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Sample records for 15-5 ph nitronic

  1. The Structure and Properties of Diffusion Assisted Bonded Joints in 17-4 PH, Type 347, 15-5 PH and Nitronic 40 Stainless Steels

    NASA Technical Reports Server (NTRS)

    Wigley, D. A.

    1981-01-01

    Diffusion assisted bonds are formed in 17-4 PH, 15-5 PH, type 347 and Nitronic 40 stainless steels using electrodeposited copper as the bonding agent. The bonds are analyzed by conventional metallographic, electron microprobe analysis, and scanning electron microscopic techniques as well as Charpy V-notch impact tests at temperatures of 77 and 300 K. Results are discussed in terms of a postulated model for the bonding process.

  2. 17-4 PH and 15-5 PH

    NASA Technical Reports Server (NTRS)

    Johnson, Howard T.

    1995-01-01

    17-4 PH and 15-5 PH are extremely useful and versatile precipitation-hardening stainless steels. Armco 17-4 PH is well suited for the magnetic particle inspection requirements of Aerospace Material Specification. Armco 15-5 PH and 17-4 PH are produced in billet, plate, bar, and wire. Also, 15-5 PH is able to meet the stringent mechanical properties required in the aerospace and nuclear industries. Both products are easy to heat treat and machine, making them very useful in many applications.

  3. Stress corrosion cracking properties of 15-5PH steel

    NASA Technical Reports Server (NTRS)

    Rosa, Ferdinand

    1993-01-01

    Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.

  4. MRT letter: extended depth from focus reconstruction method for stretch zone measurement in 15-5PH steel.

    PubMed

    De Oliveira Caltabiano, Pietro Carelli Reis; Rosa, Paulo Henrique Santos; De Campos, Kamila Amato; De Oliveira Hein, Luis Rogerio

    2012-09-01

    The stretch zone width (SZW) data for 15-5PH steel CTOD specimens fractured at -150°C to + 23°C temperature were measured based on focused images and 3D maps obtained by extended depth-of-field reconstruction from light microscopy (LM) image stacks. This LM-based method, with a larger lateral resolution, seems to be as effective for quantitative analysis of SZW as scanning electron microscopy (SEM) or confocal scanning laser microscopy (CSLM), permitting to clearly identify stretch zone boundaries. Despite the worst sharpness of focused images, a robust linear correlation was established to fracture toughness (K(C) ) and SZW data for the 15-5PH steel tested specimens, measured at their center region. The method is an alternative to evaluate the boundaries of stretched zones, at a lower cost of implementation and training, since topographic data from elevation maps can be associated with reconstructed image, which summarizes the original contrast and brightness information. Finally, the extended depth-of-field method is presented here as a valuable tool for failure analysis, as a cheaper alternative to investigate rough surfaces or fracture, compared to scanning electron or confocal light microscopes. PMID:22434578

  5. Effect of external stress on the Fe-Cr phase separation in 15-5 PH and Fe-15Cr-5Ni alloys.

    PubMed

    Danoix, F; Lacaze, J; Gibert, A; Mangelinck, D; Hoummada, K; Andrieu, E

    2013-09-01

    The effect on Fe-Cr phase separation of a uniaxial stress during thermal ageing at 425 °C is investigated on a Fe-15Cr-5Ni steel, a model alloy of commercial 15-5 PH steel. The applied stress is shown to accelerate the ageing kinetics, and influence the morphology of Cr rich domains. A dependence of the phase separation decomposition kinetics on the relative orientations of the load and the crystal local orientation has also been observed. PMID:23522972

  6. Evidence for a transient peroxynitro acid in the reaction catalyzed by nitronate monooxygenase with propionate 3-nitronate.

