. 721.6200 Section 721.6200...Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric acid ester...

2013-07-01

409

40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Fatty acid amine condensate, polycarboxylic acid salts. 721.3620 Section 721.3620 Protection...Specific Chemical Substances § 721.3620 Fatty acid amine condensate, polycarboxylic acid...

2013-07-01

410

40 CFR 721.10295 - IPDI modified isophthalic acid, neopentyl glycol and adipic acid (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false IPDI modified isophthalic acid, neopentyl glycol and adipic acid (generic). 721.10295 Section 721.10295...Substances § 721.10295 IPDI modified isophthalic acid, neopentyl glycol and adipic acid...

2013-07-01

411

40 CFR 721.10512 - Fatty acid maleic acid amides (generic).  

Code of Federal Regulations, 2013 CFR

... 32 2013-07-01 2013-07-01 false Fatty acid maleic acid amides (generic). 721.10512 Section 721.10512...for Specific Chemical Substances § 721.10512 Fatty acid maleic acid amides (generic). (a) Chemical...

2013-07-01

412

Amino Acid Composition and Terminal Amino Acids of Staphylococcal Enterotoxin B.  

National Technical Information Service (NTIS)

The amino acid composition of purified staphylococcal enterotoxin B was determined by means of an automatic amino acid analyzer. All of the naturally occurring amino acids were found with no indication of any unusual amino acids. Extraordinarily high valu...

L. Spero D. Stefanye P. I. Brecher H. M. Jacoby E. J. Schantz

1964-01-01

413

Nucleic acid polymerases use a general acid for nucleotidyl transfer  

Microsoft Academic Search

Nucleic acid polymerases catalyze the formation of DNA or RNA from nucleoside-triphosphate precursors. Amino acid residues in the active site of polymerases are thought to contribute only indirectly to catalysis by serving as ligands for the two divalent cations that are required for activity or substrate binding. Two proton-transfer reactions are necessary for polymerase-catalyzed nucleotidyl transfer: deprotonation of the 3?-hydroxyl

Christian Castro; Eric D Smidansky; Jamie J Arnold; Kenneth R Maksimchuk; Ibrahim Moustafa; Akira Uchida; Matthias Götte; William Konigsberg; Craig E Cameron

2009-01-01

414

ACID RAIN: An Assessment Based on AcidBase Considerations  

Microsoft Academic Search

The pH of atmospheric precipitation at any given location depends on the chemical nature and relative proportions of acids and bases in solution. The long-term average free acid concentration therefore depends on the temporal variability of such natural and\\/or anthropogenic compounds in precipitation. Based on these considerations and factual data, with special reference to the United States, one could arrive

Ronald Sequeira

1982-01-01

415

Sedimentary humic acid and fulvic acid as fluorescent organic materials  

Microsoft Academic Search

Fluorescence and absorption spectra of sedimentary humic acid (HA) and fulvic acid (FA), with molecular weights ranging from 300,000, were measured at 20°C and pH 8. The maximum excitation and emission wavelengths of HA were longer than those of FA, being independent of molecular weight. The excitation and emission maxima can be utilized to differentiate between sedimentary HA and FA.

Kohji Hayase; Hiroyuki Tsubota

1985-01-01

416

Growth of nitric acid hydrates on thin sulfuric acid films  

Microsoft Academic Search

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 [times] 10[sup [minus]4] Torr H[sub 2]O and 1-2.5 [times] 10[sup [minus]6] Torr HNO[sub 3]) and subjected to cooling and heating cycles. FTIR spectroscopy was used to

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

1994-01-01

417

Growth of nitric acid hydrates on thin sulfuric acid films  

Microsoft Academic Search

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

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

1994-01-01

418

PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS  

DOEpatents

A process is described for the preparation of trifluoroacetic acid. Acetone vapor diluted wlth nitrogen and fluorine also diluted with nltrogen are fed separately at a temperature of about 210 deg C into a reaction vessel containing a catalyst mass selected from-the group consisting of silver and gold. The temperature in the reaction vessel is maintained in the range of 200 deg to 250 deg C. The reaction product, trifluoroacetyl fluoride, is absorbed in aqueous alkali solution. Trifluoroacetic acid is recovered from the solution by acidification wlth an acid such as sulfuric followed by steam distillation.

Haworth, W.N.; Stacey, M.

1949-08-30

419

Properties of polyamic acid ionomers  

SciTech Connect

Polymers containing amic acid units were produced by reacting an oligomer based on polytetramethylene oxide (PTMO) with 1,2,4,5-benzenetetracarboxylic dianhydride (BRDA). Neutralization by a metal salt produced amic acid ionomers. Similar to other ionomer systems, neutralization from the acid to the ionomer led to the formation of a separate ionic phase as determined by dynamic mechanical analysis. Phase separation resulted in a substantial increase in mechanical properties. The effect of neutralization level, cation, soft-segment molecular weight, and soft-segment end group on mechanical and thermal properties was investigated.

Xuehai Yu (Nanjing Univ., Jiangsu (China)); Grady, B.P.; Reiner, R.S.; Cooper, S.L. (Univ. of Wisconsin, Madison (United States))

1993-03-05

420

Arsanilic acid toxicity in rabbits.  

PubMed

Rations from several rabbitries experiencing increased mortality, weight loss and diminished reproduction were analyzed for arsanilic acid. Levels of less than 56 ppm of arsanilic acid were found. A 30 day trial was conducted where arsanilic acid was given in doses of 1.6-16.2 mg/day in water to weanling and adult rabbits. The higher doses induced diarrhea, terminal convulsions and death. Weight loss or reduced weight gains occurred in six of seven treated groups. No significant gross or microscopic lesions were observed. Chemical analysis demonstrated the presence of increased total hepatic arsenic levels in treated compared to control rabbits. PMID:7052379

Confer, A W; Ward, B C; Hines, F A

1980-04-01

421

Be an acid rain detective  

SciTech Connect

Acid rain is discussed in a question and answer format. The article is aimed at educating sport fishermen on the subject, and also to encourage them to write their congressmen, senators, and the President about the acid rain problem. The article also announces the availability of an acid rain test kit available through the magazine, ''Sports Afield.'' The kit consists of pH-test paper that turns different shades of pink and blue according to the pH of the water tested. The color of the test paper is then compared to a color chart furnished in the kit and an approximate pH can be determined.

Atwill, L.

1982-07-01

422

Nonprotein Amino Acids from Spark Discharges and Their Comparison with the Murchison Meteorite Amino Acids  

PubMed Central

All the nonprotein amino acids found in the Murchison meteorite are products of the action of electric discharge on a mixture of methane, nitrogen, and water with traces of ammonia. These amino acids include ?-amino-n-butyric acid, ?-aminoisobutyric acid, norvaline, isovaline, pipecolic acid, ?-alanine, ?-amino-n-butyric acid, ?-aminoisobutyric acid, ?-aminobutyric acid, sarcosine, N-ethylglycine, and N-methylalanine. In addition, norleucine, alloisoleucine, N-propylglycine, N-isopropylglycine, N-methyl-?-alanine, N-ethyl-?-alanine ?,?-diaminopropionic acid, isoserine, ?,?-diaminobutyric acid, and ?-hydroxy-?-aminobutyric acid are produced by the electric discharge, but have not been found in the meteorite.

