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Sample records for phenolphthalein

  1. Plasticized phenolphthalein polycarbonate

    NASA Technical Reports Server (NTRS)

    Harrison, E. S.

    1976-01-01

    Phenolphthalein polycarbonate was successfully plasticized with polychlorinated biphenyls (e.g., Aroclor 1231) or tricresyl phosphate and cast from tetrahydrofuran to give clear films without loss of fire resistance. At loadings of 20 to 30 percent plasticizer the Tg was lowered to approximately 100 C which would render phenolphthalein polycarbonate easily moldable. Although these materials had some mechanical integrity as shown by their film forming ability, the room temperature toughness of the plasticized polymer was not significantly improved over unmodified polymer.

  2. PhenolphthaleinPink Tornado Demonstration

    NASA Astrophysics Data System (ADS)

    Prall, Bruce R.

    2008-04-01

    The phenolphthalein-pink tornado demonstration utilizes the vortex generated by a spinning magnetic stirring bar in a 1 L graduated cylinder containing 0.01 M HCl to demonstrate Le Chtelier's principle as it applies to the phenolphthalein equilibrium in water H 2 In + 2H 2 O 2H 2 O + + In 2 - where H 2 In is phenophthalein. The addition of 3-4 drops of phenolphthalein indicator solution followed immediately by 3-4 drops of 50% (w/w) NaOH to the vortex of the HCl solution results in a shift to the right in the equilibrium owing to the reaction of OH - + H 3 O + to form water. This shift is accompanied by the vortex becoming visible by the appearance of a pinkish-red color caused by an increase in In 2- concentration within the localized region of the vortex. The demonstration also provides one an excellent opportunity to discuss the topics of limiting reagent and reagent in excess. Some insight regarding the extent to which uniform mixing is achieved when using a magnetic stirrer is also provided. Included is a note from the Feature Editor, Ed Vitz.

  3. Reactions of Phenolphthalein at Various pH Values.

    ERIC Educational Resources Information Center

    Wittke, Georg

    1983-01-01

    Reactions of phenolphthalein with sodium hydroxide and sulfuric are discussed. Also discusses the sulfonation of phenolphthalein, listing experimental results related to the sulfonation reaction. (JN)

  4. Simultaneous determination of phenolphthalein and phenolphthalein glucuronide from dog serum, urine and bile by high-performance liquid chromatography.

    PubMed

    Wilhelm, J A; Bailey, L C; Shepard, T A; Venturella, V S

    1992-07-24

    A procedure is described to simultaneously quantitate phenolphthalein and its glucuronide metabolite from dog serum, urine and bile using high-performance liquid chromatography. The major advantages of this over pre-existing methods include direct analysis of the parent compound and glucuronide metabolite without enzymatic hydrolysis, increased sensitivity and the potential for automation of a large number of samples. Analytes were extracted from serum and urine using a combination of liquid- and solid-phase extraction methodology. Bile samples were analyzed directly after a twenty-fold dilution with mobile phase. The components plus internal standard were separated by reversed-phase high-performance liquid chromatography using step gradient elution and quantitated by the absorbance of ultraviolet light at 230 nm. Limits of detection from 1 ml of serum, 0.1 ml of urine and 0.05 ml of bile were 0.1, 0.5 and 10 microgram/ml for phenolphthalein and 0.1, 10 and 50 microgram/ml for phenolphthalein glucuronide, respectively. PMID:1400802

  5. FAILURE OF PHENOBARBITAL TO INDUCE RAT HEPATIC MICROSOMAL UDP-GLUCURONYLTRANSFERASE TOWARD PHENOLPHTHALEIN

    EPA Science Inventory

    Phenobarbital pretreatment was found not to induce Triton X-100 activated hepatic microsomal neonatal UDP-glucuronyltransferase activity towards phenolphthalein in male, female and pregnant female rats.

  6. Phenolphthalein and bisacodyl: assessment of genotoxic and carcinogenic responses in heterozygous p53 (+/-) mice and syrian hamster embryo (SHE) assay.

    PubMed

    Stoll, R E; Blanchard, K T; Stoltz, J H; Majeska, J B; Furst, S; Lilly, P D; Mennear, J H

    2006-04-01

    Phenolphthalein (800 and 2400 mg/kg/day by gavage and 2400 mg/kg/day by diet) and bisacodyl (800-500, 4000-2000, and 8000 mg/kg/day by gavage) were administered to 15 male and 15 female and 20 male and 20 female p53(+/-) mice respectively for 26 weeks to investigate the potential carcinogenicity of each compound. Toxicokinetic analyses confirmed systemic exposure. p-Cresidine was administered by gavage (400 mg/kg/day) and served as the positive control agent in each study. Dietary phenolphthalein reduced survival in both sexes and early deaths were attributed to thymic lymphoma. No bisacodyl-related neoplasms were observed. Regardless of route of administration to p53(+/-) mice, phenolphthalein but not bisacodyl was unequivocally genotoxic, causing increased micronuclei in polychromatic erythrocytes. In the Syrian hamster embryo (SHE) cell transformation assay, phenolphthalein caused increases in morphologically transformed colonies, thereby corroborating NTP's earlier reports, showing phenolophthalein has potential carcinogenic activity. Bisacodyl was negative in the SHE assay. Results of these experiments confirm an earlier demonstration that dietary phenolphthalein causes thymic lymphoma in p53(+/-) mice and show that (1) phenolphthalein causes qualitatively identical results in this transgenic model regardless of route of oral administration, (2) phenolphthalein shows evidence of micronucleus induction in p53(+/-) mice for up to 26 weeks, (3) phenolphthalein induced transformations in the in vitro SHE assay, and (4) bisacodyl in p53(+/-) mice induces neither drug-related neoplasm, nor micronuclei in polychromatic erythrocytes, and did not induce transformations in the in vitro SHE assay. PMID:16373391

  7. Synthesis of optically clear polymeric materials for high temperature windows. [preparation of phenolphthalein polycarbonate resin

    NASA Technical Reports Server (NTRS)

    Pannell, C. E.; Magner, J. E.

    1973-01-01

    A polymer has been developed that has excellent potential for use as windows in spacecraft as well as conventional aircraft. This polymer, phenolphthalein polycarbonate, has outstanding thermal properties, e.g., in place of melting or burning, it produces an insulating charred foam that closes off transmission of radiant heat through the window. This fact, coupled with an oxygen index of 0.43 and a 177 C tensile strength of 58 mega Newtons/sq m, makes this polymer a prime candidate for further development. Pilot plant preparation in a 20 gallon Pfaudler kettle was accomplished and large test specimens were prepared for evaluations.

  8. Cyclodextrin-poly(?-caprolactone) based nanoparticles able to complex phenolphthalein and adamantyl carboxylate

    PubMed Central

    Ailincai, Daniela

    2014-01-01

    Summary A new compound composed of poly(?-caprolactone) and ?-cyclodextrin (?-CD) was synthesized by click chemistry. This compound was used to obtain stable nanoparticles, which have been proven to be able to complex phenolphthalein and adamantyl carboxylate. The nanoparticles are characterized by a distinct morphology, i.e., a hydrophobic core formed by the polyester chain and a shell containing the CD part. Moreover, the formed nanoparticles have been proven to encapsulate umbelliferone in the polyester phase, which may serve as an example for the uptake of a drug. The formed nanoparticles were characterized in terms of sizes and morphology by both DLS and TEM. PMID:24991501

  9. End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

    PubMed Central

    Fleischmann, Carolin; Whlk, Hendrik

    2014-01-01

    Summary The synthesis of a new phenolphthalein azide derivative, which can be easily utilized in polymer analogous reactions, is presented. The subsequent cycloaddition reaction with propargyl-functionalized methoxypoly(ethylene glycol) yielded polymers bearing phenolphthalein as the covalently attached end group. In presence of per-?-cyclodextrin-dipentaerythritol, the formation of stable inclusion complexes was observed, representing an interesting approach towards the formation of star shaped polymers. The decolorization of a basic polymer solution caused by the complexation was of great advantage since this behavior enabled following the complex formation by UVvis spectroscopy and even the naked eye. PMID:25298793

  10. Phenolphthalein-Pink Tornado Demonstration

    ERIC Educational Resources Information Center

    Prall, Bruce R.

    2008-01-01

    The titration of HCl with NaOH has traditionally been used to introduce beginning chemistry students to the concepts of acid-base chemistry and stoichiometry. The demonstration described in this article utilizes this reaction as a means of providing students an opportunity to observe the dynamic motion associated with a swirling vortex and its…

  11. Phenolphthalein-Pink Tornado Demonstration

    ERIC Educational Resources Information Center

    Prall, Bruce R.

    2008-01-01

    The titration of HCl with NaOH has traditionally been used to introduce beginning chemistry students to the concepts of acid-base chemistry and stoichiometry. The demonstration described in this article utilizes this reaction as a means of providing students an opportunity to observe the dynamic motion associated with a swirling vortex and its

  12. Kinetics of the Fading of Phenolphthalein in Alkaline Solution.

    ERIC Educational Resources Information Center

    Nicholson, Lois

    1989-01-01

    Described is an experiment which illustrates pseudo-first-order kinetics in the fading of a common indicator in an alkaline solution. Included are background information, details of materials used, laboratory procedures, and sample results. (CW)

  13. Transparent polymeric laminates

    NASA Technical Reports Server (NTRS)

    Parker, J. A.; Fohlen, G. M.; Sawko, P. M.

    1973-01-01

    Laminate prepared from epoxy-boroxine and phenolphthalein polycarbonate has high mechanical strength at elevated temperature and is resistant to impact, fire, and high-energy thermal radiation. Polycarbonate is prepared by reaction of phenolphthalein with phosgene in presence of amine catalyst and immiscible organic solvent phase.

  14. Molecular Recognition: Detection of Colorless Compounds Based on Color Change

    ERIC Educational Resources Information Center

    Khalafi, Lida; Kashani, Samira; Karimi, Javad

    2016-01-01

    A laboratory experiment is described in which students measure the amount of cetirizine in allergy-treatment tablets based on molecular recognition. The basis of recognition is competition of cetirizine with phenolphthalein to form an inclusion complex with -cyclodextrin. Phenolphthalein is pinkish under basic condition, whereas it's complex form

  15. Molecular Recognition: Detection of Colorless Compounds Based on Color Change

    ERIC Educational Resources Information Center

    Khalafi, Lida; Kashani, Samira; Karimi, Javad

    2016-01-01

    A laboratory experiment is described in which students measure the amount of cetirizine in allergy-treatment tablets based on molecular recognition. The basis of recognition is competition of cetirizine with phenolphthalein to form an inclusion complex with ß-cyclodextrin. Phenolphthalein is pinkish under basic condition, whereas it's complex form…

  16. 21 CFR 177.1950 - Vinyl chloride-ethylene copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... phenolphthalein. One drop of methyl red indicator is added to the A milliliters of filtered aqueous extract and... beaker and rinsed thoroughly. The solution is cooled to room temperature and cautiously neutralized...

  17. 21 CFR 177.1950 - Vinyl chloride-ethylene copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... phenolphthalein. One drop of methyl red indicator is added to the A milliliters of filtered aqueous extract and... beaker and rinsed thoroughly. The solution is cooled to room temperature and cautiously neutralized...

  18. The Best Enzyme Investigation Ever? Probably.

    ERIC Educational Resources Information Center

    Cooper, Phil

    2000-01-01

    Uses alkaline phosphate to remove the phosphate group from phenolphthalein diphosphate. Discusses problems which include the interference of ambient light and temperature variation. Provides detailed information about the apparatus and the experimental procedure. (ASK)

  19. 27 CFR 21.131 - Sucrose octaacetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... white or cream-colored powder having an intensely bitter taste. (b) Free acid (as acetic acid). Maximum... using phenolphthalein indicator. Percent acid as acetic acid=ml NaOH used×0.6/ weight of sample (c... a steam bath, cool and titrate the excess sodium hydroxide with 0.5 N sulfuric acid...

  20. 27 CFR 21.131 - Sucrose octaacetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... white or cream-colored powder having an intensely bitter taste. (b) Free acid (as acetic acid). Maximum... using phenolphthalein indicator. Percent acid as acetic acid=ml NaOH used×0.6/ weight of sample (c... a steam bath, cool and titrate the excess sodium hydroxide with 0.5 N sulfuric acid...

  1. 27 CFR 21.131 - Sucrose octaacetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... white or cream-colored powder having an intensely bitter taste. (b) Free acid (as acetic acid). Maximum... using phenolphthalein indicator. Percent acid as acetic acid=ml NaOH used×0.6/ weight of sample (c... a steam bath, cool and titrate the excess sodium hydroxide with 0.5 N sulfuric acid...

  2. Preparation of disappearing inks and studying the fading time on different paper surfaces.

    PubMed

    El-Molla, Mohamed Mabrouk; Shama, Sayed Ahamed; Saeed, Saeed El-Sayed

    2013-01-01

    Disappearing inks have been used in different fields, but it may be abused in forgery and counterfeiting. This research was conducted on the preparation of disappearing inks using different concentrations of thymolphthalein, phenolphthalein, and their mixture. The prepared inks were applied to different types of handwriting papers. It was found that the handwriting stability increased by increasing thymolphthalein, phenolphthalein, or alkali concentration, but in the case of using 4 mL of 1 normal (N) NaOH, the handwriting stability of phenolphthalein and its mixture inks decreased. Deciphering of the faded handwriting was evaluated by different methods; using optical deciphering, the faded handwriting did not respond to the different light sources. All the faded handwriting was visible when treated with alkaline solution. There was no change in the faded handwriting when heated to 100C; phenolphthalein and mixture inks containing 0.5 mL of 1 N NaOH became red when only Azhar and Xerox papers were heated to 150C. PMID:22788417

  3. "Mud" + "Blood"--A Very Colorful Demonstration.

    ERIC Educational Resources Information Center

    Hambly, Gordon

    1998-01-01

    Describes a demonstration in which a bloodred-colored solution of hydrogen peroxide, sodium hydroxide, and phenolphthalein indicator is added to a mud-colored solution of potassium permanganate, hydrated manganous chloride, and sulfuric acid. The mixture turns clear when added together. Draws parallels between the demonstration and the Old…

  4. Overhead Projector Demonstrations.

    ERIC Educational Resources Information Center

    Kolb, Doris, Ed.

    1989-01-01

    Described are three chemistry demonstrations: (1) a simple qualitative technique for taste pattern recognition in structure-activity relationships; (2) a microscale study of gaseous diffusion using bleach, HCl, ammonia, and phenolphthalein; and (3) the rotation of polarized light by stereoisomers of limonene. (MVL)

  5. Demonstrating Diffusion

    ERIC Educational Resources Information Center

    Foy, Barry G.

    1977-01-01

    Two demonstrations are described. Materials and instructions for demonstrating movement of molecules into cytoplasm using agar blocks, phenolphthalein, and sodium hydroxide are given. A simple method for demonstrating that the rate of diffusion of a gas is inversely proportional to its molecular weight is also presented. (AJ)

  6. Colorblindness and Titrations with Visual Indicators.

    ERIC Educational Resources Information Center

    Diehl, Harvey; And Others

    1985-01-01

    Discusses various issues related to colorblind students performing titrations with visual indicators. Includes tables showing precisions in the titration of a weak acid by colorblind students using phenolphthalein and thymolphthalein and in the titration of a weak base by colorblind persons using methyl red and bromcresol green. (JN)

  7. The Plague Generation.

    ERIC Educational Resources Information Center

    Jones, Richard C.