    PubMed

    Smitherman, Crystal; Gadda, Giovanni

    2013-04-16

    Nitronate monooxygenase is a flavin-dependent enzyme that catalyzes the denitrification of propionate 3-nitronate (P3N) and other alkyl nitronates. The enzyme was previously known as 2-nitropropane dioxygenase, until its reclassification in 2010 by the IUBMB. Physiologically, the monooxygenase from fungi protects the organism from the environmental occurrence of P3N, which shuts down the Krebs cycle by inactivating succinate dehydrogenase and fumarase. The inhibition of these enzymes yields severe neurological disorders or death. Here, we have used for the first time steady-state and rapid kinetics, viscosity and pH effects, and time-resolved absorbance spectroscopy of the enzyme in turnover with P3N and the substrate analogue ethyl nitronate (EN) to elucidate the mechanism of the reaction. A transient increase in absorbance at ∼300 nm, never reported before, was seen during steady-state turnover of the enzyme with P3N and oxygen, with no concomitant changes between 400 and 600 nm. The transient species was not detected when oxygen was absent. Anaerobic reduction of the enzyme with P3N yielded anionic flavosemiquinone and was fast (e.g., ≥1900 s(-1)). Steady-state kinetics demonstrated that oxygen reacts before the release of the product of P3N oxidation from the enzyme. No pH effects were seen with P3N on kcat/Km, kcat/Koxygen, and kcat; in contrast, with EN, the kcat/Km and kcat decreased with increasing pH defining two plateaus and a pKa ∼ 8.0. Solvent viscosity at the pH optima suggested product release as being partially controlling the overall rate of turnover with the physiological substrate and its analogue. A mechanism that satisfies the kinetic results is proposed. PMID:23530838

  7. Nitrone Cycloadditions of 1,2-Cyclohexadiene

    PubMed Central

    Barber, Joyann S.; Styduhar, Evan D.; Pham, Hung V.; McMahon, Travis C.; Houk, K. N.; Garg, Neil K.

    2016-01-01

    We report the first 1,3-dipolar cycloadditions of 1,2-cyclohexadiene, a rarely exploited strained allene. 1,2-Cyclohexadiene is generated in situ under mild conditions and trapped with nitrones to give isoxazolidine products in synthetically useful yields. The reactions occur regioselectively and exhibit a notable endo preference, thus resulting in the controlled formation of two new bonds and two stereogenic centers. DFT calculations of stepwise and concerted reaction pathways are used to rationalize the observed selectivities. Moreover, the strategic manipulation of nitrone cycloadducts demonstrates the utility of this methodology for the assembly of compounds bearing multiple heterocyclic units. These studies showcase the exploitation of a traditionally avoided reactive intermediate in chemical synthesis. PMID:26854652

  8. Oxidation of alkyl nitronates catalyzed by 2-nitropropane dioxygenase from Hansenula mrakii.

    PubMed

    Mijatovic, Slavica; Gadda, Giovanni

    2008-05-01

    2-Nitropropane dioxygenase from Hansenula mrakii was expressed in Escherichia coli cells and purified in active and stable form using 60% saturation of ammonium sulfate and a single chromatographic step onto a DEAE column. MALDI-TOF mass spectrometric and spectrophotometric analyses of the flavin extracted by heat or acid denaturation of the enzyme indicated that FMN, and not FAD as erroneously reported previously, is present in a 1:1 stoichiometry with the protein. Inductively coupled plasma mass spectrometric analysis of the enzyme established that H. mrakii 2-nitropropane dioxygenase contains negligible amounts of iron, manganese, zinc, and copper ions, which are not catalytically relevant. Anaerobic substrate reduction and kinetic data using a Clark oxygen electrode to measure rates of oxygen consumption indicated that the enzyme is active on a broad range of alkyl nitronates, with a marked preference for unbranched substrates over propyl-2-nitronate. Interestingly, the enzyme reacts poorly, if at all, with nitroalkanes, as suggested by lack of both anaerobic reduction of the enzyme-bound flavin and consumption of oxygen with nitroethane, nitrobutane, and 2-nitropropane. Finally, both the tight binding of sulfite (K(d)=90 microM, at pH 8 and 15 degrees C) to the enzyme and the formation of the anionic flavosemiquinone upon anaerobic incubation with alkyl nitronates are consistent with the presence of a positively charged group in proximity of the N1-C2=O atoms of the FMN cofactor. PMID:18329375