Wolman, Yecheskel; Haverland, William J.; Miller, Stanley L.

1972-01-01

423

Organic acids enhance halogen activation on mildly acidic water surfaces  

NASA Astrophysics Data System (ADS)

Iodine species of marine origin are ubiquitous in the marine boundary layer (MBL). They are found over the open ocean (even in the absence of biogenic sources), the Antarctic coast, in rain, aerosols, ice, and snow, and participate in HOx/NOx cycles in the MBL. Surface-active organic acids coating the surface marine microlayer (SML) and marine aerosols could affect their chemical/physical properties. Recent field measurements show that organic acids represent ˜50% of the mass of fog waters collected in the US Gulf Coast. Here we report that I2(g) emissions from the heterogeneous reactions of O3(g) with I- (aq) are dramatically enhanced in the presence of surface-active organic acids under mildly acidic condition that are typical of fine marine aerosols. The amphiphilic weak carboxylic acids appear to promote I2(g) emissions by donating the interfacial protons more efficiently than water itself. We infer that the organic acids coating aerosol particles ejected from ocean's surface films could enhance I2(g) production in the MBL.

Hayase, S.; Enami, S.; Yabushita, A.; Kawasaki, M.; Hoffmann, M. R.; Colussi, A. J.

2011-12-01

424

Oleic acid-based gemini surfactants with carboxylic acid headgroups.  

PubMed

Anionic gemini surfactants with carboxylic acid headgroups have been synthesized from oleic acid. The hydrocarbon chain is covalently bound to the terminal carbonyl group of oleic acid via an ester bond, and the carboxylic acid headgroups are introduced to the cis double bond of oleic acid via disuccinyl units. The surfactants exhibit pH-dependent protonation-deprotonation behavior in aqueous solutions. In alkaline solutions (pH 9 in the presence of 10 mmol dm(-3) NaCl as the background electrolyte), the surfactants can lower the surface tension as well as form molecular assemblies, even in the region of low surfactant concentrations. Under acidic (pH 3) or neutral (pH 6-7) conditions, the surfactants are intrinsically insoluble in aqueous media and form a monolayer at the air/water interface. In this study, we have investigated physicochemical properties such as the function of the hydrocarbon chain length by means of static surface tension, pyrene fluorescence, dynamic light scattering, surface pressure-area isotherms, and infrared external reflection measurements. PMID:21768742

Sakai, Kenichi; Umemoto, Naoki; Matsuda, Wataru; Takamatsu, Yuichiro; Matsumoto, Mutsuyoshi; Sakai, Hideki; Abe, Masahiko

2011-01-01

425

Aldohexuronic Acid Catabolism by a Soil Aeromonas.  

National Technical Information Service (NTIS)

This is the first report of a bacterial oxidoreductase which reduces an aldohexuronic acid to a hexonic acid. The enzyme should prove to be a useful analytical tool for determining mannuronate in the presence of other uronic acids. (Author)

J. J. Farmer R. G. Eagon

1968-01-01

426

21 CFR 556.590 - Salicylic acid.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Salicylic acid. 556.590 Section 556...New Animal Drugs § 556.590 Salicylic acid. A tolerance of zero is established for residues of salicylic acid in milk from dairy...

2009-04-01

427

21 CFR 582.5013 - Ascorbic acid.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5013 Ascorbic acid. (a) Product. Ascorbic acid. 1 Amino acids...

2013-04-01

428

Acid preservation systems for food products  

SciTech Connect

Fumaric acid is used in combination with critical amounts of acetic acid to preserve acid containing food products from microbiological spoilage in the absence of or at reduced levels of chemical preservative.

Tiberio, J. E.; Cirigiano, M. C.

1984-10-16

429

In situ gels improve formation acidizing  

SciTech Connect

Viscosity-controlled acid effectively improves acid placement, provides more uniform damage removal, improves surface etching, and controls acid fluid loss. Viscosity-controlled acid (VCA) contains gels that break back to original viscosity 1 day after being pumped. These acids have been used for: matrix-acidizing long horizontal and vertical well intervals; controlling fluid loss in fracture acidizing to obtain longer fractures and deeper live-acid penetration. Fluid pH controls gel formation and breaking. In one operator`s horizontal wells, viscosity-controlled acid increased production by 2.5--6 fold. In carbonate formation fracture-acidizing, these acids have shown production improvements of 170 to 375%. VCA acid can be used in both cased or open hole, in vertical or deviated/horizontal wells.

Yeager, V.; Shuchart, C. [Halliburton Energy Services, Duncan, OK (United States)

1997-01-20

430

Amino acid composition in Isoparorchis hypselobagri  

Microsoft Academic Search

Summary The free amino acids of Isoparorchis hypselobagri have been determined by the chromatographic method (two-dimensional ascending). These are: leucine, valine, proline, alanine, glycine, glutamic acid and aspartic acid.

Meenakshi Srivastava; S. P. Gupta

1976-01-01

431

Genetics Home Reference: Sialic acid storage disease  

MedlinePLUS

... literature OMIM Genetic disorder catalog Conditions > Sialic acid storage disease On this page: Description Genetic changes Inheritance ... definitions Reviewed February 2008 What is sialic acid storage disease? Sialic acid storage disease is an inherited ...

432

Production of ?-Linolenic Acid and Stearidonic Acid in Seeds of Marker-Free Transgenic Soybean  

Microsoft Academic Search

desaturase can convert linoleic acid and -linolenic acid to -linolenic acid (GLA) and stearidonic acid (STA), respectively. Both GLA and storage lipids constitute 16 and 5%, respectively. STA are of interest to the pharmaceutical and nutraceutical industries. In plants, GLA is produced by the desaturation of Production of these fatty acids is costly. One potential strategy to linoleic acid via

Shirley Sato; Aiqiu Xing; Xingguo Ye; Bruce Schweiger; Anthony Kinney; George Graef; Tom Clemente

2004-01-01

433

Acidic Deposition: Sources and Ecological Effects  

Microsoft Academic Search

Acidic atmospheric deposition, popularly referred to as acid rain, is the transfer of strong acids and acid forming substances\\u000a from the atmosphere to the Earth’s surface. Acidic deposition is comprised of sulfuric and nitric acids, and ammonium derived\\u000a from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia respectively. These compounds are emitted by the\\u000a burning of fossil fuels and

Charles T. Driscoll; Kathy Fallon Lambert; Limin Chen

434

Metabolism of ?-linolenic acid in humans  

Microsoft Academic Search

?-Linolenic acid (18:3n-3) is essential in the human diet, probably because it is the substrate for the synthesis of longer-chain, more unsaturated n-3 fatty acids eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) which are required for tissue function. This article reviews the recent literature on 18:3n-3 metabolism in humans, including fatty acid ?-oxidation, recycling of carbon by fatty acid synthesis

G. C. Burdge

2006-01-01

435

A convenient synthesis of dinorbile acids  

Microsoft Academic Search

We report a convenient method for the synthesis of dinorbile acids (23,24-dinor-5?-cholan-22-oic acids, pregnane-20-carboxylic acids) in fair to good yields from norbile acid nitriles in one step by oxidative hydrolysis with oxygen in the presence of potassium-t-butoxide. The method results in stepwise overall removal of two carbon atoms in bile acid side chains in two steps. Dinorbile acids corresponding to