    1993-01-01

    Describes an activity to simulate the geometries of a spreading pathogen such as HIV throughout a generation. Students exchange "bodily fluids" three times and are then tested for the presence of "infection." Materials used include base solutions (NaOH or KOH), phenolphthalein (pH indicator), clear plastic cups, and an eye dropper. (PR)

  8. "Mud" + "Blood"--A Very Colorful Demonstration.

    ERIC Educational Resources Information Center

    Hambly, Gordon

    1998-01-01

    Describes a demonstration in which a bloodred-colored solution of hydrogen peroxide, sodium hydroxide, and phenolphthalein indicator is added to a mud-colored solution of potassium permanganate, hydrated manganous chloride, and sulfuric acid. The mixture turns clear when added together. Draws parallels between the demonstration and the Old

  9. Initial evaluation tests of General Electric Company 12.0 ampere hour nickel cadmium spacecraft cells with design variables

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1979-01-01

    All evaluation tests were performed at room ambient pressure and temperature, with discharges at a 2 hour rate. Tests consisted of phenolphthalein leak tests, three capacity tests, an auxiliary electrode test, a charge retention test, an internal short test, a charge efficiency test, overcharge tests, and a pressure versus capacity test. Results of the tests and recommendations for improvements in manufacturing are presented.

  10. Evaluation of vibrational spectroscopic methods to identify and quantify multiple adulterants in herbal medicines.

    PubMed

    Rooney, Jeremy S; McDowell, Arlene; Strachan, Clare J; Gordon, Keith C

    2015-06-01

    To counter the growth of herbal medicines adulterated with pharmaceuticals crossing borders, rapid, inexpensive and non-destructive analytical techniques, that can handle complex matrices, are required. Since mid-infrared (MIR), near infrared (NIR) and Raman spectroscopic techniques meet these criteria, their performance in identifying adulterants in seized weightloss herbal medicines is definitively determined. Initially a validated high pressure liquid chromatography methodology was used for reference identification and quantification of the adulterants sibutramine H2O·HCl, fenfluramine HCl and phenolphthalein. Of 38 products, only sibutramine and phenolphthalein were detected by HPLC. The spectroscopic measurements showed Raman was ill-suited due to sample burning and emission while NIR lacked adulterant selectivity. Conversely, MIR demonstrated apt identification performance, which manifested as spectrally meaningful separation based on the presence and type of adulterant during principal component analysis (test set validated). Partial least squares regression models were constructed from the MIR training sets for sibutramine and phenolphthalein - both models fitted the training set data well. Average test set prediction errors were 0.8% for sibutramine and 2.2% for phenolphthalein over the respective concentration ranges of 1.7-11.7% and 0.9-34.4%. MIR is apposite for the screening of anorectic and laxative adulterants and is the most viable technique for wider adulterant screening in herbal medicines. PMID:25863375

  11. Attempts to develop a new nuclear measurement technique of ?-glucuronidase levels in biological samples

    NASA Astrophysics Data System (ADS)

    nak, T.; Avcibasi, U.; Yildirim, Y.; etinkaya, B.

    2003-01-01

    ?-Glucuronidase is one of the most important hydrolytic enzymes in living systems and plays an essential role in the detoxification pathway of toxic materials incorporated into the metabolism. Some organs, especially liver and some tumour tissues, have high level of ?-glucuronidase activity. As a result the enzymatic activity of some kind of tumour cells, the radiolabelled glucuronide conjugates of cytotoxic, as well as radiotoxic compounds have potentially very valuable diagnostic and therapeutic applications in cancer research. For this reason, a sensitive measurement of ?-glucuronidase levels in normal and tumour tissues is a very important step for these kinds of applications. According to the classical measurement method of ?-glucuronidase activity, in general, the quantity of phenolphthalein liberated from its glucuronide conjugate, i.e. phenolphthalein-glucuronide, by ?-glucuronidase has been measured by use of the spectrophotometric technique. The lower detection limit of phenolphthalein by the spectrophotometric technique is about 1 3 ?g. This means that the ?-glucuronidase levels could not be detected in biological samples having lower levels of ?-glucuronidase activity and therefore the applications of the spectrophotometric technique in cancer research are very seriously limited. Starting from this consideration, we recently attempted to develop a new nuclear technique to measure much lower concentrations of ?-glucuronidase in biological samples. To improve the detection limit, phenolphthalein-glucuronide and also phenyl-N-glucuronide were radioiodinated with 131I and their radioactivity was measured by use of the counting technique. Therefore, the quantity of phenolphthalein or aniline radioiodinated with 131I and liberated by the deglucuronidation reactivity of ?-glucuronidase was used in an attempt to measure levels lower than the spectrophotometric measurement technique. The results obtained clearly verified that 0.01 pg level of phenolphthalein or aniline could easily be detected at least 106 times more sensitively. The preliminary results obtained on some biological samples have shown that ?-glucuronidase levels could reasonably be measured by use of the nuclear technique. In addition, our results also indicate the potential application of the radiolabelling technique to measure very low ?-glucuronidase levels in different biological samples in cancer research and other related fields. The objective of our study is to demonstrate the potential application of the nuclear measurement technique in different biological samples.

  12. Attempts to develop a new nuclear measurement technique of ?-glucuronidase levels in biological samples

    NASA Astrophysics Data System (ADS)

    nak, T.; Avcibasi, U.; Yildirim, Y.; etinkaya, B.

    2003-01-01

    ?-Glucuronidase is one of the most important hydrolytic enzymes in living systems and plays an essential role in the detoxification pathway of toxic materials incorporated into the metabolism. Some organs, especially liver and some tumour tissues, have high level of ?-glucuronidase activity. As a result the enzymatic activity of some kind of tumour cells, the radiolabelled glucuronide conjugates of cytotoxic, as well as radiotoxic compounds have potentially very valuable diagnostic and therapeutic applications in cancer research. For this reason, a sensitive measurement of ?-glucuronidase levels in normal and tumour tissues is a very important step for these kinds of applications. According to the classical measurement method of ?-glucuronidase activity, in general, the quantity of phenolphthalein liberated from its glucuronide conjugate, i.e. phenolphthalein-glucuronide, by ?-glucuronidase has been measured by use of the spectrophotometric technique. The lower detection limit of phenolphthalein by the spectrophotometric technique is about 1-3 ?g. This means that the ?-glucuronidase levels could not be detected in biological samples having lower levels of ?-glucuronidase activity and therefore the applications of the spectrophotometric technique in cancer research are very seriously limited. Starting from this consideration, we recently attempted to develop a new nuclear technique to measure much lower concentrations of ?-glucuronidase in biological samples. To improve the detection limit, phenolphthalein-glucuronide and also phenyl-N-glucuronide were radioiodinated with 131I and their radioactivity was measured by use of the counting technique. Therefore, the quantity of phenolphthalein or aniline radioiodinated with 131I and liberated by the deglucuronidation reactivity of ?-glucuronidase was used in an attempt to measure levels lower than the spectrophotometric measurement technique. The results obtained clearly verified that 0.01 pg level of phenolphthalein or aniline could easily be detected at least 106 times more sensitively. The preliminary results obtained on some biological samples have shown that ?-glucuronidase levels could reasonably be measured by use of the nuclear technique. In addition, our results also indicate the potential application of the radiolabelling technique to measure very low ?-glucuronidase levels in different biological samples in cancer research and other related fields. The objective of our study is to demonstrate the potential application of the nuclear measurement technique in different biological samples.

  13. Thermoplastic polymers for improved fire safety

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Hilado, C. J.

    1976-01-01

    The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use and others being considered for use in aircraft interiors are described. The properties studied included (1) thermomechanical properties such as glass transition and melt temperature, (2) changes in polymer enthalpy by differential scanning calorimetry, (3) thermogravimetric analysis in anaerobic and oxidative environments, (4) oxygen index, (5) smoke evolution, (6) relative toxicity of the volatile products of pyrolysis, and (7) selected physical properties. The generic polymers that were evaluated included: acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonatepoly (dimethyl siloxane) block polymer, phenolphthalein bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative ranking of some of the flammability, smoke, and toxicity properties are presented.

  14. Assessment of relative flammability and thermochemical properties of some thermoplastic materials

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.

    1978-01-01

    The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use and others being considered for use in aircraft interiors are described. The properties studied included (1) thermal mechanical properties such as glass transition and melt temperature, (2) changes in polymer enthalpy by differential scanning calorimetry, (3) thermogravimetric analysis in an anaerobic and oxidative environment, (4) oxygen index, (5) smoke evolution, (6) relative toxicity of the volatile products of pyrolysis, and (7) selected physical properties. The generic polymers which were evaluated included: acrylonitrile-butadiene-styrene, bisphenol A polycarbonate, bisphenol fluorenone carbonatedimethylsiloxane block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters including molding characteristics of some of the advanced polymers are described. Test results and relative rankings of some of the flammability, smoke and toxicity properties are presented.

  15. Interaction between diphenolic laxatives and intestinal bacteria in vitro.

    PubMed

    Bergan, T; Fotland, M H; Sund, R B

    1982-08-01

    The ability of the laxative diphenols desacetylbisacodyl, oxyphenisatin, and phenolphthalein to inhibit growth and cause leakage of potassium ion from microbial cells in vitro was studied with 25 aerobic and 25 anaerobic bacterial strains. None of the aerobes, but some of the anaerobes showed growth inhibition. Potassium release assayed by flame photometry was observed in strains which showed growth inhibition, but also in other strains including anaerobes and aerobes. The highest antibacterial activity among the diphenols was observed with phenolphthalein and the least with desacetylbisacodyl; this relationship as noted for both growth inhibition and potassium release. Enzymatic hydrolysis of picosulphate to the free diphenol desacetylbisacodyl carried out by three strains of anaerobic bacteria was indicated by high pressure liquid chromatography. PMID:6896788

  16. The relative fire resistance of select thermoplastic materials. [for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.

    1978-01-01

    The relative thermal stability, flammability, and related thermochemical properties of some thermoplastic materials currently used in aircraft interiors as well as of some candidate thermoplastics were investigated. Currently used materials that were evaluated include acrylonitrile butadiene styrene, bisphenol A polycarbonate, polyphenylene oxide, and polyvinyl fluoride. Candidate thermoplastic materials evaluated include: 9,9-bis(4-hydroxyphenyl)fluorene polycarbonate-poly(dimethylsiloxane) block polymer, chlorinated polyvinylchloride homopolymer, phenolphthalein polycarbonate, polyethersulfone, polyphenylene sulfide, polyarylsulfone, and polyvinylidene fluoride.

  17. Carbonation and its effects in reinforced concrete

    SciTech Connect

    Broomfield, J.P.

    2000-01-01

    Carbonation is the result of interaction of carbon dioxide (CO{sub 2}) gas in the atmosphere with the alkaline hydroxides in the concrete. CO{sub 2} diffuses through the concrete and rate of movement of the carbonation front roughly follows Fick's law of diffusion. Carbonation depth can be measured by exposing fresh concrete and spraying it with phenolphthalein indicator solution. An example of the test on a reinforced concrete mullion is given.

  18. On the mechanism of floating and sliding of liquid marbles.

    PubMed

    Bormashenko, Edward; Bormashenko, Yelena; Musin, Albina; Barkay, Zahava

    2009-03-01

    The mechanisms of floating and sliding of liquid marbles are studied. Liquid marbles containing CaCl(2) and marbles containing NaOH water solutions float on water containing Na(2)CO(3) and an alcoholic solution of phenolphthalein with no chemical reaction. Sliding of liquid marbles, consisting of NaOH water solutions, on polymer substrates coated with phenolphthalein is studied as well. No chemical reaction is observed. These observations supply direct experimental evidence for the suggestion that interfaces are separated by an air layer when marbles roll on solid substrates. It is concluded that a liquid marble rests on hydrophobic particles coating the liquid. In contrast, drops containing an NaOH water solution sliding on superhydrophobic surfaces coated with phenolphthalein leave a colored trace. The mechanism of low-friction sliding of drops deposited on superhydrophobic surfaces and liquid marbles turns out to be quite different: there is no direct contact between liquid and solid in the case of marbles' motion. PMID:19177484

  19. Acid-base titrations using microfluidic paper-based analytical devices.

    PubMed

    Karita, Shingo; Kaneta, Takashi

    2014-12-16

    Rapid and simple acid-base titration was accomplished using a novel microfluidic paper-based analytical device (?PAD). The ?PAD was fabricated by wax printing and consisted of ten reservoirs for reaction and detection. The reaction reservoirs contained various amounts of a primary standard substance, potassium hydrogen phthalate (KHPth), whereas a constant amount of phenolphthalein was added to all the detection reservoirs. A sample solution containing NaOH was dropped onto the center of the ?PAD and was allowed to spread to the reaction reservoirs where the KHPth neutralized it. When the amount of NaOH exceeded that of the KHPth in the reaction reservoirs, unneutralized hydroxide ion penetrated the detection reservoirs, resulting in a color reaction from the phenolphthalein. Therefore, the number of the detection reservoirs with no color change determined the concentration of the NaOH in the sample solution. The titration was completed within 1 min by visually determining the end point, which required neither instrumentation nor software. The volumes of the KHPth and phenolphthalein solutions added to the corresponding reservoirs were optimized to obtain reproducible and accurate results for the concentration of NaOH. The ?PADs determined the concentration of NaOH at orders of magnitude ranging from 0.01 to 1 M. An acid sample, HCl, was also determined using Na2CO3 as a primary standard substance instead of KHPth. Furthermore, the ?PAD was applicable to the titrations of nitric acid, sulfuric acid, acetic acid, and ammonia solutions. The ?PADs were stable for more than 1 month when stored in darkness at room temperature, although this was reduced to only 5 days under daylight conditions. The analysis of acidic hot spring water was also demonstrated in the field using the ?PAD, and the results agreed well with those obtained by classic acid-base titration. PMID:25423320

  20. An improved method for analysis of hydroxide and carbonate in alkaline electrolytes containing zinc

    NASA Technical Reports Server (NTRS)

    Reid, M. A.

    1978-01-01

    A simplified method for titration of carbonate and hydroxide in alkaline battery electrolyte is presented involving a saturated KSCN solution as a complexing agent for zinc. Both hydroxide and carbonate can be determined in one titration, and the complexing reagent is readily prepared. Since the pH at the end point is shifted from 8.3 to 7.9 - 8.0, m-cresol purple or phenol red are used as indicators rather than phenolphthalein. Bromcresol green is recommended for determination of the second end point of a pH of 4.3 to 4.4.

  1. An improved method for analysis of hydroxide and carbonate in alkaline electrolytes containing zinc

    NASA Technical Reports Server (NTRS)

    Reid, M. A.

    1978-01-01

    A simplified method for titration of carbonate and hydroxide in alkaline battery electrolyte is presented involving a saturated KSCN solution as a complexing agent for zinc. Both hydroxide and carbonate can be determined in one titration, and the complexing reagent is readily prepared. Since the pH at the end point is shifted from 8.3 to 7.9-8.0, m-cresol purple or phenol red are used as indicators rather than phenolphthalein. Bromcresol green is recommended for determination of the second end point of a pH of 4.3 to 4.4.