  9. Dienamine-Catalyzed Nitrone Formation via Redox Reaction.

    PubMed

    Fraboni, Americo J; Brenner-Moyer, Stacey E

    2016-05-01

    The first catalytic method to directly introduce nitrone functionality onto aldehyde substrates is described. This reaction proceeds by an unprecedented organocatalytic redox mechanism in which an enal is oxidized to the γ-nitrone via dienamine catalysis, thereby reducing an equivalent of nitrosobenzene. This reaction is a unique example of divergent reactivity of an enal, which represents a novel strategy for rapidly accessing small libraries of N,O-heterocycles. Alternatively, divergent reactivity can be suppressed simply by changing solvents. PMID:27070296

  10. Mechanical threshold of dynamically deformed copper and Nitronic 40

    SciTech Connect

    Follansbee, P.S.; Kocks, U.F.; Regazzoni, G.

    1985-01-01

    Measurements of the mechanical threshold, or threshold stress, are reported on quasi-statically and dynamically deformed copper and Nitronic 40. Results for copper show that the increase of the threshold stress with strain rate is similar to that of the flow stress. In Nitronic 40 the results show that the ratio of the flow stress to the threshold stress is approx.0.6. Both results indicate that the increased rate sensitivity found in these materials at high strain rates is not due to the predominance of a viscous drag deformation mechanism, as has been previously suggested.

  11. 30 CFR 15.5 - Test samples.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test samples. 15.5 Section 15.5 Mineral... § 15.5 Test samples. (a) Submission of test samples. (1) The applicant shall not submit explosives or... magazine for at least 30 days before gallery tests are conducted....

  12. 43 CFR 15.5 - Wrecks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Wrecks. 15.5 Section 15.5 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.5 Wrecks. No person... coral formation....

  13. 43 CFR 15.5 - Wrecks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Wrecks. 15.5 Section 15.5 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.5 Wrecks. No person... coral formation....

  14. 43 CFR 15.5 - Wrecks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Wrecks. 15.5 Section 15.5 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.5 Wrecks. No person... coral formation....

  15. 43 CFR 15.5 - Wrecks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Wrecks. 15.5 Section 15.5 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.5 Wrecks. No person... coral formation....

  16. 30 CFR 15.5 - Test samples.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Test samples. 15.5 Section 15.5 Mineral... § 15.5 Test samples. (a) Submission of test samples. (1) The applicant shall not submit explosives or... magazine for at least 30 days before gallery tests are conducted....

  17. 30 CFR 15.5 - Test samples.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Test samples. 15.5 Section 15.5 Mineral... § 15.5 Test samples. (a) Submission of test samples. (1) The applicant shall not submit explosives or... magazine for at least 30 days before gallery tests are conducted....

  18. 46 CFR 196.15-5 - Drafts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Drafts. 196.15-5 Section 196.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Test, Drills, and Inspections § 196.15-5 Drafts. (a) The master of every vessel on an ocean, coastwise, or Great Lakes voyage shall enter the drafts of the...

  19. 46 CFR 196.15-5 - Drafts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Drafts. 196.15-5 Section 196.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS OPERATIONS Test, Drills, and Inspections § 196.15-5 Drafts. (a) The master of every vessel on an ocean, coastwise, or Great Lakes voyage shall enter the drafts of the...

  20. 7 CFR 15.5 - Compliance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... financial assistance to any other recipient, such other recipient shall also submit such compliance reports... 7 Agriculture 1 2010-01-01 2010-01-01 false Compliance. 15.5 Section 15.5 Agriculture Office of... Department of Agriculture-Effectuation of Title VI of the Civil Rights Act of 1964 § 15.5 Compliance....

  1. 7 CFR 15.5 - Compliance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... financial assistance to any other recipient, such other recipient shall also submit such compliance reports... 7 Agriculture 1 2013-01-01 2013-01-01 false Compliance. 15.5 Section 15.5 Agriculture Office of... Department of Agriculture-Effectuation of Title VI of the Civil Rights Act of 1964 § 15.5 Compliance....