Ashok K. Batta; Subhash C. Datta; G. Stephen Tint; David S. Alberts; David L. Earnest; Gerald Salen

1999-01-01

436

Nucleic acid arrays and methods of synthesis  

DOEpatents

The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

Sabanayagam, Chandran R. (Allston, MA); Sano, Takeshi (Needham, MA); Misasi, John (Syracuse, NY); Hatch, Anson (Seattle, WA); Cantor, Charles (Del Mar, CA)

2001-01-01

437

The Assimilation of Glutamic Acid by Yeast  

Microsoft Academic Search

SUMMARY : Using the corresponding amino-acid decarboxylases, the six amino-acids arginine, glutamic acid, histidine, lysine, ornithine and tyrosine were found to be free inside the cells of yeast. They are present when growth takes place in the absence of amino-acids, but their concentration may be increased by growing the organisms in media rich in amino-acids. Uptake of glutamic acid from

E. SHIRLEY TAYLOR

1949-01-01

438

Phosphonic acid based exchange resins  

DOEpatents

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1995-01-01

439

Making cents of acid recovery  

SciTech Connect

Acid recovery may be expensive, but rising transportation and landfill costs may soon make it the only alternative. Traditionally, acids used in processes from titanium dioxide production to gasoline alkylation and metal pickling were neutralized and discharged into waterways or injected into deep wells. Today, however, discharge permits are being phased out in many countries, and deep well injection is coming under closer scrutiny. An even cheaper option was selling spent acid to fertilizer producers, who used it to dissolve phosphate ores. Health concerns, a depressed fertilizer market and tightening disposal regulations for gypsum byproduct have dried up this option. The paper discusses the processes and costs involved in spent acid regeneration, gypsum-free gas treatments, and problems with explosive contaminants.

Ondrey, G.; Shanley, A.

1993-04-01

440

Disorders of Amino Acid Metabolism  

MedlinePLUS

... dialysis (see Dialysis ). Some children with mild disease benefit from injections of vitamin B 1 (thiamin). After the disease has been brought under control, children must always consume a special artificial diet that is low in three amino acids ( ...

441

Mannuronic Acids: Reactivity and Selectivity  

Microsoft Academic Search

This review describes our recent studies toward the reactivity and selectivity of mannopyranosyl uronic acid donors, which have been found to be very powerful donors for the construction of ?-mannosidic linkages.

Jeroen D. C. Codée; Marthe T. C. Walvoort; Ana-Rae de Jong; Gerrit Lodder; Herman S. Overkleeft; Gijsbert A. van der Marel

2011-01-01

442

Molecular Structure of Abscisic acid  

NSDL National Science Digital Library

Abscisic acid (ABA) was first identified and characterized by Frederick Addicott in 1963. ABA is a naturally occurring compound in plants synthesized partially in the chloroplasts. It is a phytohormone that plays an important role in regulating transpiration, stress responses, germination of seeds and embryogenesis in plants. Abscisic acid influences most aspects of plant growth and development to some level, in part due to interactions with other phytohormones. Abscisic acid also promotes abscission of leaves and fruits, and for this reason the name abscisic is given. This plant hormone is the key factor in the adaptation of the plant to environmental stresses such as salinity, drought or water loss, and freezing temperatures. Abscisic acid promotes dormancy and helps the plant tolerate stressful conditions by suspending primary and secondary growth.

2004-11-09

443

Simulated acid rain on crops  

SciTech Connect

In 1981, simulated H/sub 2/SO/sub 4/ acid rain was applied to alfalfa and tall fescue and a 2:1 ratio of H/sub 2/SO/sub 4/:HNO/sub 3/ acid rain was applied to alfalfa, tall fescue, barley, wheat, potato, tomato, radish, and corn crops growing in the open field at Corvallis, Oregon. Careful attention was given to effects of the acid rain on the appearance of the foliage, and the effects on yield were measured. Because the effect of pH 4.0 rain on corn yield was the only significant effect noted in the 1981 studies, in 1982, more-extensive studies of the effect of simulated H/sub 2/SO/sub 4//HNO/sub 3/ rain on corn were conducted. No significant effects of acid rain were found on foliage appearance, or on yield of grain or stover in the 1982 studies.

Plocher, M.D.; Perrigan, S.C.; Hevel, R.J.; Cooper, R.M.; Moss, D.N.

1985-10-01

444

Phosphanilic Acid Inhibits Dihydropteroate Synthase.  

National Technical Information Service (NTIS)

Intact cells of Pseudomonas aeruginosa were more susceptible to phosphanilic acid (PA) than cells of Escherichia coli. In cell extract, the dihydropteroate synthases of P. aeruginosa and E. coli were about equally susceptible to inhibition by PA. These re...

R. G. Eagon A. T. McManus

1989-01-01

445

EXPOSURE MODELING OF ACID AEROSOLS  

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) is conducting an intensive characterization and human exposure monitoring program of acid species and related air pollutants in an urban environment. he EPA's Atmospheric Research and Exposure Assessment Laboratory (AREAL) in coopera...

446

Biotechnological production of citric acid  

PubMed Central

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.

Max, Belen; Salgado, Jose Manuel; Rodriguez, Noelia; Cortes, Sandra; Converti, Attilio; Dominguez, Jose Manuel

2010-01-01

447

Polylactic Acid for Surgical Implants.  

National Technical Information Service (NTIS)

High molecular weight polymer from lactic acid can be made from the cyclic lactide intermediate, suitable for casting films or spinning fibers. The films are quire permeable to water vapor and can soften in presence of water. Histological studies indicate...

R. K. Kulkarni K. C. Pani C. Neuman F. Leonard

1966-01-01

448

Bullhead acidizing succeeds offshore California  

SciTech Connect

High acid-injection rates, within the friction dominant region, proved successful in stimulating oil wells completed in a naturally fractured reservoir. The bullhead technique was effective without any chemical or mechanical diversion. Chevron U.S.A. Production Co.'s Santa Clara field produces through wells on Platform Grace, in 318 ft of water. After repeated unsuccessful attempts to stimulate these wells, three basic types of formation damage were discovered: Drilling mud invasion; Solids precipitation; and Emulsion blocks. Accurate identification of the damage, in 1989, led to the first successful stimulation response 9 years after the first completion. One of the keys to successfully acidizing the Monterey is to treat the damaged zones with the stimulation fluids. The paper describes the three formation damages mechanisms, and treatment design including surfactants, acid volumes, retarding and sequestering, and wettability restoration. Acid placement, fluid dynamics, and results are also discussed.

Juprasert, M.S. (Chevron U.S.A. Production Co., Bakersfield, CA (United States))

1994-04-11

449

Esters of Aromatic Sulfonic Acids.  

National Technical Information Service (NTIS)

Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m- amidinophenylmethane-sulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenyl-methan...

Wong Shaw

1976-01-01

450

Acid Rain Students Site: Glossary  

EPA Pesticide Factsheets

Aluminum:  A soft, lightweight metal that occurs naturally in the environment. Many things are made out of aluminum, including soda cans, automobile parts, and electrical equipment.   From Acid Rain Students Site: Glossary  -  Search all glossaries for terms containing Aluminum

2012-05-09

451

Biopolymers: Proteins and Nucleic Acids.  