  2. Study of thermal stability and degradation of fire resistant candidate polymers for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Hsu, M. T. S.

    1976-01-01

    The thermochemistry of bismaleimide resins and phenolphthalein polycarbonate was studied. Both materials are fire-resistant polymers and may be suitable for aircraft interiors. The chemical composition of the polymers has been determined by nuclear magnetic resonance and infrared spectroscopy and by elemental analysis. Thermal properties of these polymers have been characterized by thermogravimetric analyses. Qualitative evaluation of the volatile products formed in pyrolysis under oxidative and non-oxidative conditions has been made using infrared spectrometry. The residues after pyrolysis were analyzed by elemental analysis. The thermal stability of composite panel and thermoplastic materials for aircraft interiors was studied by thermogravimetric analyses.

  3. Thermochemical characterization of some thermoplastic materials. [flammability and toxicity properties for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Hilado, C. J.

    1977-01-01

    The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use or being considered for use in aircraft interiors are described. The properties studied included thermomechanical properties such as glass-transition and melt temperature, changes in polymer enthalpy, thermogravimetric analysis in anerobic and oxidative environments, oxygen index, smoke evolution, relative toxicity of the volatile products of pyrolysis, and selected physical properties. The generic polymers evaluated included acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonate-poly (dimethylsiloxane) block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative rankings of some of the flammability, smoke, and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic than or equivalent to polymers in current use.

  4. Xenbiotic metabolism in microsomes and isolated nuclei after hepatic insult

    SciTech Connect

    Arnold, M.E.

    1985-01-01

    A technique is described for the isolation of rat hepatic nuclei providing a very pure organelle preparation containing extremely low levels of other organelle contamination. Five methods for determining the purity of the nuclear preparation are described. The metabolism of /sup 14/C-N,N'-dimethylphenobarbital (DMPB) by a nuclear NADPH-dependent cytochrome P450-mediated N-demethylation reaction was investigated. The radiometric assay to measure metabolism was rapid and convenient. The primary metabolite is methylphenobarbital. No other metabolites were detected by HPLC at the specific activity employed (4.0 uCi/mg). /sup 14/C-DMPB was shown to be a superior substrate over ethylmorphine for the determination of nuclear N-demethylation. Glucuronide conjugation of phenolphthalein (PHE) in nuclear and microsomal preparations was described. Phenolphthalein was metabolized by nuclei and microsomes, to only one product, the glucuronide, under the conditions employed. /sup 3/H-Benzo(a)pyrene (B(a)P) was shown to be metabolized by nuclear and microsomal preparations by an NADPH-dependent mechanism to reactive species. The effects of three chemical hepatic insults on microsomal and nuclear metabolism of DMPB, PHE, and B(a)P are described. Theories are proposed which describe the mechanisms involved in the production of the effects observed for the three hepatic insults.

  5. Development and the Educational Effect of a System of the Corrosion of Iron and the Anti-corrosion Ability of Conductive Polymer Polyaniline

    NASA Astrophysics Data System (ADS)

    Yano, Jun; Nakamura, Noriyuki; Yamazaki, Suzuko; Ichimori, Hayato; Osaki, Nobukazu; Okano, Hiroshi

    Few general chemistry textbooks of high schools, colleges and universities introduce the corrosion of iron into the oxidation-reduction (redox) section, although the corrosion is very popular phenomena for students. Besides, no description appears about conductive polymers as anti-corrosion materials. The corrosion is a redox reaction proceeding through the local cell mechanism : the iron oxidation half-cell reaction at the local anode and the reduction of oxygen at the local cathode. To prepare a teaching tool for understanding of the mechanism, the visualization of the corrosion was attempted using phenolphthalein and potassium hexacyanoferrate (III) as color couplers for the anodic and cathodic products : Fe2+ and OH-. The local anode and cathode were obviously shown as gradual blue and red coloration when commercial nails were soaked in 4% NaCl aqueous solution containing phenolphthalein and potassium hexacyanoferrate (III) . On the other hand, no coloration occurred for the nail covered with a conductive polymer polyaniline. To know the anti-corrosion mechanism, the open-circuit potential of the nail was measured. The fact that the potential was kept at the potential range where iron was passivated implied that polyaniline acted as an in-situ oxidant. The visualization was experimentally performed at an actual chemistry class and the utility value was estimated. As a result, the visualization is expected to be a useful teaching tool for the corrosion and the understanding of the role of polyaniline as the anti-corrosion material.

  6. Identification and Determination of Synthetic Pharmaceuticals as Adulterants in Eight Common Herbal Weight Loss Supplements

    PubMed Central

    Khazan, Marjan; Hedayati, Mehdi; Kobarfard, Farzad; Askari, Sahar; Azizi, Fereidoun

    2014-01-01

    Background: Adulterated herbal weight loss products with containing undeclared synthetic drugs are common and responsible for many serious health damages. Objectives: The purpose of the study was to determine five synthetic adulterants in eight common herbal weight loss supplements, which are currently sold in Iran markets, to verify their presence in supplements, without mentioning on the labels. Materials and Methods: Eight common herbal weight loss samples were obtained from the Iran pharmaceutical market after advertising in the Persian language on satellite channels and internet. Five pharmacological classes of drugs used for weight loss, namely sibutramine, phenolphthalein, phenytoin, bumetanide and rimonabant, were investigated and quantified by GC-MS for the first three and LC-MS for the last two medications. Results: The most undeclared ingredients, which were illegally added include sibutramine, phenolphthalein, bumetanide, and phenytoin in the original super slim, herbaceous essence, super slim green lean, and fat loss, supplements, respectively. Rimonabant was not found. Caffeine, pseudoephedrine, theobromine and amfepramone were also found in the supplements using GC-MS assay. Conclusions: Adulterated synthetic substances were detected in the herbal weight loss products. Health care professionals should make people aware of the risks of taking herbal weight-loss supplements. PMID:24829782

  7. Structure-based discovery of inhibitors of thymidylate synthase.

    PubMed

    Shoichet, B K; Stroud, R M; Santi, D V; Kuntz, I D; Perry, K M

    1993-03-01

    A molecular docking computer program (DOCK) was used to screen the Fine Chemical Directory, a database of commercially available compounds, for molecules that are complementary to thymidylate synthase (TS), a chemotherapeutic target. Besides retrieving the substrate and several known inhibitors, DOCK proposed putative inhibitors previously unknown to bind to the enzyme. Three of these compounds inhibited Lactobacillus casei TS at submillimolar concentrations. One of these inhibitors, sulisobenzone, crystallized with TS in two configurations that differed from the DOCK-favored geometry: a counterion was bound in the substrate site, which resulted in a 6 to 9 angstrom displacement of the inhibitor. The structure of the complexes suggested another binding region in the active site that could be exploited. This region was probed with molecules sterically similar to sulisobenzone, which led to the identification of a family of phenolphthalein analogs that inhibit TS in the 1 to 30 micromolar range. These inhibitors do not resemble the substrates of the enzyme. A crystal structure of phenolphthalein with TS shows that it binds in the target site in a configuration that resembles the one suggested by DOCK. PMID:8451640

  8. The experimental investigation of concrete carbonation depth

    SciTech Connect

    Chang, C.-F. . E-mail: s83808@yahoo.com.tw; Chen, J.-W.

    2006-09-15

    Phenolphthalein indicator has traditionally been used to determine the depth of carbonation in concrete. This investigation uses the thermalgravimetric analysis (TGA) method, which tests the concentration distribution of Ca(OH){sub 2} and CaCO{sub 3}, while the X-ray diffraction analysis (XRDA) tests the intensity distribution of Ca(OH){sub 2} and CaCO{sub 3}. The Fourier transformation infrared spectroscopy (FTIR) test method detects the presence of C-O in concrete samples as a basis for determining the presence of CaCO{sub 3}. Concrete specimens were prepared and subjected to accelerated carbonation under conditions of 23 deg. C temperature, 70% RH and 20% concentration of CO{sub 2}. The test results of TGA and XRDA indicate that there exist a sharp carbonation front. Three zones of carbonation were identified according to the degree of carbonation and pH in the pore solutions. The TGA, XRDA and FTIR results showed the depth of carbonation front is twice of that determined from phenolphthalein indicator.

  9. A plate method for screening of bacteria capable of degrading aliphatic nitriles.

    PubMed

    Santoshkumar, M; Nayak, Anand S; Anjaneya, O; Karegoudar, Timmanagouda B

    2010-01-01

    A novel indicator plate method was developed for screening of aliphatic-nitrile-degrading bacteria. Isolated bacteria were tested for utilization of acetonitrile as sole source of carbon and nitrogen with the release of ammonia. The released ammonia causes increase of the pH of the medium. Phenol red indicator is used for detection of ammonia based on colour change of the indicator dye from red to pink. The liberation of ammonia from aliphatic-nitrile-utilizing bacteria is also studied in plates containing other indicators such as bromothymol blue and phenolphthalein. The usefulness of the indicator plate is demonstrated for bacteria that degrade certain aliphatic nitriles. Bacteria degrading nitriles as a nitrogen source can also be isolated with a medium containing additional carbon source. This plate method would be useful in isolation and screening of bacteria for degradation of aliphatic nitriles and also for production of nitrile-hydrolyzing enzymes. PMID:19921293

  10. Phthalide Cardo Chain Extended Siloxane Core Skeletal Modified Polyimide/Multi-Walled Carbon Nanotube Nanocomposites.

    PubMed

    Priya, R Padhma; Gunasekaran, S G; Dharmendirakumar, M

    2015-09-01

    A new type of siloxane core modified phthalide cardo chain based polyimide (PI) was successfully prepared from siloxane core dianhydride and ether linked phenolphthalein diamine moiety. This PI was further modified with different weight percentages of multi-walled carbon nanotubes (MWCNTs) to obtain MWCNT reinforced PI nanocomposites. The enhancement in the glass transition temperature and improved thermal stability could be afforded by the restrained motion of polymeric chain, caused from nanoreinforcement effect of MWCNTs. The successive increment in the concentration of MWCNTs resulted in augmented dielectric constant because of interfacial polarization of MWCNTs. This PI shows better solubility and low water uptake percentage of 0.42-0.58%. The morphological studies ascertain the molecular level dispersion of MWCNT throughout the PI matrix. PMID:26716238

  11. Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.

    PubMed

    Chung, W S; Yu, M J; Lee, H D

    2004-01-01

    The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area. PMID:14982159

  12. Approaches to flame resistant polymeric materials

    NASA Technical Reports Server (NTRS)

    Liepins, R.

    1975-01-01

    Four research and development areas are considered for further exploration in the quest of more flame-resistant polymeric materials. It is suggested that improvements in phenolphthalein polycarbonate processability may be gained through linear free energy relationship correlations. Looped functionality in the backbone of a polymer leads to both improved thermal resistance and increased solubility. The guidelines used in the pyrolytic carbon production constitute a good starting point for the development of improved flame-resistant materials. Numerous organic reactions requiring high temperatures and the techniques of protected functionality and latent functionality constitute the third area for exploration. Finally, some well-known organic reactions are suggested for the formation of polymers that were not made before.

  13. Effects of ?-cyclodextrin on selected properties of electrospun thermoplastic polyurethane nanofibres.

    PubMed

    Akakoca Kumbasar, E Perrin; Akduman, Ci?dem; Cay, Ahmet

    2014-04-15

    Cyclodextrins are one of the most promising materials for the development of products with advanced properties due to inclusion complex formation ability with a wide variety of substances. More specifically, incorporation of cyclodextrins into electrospun nanofibrous materials is considered as potential candidates for functional textile applications. This study examines the electrospinning of thermoplastic polyurethane (TPU) nanofibres including ?-cyclodextrin and investigates the effects of ?-cyclodextrin (?-CD) on resultant fibre properties. TPU/CD nanofibres were characterized by scanning electron microscopy, FTIR, TGA and DSC analysis. Additionally phenolphthalein absorption tests were applied. It was observed that the incorporation of ?-CD increased the mean fibre diameter and heterogeneity of nanofibrous membranes. The effects of ?-CD on the thermal properties of TPU membranes were shown. It was proven that ?-CD within TPU nanostructure could be able to form inclusion complexes. TPU/CD nanofibres are believed to have good potentials for functional textile applications. PMID:24607158

  14. Solid state amorphization of organic molecular crystals using a vibrating mill

    NASA Astrophysics Data System (ADS)

    Tsukushi, Itaru; Yamamuro, Osamu; Matsuo, Takasuke

    1995-06-01

    The solid-state amorphization of organic molecular crystals was studied by differential scanning calorimetry (DSC) and X-ray powder diffraction. Two clathrate compounds of tri- O-methyl-?-cyclodextrin (TMCD) containing p-nitrobenzoic acid (NBA) and p-hydroxybenzoic acid (HBA), and seven other organic compounds, sucrose (SUC), salicin (SAL), phenolphthalein (PP), 1,3,5-tri-?-naphthylbenzene (TNB), p-quaterphenyl ( p-QP), p-terphenyl ( p-TP) and 1,3,5-triphenylbenzene (TPB) were ground for 2-16 h with a vibrating mill at room temperature. A halo diffraction pattern and exothermic effect due to the crystallization were observed in TMCD-NBA, TMCD-HBA, SUC, SAL, PP and TNB, indicating amorphization of these crystals. The ability of solid-state amorphization in organic molecular crystals was discussed from a thermodynamic point of view.

  15. Structural Relaxations and Thermodynamic Properties of Molecular Amorphous Solids by Mechanical Milling

    NASA Astrophysics Data System (ADS)

    Tsukushi, I.; Yamamuro, O.; Matsuo, T.

    The organic crystals of tri-O-methyl-?-cyclodextrin (TMCD) and its three clathrate compounds containing benzoic acid (BA), p-nitrobenzoic acid (NBA) and p-hydroxybenzoic acid (HBA), sucrose (SUC), salicin (SAL), phenolphthalein (PP), 1,3,5-tri-?-naphthylbenzene (TNB) were amorphized by milling with a vibrating mill for 2 16 hours at room temperature. The amorphization was checked by differential scanning calorimetry (DSC) and X-ray powder diffraction. The heat capacities of crystals, liquid quenched glasses (LQG), and mechanically-milled amorphous solid (MMAS) of TMCD and TNB were measured with an adiabatic calorimeter in the temperature range between 12 and 375 K. For both compounds, the enthalpy relaxation of MMAS appeared in the wide temperature range below Tg and the released configurational enthalpy was much larger than that of LQG, indicating that MMAS is more disordered and strained than LQG.

  16. An automatic system for acidity determination based on sequential injection titration and the monosegmented flow approach.

    PubMed

    Kozak, Joanna; Wjtowicz, Marzena; Gawenda, Nadzieja; Ko?cielniak, Pawe?

    2011-06-15

    An automatic sequential injection system, combining monosegmented flow analysis, sequential injection analysis and sequential injection titration is proposed for acidity determination. The system enables controllable sample dilution and generation of standards of required concentration in a monosegmented sequential injection manner, sequential injection titration of the prepared solutions, data collecting, and handling. It has been tested on spectrophotometric determination of acetic, citric and phosphoric acids with sodium hydroxide used as a titrant and phenolphthalein or thymolphthalein (in the case of phosphoric acid determination) as indicators. Accuracy better than |4.4|% (RE) and repeatability better than 2.9% (RSD) have been obtained. It has been applied to the determination of total acidity in vinegars and various soft drinks. The system provides low sample (less than 0.3 mL) consumption. On average, analysis of a sample takes several minutes. PMID:21641455

  17. Visualization of turbulent reactive mixing in a planar microscale confined impinging-jet reactor

    NASA Astrophysics Data System (ADS)

    Shi, Yanxiang; Somashekar, Vishwanath; Fox, Rodney O.; Olsen, Michael G.