  2. 7 CFR 15.5 - Compliance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... financial assistance to any other recipient, such other recipient shall also submit such compliance reports... 7 Agriculture 1 2014-01-01 2014-01-01 false Compliance. 15.5 Section 15.5 Agriculture Office of... Department of Agriculture-Effectuation of Title VI of the Civil Rights Act of 1964 § 15.5 Compliance....

  3. 7 CFR 15.5 - Compliance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Compliance. 15.5 Section 15.5 Agriculture Office of the Secretary of Agriculture NONDISCRIMINATION Nondiscrimination in Federally-Assisted Programs of the Department of Agriculture-Effectuation of Title VI of the Civil Rights Act of 1964 § 15.5 Compliance. (a) Cooperation and assistance. Each...

  4. 7 CFR 15.5 - Compliance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... financial assistance to any other recipient, such other recipient shall also submit such compliance reports... 7 Agriculture 1 2012-01-01 2012-01-01 false Compliance. 15.5 Section 15.5 Agriculture Office of... Department of Agriculture-Effectuation of Title VI of the Civil Rights Act of 1964 § 15.5 Compliance....

  5. 43 CFR 15.5 - Wrecks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Wrecks. 15.5 Section 15.5 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.5 Wrecks. No person shall willfully destroy molest, remove, deface, displace, or tamper with any wrecks, parts of wrecks or any cargo pertaining to such wrecks...

  6. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory §...

  7. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory §...

  8. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory §...

  9. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory §...

  10. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory §...

  11. Copper-Catalyzed Divergent Addition Reactions of Enoldiazoacetamides with Nitrones.

    PubMed

    Cheng, Qing-Qing; Yedoyan, Julietta; Arman, Hadi; Doyle, Michael P

    2016-01-13

    Catalyst-controlled divergent addition reactions of enoldiazoacetamides with nitrones have been developed. By using copper(I) tetrafluoroborate/bisoxazoline complex as the catalyst, a [3+3]-cycloaddition reaction was achieved with excellent yield and enantioselectivity under exceptionally mild conditions, which represents the first highly enantioselective base-metal-catalyzed vinylcarbene transformation. When the catalyst was changed to copper(I) triflate, Mannich addition products were formed in high yields with near exclusivity under otherwise identical conditions. PMID:26699516

  12. Copper-Catalyzed Homo-Dimerization of Nitronates and Enolates under Oxygen Atmosphere

    PubMed Central

    Do, Hien-Quang; Tran-Vu, Hung

    2012-01-01

    A method for copper-catalyzed oxidative dimerization of nitronates and enolates using oxygen as terminal oxidant has been developed. Cyclization through oxidative intramolecular coupling is also feasible for both nitronates and enolates. The mild reaction conditions lead to good functional group tolerance. PMID:23413317

  13. Reactive Nitrogen Species Reactivities with Nitrones: Theoretical and Experimental Studies

    PubMed Central

    Nash, Kevin M.; Rockenbauer, Antal; Villamena, Frederick A.

    2012-01-01

    Reactive nitrogen species (RNS) such as nitrogen dioxide (•NO2), peroxynitrite (ONOO–), and nitrosoperoxycarbonate (ONOOCO2–) are among the most damaging species present in biological systems due to their ability to cause modification of key biomolecular systems through oxidation, nitrosylation and nitration. Nitrone spin traps are known to react with free radicals and non-radicals via electrophilic and nucleophilic addition reactions, and have been employed as reagents to detect radicals using electron paramagnetic resonance (EPR) spectroscopy, and as pharmacological agents against oxidative stress-mediated injury. This study examines the reactivity of cyclic nitrones such as 5,5-dimethylpyrroline N-oxide (DMPO) with, •NO2, ONOO–, ONOOCO2–, SNAP and SIN-1 using EPR. The thermochemistries of nitrone reactivity with RNS, and isotropic hfsc's of the addition products were also calculated at the PCM(water)/B3LYP/6-31+G**//B3LYP/6-31G* level of theory with and without explicit water molecules in order to rationalize the nature of the observed EPR spectra. Spin trapping of other RNS such as azide (•N3), nitrogen trioxide (•NO3), amino (•NH2) radicals, and nitroxyl (HNO) were also theoretically and experimentally investigated by EPR spin trapping and mass spectrometry. This study also shows other spin traps such as AMPO, EMPO and DEPMPO can react with radical and non-radical RNS, thus, making spin traps suitable probes as well as antioxidants against RNS mediated oxidative damage. PMID:22775566