National Technical Information Service (NTIS)

Our work focuses on molecular recognition by biopolymers as a model for interactions between macromolecules in general. Specifically we are learning the rules that govern protein-nucleic acid (both DNA and RNA) binding. Chemical synthesis, molecular genet...

J. H. Richards J. N. Abelson P. B. Dervan L. E. Hood M. I. Simon

1990-01-01

452

Amino Acids and the Mitochondria  

Microsoft Academic Search

\\u000a This chapter describes some of the important physiological functions of amino acids in the mitochondria and the alterations\\u000a caused by specific pathologies. To some extent all of the featured items are dependent upon the movement of amino acids across\\u000a the highly selective permeability barrier that is the inner mitochondrial membrane. The performance of this transport by specific\\u000a carriers is the

Nicola King

453

Enzymatic labeling of nucleic acids  

Microsoft Academic Search

Enzymatic labeling of nucleic acids is a fundamental tool in molecular biology with virtually every aspect of nucleic acid\\u000a hybridization technique involving the use of labeled probes. Different methods for enzymatic labeling of DNA, RNA and oligonucleotide\\u000a probes are available today. In this review, we will describe both radioactive and nonradioactive labeling methods, yet the\\u000a choice of system for labeling

Jamal Temsamani; Sudhir Agrawal

1996-01-01

454

Microbial metabolism of methanesulfonic acid  

Microsoft Academic Search

Methanesulfonic acid is a very stable strong acid and a key intermediate in the biogeochemical cycling of sulfur. It is formed\\u000a in megatonne quantities in the atmosphere from the chemical oxidation of atmospheric dimethyl sulfide (most of which is of\\u000a biogenic origin) and deposited on the Earth in rain and snow, and by dry deposition. Methanesulfonate is used by diverse

D. P. Kelly; J. C. Murrell

1999-01-01

455

Factors controlling naphthenic acid corrosion  

SciTech Connect

A laboratory study was conducted to elucidate the influence of chemical and physical parameters on corrosion of type 1018 carbon steel (CS, UNS G10180) and 5% Cr-0.5% Mo steel in oils containing naphthenic acids (NAs) for application to crude oil refinery systems. Effects of test duration, temperature, and acid concentration were assessed for a range of single acids of varying carbon numbers and for NA mixtures in mineral oil (MO) and in heavy vacuum gas oil (HGVO). In addition, a limited study of the effect of hydrogen sulfide (H{sub 2}S) addition to the acid-oil mixture was conducted. Use of the total acid number (TAN) as a measure of corrosiveness of a crude oil was discredited further. For the same TAN value, molecular size and structure of the acid were shown to have an important influence. Tests conducted in HGVO showed lower corrosion rates than in MO, suggesting inhibition caused by S species in the oil or the steric hindrance of naphtheno-aromatic acids. In oil containing the mixture of NAs, the corrosion rate of type 1018 CS was lower than that for 5% Cr-0.5% Mo steel. The 0.1% H{sub 2}S that passed through the acid-oil mixtures had an inhibiting effect on corrosion. Predicting corrosiveness of a crude oil from the measurement of TAN, distribution of NA composition, and S content and form was particularly challenging. The simple tests used were informative, but further work will be required to establish a standard test method that can provide an adequate ranking of crudes.

Turnbull, A. [National Physical Lab., Teddington (United Kingdom); Slavcheva, E. [Bulgarian Academy of Sciences, Sofia (Bulgaria); Shone, B. [Ty Isa, Nr Mold (United Kingdom)

1998-11-01

456

Hydrothermal synthesis of amino acids  

SciTech Connect

This study presents further evidence that amino acids can be synthesized rapidly in hydrothermal solutions from reactants that may have been present in primitive environments. Aqueous NH[sub 4]HCO[sub 3] solutions were reacted with C[sub 2]H[sub 2], H[sub 2], and O[sub 2] (formed in situ from CaC[sub 2], Ca, and H[sub 2]O[sub 2]) at 200-275[degrees]C over 0.2-2 h periods to synthesize several amino acids and abundant amines. These amino acid and amine producing reactions were not observed to occur below 150[degrees]C. Amino acids and amines also were synthesized at 210[degrees]C from solutions of NH[sub 4]OH, HCHO, NaCN, and H[sub 2]. When NH[sub 4]OH was replaced by NH[sub 4]HCO[sub 3], the syntheses predominantly confirmed the recent results of Hennet et al. (1992). Additionally, amino acids and amines were observed to form by reactions among NH[sub 4]OH, HCHO, and H[sub 2] at hydrothermal conditions, essentially confirming the results of Fox and Windsor (1970). Inclusion of both carbonate and O[sub 2] in these latter solutions greatly enhanced the production rate of amino acids. The amines synthesized hydrothermally could be significant if they are precursors in the amino acid syntheses either at hydrothermal or later at lower temperatures. These observations provide additional input to the current questions of synthesis, stability, and decomposition of amino acids at hydrothermal conditions, and their possible relevance to the origin of life.

Marshall, W.L. (Oak Ridge National Lab., TN (United States))

1994-05-01

457

Molecular Structure of Glucuronic acid  

NSDL National Science Digital Library

Glucuronic acid is a substance derived from uronic acid, and is found in both plants and animals, usually in combination with phenols or alcohols. It is primarily used in detoxifying drugs and toxins to ensure easy elimination from the body. This substance is soluble in water and alcohol and has a melting point of 165 degrees Celsius. It exhibits mutarotation in the crystal form or its specific rotation of light changes depending on the way the crystals were prepared.

2003-05-08

458

Assessing acid–base disorders  

Microsoft Academic Search

Effective management of acid–base disorders depends on accurate diagnosis. Three distinct approaches are currently used in assessing acid–base disorders: the physiological approach, the base-excess approach, and the physicochemical approach. There are considerable differences among the three approaches. In this review, we first describe the conceptual framework of each approach, and comment on its attributes and drawbacks. We then highlight the

Horacio J Adrogué; F John Gennari; John H Galla; Nicolaos E Madias

2009-01-01

459

Understanding acid–base balance  

Microsoft Academic Search

Traditionally, the Hendersen–Hasselbalch model has been used to analyse clinical acid–base problems. Simplistically, this approach defines pH as a function of carbon dioxide and bicarbonate concentrations in aqueous solutions. The definition of the metabolic component of an acid–base relationship with this approach is, however, limited as bicarbonate varies with the concentration of dissolved carbon dioxide. These limitations are partly overcome

Andrew Durward; Ian Murdoch

2003-01-01

460

Acidity and reactivity of trifluoromethanesulfonic acid in liquid and solid acid catalysts  

Microsoft Academic Search

The acidic properties of CF3SO3H\\/SiO2 acid catalysts have been investigated by the protonation of weak bases (B) (B+H+?BH+) and the proton-transfer process from (H+A?) to (BH+A?) has been analysed by a thermodynamic procedure used to account the variation of the activity coefficient terms of the species involved. Acid–base systems with different substituted pyridines as back-titrating agents of BH+ (i.e. BH+?B)