    2011-11-01

    Turbulent reactive mixing in a rectangular microscale confined impinging-jet reactor was investigated using the pH indicator phenolphthalein in this study for three different jet Reynolds numbers Rej = 25, 1000 and 1500. Laminar flow was observed at Rej = 25 whereas the flow was turbulent at Rej = 1000 and 1500. An image processing technique was applied to instantaneous images to extract quantitative mixing data by identifying regions with pH >= 9.3 and regions with pH < 9.3. Ensemble averages were computed using these thresholded images to compare mixing performance between different Reynolds numbers. Finally, the spatial auto-correlation fields of the thresholded image fluctuations were evaluated, based on which large-scale turbulent structures were analyzed.

  18. Sequestration of CO2 by concrete carbonation.

    PubMed

    Galan, Isabel; Andrade, Carmen; Mora, Pedro; Sanjuan, Miguel A

    2010-04-15

    Carbonation of reinforced concrete is one of the causes of corrosion, but it is also a way to sequester CO2. The characteristics of the concrete cover should ensure alkaline protection for the steel bars but should also be able to combine CO2 to a certain depth. This work attempts to advance the knowledge of the carbon footprint of cement. As it is one of the most commonly used materials worldwide, it is very important to assess its impact on the environment. In order to quantify the capacity of cement based materials to combine CO2 by means of the reaction with hydrated phases to produce calcium carbonate, Thermogravimetry and the phenolphthalein indicator have been used to characterize several cement pastes and concretes exposed to different environments. The combined effect of the main variables involved in this process is discussed. The moisture content of the concrete seems to be the most influential parameter. PMID:20225850

  19. Detection of bacterial phosphatase activity by means of an original and simple test.

    PubMed Central

    Satta, G; Grazi, G; Varaldo, P E; Fontana, R

    1979-01-01

    A new test for the detection of bacterial phosphatase activity has been devised. The test is performed using agar media containing both methyl green (MG) and phenolphthalein diphosphate (PDP); in these media phosphatase-producing strains grow deep-green-stained colonies whereas non-producing strains do not. A total of 739 different strains were tested, including 593 staphylococci, 95 micrococci, 11 streptococci, 10 corynebacteria, 14 enterobacteria, and 16 candidae. All strains found phosphatase-positive according to the conventional phosphatase test displayed deep-green-stained colonies on MG-PDP media, whereas all phosphatase-negative strains showed unstained colonies on the same media. The main advantages of the present phosphatase test as compared with other conventional ones are that it is more simple to perform, it can reveal the phosphatase activity of colonies grown in deep agar, and can be incorporated into commercial multitest kits. PMID:87403

  20. Flammability and Photo-Stability of Selected Polymer Systems

    NASA Technical Reports Server (NTRS)

    Lo, Jeelin

    1981-01-01

    A systematic approach to the improvement of the flammability of epoxy resins, bisphenol-A polycarbonate poly(butylene terephthalate), and Nylon 6.6 by introducing halogens and loop functionality into the flame retardants is described. The phthalides (the loop functionality containing molecules) include 3,3-bis(4-bromophenyl)-phthalide, 3,3-bis(4-chlorophenyl)phthalide, and phenolphthalein. The phthalide containing epoxy resins are synthesized and characterized in comparison with the bisphenol-A epoxy resins in terms of flammability in the copolymer systems. The resins include diglycidyl ethers of phenolphthalein, bisphenol-A. tetrabromobisphenol-A, and tetraoromophenolphthalein. The vaporization of the phthalide additive in the polymers is observed in Thermal Gravimetric Analysis. The flame retardancy is primarily due to the presence of halogens. In the poly(butylene terephthalate) system, the cleavage of the C(sub aromatic) -B bond of the flame retardant additive enhances the crosslinking react ions between the aromatic rings resulting in an increase of char formation. In the epoxy resin systems, loop functionality contributes to char formation to a larger extent. The interaction between the epoxy resin and poly-(butylene terephthalate) follows the mechanism of insertion of the oxirane ring into the ester bond. This mechanism is studied by FT-IR. The investigation of the thermal properties of the char-forming phenol-formaldehyde resins is conducted to provide information for the systematic design of high temperature flame-resistant phenolics. NMR and FT-IR are used to characterize the oligomeric resins and the cured resins. The curing agents used in the study include formaldehyde, s-trioxane and terephthaloyl chloride. The brominated phenolic resins are found to have higher oxygen indices with lower char yields.

  1. Design and characterization of a plastic optical fiber pH sensor

    NASA Astrophysics Data System (ADS)

    Ferreira, Licnio; Simes, Pedro; Carvalho, Rui S.; Lopes, Paulo; Ferreira, Mrio

    2013-11-01

    In this paper are present the design and characterization of a pH sensor using plastic optical fiber (POF) technology and a material produced by the sol-gel process with TEOS (tetraethyl orthosilicate) to immobilize universal indicator of pH (comprised of Thymol Blue, Methyl Red, Bromothymol Blue and Phenolphthalein) inside the silica matrix. This matrix is positioned between two extensions of plastic optical fiber tightly positioned at each side with both fibers aligned and sharing a common optical axis. This set will work as a pH sensor since the matrix embedded with indicator and in the presence of a solution (basic or acid solution) will change the optical transmittance properties. The optical source is a superluminescent white LED and the receiver is a photodiode having a good and linear responsivity in the visible spectrum. This pH sensitive matrix has large pores which allow the diffusion of the surrounding fluid molecules into the matrix and thus the close contact of these to the indicator molecules. This contact causes the change of color of the whole matrix allowing proper colorimetric detection by the photodiode. This variation of color associated with the detector wavelength linear response is the base of operation of the proposed device. This pH sensor presents many advantages over the standard and commercial pH meters namely, lightweight, portability and a low cost.

  2. Carbonation and pH in mortars manufactured with supplementary cementitious materials

    SciTech Connect

    McPolin, D.O.; Basheer, P.A.M.; Long, A.E.

    2009-05-15

    An investigation of carbonation in mortars and methods of measuring the degree of carbonation and pH change is presented. The mortars were manufactured using ordinary portland cement, pulverized fuel ash, ground granulated blast-furnace slag, metakaolin, and microsilica. The mortars were exposed to a carbon dioxide-rich environment (5% CO{sub 2}) to accelerate carbonation. The resulting carbonation was measured using phenolphthalein indicator and thermogravimetric analysis. The pH of the pore fluid and a powdered sample, extracted from the mortar, was measured to give an accurate indication of the actual pH of the concrete. The pH of the extracted powder mortar sample was found to be similar to the pH of the pore fluid expressed from the mortars. The thermogravimetric analysis suggested two distinct regions of transport of CO{sub 2} within mortar, a surface region where convection was prevalent and a deeper region where diffusion was dominant. The use of microsilica has been shown to decrease the rate of carbonation, while pulverized fuel ash and ground granulated blast-furnace slag have a detrimental effect on carbonation. Metakaolin has little effect on carbonation.

  3. Analysis of adulterated herbal medicines and dietary supplements marketed for weight loss by DOSY 1H-NMR.

    PubMed

    Vaysse, J; Balayssac, S; Gilard, V; Desoubdzanne, D; Malet-Martino, M; Martino, R

    2010-07-01

    Twenty herbal medicines or dietary supplements marketed as natural slimming products were analysed by diffusion ordered spectroscopy (DOSY) 1H-nuclear magnetic resonance (NMR) and DOSY-COSY 1H-NMR. The method allows analysis of the whole sample with the detection of both active and inactive ingredients in these complex matrices. Among the 20 formulations analysed, two were strictly herbal and four had a composition corresponding to declared ingredients on the packaging or the leaflet. The others were all adulterated. Eight formulations contain sibutramine alone at doses ranging from 4.4 to 30.5 mg/capsule. Five formulations contain sibutramine (from 5.0 to 19.6 mg/capsule or tablet) in combination with phenolphthalein (from 4.4 to 66.1 mg/capsule), and the last formulation was adulterated with synephrine (19.5 mg/capsule). Quantification of the actives was carried out with 1H-NMR. Several other compounds were also characterized including methylsynephrine, vitaberin, sugars, vitamins, etc. DOSY NMR is thus proposed as a useful tool for detection of unexpected adulteration. PMID:20437283

  4. Monitoring accelerated carbonation on standard Portland cement mortar by nonlinear resonance acoustic test

    NASA Astrophysics Data System (ADS)

    Eiras, J. N.; Kundu, T.; Popovics, J. S.; Monzó, J.; Borrachero, M. V.; Payá, J.

    2015-03-01

    Carbonation is an important deleterious process for concrete structures. Carbonation begins when carbon dioxide (CO2) present in the atmosphere reacts with portlandite producing calcium carbonate (CaCO3). In severe carbonation conditions, C-S-H gel is decomposed into silica gel (SiO2.nH2O) and CaCO3. As a result, concrete pore water pH decreases (usually below 10) and eventually steel reinforcing bars become unprotected from corrosion agents. Usually, the carbonation of the cementing matrix reduces the porosity, because CaCO3 crystals (calcite and vaterite) occupy more volume than portlandite. In this study, an accelerated carbonation-ageing process is conducted on Portland cement mortar samples with water to cement ratio of 0.5. The evolution of the carbonation process on mortar is monitored at different levels of ageing until the mortar is almost fully carbonated. A nondestructive technique based on nonlinear acoustic resonance is used to monitor the variation of the constitutive properties upon carbonation. At selected levels of ageing, the compressive strength is obtained. From fractured surfaces the depth of carbonation is determined with phenolphthalein solution. An image analysis of the fractured surfaces is used to quantify the depth of carbonation. The results from resonant acoustic tests revealed a progressive increase of stiffness and a decrease of material nonlinearity.

  5. Effects of subacute treatment with cocaine on activities of n-demethylase, UDP-glucuronyltransferase and sulfotransferase in WKY and SHR rat liver - sex and strain differences

    SciTech Connect

    Watanabe, H.K.; Hoskins, B.; Ho, I.K.

    1988-01-01

    The effects of subacute treatment with cocaine on activities of cocaine N-demethylase, UDP-glucuronyltransferase (GT) toward 4-nitrophenol and phenolphthalein and sulfotransferase (ST) toward androsterone and 4-nitrophenol in livers from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were investigated. Hepatic metabolism of cocaine was different between the sexes (with males having higher N-demethylase activity) and the strains (with WKY rats having higher activity). The effects of subacute cocaine administration on the activity of cocaine N-demethylase were also sex- and strain-related. Whereas cocaine administration increased activity of hepatic N-demethylase in both female strains, it decreased activity in male WKY and had no effect on activity in male SHR. Sex and strain-related as well as cocaine-induced differences were also found in activities of hepatic GT toward 4-nitrophenol and phenolphtalein as well as in activity of hepatic ST towards andersterone and 4-nitrophenol. These results suggest that some of the individual variation in the effects of cocaine may be due to sex and genetic differences in the hepatic metabolism of cocaine and/or in sexually and/or genetically-determined differences in how cocaine affects hepatic metabolism of other xenobiotics. 20 references, 4 figures.

  6. Solvothermal synthesis of V{sub 4}O{sub 9} flake-like morphology and its photocatalytic application in the degradation of methylene blue

    SciTech Connect

    Chine, M.K.; Sediri, F.; Gharbi, N.

    2012-11-15

    Highlights: ► Flake-like nanocrystalline V{sub 4}O{sub 9} was synthesized by a solvothermal route. ► Photocatalytic activity has been evaluated by the degradation of methylene blue under visible light irradiation. ► V{sub 4}O{sub 9} nanoflakes exhibited much higher photocatalytic activity two times higher than the bulk V{sub 2}O{sub 5}. -- Abstract: Flake-like nanocrystalline V{sub 4}O{sub 9} has been successfully synthesized by solvothermal process using V{sub 2}O{sub 5} as vanadium source and phenolphthalein as a reducing agent and a structure-directing template. Techniques X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and ultraviolet–visible (UV–vis) spectroscopy have been used to characterize the structure, the morphology and the composition of the material. The photocatalytic activity of the material has been evaluated by the degradation of methylene blue under visible light irradiation. As a result, after the lapse of 150 min, around 93.54% bleaching was observed, with V{sub 4}O{sub 9} nanoflakes yielding more photodegradation compared to that of bulk V{sub 2}O{sub 5}. This presents a degradation percentage of about 44.67%.

  7. Time evolution of the fractal dimension of a mixing front

    NASA Astrophysics Data System (ADS)

    Lopez Gonzalez-Nieto, P.; Grau, J.

    2009-04-01

    We present a description of an experimental study of an array of turbulent plumes (from one to nine plumes), investigating the time evolution of the fractal dimension of the plumes and also the spatial evolution of the fractal dimension from one plume to other. We also investigate the effects of bouyancy (different Atwood numbers), the number of plumes and the height of the bouyancy source on the fractal dimension. The plumes are formed by injecting a dense fluid from a small source (from one to nine orifices) into a stationary body of lighter brime (saline solution) contained in a tank. The source fluid was dyed with fluorescein and we use the LIF technique. The plumes were fully turbulent and we have both momentum and bouyancy regimes. The fractal dimensions of contours of concentration were measured. The fractal analysis of the turbulent convective plumes was performed with the box counting algorithm for different intensities of evolving plume images using the special software Ima_Calc. Fractal dimensions between 1.3 and 1.35 are obtained from box counting methods for free convection and neutral boundary layers. Other results have been published which use the box counting method to analyze images of jet sections -produced from LIF techniques. The regions where most of the mixing takes place are also compared with Reactive flow experiments using phenolphthalein and acid-base interfaces performed by Redondo(1994) IMA 43. Eds M. Farge, JC Hunt and C. Vassilicos.

  8. Tracer-monitored flow titrations.

    PubMed

    Sasaki, Milton K; Rocha, Diogo L; Rocha, Fábio R P; Zagatto, Elias A G

    2016-01-01

    The feasibility of implementing tracer-monitored titrations in a flow system is demonstrated. A dye tracer is used to estimate the instant sample and titrant volumetric fractions without the need for volume, mass or peak width measurements. The approach was applied to spectrophotometric flow titrations involving variations of sample and titrant flow-rates (i.e. triangle programmed technique) or concentration gradients established along the sample zone (i.e. flow injection system). Both strategies required simultaneous monitoring of two absorbing species, namely the titration indicator and the dye tracer. Mixing conditions were improved by placing a chamber with mechanical stirring in the analytical path aiming at to minimize diffusional effects. Unlike most of flow-based titrations, the innovation is considered as a true titration, as it does not require a calibration curve thus complying with IUPAC definition. As an application, acidity evaluation in vinegars involving titration with sodium hydroxide was selected. Phenolphthalein and brilliant blue FCF were used as indicator and dye tracer, respectively. Effects of sample volume, titrand/titrant concentrations and flow rates were investigated aiming at improved accuracy and precision. Results were reliable and in agreement with those obtained by a reference titration procedure. PMID:26703261

  9. A Low-Cost Device for Automatic Photometric Titrations

    NASA Astrophysics Data System (ADS)

    Rocha, Fbio R. P.; Reis, Boaventura F.