  14. Characteristic of Nitron for Use as a Chemical Sensor in Studies of the Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Meadows, Kapres; Wright, Cassandra K.; Sims, S. C.; Morris, V. R.

    1997-01-01

    We are investigating the use of nitron as a potential chemical sensor for nitric acid and other electron deficient nitrogen oxides. Solutions of nitron in 1-propanol, toluene, and chloroform have been tested for use on a piezoelectric quartz crystal microbalance. We are testing various solvents and metal cations which can maximize the lifetime and reaction specificity of nitron so that they may be used as chemical coatings for stratospheric measurement of trace gases. Results of the work to date will be shown, and future direction discussed.

  15. Enantioselective 1,3-dipolar cycloaddition of nitrones to methacrolein catalyzed by (eta5-C5Me5)M{(R)-prophos} containing complexes (M = Rh, Ir; (R)-prophos = 1,2-bis(diphenylphosphino)propane): on the origin of the enantioselectivity.

    PubMed

    Carmona, Daniel; Lamata, M Pilar; Viguri, Fernando; Rodríguez, Ricardo; Oro, Luis A; Lahoz, Fernando J; Balana, Ana I; Tejero, Tomás; Merino, Pedro

    2005-09-28

    The rhodium and iridium Lewis-acid cations [(eta(5)-C(5)Me(5))M{(R)-Prophos}(H(2)O)](2+) ((R)-Prophos = 1,2-bis(diphenylphosphino)propane) efficiently catalyze the enantioselective 1,3-dipolar cycloaddition of nitrones to methacrolein. Reactions occur with perfect endo selectivity and with enantiomeric excesses up to 96%. Intermediates [(eta(5)-C(5)Me(5))M{(R)-Prophos}(methacrolein)](SbF(6))(2) (M = Rh (3), Ir (4)) have been spectroscopically and crystallographically characterized. The nitrone complexes [(eta(5)-C(5)Me(5))M{(R)-Prophos}(nitrone)](SbF(6))(2) (M = Rh, nitrone = 1-pyrrolidine N-oxide (5), 2,3,4,5,-tetrahydropyridine N-oxide (6), 3,4-dihydroisoquinoline N-oxide (7); M = Ir, nitrone = 1-pyrrolidine N-oxide (8)) have been isolated and characterized including the X-ray crystal structure of compounds 6 and 8. The equilibrium between methacrolein and nitrone complexes is also studied. [Ir]-adduct complexes are detected by (31)P NMR spectroscopy. A catalytic cycle involving [M]-methacrolein, [M]-nitrone, as well as [M]-adduct species is proposed, the first complex being the true catalyst. The absolute configuration of the adduct 4-methyl-2-N,3-diphenyl-isoxazolidine-4-carbaldehyde (9) was determined through its (S)-(-)-alpha-methylbenzylamine derivative diastereomer. Structural parameters strongly suggest that the disposition of the methacrolein in 3 and 4 is fixed by CH/pi attractive interactions between the pro-S phenyl ring of the Ph(2)PCH(CH(3)) moiety of the (R)-Prophos ligand and the CHO aldehyde proton. Proton NMR data indicate that this conformation is maintained in solution. From the structural data and the results of catalysis the origin of the enantioselectivity is discussed. PMID:16173773

  16. Spin Trapping and Cytoprotective Properties of Fluorinated Amphiphilic Carrier Conjugates of Cyclic versus Linear Nitrones

    PubMed Central

    Durand, Grégory; Prosak, Robert A.; Han, Yongbin; Ortial, Stéphanie; Rockenbauer, Antal; Pucci, Bernard; Villamena, Frederick A.