Nunziata Clara Marziano; Lucio Ronchin; Claudio Tortato; Armando Zingales; Abdiqafar A Sheikh-Osman

2001-01-01

461

Acidic precipitation and lake acidification  

SciTech Connect

This research paper investigated 1) the history of the acidic precipitation problem in the United States, 2) the chemistry, characteristics and causes of acidic precipitation, and 3) the effects of lake acidification with emphasis on the factors which render a lake susceptible to acidification by acidic precipitation. It appears precipitation in the eastern United States has been acidic since the mid-1950's and the extent and severity have been increasing subsequently. Acidic precipitation is precipitation with pH less than 5.65. Acidic precipitation is mainly due to SO/sub 2/ and No/sub x/ emissions from the combustion of fossil fuels. Lake acidification results in shifts in species, populations and communities. All trophic levels are affected. Energy flow and nutrient cycling are reduced and as a result, the number of organisms that can exist in the system is reduced. Lake sensitivity to acidification is, in order of importance, a function of geology, pedology, meterology and watershed characteristics. The highly resistant igneous rocks are the most sensitive to acidification. Sensitive soils are those which have little or no cation exchange capacity and no free carbonates. The only practical long-term solution to lake acidification is to curb the SO/sub 2/ and NO/sub x/ emissions.

Brown, W.E. Jr.

1981-01-01

462

Photodissociation dynamics of hydroxybenzoic acids  

NASA Astrophysics Data System (ADS)

Aromatic amino acids have large UV absorption cross-sections and low fluorescence quantum yields. Ultrafast internal conversion, which transforms electronic excitation energy to vibrational energy, was assumed to account for the photostability of amino acids. Recent theoretical and experimental investigations suggested that low fluorescence quantum yields of phenol (chromophore of tyrosine) are due to the dissociation from a repulsive excited state. Radicals generated from dissociation may undergo undesired reactions. It contradicts the observed photostability of amino acids. In this work, we explored the photodissociation dynamics of the tyrosine chromophores, 2-, 3- and 4-hydroxybenzoic acid in a molecular beam at 193 nm using multimass ion imaging techniques. We demonstrated that dissociation from the excited state is effectively quenched for the conformers of hydroxybenzoic acids with intramolecular hydrogen bonding. Ab initio calculations show that the excited state and the ground state potential energy surfaces change significantly for the conformers with intramolecular hydrogen bonding. It shows the importance of intramolecular hydrogen bond in the excited state dynamics and provides an alternative molecular mechanism for the photostability of aromatic amino acids upon irradiation of ultraviolet photons.

Yang, Yi Lin; Dyakov, Yuri; Lee, Y. T.; Ni, Chi-Kung; Sun, Yi-Lun; Hu, Wei-Ping

2011-01-01

463

Molecular Structure of Oxalic acid  

NSDL National Science Digital Library

Oxalic acid is an odorless, colorless powder or granular solid. It is used as a scouring agent in textiles for finishing, stripping, cleaning, and as a bleaching agent for stain removal. Oxalic acid is also used as a rust remover as well as a grease and wax removing agent in metal cleaning. It is also used to clean and sterilize equipment, slso as a purifying agent in the pharmaceutical industry, in the waste water treatment industry and is also used to remove calcium from water. Oxalic acid is found in many plants and in many vegetables, for example sorrel, spinach and rhubarb, usually as its calcium or potassium salts. Oxalic acid is produced commercially by nitric acid oxidation of starch. It also can be made by fusing sawdust (or other forms of cellulose) with a mixture of sodium hydroxide and potassium hydroxide. Oxalic acid may be released to the environment in tobacco smoke, automobile exhaust, rendering, in waste streams from pulp bleaching, and by photochemical oxidations of anthropogenic compounds during long range transport.

2004-11-10

464

The essentiality of arachidonic acid and docosahexaenoic acid  

PubMed Central

Objective The purpose of this review is to correlate the clinical finding that patients receiving parenteral nutrition with a fish oil-based lipid emulsion do not develop essential fatty acid deficiency (EFAD) with an experimental murine model, thus showing that arachidonic acid (AA) and docosahexaenoic acid (DHA) are likely to be the essential fatty acids. Background Conventional belief is that linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3) are the essential fatty acids (EFAs). We have shown that a fish oil-based lipid emulsion containing AA (omega-6) and docosahexaenoic acid (DHA, omega-3) and insignificant quantities of LA and ALA is efficacious in the treatment of parenteral nutrition-associated liver disease (PNALD), a major cause of liver-related morbidity and mortality. The prospect of using a fish oil-based lipid emulsion as monotherapy has raised concerns of EFAD development, hindering its adoption into clinical practice. Design Data from patients in our institution who received PN with a fish oil-based lipid emulsion was reviewed for clinical and biochemical evidence of EFAD, defined as an elevated triene-tetraene ratio (Mead acid/AA >0.2). We also investigated the minimum amount of fish oil required to prevent EFAD in a murine model and determined whether DHA and AA alone can prevent EFAD. Results No patients receiving PN with a fish oil-based lipid emulsion in our institution have developed biochemical or clinical evidence of EFAD such as an elevated triene-tetraene ratio, growth retardation or dermatitis. This observation parallels our previously published animal studies, which demonstrated prevention of EFAD when thirteen percent of total calories were from fish oil. Moreover, current work in our laboratory shows that AA and DHA provision alone is sufficient to prevent biochemical and physiologic evidence of EFAD in a murine model. Conclusions When dosed appropriately, fish oil-based lipid emulsions contain sufficient EFAs to prevent EFAD. Furthermore, AA and DHA alone may be the true EFAs.

Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Gura, Kathleen M.; Puder, Mark

2012-01-01

465

Conjugated Linoleic Acid Accumulation via 10Hydroxy12-Octadecaenoic Acid during Microaerobic Transformation of Linoleic Acid by Lactobacillus acidophilus  

Microsoft Academic Search

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

JUN OGAWA; KENJI MATSUMURA; SHIGENOBU KISHINO; YORIKO OMURA; SAKAYU SHIMIZU

2001-01-01

466

Thermochemical comparisons of homogeneous and heterogeneous acids and bases. 1. Sulfonic acid solutions and resins as prototype Broensted acids  

Microsoft Academic Search

Heats of ionization by thermometric titration for a series of bases (or acids) can be used to compare solid acids (or bases) with liquid analogues bearing the same functionalities in homogeneous solutions. The method is demonstrated for Broensted acids by reacting a series of substituted nitrogen bases with solutions of p-toluenesulfonic acid (PTSA) in acetonitrile and with suspensions of the

Edward M. Arnett; Rebecca A. Haaksma; B. Chawla; Marguerite H. Healy

1986-01-01

467

Effect of valproic acid on glycine conjugation of benzoic acid.  