    2000-02-01

    Electronics is an important topic in chemistry courses. However, the introduction of basic concepts is often difficult and the lab instruments are frequently seen as "black boxes". To address this problem, we propose the construction of a simple, low-cost (about $150 U.S.) automatic photometric titrator employing a light-emitting diode (LED) and a phototransistor. The electronic circuit can be assembled by the students themselves. The device was employed to implement a common procedure in chemical labs, making feasible the introduction of concepts related to electronics in undergraduate chemistry courses. The titrator is able to work automatically, since a feedback system permits stopping the addition of titrant solution when the end-point is achieved. With this demonstration, it can be stressed that automatic procedures can be implemented without expensive instruments. Additionally, a classical procedure becomes more attractive to the students and its importance to chemical analysis can be emphasized. The feasibility of the titrator was demonstrated by acid-base titrations of HCl solutions with NaOH in the presence of phenolphthalein and by iodimetric determination of ascorbic acid in vitamin C tablets and lemon juice. Precise results (0.7% relative standard deviation, n = 10) in agreement at the 95% confidence level with those attained by a conventional procedure were obtained.

  10. Qualitative Analysis of Fourteen White Solids and Two Mixtures Using Household Chemicals

    NASA Astrophysics Data System (ADS)

    Oliver-Hoyo, Maria; Allen, Deedee; Solomon, Sally; Brook, Bryan; Ciraolo, Justine; Daly, Shawn; Jackson, Leia

    2001-11-01

    This is a revised and expanded version of a previously published qualitative analysis scheme for the identification of 11 white solids using materials readily available in drugstores, supermarkets, or variety stores. Phenolphthalein has been eliminated because the FDA banned its use in over-the-counter laxatives; instead, tests for pH are conducted using red cabbage indicator. Once commonly used by diabetics to test urine, copper reduction tablets are no longer widely available and are replaced by a mixture of ingredients. Three white solids and two types of mixtures, commercial antacid tablets and baking powder, have been added to the scheme. All procedures can be done with the simplest of equipment. Amounts of solids are measured volumetrically and heat is supplied by contact with hot tap water. The use of household chemicals reduces waste disposal problems while making the experiment suitable for a laboratory exercise in a distance-learning course. This experiment can be adapted for many levels of instruction. In middle school only the safer tests should be included; honors general chemistry students can be asked to design an analysis scheme for the 14 household chemicals.

  11. Number of bacteria decomposing organic phosphorus compounds and phosphatase activity in the sand of two marine beaches differing in the level of anthropopressure.

    PubMed

    Mudryk, Z J; Perli?ski, P; Antonowicz, J; Robak, D

    2015-12-30

    Number of heterotrophic bacteria ability to decompose organic phosphorus compounds and the level of phosphatase activity in the sand of two marine beaches (southern coast of the Baltic Sea) differing in the level of anthropopressure were studied. The study showed that the number of bacteria and level phosphatase activity were higher in the sand of the beach subjected to stronger anthropopressure. In both studied beaches bacteria hydrolysing DNA were the most numerous (92.7-302.8CFUg(-1) d.w.). The least numerous were phytin (26.010(3)CFUg(-1) d.w.) and phenolphthalein diphosphate (11.110(3)CFUg(-1) d.w.) decomposing bacteria. Number of bacteria able to attack tested organic phosphorus compounds were the most numerous in dry zones (10.77-739.92CFUg(-1) d.w.) then wet zones (3.34-218.15CFUg(-1) d.w.). In both studied beaches bacteria hydrolysing organic phosphorus compounds and phosphatase activity generally were more numerous in surface sand layer. Seasonal variation in the occurrence of bacteria in both studied beaches was observed. PMID:26522162

  12. Electric charge-mediated coalescence of water droplets for biochemical microreactors

    PubMed Central

    Jung, Yong-Mi; Kang, In Seok

    2010-01-01

    This work proposes the use of charged droplets driven by the Coulombic force as solution-phase reaction chambers for biological microreactions. A droplet can be charged near an electrode under dc voltage by direct contact to the electrode. This process is called electrical charging of droplet (ECOD). This charged droplet can then be transported rapidly between electrodes following the arc of an electric field line by exploiting electrostatic force. As on-demand electrocoalescence, both alkalization of phenolphthalein and bioluminescence reaction of luciferase in the presence of adenosine triphosphate are studied to test the feasibility of the biochemical microreactors using ECOD. Two oppositely charged droplets are merged to have a color change immediately after microchemical reaction. The applicability of an ECOD-driven droplet to measurement of glucose concentration is also tested. The glucose concentration is measured using a colorimetric enzyme-kinetic method based on Trinders reaction [J. Clin. Pathol. 22, 158 (1969)]. The color change in the merged droplet is detected with an absorbance measurement system consisting of a photodiode and a light emitting diode. PMID:20697585

  13. Quantitative estimation of carbonation and chloride penetration in reinforced concrete by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Eto, Shuzo; Matsuo, Toyofumi; Matsumura, Takuro; Fujii, Takashi; Tanaka, Masayoshi Y.

    2014-11-01

    The penetration profile of chlorine in a reinforced concrete (RC) specimen was determined by laser-induced breakdown spectroscopy (LIBS). The concrete core was prepared from RC beams with cracking damage induced by bending load and salt water spraying. LIBS was performed using a specimen that was obtained by splitting the concrete core, and the line scan of laser pulses gave the two-dimensional emission intensity profiles of 100 80 mm2 within one hour. The two-dimensional profile of the emission intensity suggests that the presence of the crack had less effect on the emission intensity when the measurement interval was larger than the crack width. The chlorine emission spectrum was measured without using the buffer gas, which is usually used for chlorine measurement, by collinear double-pulse LIBS. The apparent diffusion coefficient, which is one of the most important parameters for chloride penetration in concrete, was estimated using the depth profile of chlorine emission intensity and Fick's law. The carbonation depth was estimated on the basis of the relationship between carbon and calcium emission intensities. When the carbon emission intensity was statistically higher than the calcium emission intensity at the measurement point, we determined that the point was carbonated. The estimation results were consistent with the spraying test results using phenolphthalein solution. These results suggest that the quantitative estimation by LIBS of carbonation depth and chloride penetration can be performed simultaneously.

  14. Therapeutic proposals for the treatment of idiopathic constipation.

    PubMed

    Sez, L R

    1991-11-01

    The objectives to be achieved by a medical therapy of constipation are: 1) to protect the patient from excessive use of dangerous drugs (laxatives), 2) to help the patient to understand what is a "normal" intestinal function, 3) to reduce or eliminate pain and 4) to avoid complications. The first step consists in general measures (reduced stress, regular meals and physical exercise) and some modifications in diet habits (greater than 1.5 1 of water a day, vegetables, fruits, whole wheat bread). The pharmacological therapy is based on drugs which act in different ways: a) some contain unabsorbable substances (i.e. cellulose, emicellulose) that increase the volume of the stools: b) unabsorbable sugars (i.e. lactulose, lactose) or salts (Mg-sulphate, citrate and Na-sulphate) that provoke an osmotic effect and stimulate the colonic motility; c) suppositories that stimulate the defecation reflex; d) drugs able to stimulate colonic secretion and propulsive motility (i.e. anthraquinones, oral bisacodyl, phenolphthalein, castor oil, prokinetics). There are many conditions in which medical therapy fails its objective: in these cases it is important to exclude other causes of constipation (i.e. drug-related constipation, endocrine disorders, metabolic diseases, systemic illnesses or lesion of the enteric plexus) in order to obtain an improvement of this symptom. PMID:1661627

  15. Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid.

    PubMed

    Lenghor, Narong; Jakmunee, Jaroon; Vilen, Michael; Sara, Rolf; Christian, Gary D; Grudpan, Kate

    2002-12-01

    Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l(-1) was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l(-1) ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid-base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2-8% w v(-1) of acetic acid with a relative standard deviation of 4.8% (5.0% w v(-1) acetic acid, n=11) was obtained. Sample throughputs of 60 h(-1) were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively. PMID:18968850

  16. A screening method for establishing laxative abuse.

    PubMed

    de Wolff, F A; de Haas, E J; Verweij, M

    1981-06-01

    Abuse of laxatives, most of them belonging to the group of colonic stimulants or cathartics, can cause various disorders. Extensive diagnostic work can be avoided by early toxicological screening of the suspected patients with respect to laxatives. Because no screening method of this kind was available, we developed a procedure with which all phenolic and anthraquinone laxatives--except sodium picosulfate--can be detected in urine. This method is based on high-performance thin-layer chromatography in two systems after pretreatment of a 20-mL urine sample with beta-glucuronidase and subsequent column extraction. The procedure is very sensitive: at least 32 h after a single dose of bisacodyl, danthron, phenolphthalein, or sennoside, the drug can be detected in the urine. Bisoxatin and oxyphenisatin are still detectable in the urine 18 h after intake. The method is also highly specific; none of 73 other drugs interfered in either of the two chromatographic systems. This procedure can be helpful for the early diagnosis of laxative abuse. PMID:6894566

  17. Structure and properties of PVDF membrane with PES-C addition via thermally induced phase separation process

    NASA Astrophysics Data System (ADS)

    Wu, Lishun; Sun, Junfen

    2014-12-01

    Polyvinylidene fluoride (PVDF) membrane and PVDF membrane with phenolphthalein polyethersulfone (PES-C) addition were prepared via thermally induced phase separation (TIPS) method by using diphenyl carbonate (DPC) and dimethyl acetamide (DMAc) as mixed diluents. The effects of coagulation temperature and pre-evaporation time on structure and properties of membranes were studied. The changes of sewage flux in MBR and the attenuation coefficient of sewage flux were investigated. The resistance distributions of PVDF and PVDF/PES-C membranes were compared by resistance analysis. Membrane composition and structure were characterized by ATR-FTIR, TGA, SEM and AFM. The foulant on membranes was analyzed by FTIR. The contact angle of PVDF/PES-C membrane was lower than that of PVDF membrane. A thinner skin layer and a porous cellular support layer formed in PVDF/PES-C membrane and resulted in a higher porosity and pure water flux. The pure water flux and porosity of PVDF/PES-C membrane increased with rising coagulation temperature and decreased with extending pre-evaporation time. The flux attenuation coefficient, the cake layer resistance and internal fouling resistance of PVDF/PES-C membrane in MBR were smaller than those of PVDF membrane in MBR. The FTIR spectrum of foulant on membrane indicated that the foulant on PVDF/PES-C membrane was mostly composed of protein and polysaccharide, while the foulant on pure PVDF membrane included biopolymer clusters besides protein and polysaccharide.

  18. Functional heterogeneity of UDP-glucuronosyltransferase as indicated by its differential development and inducibility by glucocorticoids. Demonstration of two groups within the enzyme's activity towards twelve substrates.

    PubMed Central

    Wishart, G J

    1978-01-01

    1. UDP-glucuronosyltransferase activity towards 12 substrates has been assessed in rat liver during the perinatal period. 2. Between days 16 and 20 of gestation, enzyme activities towards the substrates 2-aminophenol, 2-aminobenzoate, 4-nitrophenol, 1-naphthol, 4-methylumbelliferone and 5-hydroxytryptamine (the 'late foetal' group) surge to reach adult values, while activities towards bilirubin, testosterone, beta-oestradiol, morphine, phenolphthalein, and chloramphenicol (the 'neonatal' group) remain negligible or at less than 10% of adult values. 3. By the second postnatal day, enzyme activities towards the neonatal group have attained, or approached adult values. 4. Dexamethasone precociously stimulates in 17-day foetal liver in utero transferase activities in the late foetal, but not the neonatal group. A similar inductive pattern is found for 15-day foetal liver in organ culture. 5. It is suggested that foetal glucocorticoids, whose synthesis markedly increases between days 16 and 20 of gestation, are responsibile for triggering the simultaneous surge of all the hepatic UDP-glucuronosyltransferase activities in the late foetal group. The neonatal group of activities apparently require a different or additional stimulus for their appearance. 6. The relationship of these two groups of transferase activities to other similar groups observed during induction by xenobiotics and enzyme purification is discussed. PMID:101211

  19. A new cyclodextrin-grafted viscose loaded with aescin formulations for a cosmeto-textile approach to chronic venous insufficiency.

    PubMed

    Cravotto, G; Beltramo, L; Sapino, S; Binello, A; Carlotti, M E

    2011-10-01

    Cosmeto-textile applications can be used in the treatment of chronic venous insufficiency in legs by means of elastic bandages loaded with natural products which possess flebotonic properties. We have developed an efficient synthetic procedure for the preparation of ?-cyclodextrin (?-CD)-grafted viscose by means of a 2-step ultrasound-assisted reaction. The highly grafted fabric bearing bis-urethane bridged ?-CD has been characterized by ATR-FTIR and CP-MAS spectra and by an empiric colorimetric method which used phenolphthalein as the CD guest. We have also developed a suitable cosmetic preparation containing natural substances and extracts (aescin, menthol, Centella asiatica and Ginkgo biloba) to recharge the CD-grafted textile. The efficacy of the new cosmeto-textile has been corroborated by in vitro studies of diffusion through membranes, cutaneous permeation and accumulation in porcine skin. Aescin was taken as a reference compound and its concentration in the different compartments was monitored by HPLC analysis. This cost effective cosmeto-textile shows excellent application compliance and is easily recharged and so has the strong base characteristics needed for possible industrial production. PMID:21805331

  20. A Full Automatic Device for Sampling Small Solution Volumes in Photometric Titration Procedure Based on Multicommuted Flow System

    PubMed Central

    Borges, Sivanildo S.; Vieira, Gláucia P.; Reis, Boaventura F.

    2007-01-01

    In this work, an automatic device to deliver titrant solution into a titration chamber with the ability to determine the dispensed volume of solution, with good precision independent of both elapsed time and flow rate, is proposed. A glass tube maintained at the vertical position was employed as a container for the titrant solution. Electronic devices were coupled to the glass tube in order to control its filling with titrant solution, as well as the stepwise solution delivering into the titration chamber. The detection of the titration end point was performed employing a photometer designed using a green LED (λ=545 nm) and a phototransistor. The titration flow system comprised three-way solenoid valves, which were assembled to allow that the steps comprising the solution container loading and the titration run were carried out automatically. The device for the solution volume determination was designed employing an infrared LED (λ=930 nm) and a photodiode. When solution volume delivered from proposed device was within the range of 5 to 105 μl, a linear relationship (R = 0.999) between the delivered volumes and the generated potential difference was achieved. The usefulness of the proposed device was proved performing photometric titration of hydrochloric acid solution with a standardized sodium hydroxide solution and using phenolphthalein as an external indicator. The achieved results presented relative standard deviation of 1.5%. PMID:18317510

  1. A serpentine laminating micromixer combining splitting/recombination and advection.

    PubMed

    Kim, Dong Sung; Lee, Se Hwan; Kwon, Tai Hun; Ahn, Chong H

    2005-07-01

    Mixing enhancement has drawn great attention from designers of micromixers, since the flow in a microchannel is usually characterized by a low Reynolds number (Re) which makes the mixing quite a difficult task to accomplish. In this paper, a novel integrated efficient micromixer named serpentine laminating micromixer (SLM) has been designed, simulated, fabricated and fully characterized. In the SLM, a high level of efficient mixing can be achieved by combining two general chaotic mixing mechanisms: splitting/recombination and chaotic advection. The splitting and recombination (in other terms, lamination) mechanism is obtained by the successive arrangement of "F"-shape mixing units in two layers. The advection is induced by the overall three-dimensional serpentine path of the microchannel. The SLM was realized by SU-8 photolithography, nickel electroplating, injection molding and thermal bonding. Mixing performance of the SLM was fully characterized numerically and experimentally. The numerical mixing simulations show that the advection acts favorably to realize the ideal vertical lamination of fluid flow. The mixing experiments based on an average mixing color intensity change of phenolphthalein show a high level of mixing performance was obtained with the SLM. Numerical and experimental results confirm that efficient mixing is successfully achieved from the SLM over the wide range of Re. Due to the simple and mass producible geometry of the efficient micromixer, SLM proposed in this study, the SLM can be easily applied to integrated microfluidic systems, such as micro-total-analysis-systems or lab-on-a-chip systems. PMID:15970967

  2. Detection of hazardous weight-loss substances in adulterated slimming formulations using ultra-high-pressure liquid chromatography with diode-array detection.