PubMed

Conjugation with glycine proceeds through ATP-dependent coupling of carboxylic acids with coenzyme A (CoA). Therefore, chemicals that form CoA esters may interfere with glycine conjugation. We tested the hypothesis that valproic acid (VPA), which is esterified with CoA in the first step of its mitochondrial beta-oxidation, may compromise glycine conjugation of aromatic carboxylic acids, by investigating the effect of acute VPA administration on glycine conjugation of benzoic acid in rats. VPA administered 1 hr before injection of benzoate only decreased the blood clearance of benzoate and the urinary excretion of benzoylglycine slightly in normal rats. However, in rats loaded with glycine, 2 and 3 mmol/kg of VPA reduced the blood clearance of benzoate by 34 and 59%, diminished the peak blood level of the glycine conjugate and depressed the maximal urinary excretion rate of benzoylglycine by 28 and 66%, respectively. To elucidate the mechanism of VPA-induced inhibition of benzoylglycine formation, the effects of VPA on hepatic levels of cosubstrates and the activities of enzymes involved in glycine conjugation were also determined. One hour after administration of VPA, hepatic ATP levels remained unchanged, whereas the concentration of CoA was reduced by 67 to 73% and that of glycine was increased by 58 to 67%. Activities of the enzymes of glycine conjugation were not influenced by VPA. However, 2-n-propyl-4-pentenoic acid, a metabolite of VPA, inhibited benzoyl-CoA synthetase. In summary, VPA minimally influenced the capacity of glycine conjugation of benzoic acid in normal rats, but decreased it markedly in glycine-loaded rats.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8263766

Gregus, Z; Fekete, T; Varga, F; Klaassen, C D

1993-12-01

468

Acidic properties of aqueous phosphoric acid solutions: a microscopic view  

NASA Astrophysics Data System (ADS)

We report on new neutron and x-ray diffraction data on D2O:D3PO4 solutions at two concentrations, 1:1 and 3:1. The experimental datasets were modelled simultaneously by the reverse Monte Carlo (RMC) method. From the resulting models, partial radial distribution functions (prdf) and coordination numbers were obtained. The acidity was found to decrease with increasing D3PO4 concentration. The ratio of dissociated acidic protons was estimated by dedicated simulation runs using average coordination number constraints. It was found that in the saturated solution the ratio of dissociated protons cannot exceed 20%.

Harsányi, I.; Pusztai, L.; Jóvári, P.; Beuneu, B.

2013-11-01

469

Gallic Acid, Ellagic Acid and Pyrogallol Reaction with Metallic Iron  

NASA Astrophysics Data System (ADS)

The reaction between gallic acid, ellagic acid and pyrogallol with metallic iron was studied using infrared and Mössbauer spectroscopy. Most hydrolysable tannins with interesting anticorrosive or inhibition properties are structurally related to these compounds, thus they may be used as models for the study of hydrolysable tannins and related polyphenols. The interaction was followed up to 3 months. Results indicated two different behaviors. At polyphenol concentrations higher than 1% iron converts to sparingly soluble and amorphous ferric (and ferrous) polyphenolate complexes. At lower concentrations (0.1%), the hydrolysis reactions are dominant, resulting in the formation of oxyhydroxides, which can be further reduced to compounds like magnetite by the polyphenols.

Jaén, J. A.; González, L.; Vargas, A.; Olave, G.

2003-06-01

470

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

Microsoft Academic Search

The molar enthalpy of solution of solid nicotinic acid (NA) at T=298.15K, to give an aqueous solution of molality m=3.748·10?3mol·kg?1, was determined as ?solHm=(19,927±48)J·mol?1, by solution calorimetry. Enthalpies of dilution, ?dilHm, of 0.1005mol·kg?1 aqueous nicotinic acid to yield final solutions with molality in the approximate range (0.03 to 0.09)mol·kg?1 were also measured by flow calorimetry. Combining the two sets of

Elsa M. Gonçalves; Talita S. Rego; Manuel E. Minas da Piedade

2011-01-01

471

Acidic properties of aqueous phosphoric acid solutions: a microscopic view.  

PubMed

We report on new neutron and x-ray diffraction data on D2O:D3PO4 solutions at two concentrations, 1:1 and 3:1. The experimental datasets were modelled simultaneously by the reverse Monte Carlo (RMC) method. From the resulting models, partial radial distribution functions (prdf) and coordination numbers were obtained. The acidity was found to decrease with increasing D3PO4 concentration. The ratio of dissociated acidic protons was estimated by dedicated simulation runs using average coordination number constraints. It was found that in the saturated solution the ratio of dissociated protons cannot exceed 20%. PMID:24140599

Harsányi, I; Pusztai, L; Jóvári, P; Beuneu, B

2013-10-18

472

New findings on acid rain  

NASA Astrophysics Data System (ADS)

Increases in acidity by 1 pH unit in the Adirondack lakes of New York—changes that normally occur over hundreds or thousands of years—occurred during 2 to 4 decades in some New York lakes in the middle of this century, according to a study released March 14, 1986, by a committee of the National Research Council (NRC). On the basis of their analyses, the Committee on Monitoring and Assessment of Trends in Acid Deposition concluded that there is a cause and effect relationship between sulfur emissions produced by the burning of fossil fuels and acid rain.At the same time, the committee found that “lake acidification is not a uniform problem,” according to committee chairman James H. Gibson. Individual lakes vary widely in their responses to acid deposition, and some of the northeastern U.S. lakes that the committee studied have even become more alkaline in recent decades, said Gibson, who is coordinator of the National Resources Ecology Laboratory at Colorado State University in Fort Collins. “Differences in the geologies of watersheds and in the histories of land use practices within watersheds can cause surface waters in a region to respond differently even when they are receiving equivalent amounts of acidity from atmospheric inputs,” the report said.

Katzoff, Judith A.

473

Scientist, researchers, and acid rain  

SciTech Connect

The role of the hidden participants in agenda-setting for environmental issues is discussed. These personnel involve academics, researchers, career bureaucrats, congressional staffers, consultants, and administration appointees below the top level. Scientists have been publicly involved in the acid rain issue from the beginning, using the media to dramatize the possible catastrophic consequences of acid rain. Presently, the scientific community is not in consensus about the solutions to the problem. Since the initial enactment of the National Acid Precipitation Act in 1980, not a single acid rain law has been passed, although many bills have been proposed. Spokesman for the coal and utility industries and Reagan administration personnel have used the scientific disagreements to delay abatement actions and refute claims that acid rain is a severe problem. Another result of the confusion is a distrust and even disdain for academic work. One possible solution to the stalemate is an accurate form for resolving scientific disputes that have a strong political component and that the forum should have a mechanism for converging on accurate science. 19 refs.

Alm, L.R. (Colorado State Univ., Fort Collins (USA))

1989-01-01

474

Amino acids and cell regulation.  

PubMed Central

Free amino play an important role in regulating cell volume in fishes. Four tissues/cells (skeletal muscle, RBC, brain, and myocardium) of the little skate, Raja erinacea, were selected for detailed study because of their special importance or unique advantage as experimental models. Three particular amino acids, beta-alanine, taurine, and sarcosine play a predominant role in all four tissues. As in higher vertebrates, amino acid uptake in skate brain, heart, and RBC is mediated via a Na+-dependent process. Amino acids leave the skate brain rapidly in response to a sudden decrease in plasma osmolality and/or to a simultaneous drop in extracellular Na+ concentration. However, although amino acids are important for volume regulation in normal brain cells, they do not appear to be likely candidates for the unidentified "idiogenic" osmolytes in mammalian brain cells. The high concentration of taurine in skate myocardium is of special interest because of the special role of this amino acid in myocardial contractility. Thus, unlike beta-alanine and sarcosine, taurine may play a dual role in regulating both cell volume and contractility of myocardial cells. The isolated skate atrium is well suited for in vitro studies of these two processes.