    PubMed

    Rebiere, H; Guinot, P; Civade, C; Bonnet, P-A; Nicolas, A

    2012-01-01

    The presence on the market of illegal products for slimming purposes or the treatment of overweight is a public health issue. These products may contain illicit chemicals in order to improve their effectiveness. Some of these weight-loss compounds are responsible for adverse events, including fatal outcomes. A general strategy for the analysis of any suspect formulation begins with a large screening for the general search of a wide range of compounds. A methodology for the qualitative and quantitative determination of 34 compounds in slimming preparations (such as dietary supplements or medicinal products) was used for the control of slimming formulations from the market, including over the Internet. The fast liquid chromatography system (ultra-high-pressure liquid chromatography) used a gradient of solvent (phosphate buffer and acetonitrile), a C18 endcapped column and a diode array detector. This system allows dual identification based on retention time and UV spectra. The analytical method is simple, fast and selective since 34 weight-loss compounds can be detected in a 15-min run time. Thus, 32 commercial slimming formulations were analysed using this method, allowing the detection and quantification of hazardous active substances: caffeine, clenbuterol, nicotinamide, phenolphthalein, rimonabant, sibutramine, didesmethylsibutramine, synephrine and yohimbine. PMID:22150438

  3. An improved microfluidics approach for monitoring real-time interaction profiles of ultrafast molecular recognition

    NASA Astrophysics Data System (ADS)

    Batabyal, Subrata; Rakshit, Surajit; Kar, Shantimoy; Pal, Samir Kumar

    2012-04-01

    Our study illustrates the development of a microfluidics (MF) platform combining fluorescence microscopy and femtosecond/picosecond-resolved spectroscopy to investigate ultrafast chemical processes in liquid-phase diffusion-controlled reactions. By controlling the flow rates of two reactants in a specially designed MF chip, sub-100 ns time resolution for the exploration of chemical intermediates of the reaction in the MF channel has been achieved. Our system clearly rules out the possibility of formation of any intermediate reaction product in a so-called fast ionic reaction between sodium hydroxide and phenolphthalein, and reveals a microsecond time scale associated with the formation of the reaction product. We have also used the developed system for the investigation of intermediate states in the molecular recognition of various macromolecular self-assemblies (micelles) and genomic DNA by small organic ligands (Hoechst 33258 and ethidium bromide). We propose our MF-based system to be an alternative to the existing millisecond-resolved "stopped-flow" technique for a broad range of time-resolved (sub-100 ns to minutes) experiments on complex chemical/biological systems.

  4. Use of trehalose-mannitol-phosphatase agar to differentiate Staphylococcus epidermidis and Staphylococcus saprophyticus from other coagulase-negative staphylococci.

    PubMed Central

    Stevens, D L; Jones, C

    1984-01-01

    Using a plate medium containing trehalose, mannitol, and phenolphthalein diphosphate (TMPA), we differentiated significant clinical isolates of Staphylococcus epidermidis by their lack of acid production in 18 h from other coagulase-negative staphylococci, with our results having a sensitivity (R. S. Galen and S. R. Gambino, Beyond Normality: The Predictive Value and Efficiency of Medical Diagnoses) of 100%, a specificity of 89.9%, and a positive predictive value of 94.8%. With a Taxo A bacitracin disk, which differentiates Staphylococcus species from Micrococcus species, no zone of inhibition was seen for 96% of all staphylococcal strains, with 5 of 26 strains of Staphylococcus saprophyticus exhibiting zone diameters up to 10 mm. By using resistance to a 5-microgram novobiocin disk, we differentiated S. saprophyticus, with our results having a sensitivity of 100%, a specificity of 97.1%, and a positive predictive value of 83.9% on TMPA. These two species represented 77.8% of coagulase-negative staphylococci isolated. Reference strains fo Staphylococcus and Micrococcus species were differentiated by TMPA. The cost of TMPA was compared with that of another method. TMPA was found to offer an inexpensive, sensitive method for rapidly differentiating coagulase-negative Staphylococcus isolates. PMID:6096398

  5. Immobilized ?-cyclodextrin on surface-modified carbon-coated cobalt nanomagnets: reversible organic contaminant adsorption and enrichment from water.

    PubMed

    Fuhrer, Roland; Herrmann, Inge K; Athanassiou, Evagelos K; Grass, Robert N; Stark, Wendelin J

    2011-03-01

    Surface-modified magnetic nanoparticles can be used in extraction processes as they readily disperse in common solvents and combine high saturation magnetization with excellent accessibility. Reversible and recyclable adsorption and desorption through solvent changes and magnetic separation provide technically attractive alternatives to classical solvent extraction. Thin polymer layered carbon-coated cobalt nanoparticles were tagged with ?-cyclodextrin. The resulting material reversibly adsorbed organic contaminants in water within minutes. Isolation of the immobilized inclusion complex was easily carried out within seconds by magnetic separation due to the strong magnetization of the nanomagnets (metal core instead of hitherto used iron oxide). The trapped molecules were fully and rapidly recovered by filling the cyclodextrin cavity with a microbiologically well accepted substitute, e.g., benzyl alcohol. Phenolphthalein was used as a model compound for organic contaminants such as polychlorinated dibenzodioxins (PCDDs) or bisphenol A (BPA). Fast regeneration of nanomagnets (compared to similar cyclodextrin-based systems) under mild conditions resulted in 16 repetitive cycles (adsorption/desorption) at full efficiency. The high removal and regeneration efficiency was examined by UV-vis measurements at chemical equilibrium conditions and under rapid cycling (5 min). Experiments at ultralow concentrations (160 ppb) underline the high potential of cyclodextrin modified nanomagnets as a fast, recyclable extraction method for organic contaminants in large water streams or as an enrichment tool for analytics. PMID:21244073

  6. A novel eco-friendly technique for efficient control of lime water softening process.

    PubMed

    Ostovar, Mohamad; Amiri, Mohamad

    2013-12-01

    Lime softening is an established type of water treatment used for water softening. The performance of this process is highly dependent on lime dosage. Currently, lime dosage is adjusted manually based on chemical tests, aimed at maintaining the phenolphthalein (P) and total (M) alkalinities within a certain range (2 P - M > or = 5). In this paper, a critical study of the softening process has been presented. It has been shown that the current method is frequently incorrect. Furthermore, electrical conductivity (EC) has been introduced as a novel indicator for effectively characterizing the lime softening process.This novel technique has several advantages over the current alkalinities method. Because no chemical reagents are needed for titration, which is a simple test, there is a considerable reduction in test costs. Additionally, there is a reduction in the treated water hardness and generated sludge during the lime softening process. Therefore, it is highly eco-friendly, and is a very cost effective alternative technique for efficient control of the lime softening process. PMID:24597044

  7. Modulation of rat intestinal nuclear factor NF-kappaB by gum arabic.

    PubMed

    Wapnir, Raul A; Sherry, Barbara; Codipilly, Champa N; Goodwin, Leslie O; Vancurova, Ivana

    2008-01-01

    The objective of this study was to test the hypothesis that in an animal model of cathartic-induce intestinal dysfunction the proabsorptive effects of gum arabic (GA) could be associated with modulation of nuclear factor-kappaB (NF-kappaB) and with reduction of the inflammatory response caused by cathartics, as evidenced by intestinal mucosa cytokine production and gene expression. Juvenile male rats were given a phenolphthalein-magnesium citrate solution for 6 days, by itself or supplemented with either 10 or 20 g L(-1) GA, as a sole source of fluid. The controls given were tap water alone or with added 20 g L(-1) GA. The animals were euthanized and small-intestinal mucosa nuclear fractions and RNA were isolated. NF-kappaB p65 activity was highest after administration of cathartics, lowest in controls, and intermediate in GA-treated rats. Mucosal IL-1beta was overexpressed in tissues from cathartic-treated rats and from rats given high-GA solutions. Gene-array analysis revealed a complex pattern of gene regulation by cathartics which selectively upregulated several subfamilies of cytochrome P-450 family 2 genes. Co-administration of GA did not block this effect. These findings suggest that local anti-inflammatory effects on the small intestine could be obtained by administration of a nonabsorbable proteoglycan such as GA. PMID:17486449

  8. Novel approaches to analysis by flow injection gradient titration.

    PubMed

    Wjtowicz, Marzena; Kozak, Joanna; Ko?cielniak, Pawe?

    2007-09-26

    Two novel procedures for flow injection gradient titration with the use of a single stock standard solution are proposed. In the multi-point single-line (MP-SL) method the calibration graph is constructed on the basis of a set of standard solutions, which are generated in a standard reservoir and subsequently injected into the titrant. According to the single-point multi-line (SP-ML) procedure the standard solution and a sample are injected into the titrant stream from four loops of different capacities, hence four calibration graphs are able to be constructed and the analytical result is calculated on the basis of a generalized slope of these graphs. Both approaches have been tested on the example of spectrophotometric acid-base titration of hydrochloric and acetic acids with using bromothymol blue and phenolphthalein as indicators, respectively, and sodium hydroxide as a titrant. Under optimized experimental conditions the analytical results of precision less than 1.8 and 2.5% (RSD) and of accuracy less than 3.0 and 5.4% (relative error (RE)) were obtained for MP-SL and SP-ML procedures, respectively, in ranges of 0.0031-0.0631 mol L(-1) for samples of hydrochloric acid and of 0.1680-1.7600 mol L(-1) for samples of acetic acid. The feasibility of both methods was illustrated by applying them to the total acidity determination in vinegar samples with precision lower than 0.5 and 2.9% (RSD) for MP-SL and SP-ML procedures, respectively. PMID:17903467

  9. Physical Selectivity of Molecularly Imprinted polymers evaluated through free volume size distributions derived from Positron Lifetime Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pasang, T.; Ranganathaiah, C.

    2015-06-01

    The technique of imprinting molecules of various sizes in a stable structure of polymer matrix has derived multitudes of applications. Once the template molecule is extracted from the polymer matrix, it leaves behind a cavity which is physically (size and shape) and chemically (functional binding site) compatible to the particular template molecule. Positron Annihilation Lifetime Spectroscopy (PALS) is a well known technique to measure cavity sizes precisely in the nanoscale and is not being used in the field of MIPs effectively. This method is capable of measuring nanopores and hence suitable to understand the physical selectivity of the MIPs better. With this idea in mind, we have prepared molecular imprinted polymers (MIPs) with methacrylicacid (MAA) as monomer and EGDMA as cross linker in different molar ratio for three different size template molecules, viz. 4-Chlorophenol (4CP)(2.29 ), 2-Nephthol (2NP) (3.36 ) and Phenolphthalein (PP) (4.47). FTIR and the dye chemical reactions are used to confirm the complete extraction of the template molecules from the polymer matrix. The free volume size and its distribution have been derived from the measured o-Ps lifetime spectra. Based on the free volume distribution analysis, the percentage of functional cavities for the three template molecules are determined. Percentage of functional binding cavities for 4-CP molecules has been found out to be 70.2% and the rest are native cavities. Similarly for 2NP it is 81.5% and nearly 100% for PP. Therefore, PALS method proves to be very precise and accurate for determining the physical selectivity of MIPs.

  10. Poly(ε-caprolactone) nanowebs functionalized with α- and γ-cyclodextrins.

    PubMed

    Narayanan, Ganesh; Gupta, Bhupender S; Tonelli, Alan E

    2014-11-10

    The effects of alpha- and gamma-cyclodextrins (α- and γ-CDs) on the thermal and crystal nucleation behavior of electrospun poly(ε-caprolactone) (PCL) nanofibers have been investigated. PCL/CD composite nanofibers were obtained for the first time by electrospinning the mixture from chloroform/N,N-dimethylformamide (60:40). Scanning electron microscopy analyses indicated that neat PCL nanofibers have an average diameter of 400 nm, which increases with the addition of CDs. The presence of CDs on or in the electrospun PCL fibers in the electrospun mats was investigated using Fourier transform infrared spectroscopy, thermogravimetric analysis, and wide-angle X-ray diffraction analysis. Differential scanning calorimetry showed that the PCL/CD composite fibers exhibit higher crystallization temperatures and sharper crystallization exotherms with increased CD loading, indicating the ability of CDs to nucleate PCL crystallization. Water contact angle (WCA) measurements indicate an inverse relationship between WCA and α- or γ-CD concentration up to 30% loading. Phenolphthalein absorption tests were performed to study the kinetics of their inclusion complex (IC) formation with CDs. Unexpectedly, γ-CD-functionalized nanowebs performed better than α-CD. This might be because at elevated loadings some α-CDs may have threaded over PCL chains and formed ICs, whereas γ-CD did not. With their encapsulation capabilities and their lowered hydrophobicity, PCL/CD composite fibers might have potential uses in medical applications, in particular as wound odor absorbants in dressings, because it is well known that CDs can form ICs with these odorants, thereby effectively removing them. PMID:25296366

  11. Study of dynamics and crystallization kinetics of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile at ambient and elevated pressure

    NASA Astrophysics Data System (ADS)

    Adrjanowicz, K.; Kaminski, K.; Paluch, M.; Ngai, K. L.; Yu, Lian

    2012-06-01

    The organic liquid ROY, i.e., 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, has been a subject of detailed study in the last few years. One interest in ROY lies in its polymorph-dependent fast crystal growth mode below and above the glass transition temperature. This growth mode is not diffusion controlled, and the possibility that it is enabled by secondary relaxation had been suggested. However, a previous study by dielectric relaxation spectroscopy had not been able to find any resolved secondary relaxation. The present paper reports new dielectric measurements of ROY in the liquid and glassy states at ambient pressure and elevated pressure, which were performed to provide more insight into the molecular dynamics as well as the crystallization tendency of ROY. In the search of secondary relaxation, a special glassy state of ROY was prepared by applying high pressure to the liquid state, from which secondary relaxation was possibly resolved. Thus, the role of secondary relaxation in crystallization of ROY remains to be clarified. Notwithstanding, the secondary relaxation present is not necessarily the sole enabler of crystallization. In an effort to search for possible cause of crystallization other than secondary relaxation, we also performed crystallization kinetics studies of ROY at different T and P combinations while keeping the structural relaxation time constant. The results show that crystallization of ROY speeds up with pressure, opposite to the trend found in the crystallization of ibuprofen studied up to 1 GPa. The dielectric relaxation and thermodynamic properties of ROY with phenolphthalein dimethylether (PDE) are similar in many respects, but PDE does not crystallize. Taking all the above into account, besides the secondary relaxation, the specific chemical structure, molecular interactions and packing of the molecules are additional factors that could affect the kinetics of crystallization found in ROY.