Forster, R. P.; Goldstein, L.

1979-01-01

475

Fatty acid biosynthesis in actinomycetes  

PubMed Central

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 for elucidating the type II FAS pathways in other bacteria (White et al., 2005). However, fatty acid biosynthesis is more diverse in the phylum Actinobacteria: Mycobacterium, possess both FAS systems while Streptomyces species have only the multi-enzyme FAS II system and Corynebacterium species exclusively FAS I. In this review we present an overview of the genome organization, biochemical properties and physiological relevance of the two FAS systems in the three genera of actinomycetes mentioned above. We also address in detail the biochemical and structural properties of the acyl-CoA carboxylases (ACCases) that catalyzes the first committed step of fatty acid synthesis in actinomycetes, and discuss the molecular bases of their substrate specificity and the structure-based identification of new ACCase inhibitors with anti-mycobacterial properties.

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

2011-01-01

476

A review of the role of acid-base balance in amino acid nutrition  

Microsoft Academic Search

ABSTRACT Acid-base balance and amino acid metabolism are intimately related. Changes in acid-base balance influence the metabolic fate of many amino acids. Also, acid-base homeostasis is achieved in part by alteration of amino acid metabolism, not only in the kidney, but also in liver, muscle and splanchnic tissue. Glutamine is the primary amino acid involved in renal ammonia- genesis, a

J. F. Patience; J. E Patience

2010-01-01

477

Organic acid induced olefination reaction of lactones.  

PubMed

(Z)-Selective olefination of several lactones with ketene silyl acetals was achieved by the catalysis of carbon acids (C-H acids) having a bis(triflyl)methyl group as an acidic functionality; in particular, the triple carbon acid having three bis(triflyl)methyl groups in phloroglucinol shows an excellent catalytic performance. PMID:22850596

Yanai, Hikaru; Taguchi, Takeo

2012-07-31

478

Asymmetric syntheses of pipecolic acid and derivatives  

Microsoft Academic Search

Summary Results in the field of asymmetric synthesis of pipecolic acid derivatives are reviewed. Three sections describe the asymmetric syntheses of the title compounds (i) from the chiral pool (a-amino acids or carbohydrates) (ii) using a chiral auxiliary either derived from terpenes,a-amino acids, tartaric acid, an amine orß-amino alcohols (iii) by means of asymmetric catalysis.

François Couty

1999-01-01

479

Cheese flavour formation by amino acid catabolism  

Microsoft Academic Search

Amino acid catabolism is a major process for flavour formation in cheese. The ability of lactic acid bacteria (LAB) and other cheese micro-organisms to degrade amino acids to aroma compounds is highly strain dependent. Generally, amino acid catabolism proceeds by 2 different pathways. The first one, mainly observed for methionine, is initiated by elimination reaction and leads to major sulphur

Mireille Yvon; Liesbeth Rijnen

2001-01-01

480

Digestible amino acids for poultry and swine  

Microsoft Academic Search

A review and comparison of feedstuff amino acid digestibility values for poultry and swine is presented and the use of amino acid digestibility and availability is discussed. The effect of overprocessing on amino acid digestibility of oilseed meals is also reviewed. In general, true digestible amino acid values determined in cecectomized roosters are 5–10% higher than apparent digestibility values determined

Carl M. Parsons

1996-01-01

481

Amyloid-Associated Nucleic Acid Hybridisation  

Microsoft Academic Search

Nucleic acids promote amyloid formation in diseases including Alzheimer's and Creutzfeldt-Jakob disease. However, it remains unclear whether the close interactions between amyloid and nucleic acid allow nucleic acid secondary structure to play a role in modulating amyloid structure and function. Here we have used a simplified system of short basic peptides with alternating hydrophobic and hydrophilic amino acid residues to

Sebastian Braun; Christine Humphreys; Elizabeth Fraser; Andrea Brancale; Matthias Bochtler; Trevor C. Dale

2011-01-01

482

21 CFR 184.1007 - Aconitic acid.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Aconitic acid. 184.1007 Section 184.1007 Food and Drugs...Substances Affirmed as GRAS § 184.1007 Aconitic acid. (a) Aconitic acid (1,2,3-propenetricarboxylic acid (C6...

2013-04-01

483

21 CFR 189.155 - Monochloroacetic acid.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Monochloroacetic acid. 189.155 Section 189.155 Food and Drugs...Use as Human Food § 189.155 Monochloroacetic acid. (a) Monochloroacetic acid is the chemical chloroacetic acid, C2 H3...

2013-04-01

484

Acid Rain: Effects on Fish and Wildlife.  

National Technical Information Service (NTIS)

This report discusses: What is acid rain; What causes acid rain; Where do sulfur and nitrogen oxides originate; What areas in the U.S. are susceptible to acid rain; Are there early warning signals of acidification to aquatic resources; How does acid rain ...

K. S. Mayer E. P. Multer R. K. Schreiber

1984-01-01

485

Well stimulation method using foamed acid  

Microsoft Academic Search

Improved fluid loss control is realized in an acidizing treatment of a subterranean formation of the type using foamed acid, particularly in a foamed fracture acidizing type treatment, by injecting a gelled, substantially unfoamed fluid as a pad ahead of the foamed acid. I.

Scherubel

1980-01-01

486

Well stimulation method using foamed acid  

SciTech Connect

Improved fluid loss control is realized in an acidizing treatment of a subterranean formation of the type using foamed acid, particularly in a foamed fracture acidizing type treatment, by injecting a gelled, substantially unfoamed fluid as a pad ahead of the foamed acid. I.

Scherubel, G.A.

1980-12-09

487

Acid sorption regeneration process using carbon dioxide  

US Patent & Trademark Office Database

Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent in the presence of carbon dioxide under pressure. The acids are freed from the sorbent phase by a suitable regeneration method, one of which is treating them with an organic alkylamine solution thus forming an alkylamine-carboxylic acid complex which thermally decomposes to the desired carboxylic acid and the alkylamine.

2001-11-13

488

Production of Volatile Fatty Acids by Some Lactic Acid Bacteria. II. Selective Formation of Volatile FattyAcids by Degradation of Amino Acids1  

Microsoft Academic Search

The kinds and amounts of volatile fatty acids (VFA) produced from single amino acids, modified amino acid mixtures, and pyruvate by resting cells of some streptococci and lactobacilli have been investigated. The effects of pit of substrate, temperature of incubation, and oxygen removal from substrate on VFA production from some selected amino acids were also studied. Two strains of lactic

T. Nakae; J. A. Elliott

1965-01-01

489

21 CFR 184.1021 - Benzoic acid.  

Code of Federal Regulations, 2010 CFR

... 3 2010-01-01 2009-04-01 true Benzoic acid. 184.1021 Section 184.1021 Food and...Specific Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7...

2010-01-01

490

21 CFR 184.1021 - Benzoic acid.  

Code of Federal Regulations, 2010 CFR

... 3 2009-04-01 2009-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and...Specific Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7...

2009-04-01

491

Biosynthesis of cyclopentenyl fatty acids. Cyclopentenylglycine, a non-proteinogenic amino acid as precursor of cyclic fatty acids in Flacourtiaceae.  

PubMed

In seeds of Hydnocarpus anthelminthica of Flacourtiaceae, cyclopentenylglycine and cyclopentenyl fatty acids are found naturally. The non-proteinogenic amino acid may serve as precursor of cyclopentenyl fatty acids via aleprolic acid, the starter molecule for these long-chain compounds. After administration of cyclopentenyl[2-14C]glycine to maturing seeds of H. anthelminthica, labelled cyclopentenyl fatty acids were synthesized. Comparative activities were observed, when [1-14C]aleprolic acid was supplied to the seeds. Incorporation studies with [1-14C]acetate revealed that the chain-lengthening systems for straight-chain and cyclic fatty acids were still functioning in mature seeds. Endosperm and embryo of H. Anthelminthica seeds synthesized cyclopentenyl fatty acids from cyclopentenyl[2-14C]glycine, [1-14C]aleprolic acid and [1-14C]acetate. In embryonic tissue, a dilution experiment proved the following path for cyclopentenyl fatty acid biosynthesis: cyclopentenylglycine leads to aleprolic acid leads to cyclopentenyl fatty acids. The conversion of cyclopentenylglycine to aleprolic acid may occur via transamination and oxidative decarboxylation; activated aleprolic acid is then lengthened by C2-units to cyclopentenyl fatty acids. PMID:856584

Cramer, U; Spener, F

1977-04-15

492

REGULATION OF FATTY ACID SYNTHESIS.  

PubMed

All plant cells produce fatty acids from acetyl-CoA by a common pathway localized in plastids. Although the biochemistry of this pathway is now well understood, much less is known about how plants control the very different amounts and types of lipids produced in different tissues. Thus, a central challenge for plant lipid research is to provide a molecular understanding of how plants regulate the major differences in lipid metabolism found, for example, in mesophyll, epidermal, or developing seed cells. Acetyl-CoA carboxylase (ACCase) is one control point that regulates rates of fatty acid synthesis. However, the biochemical modulators that act on ACCase and the factors that in turn control these modulators are poorly understood. In addition, little is known about how the expression of genes involved in fatty acid synthesis is controlled. This review evaluates current knowledge of regulation of plant fatty metabolism and attempts to identify the major unanswered questions. PMID:15012259

Ohlrogge, John B.; Jaworski, Jan G.

1997-06-01

493

Identification of Urinary Metabolites of Orally Administered N,N-Dimethyl-p-Toluidine in Male F344 Rats  

Microsoft Academic Search

The metabolism of orally administered N,N-dimethyl-p-toluidine (DMPT) in male F344 rats was investigated. The rat urinary metabolite profile was determined by analytical reverse-phase high performance liquid chromatography (HPLC). Four radiolabeled peaks were observed, isolated, and purified by solid-phase extraction (SPE) and preparative HPLC methods. The 4 peaks were identified as p-(N-acetylhydroxyamino)hippuric acid (M1), DMPT N-oxide (M2), N-methyl-p-toluidine (M3), and parent

Nam-Cheol Kim; Katayoon Ghanbari; Dean A. Kracko; Waylon M. Weber; Jacob D. McDonald; Kelly J. Dix

2007-01-01

494

Thermotolerant Campylobacter with no or weak catalase activity isolated from dogs  

Microsoft Academic Search

ThermotolerantCampylobacter strains isolated from dog feces were characterized by phenotypical tests, DNA base composition, and DNA-DNA-hybridization. Out of 98 strains, 63 were catalase negative or weakly reacting (CNW); they were found in diarrheic as well as in healthy dogs. The CNW strains were all nalidixic-acid sensitive, hippurate negative, and grew at 42°C but not at 25°C. Seven strains were further

Karin Sandstedt; Jan Ursing; Mats Walder

1983-01-01

495

Structure of beta-Boswellinic Acid  

Microsoft Academic Search

THE investigations of Ruzicka, and of Winterstein and their co-workers, have shown that the majority of the triterpene acids (hederagenin, gypsogenin, oleanolic acid, sia- and suma-resinolic acids) are in all probability theta-hydroxy-gamma : delta-unsaturated mono-basic acids, as indicated in the accompanying formula1. On the other hand, (beta-boswellinic acid, C29H46(OH)COOH, one of the principal triterpene constituents of frankincense, evidently possesses a

J. C. E. Simpson

1937-01-01

496

Phenol biosynthesis in higher plants. Gallic acid  

PubMed Central

The biosynthesis of gallic acid in a number of higher plants was investigated by using l-[U-14C]phenylalanine, (?)-[G-14C]shikimic acid, d-[1-14C]glucose and d-[6-14C]glucose as tracers. The results are compared with those obtained similarly for caffeic acid and are interpreted in terms of the dehydrogenation of 5-dehydroshikimic acid as a normal route of metabolism for gallic acid.

Dewick, P. M.; Haslam, E.

1969-01-01

497

Antimicrobial agents derived from fatty acids  

Microsoft Academic Search

The author reviews his research, since 1966, for the ideal germicide. The relationship between structure of fatty acids, their\\u000a corresponding esters, and antimicrobial activity is presented. Saturated fatty acids have their highest activity when the\\u000a chain length is twelve carbons (C12) long; monounsaturated fatty acids reach their peak with palmitoleic acid (C16?1); the most active polyunsaturated fatty acid is linoleic.Trans

John J. Kabara

1984-01-01

498

Inhibitors of Fatty Acid Synthesis and Elongation  

NSDL National Science Digital Library

Fatty acid synthesis and fatty acid elongation are two parts of a critically important pathway in plants. The endproducts are essential components of cell membranes, waxes, and suberin. Two chemical families of herbicide (groups that share similar chemical structures) inhibit fatty acid synthesis, while fatty acid elongation is inhibited by two other families. This lesson will provide an overview of fatty acid synthesis and elongation, and explain where herbicides inhibit the pathway. Mechanisms of resistance to these herbicides will be described.

499

Biolubricant basestocks from chemically modified ricinoleic acid  

Microsoft Academic Search

This paper presents a series of chemically modified biolubricant basestocks derived from ricinoleic acid. The reactions were monitored and products were confirmed by NMR and FTIR. The synthesis protocol is carried out in three stages: (1) epoxidation of ricinoleic acid; (2) synthesis of 10,12-dihydroxy-9-acyloxystearic acid from epoxidized ricinoleic acid; (3) esterification of the acyloxystearic acid products with 2-ethylhexanol to yield

Jumat Salimon; Nadia Salih; Emad Yousif

2010-01-01

500

New sialic acid-containing sulfolipid: ' 'ungulic acid  

Microsoft Academic Search

Human epidermis, hair, nails, and kidney as well as bovine and horses' hooves were found to contain a lipid fraction, which on thin-layer chromatography migrated slightly ahead of the cerebroside sulfate esters and gave the color reac- tion specific for sialic acid. This fraction was isolated from horse hoof, in which it constituted nearly half of the total lipids. The

E. LEIKOLA; ELNA NIEMINEN; ANNA-MAIJA TEPP