  12. [Preparation of molecularly imprinted polymers using dummy template and the applications in selective solid-phase extraction of seven bisphenols from human urine, bovine serum and beer samples].

    PubMed

    Yang, Jiajia; Li, Yun; Wang Jinchengt; Sun, Xiaoli; Chen, Jiping

    2015-05-01

    A molecularly imprinted polymer (MIP) for selective recognition of seven bisphenols (BPs) was prepared using dummy template phenolphthalein (PP) by bulk polymerization. The characterization results of scanning electron microscopy and nitrogen adsorption-desorption measurements showed that the prepared PP-MIP possessed narrow particle diameter distribution (40-60 m), a specific surface area (S(BET)) of 359.77 m2/g and a total pore volume (Vt) of 0.730 cm3/g. The adsorption capacity for bisphenol A (BPA) of PP-MIP was evaluated by static adsorption experiment. And the Scatchard analysis revealed that the maximum specific adsorption capacity of PP-MIP was 4.661 mol/g. Good class selectivity for BPA and its six structural analogues of bisphenol B (BPB) , bisphenol E (BPE), bisphenol AF (BPAF), bisphenol S (BPS), bisphenol AP (BPAP) and bisphenol Z (BPZ) was demonstrated by the chromatographic evaluation experiment. The prepared PP-MIP was successfully used as solid-phase extraction (SPE) sorbent for the separation and purification of the seven BPs in human urine, bovine serum and beer samples. Meanwhile, an accurate and sensitive MIP-SPE-HPLC method was established for the determination of the seven BPs in human urine, bovine serum and beer samples. The limits of detection (LODs) for the three samples were in the range of 1.2-2.0 g/L. The results showed that good linearities were obtained in the range of 0.02-2 mg/L for the seven BPs and the correlation coefficients (r) were higher than 0.999 8. The recoveries of the BPs spiked in blank samples at two spiked levels (100 and 500 g/L for each BP) were in the range of 90.1%-107.1% with the RSDs ? 8.1%. The proposed method is simple and reliable for the rapid detection of the seven BPs in human urine, bovine serum and beer samples. PMID:26387203

  13. Measurements of Molecular Mixing in a High Schmidt Number Rayleigh-Taylor Mixing Layer

    SciTech Connect

    Mueschke, N J; Schilling, O; Youngs, D L; Andrews, M

    2007-12-03

    Molecular mixing measurements are performed for a high Schmidt number (Sc {approx} 10{sup 3}), small Atwood number (A {approx} 7.5 x 10{sup -4}) buoyancy-driven turbulent Rayleigh-Taylor mixing layer in a water channel facility. Salt was added to the top stream to create the desired density difference. The degree of molecular mixing was measured as a function of time by monitoring a diffusion-limited chemical reaction between the two fluid streams. The pH of each stream was modified by the addition of acid or alkali such that a local neutralization reaction occurred as the two fluids molecularly mixed. The progress of this neutralization reaction was tracked by the addition of phenolphthalein - a pH-sensitive chemical indicator - to the acidic stream. Accurately calibrated backlit optical techniques were used to measure the average concentration of the colored chemical indicator. Comparisons of chemical product formation for pre-transitional buoyancy- and shear-driven mixing layers are given. It is also shown that experiments performed at different equivalence ratios (acid/alkali concentration) can be combined to obtain a mathematical relationship between the colored product formed and the density variance. This relationship was used to obtain high-fidelity, quantitative measures of the degree of molecular mixing which are independent of probe resolution constraints. The dependence of such mixing parameters on the Schmidt and Reynolds numbers is examined by comparing the current Sc {approx} 10{sup 3} measurements with Sc = 0.7 gas-phase and Pr = 7 liquid-phase measurements. This comparison indicates that the Schmidt number has a large effect on the bulk quantity of mixed fluid at small Reynolds numbers Re{sub h} < 10{sup 3}. At late times, all mixing parameters indicated a greater degree of molecular mixing and a decreased Schmidt number dependence. Implications for the development and quantitative assessment of turbulent transport and mixing models appropriate for Rayleigh?Taylor instability-induced mixing are discussed.

  14. Comparative Evaluation of Four Presumptive Tests for Blood to Detect Epithelial Injury on Fish

    SciTech Connect

    Colotelo, Alison HA; Smokorowski, Karen; Haxton, Tim; Cooke, Steven J.

    2014-06-01

    Current methods of fish epithelial injury detection are limited to gross macroscopic examination that has a subjective bias as well as an inability to reliably quantify the degree of injury. Fluorescein, a presumptive test for blood, has been shown to have the capability to detect and quantify fish epithelial injury. However, there are several other presumptive tests for blood (Bluestar*, phenolphthalein, and HemastixH) that may have benefits over the use of fluorescein, particularly for field research on wild fish. This study investigated the capabilities of these four tests to detect and quantify a variety of injuries commonly encountered by fish (abrasion, cuts, fin frays, and punctures) using the freshwater bluegill Lepomis macrochirus as a model. Fluorescein was consistently found to be the most reliable (i.e., detected the highest proportion of true positive results and rarely detected false positive reactions) of the four presumptive tests for blood compared. Further testing was conducted to examine the reliability of fluorescein. By 24 h after an injury was inflicted, the injury was no longer detectable by fluorescein, and when fluorescein was applied to an injured fish, the fluorescein was no longer detectable 3 h after application. In a comparison of two common anaesthetics used in fisheries research, there was no significant difference in the proportion of injury detected when 3- aminobenzoic acid ethyl ester methanesulfate (tricaine) was used compared with a clove oil and ethanol (1:9) solution. In summary, fluorescein was the most reliable presumptive test for blood examined in this study for the detection and quantification of recent (hours) fish epithelial injury.

  15. Denture adhesives--pH and buffering capacity.

    PubMed

    Love, W B; Biswas, S

    1991-09-01

    Aqueous solutions of some denture adhesives will produce a pH below the critical pH of hydroxyapatite. This article measured the pH of selected denture adhesives. The pH and buffering capacity were established for 10 readily available denture adhesives. The pH was determined from samples in dilutions of 1:10, 1:20, 1:30, and 1:40 denture adhesive to deionized water. A glass pH electrode coupled to a pH meter was used for pH determination. Six of the 10 denture adhesives tested had pH values below the critical pH of hydroxyapatite. This pH was maintained for the 2-hour duration of the testing. Prolonged contact of denture adhesive and tooth substances may dissolve hydroxyapatite crystals. Samples of denture adhesives to determine buffering capacity were prepared in a ratio of 1:20 by weight of denture adhesive to deionized water. Another series of samples was prepared in a ratio of 1:20 by weight of adhesive to freshly cannulated submandibular saliva. The pH was determined at the 24-hour time interval. Samples were then titrated with 0.1N sodium hydroxide solution in the presence of phenolphthalein. The same denture adhesives demonstrated low pH values at the 2-hour and 24-hour time intervals. These samples tended to be well buffered. It is recommended that denture adhesives with low pH values not be used in an environment with natural teeth or remnants of natural teeth. PMID:1800733

  16. Interaction of microbial ?-glucuronidase with vegetable pectins.

    PubMed

    Borisenkov, Mikhail F; Bakutova, Larissa A; Latkin, Dmitry S; Golovchenko, Victoria V; Vityazev, Fedor V

    2011-09-28

    The purpose of this study was to investigate the in vitro effects of vegetable carbohydrates on the activity of microbial ?-glucuronidase (?G) and the adsorption of the enzyme on carbohydrates. This study used pectin-protein complexes (PPCs) with molecular weights of 300 kDa isolated under conditions simulating a gastric environment from cabbage (HCl-PPCC and HCl+pepsin-PPCCP) and sweet pepper (PPCP and PPCPP). As a sample for comparison, microcrystalline cellulose was used. The activity of ?G from Escherichia coli was determined spectrophotometrically by the formation of the colored product from the breakdown of phenolphthalein-?-D-glucuronide. Adsorption of ?G on biopolymers was studied by the retention of the enzyme on the membrane of a concentrator with a pore diameter of 300 kDa and by native PAGE. PPCCP and PPCC were established to increase the activity of ?G by 50 and 100%, respectively. Cellulose had a weak effect, whereas pepper PPC had no effect. All studied carbohydrates adsorb on ?G. The maximum ?G adsorption (15%) was observed with PPCC, whereas PPCCP absorbed 5% of the enzyme. Pepper PPCs and cellulose adsorbed up to 10% of the enzyme. There was a positive correlation between the increase of ?G activity in the presence of carbohydrates and enzyme adsorption on the polymers (r=0.80; P<0.01). The activity of the enzyme in the gel after electrophoresis of the PPCC+?G mixture was inversely proportional to the concentration of PPCC in the mixture. A model explaining the effects of cabbage PPCs on the excretion of estrogens is proposed. PMID:21859154

  17. p53 induction as a genotoxic test for twenty-five chemicals undergoing in vivo carcinogenicity testing.

    PubMed Central

    Duerksen-Hughes, P J; Yang, J; Ozcan, O

    1999-01-01

    In vivo carcinogenicity testing is an expensive and time-consuming process, and as a result, only a relatively small fraction of new and existing chemicals has been tested in this manner. Therefore, the development and validation of alternative approaches is desirable. We previously developed a mammalian in vitro assay for genotoxicity based on the ability of cells to increase their level of the tumor-suppressor protein p53 in response to DNA damage. Cultured cells are treated with various amounts of the test substances, and at defined times following treatment, they are harvested and lysed. The lysates are analyzed for p53 by Western blot and/or enzyme-linked immunosorbent assay analysis. An increase in cellular p53 following treatment is interpreted as evidence for DNA damage. To determine the ability of this p53-induction assay to predict carcinogenicity in rodents and to compare such results with those obtained using alternate approaches, we subjected 25 chemicals from the predictive toxicology evaluation 2 list to analysis with this method. Five substances (citral, cobalt sulfate heptahydrate, D&C Yellow No. 11, oxymetholone, and t-butylhydroquinone) tested positive in this assay, and three substances (emodin, phenolphthalein, and sodium xylenesulfonate) tested as possibly positive. Comparisons between the results obtained with this assay and those obtained with the in vivo protocol, the Salmonella assay, and the Syrian hamster embryo (SHE) cell assay indicate that the p53-induction assay is an excellent predictor of the limited number of genotoxic carcinogens in this set, and that its accuracy is roughly equivalent to or better than the Salmonella and SHE assays for the complete set of chemicals. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:10504146

  18. Reductive metabolism of nabumetone by human liver microsomal and cytosolic fractions: exploratory prediction using inhibitors and substrates as marker probes.

    PubMed

    Matsumoto, Kaori; Hasegawa, Tetsuya; Koyanagi, Junichi; Takahashi, Tamiko; Akimoto, Masayuki; Sugibayashi, Kenji

    2015-06-01

    The metabolic reduction of nabumetone was examined by inhibition and correlation studies using human liver microsomes and cytosol. This reduction was observed in both fractions, with the V(max) values for reduction activity being approximately fourfold higher, and the V(max)/K(m) values approximately three-fold higher, in the microsomes than in the cytosol. The reduction of nabumetone was inhibited by 18β-glycyrrhetinic acid, an 11β-hydroxysteroid dehydrogenase (11β-HSD) inhibitor, in the microsomal fraction. The reduction activity was also inhibited by quercetin and menadione [carbonyl reductase (CBR) inhibitors], and by phenolphthalein and medroxyprogesterone acetate [potent inhibitors of aldo-keto reductase (AKR) 1C1, 1C2 and 1C4] in the cytosol. A good correlation (r² = 0.93) was observed between the reduction of nabumetone and of cortisone, as a marker of 11β-HSD activity, in the microsomal fractions. There was also an excellent relationship between reduction of nabumetone and of the AKR1C substrates, acetohexamide, and ethacrynic acid (r 2 = 0.92 and 0.93, respectively), in the cytosol fractions. However, a poor correlation was observed between the formation of 4-(6-methoxy-2-naphthyl)-butan-2-ol (MNBO) from nabumetone and CBR activity (with 4-benzoyl pyridine reduction as a CBR substrate) in the cytosol fractions (r² = 0.24). These findings indicate that nabumetone may be metabolized by 11β-HSD in human liver microsomes, and primarily by AKR1C4 in human liver cytosol, although multiple enzymes in the AKR1C subfamily may be involved. It cannot be completely denied that CBR is involved to some extent in the formation of MNBO from nabumetone in the cytosol fraction. PMID:24659525

  19. Adsorption properties of cross-linked cellulose-epichlorohydrin polymers in aqueous solution.

    PubMed

    Udoetok, Inimfon A; Dimmick, Raquel M; Wilson, Lee D; Headley, John V

    2016-01-20

    Cellulose was cross-linked with epichlorohydrin (EP) at variable levels (CLE-0.5, CLE-2 and CLE-4), where CLE-i denotes the cellulose to EP mole ratios. The cross-linked products were characterized by TGA and FT-IR spectroscopy, pH at the point of zero charge (pHpzc), water swelling, and dye-adsorption methods employing two types of dyes [phenolphthalein (phth) and p-nitrophenol (PNP)]. The characterization methods provide evidence of cross-linking of cellulose in accordance with variations in surface area, PZC, available surface hydroxyl groups, and thermal stability when compared against pristine cellulose. The pHpzc of the sorbent materials was ?6.5 indicating a negative surface charge occurs above pHpzc. The cross-linked polymers possess greater swelling properties relative to pristine cellulose. Detailed adsorption studies were carried out at pH 9 for cellulose and CLE-i with five types single component carboxylate anions [2-hexyldecanoic acid (S1), trans-4-pentylcyclohexanecarboxylic acid (S2), 2-dicyclohexylacetic acid (S3), adamantane carboxylic acid (S4), and cyclohexane carboxylic acid (S5)] at 295K. The uptake properties of PNP with cellulose and CLE-i were also compared at pH 5 and 9, respectively. CLE-2 had the highest uptake of PNP (Qm=1.2210(-1)mmol/g, pH 9) and S1 (Qm=4.27mg/g) while cellulose and CLE-4 had the strongest binding affinity (1.43L/mmol and 5.9010(-2)L/mg), respectively. Uptake of PNP by CLE-0.5 at pH 5 (Qm=5.3010(-2)mmol/g) was higher than uptake at pH 9 (Qm=3.1110(-2)mmol/g). Sorption of CLE-4 with S1, S2 and S3 showed that relative uptake of the surrogates had the following order: S3>S2>S1, where S2 had the strongest binding affinity to CLE-i. CLE-2 had the highest sorption capacity towards Si in an equimolar mixture with evidence of molecular selective uptake. At pH 9, low uptake was mainly related to electrostatic repulsion between the negatively charged sorbent surface and the carboxylate head groups of Si. PMID:26572363

  20. Net alkalinity and net acidity 1: Theoretical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A., III

    2005-01-01

    Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a standard method "hot peroxide" acidity titration, provided that labs report negative values. The authors recommend the third approach; i.e., net alkalinity = -Hot Acidity. ?? 2005 Elsevier Ltd. All rights reserved.

  1. Roles of the C-terminal domains of human dihydrodiol dehydrogenase isoforms in the binding of substrates and modulators: probing with chimaeric enzymes.

    PubMed Central

    Matsuura, K; Hara, A; Deyashiki, Y; Iwasa, H; Kume, T; Ishikura, S; Shiraishi, H; Katagiri, Y

    1998-01-01

    Human liver dihydrodiol dehydrogenase (DD; EC 1.3.1.20) exists in isoforms (DD1, DD2 and DD4) composed of 323 amino acids. DD1 and DD2 share 98% amino acid sequence identity, but show lower identities (approx. 83%) with DD4, in which a marked difference is seen in the C-terminal ten amino acids. DD4 exhibits unique catalytic properties, such as the ability to oxidize both (R)- and (S)-alicyclic alcohols equally, high dehydrogenase activity for bile acids, potent inhibition by steroidal anti-inflammatory drugs and activation by sulphobromophthalein and clofibric acid derivatives. In this study, we have prepared chimaeric enzymes, in which we exchanged the C-terminal 39 residues between the two enzymes. Compared with DD1, CDD1-4 (DD1 with the C-terminal sequence of DD4) had increased kcat/Km values for 3alpha-hydroxy-5beta-androstanes and bile acids of 3-9-fold and decreased values for the other substrates by 5-100-fold. It also became highly sensitive to DD4 inhibitors such as phenolphthalein and hexoestrol. Another chimaeric enzyme, CDD4-1 (DD4 with the C-terminal sequence of DD1), showed the same (S)-stereospecificity for the alicyclic alcohols as DD1, had decreased kcat/Km values for bile acids with 7beta- or 12alpha-hydroxy groups by more than 120-fold and was resistant to inhibition by betamethasone. In addition, the activation effects of sulphobromophthalein and bezafibrate decreased or disappeared for CDD4-1. The recombinant DD4 with the His314-->Pro (the corresponding residue of DD1) mutation showed intermediate changes in the properties between those of wild-type DD4 and CDD4-1. The results indicate that the binding of substrates, inhibitors and activators to the enzymes is controlled by residues in their C-terminal domains; multiple residues co-ordinately act as determinants for substrate specificity and inhibitor sensitivity. PMID:9820821

  2. Self-Irradiation Effects on 99Mo Reagents and Products

    SciTech Connect

    Carson, S.D.; Garcia, M.J.; McDonald, M.J.; Simpson, R.L.; Tallant, D.R.

    1998-10-07

    produced in 1996 and shipped to pharmaceutical houses for evaluation of compatibility with oxime solution used to precipitate `?vfo as the oxime complex is both air and light-sensitive, and containing a black precipitate that forms during shipment, presumably as a result of self- irradiation. Addition of sodium hypochlorite to the product solution prior to shipment prevents precipitate formation, indicating the precipitate is a reduced form of `%lo. to remove any precipitate. Duplicate aliquots of the filtered samples were titrated to a phenolphthalein irradiation and afler standing at room temperature for 86.4 hours. Precipitates were washed to a FTIR analysis of the white precipitate showed it to be alpha benzoin oxime. Since the basic After 86.4 hours, no precipitate had formed in bottles containing sodium hypochlorite. Black precipitate had formed in all bottles that did not contain sodium hypochlorite after 14.4 hours. The precipitate appeared to initially form on the surface of the HDPE sample bottles and Black precipitate was first noticed in sample set 1 after 28.8 hrs' irradiation. No visible sample containing precipitate was kept at room temperature in the original bottle. Precipitate in sample sets 2 and 3. Since no precipitate formed in these bottles, this was equivalent to duplicate samples. Once the precipitate in the 20-mL aliquots that had been set aside had returned to sample sets 1 through 3 and the samples with redissolved precipitate all experienced an average decrease in base strength of 0.013 meq mL-l. Sample 1-C had a decrease of 0.004 meq mL-l and sample 1-D had returned to the initial value of 0.198 meq mL-l. Raman spectra for the black precipitate from samples l-C, 1-D and supplemental sample set 1 Fig. 2. Raman spectra of the black precipitate formed in 9%40 product solutions after 28.8,43.2, 72 and 86.4 hours of `oCo irradiation in Sandia's Gamma Irradiation Facility. increase with time, as seen in the titration of 1-C and 1-D samples. The precipitate does not expect to see precipitate in the glass bottles. The fact that no precipitate is observed when the no precipitate is observed in a glass container is an indication that the rates of molybdenum that precipitate does not form when the solution is in a glass bottle. A hydrogen source other

  3. Application of experimental and numerical simulation techniques to microscale devices

    NASA Astrophysics Data System (ADS)

    Somashekar, Vishwanath

    Two of the areas that have become relevant recently are the areas of mixing in micro-scale devices, and manufacturing of functional nanoparticles. MicroPIV experiments were performed on two different mixers, one a wide microchannel with the surface grooves, in the laminar regime, and the other, a confined impinging jets reactor, in the laminar and turbulent regimes. In the wide microchannel with surface grooves, microPIV data were collected at the interface and the midplane at the Reynolds numbers of 0.08, 0.8, and 8. The experiments were performed on three internal angles of the chevrons, namely 135°, 90°, and 45°. The normalized transverse velocity generated in the midplane due to the presence of the grooves, is the strongest for the internal angle of 135°, and in that, the normalized transverse velocity is maximum at the Reynolds numbers of 0.08 and 0.8. MicroPIV experiments were performed in a confined impinging jets reactors at Reynolds numbers of 200, 1000, and 1500. The data was collected in the midplane, and turbulent statistics were further computed. The high velocity jets impinge along the centerline of the reactor. Upon impinging, part of the fluid turns towards the top wall and the majority of it turn towards the outlet. This high velocity impingement causes and unstable zone called the impingement zone, which moves about the centerline line, causing the jets to flap back and forth. Spatial correlations were computed to get an estimate of the size of the coherent structures. Large eddy simulation was performed on the CIJR for the Reynolds numbers of 1000 and 1500, using OpenFOAM. The Reynolds number is based on the inlet jet hydraulic diameter. Excellent agreement was found with the experimental and simulation data. Turbulent reactive mixing in a rectangular microscale confined impinging-jets reactor (CIJR) was investigated using the pH indicator phenolphthalein in this study for three different jet Reynolds numbers of 25, 1000 and 1500. Laminar flow regime was observed at Reynolds number of 25 whereas the flow was turbulent at Reynolds numbers of 1000 and 1500. An image processing technique was applied to instantaneous images to extract quantitative mixing data by identifying regions with pH ≥ 9.3 and regions with pH < 9.3. The ensemble-averages were computed using these thresholded images to compare mixing performance between different Reynolds numbers. Finally, the spatial auto-correlation fields of the thresholded images fluctuations were evaluated, based on which large-scale turbulent structure were analyzed.

  4. Effects of the use of ultrasonic waves on biodiesel production in alkaline transesterification of bleached tallow and vegetable oils: Cavitation model

    NASA Astrophysics Data System (ADS)

    Alape Benitez, Fabio

    Experiments of biodiesel production via methanolysis were performed at methanol/triglyceride molar ratios of 3, 4.5, and 6 and temperatures of 25°C, 40°C and 60°C; the reaction was monitored by HPLC, X-Ray, and GC-MS until equilibrium. A mathematical model called CAVITATION MODEL was developed to deal with mass transfer aspects of the alkaline transesterification reaction of vegetable oils; a comparison between the cavitation model and diffusion through spherical pores was made. Gas-vapor bubble dynamics for the methanol-soybean oil and methanol-tallow system were examined at 40°C and 42°C, respectively. The Rayleight-Plesset equations were used to describe the isothermal growth and adiabatic collapse of the bubble formed when a field of ultrasound at 20 KHz is applied. Temperatures of 2265 K and 426 K were estimated for a bubble in soybean oil-methanol and tallow-methanol systems, respectively. These "Hot Spots" could be responsible for the increment of the temperature occurred and the acoustic streaming observed during the alkaline transesterification reaction. Also, a diffusion analysis with the pore model was made to predict the concentration profile of the triglycerides within the liquid drops of alcohol created after the collapse of the gas-vapor bubbles; spherical shapes were studied. A computational model was made in MathCad to evaluate the effectiveness at different Thiele modulus values in order to estimate mass transfer coefficients for the most critical conditions of pure diffusion and these coefficients were compared with those found by the cavitation model estimation. Pictures of the reactant system soybean oil-methanol-potassium hydroxide, with the red dyed methanol using phenolphthalein, showed that the alkalinity of the system represented by potassium hydroxide remains in the interface alcohol-oil and then is displaced into the glycerol or down layer. The present study serves as a basis for the analysis of heterogeneous reactions with immiscible liquids using ultrasonic agitation.

  5. ORGANIC MATTER IN THE EXPIRED BREATH WITH ESPECIAL REFERENCE TO ITS INHIBITING POWER ON OXIDIZING FERMENTS.

    PubMed

    Amoss, H L

    1913-02-01

    Weichardt claims to have demonstrated the presence of an organic body in the expired air. He allowed the exhaled breath to pass through hydrochloric acid solution, evaporated the resulting solution to dryness on a water bath, and obtained a weighable residue which charred on ignition. If he neutralized the acid solution and concentrated it under reduced pressure, he obtained a solution which inhibited the bluing of the guaiacum indicator by blood. By exposing calcium chloride in a room in which the air had been vitiated, he claimed also to have obtained a substance from the air which prevented the bluing of the guaiacum indicator by blood. The experiments here recorded show that a variable amount of matter is retained by weak hydrochloric solution when exhaled breath is passed through it, and that this matter is volatile on ignition. Contrary to the findings of Weichardt, there is no charring or blackening. Nesslerization shows the residue to consist mainly, if not wholly, of ammonium chloride. This ammonia is believed to have come from the decomposition of food particles about the teeth. In one case the person (S.) had smoked just before the experiment, so that a small amount of the ammonia from the tobacco smoke may have been held temporarily by the saliva and food particles in the mouth and been given off gradually during the experiment. Weichardt's experiments on the inhibition of the guaiacum test for blood by means of the substances retained when exhaled breath is passed through hydrochloric acid or over calcium chloride crystals are not corroborated. It is further shown that the guaiacum indicator is unreliable for these tests in view of the fact that a small amount of free acid or free alkali will inhibit the guaiacum test for blood. This fact is offered as a probable explanation of Weichardt's results. Calcium chloride alone gives a deep blue color with the guaiacin indicator. Weichardt used this salt to collect from the expired breath certain unknown substances which he claims inhibit the oxidation of guaiacum by blood. His results are therefore inconclusive. The phenolphthalin test for blood has been studied in this connection and further light has been thrown on this reaction. The sodium salt of phenolphthalin is colorless in alkaline solution, and is readily oxidized by minute quantities of blood to phenolphthalein which gives a characteristic deep purplish red color in alkaline solution. It has been found that the presence of calcium chloride and ammonium chloride in small amounts retards and, in large amounts, prevents this reaction. It is believed that any salt composed of a weak base combined with a strong acid will have the same effect. This is discussed in the text. It has also been shown that the presence of calcium chloride or ammonium chloride decreases the depth of color of phenolphthalein in sodium hydroxide solution. Carbon dioxide also prevents the oxidation of phenolphthalin by blood. Of course this does not mean that carbon dioxide prevents the action of the oxidizing ferments generally. In this particular case the substance to be oxidized, namely phenolphthalin, was not allowed by reason of the presence of the carbon dioxide to combine with the alkali and thereby assume a state in which it could be easily oxidized. The results of one experiment seem to indicate a relation between the amount of dissolved oxygen in the solutions and the percentage of oxidation. Sodium chloride either alone or with the aid of hydrogen peroxide is able to bring about the oxidation of phenolphthalin in alkali to a very slight extent (3.5 to 5 per cent. in twenty-four hours). Therefore phenolphthalin as a test for oxidizing ferments should not be used in the presence of an appreciable amount of inorganic salts or carbon dioxide. Complete dialysis is recommended in these cases. It is also to be noted that the great delicacy of the test allows considerable dilution. Liquids were obtained from the expired breath by passing this through weak hydrochloric acid or by condensing the moisture in it by conducting it through cooled Drechsel bottles. Attempts were then made to prove the presence in these liquids of some substance which inhibits the oxidation of phenolphthalin by blood, but all were unsuccessful. Moreover attempts to concentrate these liquids by evaporation under reduced pressure or by the passage of a direct current (colloidal travel) were also unsuccessful. It is planned to improve upon the apparatus used to concentrate colloids by the passage of a direct current, and to test the effect of expired breath products on the rate of oxidation of phenolphthalin by blood. PMID:19867631

  6. Substrate specificity of the luminal Na(+)-dependent sulphate transport system in the proximal renal tubule as compared to the contraluminal sulphate exchange system.

    PubMed

    David, C; Ullrich, K J

    1992-08-01

    The efflux of [35S]sulphate from the lumen of the proximal renal tubule into tubular cells of rats was measured by the stop-flow tubular-lumen microperfusion technique. The transport parameters obtained and the apparent Ki values of competing substrates were compared with those of the contraluminal influx of [35S]-sulphate from the interstitium into tubular cells. For the luminal sulphate efflux a Km(l, SO4(2-)) of 0.8 mmol/l and a Jmax(l, SO4(2-)) of 0.2 pmol s-1 cm-1 were found. The corresponding contraluminal values were Km(cl,SO4(2-)) 1.4 mmol/l and Jmax(cl,SO4(2-)) 1.2 pmol s-1 cm-1. Omission of Na+ from the perfusates reduced the luminal efflux of sulphate by 83%, while the contraluminal influx of sulphate was not changed. Increase in HCO3- concentration inhibited both luminal efflux and contraluminal influx of sulphate, while a change of pH from 6.0 to 8.0 was without effect. Comparing the apparent Ki(SO4(2-)) values for luminal and contraluminal sulphate transport, a relationship close to 1:1 was seen for some inorganic substrates with tetrahedral molecular structure (thiosulphate, sulphate, molybdate and selenate). The same holds for phosphate, while for oxalate the contraluminal Ki(SO4(2-)) value was lower than the luminal one (1.2 and 4.5 mmol/l). Some of the dicarboxylates and disulphonates tested show the same affinity to the luminal Na(+)-dependent sulphate transporter and the contraluminal sulphate exchange system, whereas most of the benzene carboxylate and benzenesulphonate derivatives tested exhibit higher luminal than contraluminal Ki values. The inhibitory potency increased with rising numbers of substituents on the benzene ring. This effect was more pronounced for the contraluminal sulphate transporter. In general, only disulphonates and analogues as well as similarly structured compounds (5-sulphosalicylate, 2-hydroxy-5-nitrobenzenesulphonate, eosine-5-isothiocyanate) have a good inhibitory potency toward the luminal sulphate transporter [apparent Ki 0.9-3.1 mmol/l]. All the tested sulphamoyl and phenoxy diuretics, and fluorescein and phenolphthalein dyes showed no or a smaller inhibitory potency to the luminal sulphate transport system than to the contraluminal. The most effective inhibitors of both sulphate transport systems are 8-anilino-1-naphthalenesulphonate, orange G, and H2-DIDS. The data indicate that the Na(+)-dependent luminal and the Na(+)-independent contraluminal sulphate transport systems accommodate a similar spectrum of anionic substrates, whereby the inhibitory potency against the luminal Na(+)-dependent sulphate transport system is identical or smaller than against the contraluminal transporter. PMID:1461715