    2009-01-01

    Nitrone spin traps have been employed as pharmacological agent against neurodegenerative diseases and ischemia-reperfusion induced injury. The structure-activity relationship was explored for the two types of nitrones, i.e., cyclic (DMPO) and linear (PBN), which are conjugated to a fluorinated amphiphilic carrier (FAC) for their cytoprotective properties against hydrogen peroxide (H2O2), 3-morpholinosynonimine hydrochloride (SIN-1) and 4-hydroxynonenal (HNE) induced cell death on bovine aortic endothelial cells. The compound FAMPO was synthesized and characterized, and its physical-chemical and spin trapping properties were explored. Cytotoxicity and cytoprotective properties of various nitrones either conjugated and non-conjugated to FAC (i.e., AMPO, FAMPO, PBN and FAPBN) were assessed using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT) reduction assay. Results show that of all the nitrones tested, FAPBN is the most protective against H2O2, but FAMPO and to a lesser extent its unconjugated form, AMPO, are more protective against SIN-1 induced cytotoxicity. However, none of the nitrones used protect the cells from HNE-induced cell death. The difference in the cytoprotective properties observed between the cyclic and linear nitrones may arise from the differences in their intrinsic antioxidant properties and localization in the cell. PMID:19678661

  17. Spin trapping and cytoprotective properties of fluorinated amphiphilic carrier conjugates of cyclic versus linear nitrones.

    PubMed

    Durand, Grégory; Prosak, Robert A; Han, Yongbin; Ortial, Stéphanie; Rockenbauer, Antal; Pucci, Bernard; Villamena, Frederick A

    2009-09-01

    Nitrones have been employed as spin trapping reagent as well as pharmacological agent against neurodegenerative diseases and ischemia-reperfusion induced injury. The structure-activity relationship was explored for the two types of nitrones, i.e., cyclic (DMPO) and linear (PBN), which are conjugated to a fluorinated amphiphilic carrier (FAC) for their cytoprotective properties against hydrogen peroxide (H(2)O(2)), 3-morpholinosynonimine hydrochloride (SIN-1), and 4-hydroxynonenal (HNE) induced cell death on bovine aortic endothelial cells. The compound FAMPO was synthesized and characterized, and its physical-chemical and spin trapping properties were explored. Cytotoxicity and cytoprotective properties of various nitrones either conjugated and nonconjugated to FAC (i.e., AMPO, FAMPO, PBN, and FAPBN) were assessed using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT) reduction assay. Results show that of all the nitrones tested, FAPBN is the most protective against H(2)O(2), but FAMPO and to a lesser extent its unconjugated form, AMPO, are more protective against SIN-1 induced cytotoxicity. However, none of the nitrones used protect the cells from HNE-induced cell death. The difference in the cytoprotective properties observed between the cyclic and linear nitrones may arise from the differences in their intrinsic antioxidant properties and localization in the cell. PMID:19678661

  18. Kinetic evidence for an anion binding pocket in the active site of nitronate monooxygenase.

    PubMed

    Francis, Kevin; Gadda, Giovanni

    2009-10-01

    A series of monovalent, inorganic anions and aliphatic aldehydes were tested as inhibitors for Hansenula mrakii and Neurospora crassa nitronate monooxygenase, formerly known as 2-nitropropane dioxygenase, to investigate the structural features that contribute to the binding of the anionic nitronate substrates to the enzymes. A linear correlation between the volumes of the inorganic anions and their effectiveness as competitive inhibitors of the enzymes was observed in a plot of pK(is)versus the ionic volume of the anion with slopes of 0.041+/-0.001 mM/A(3) and 0.027+/-0.001 mM/A(3) for the H. mrakii and N. crassa enzymes, respectively. Aliphatic aldehydes were weak competitive inhibitors of the enzymes, with inhibition constants that are independent of their alkyl chain lengths. The reductive half reactions of H. mrakii nitronate monooxygenase with primary nitronates containing two to four carbon atoms all showed apparent K(d) values of approximately 5 mM. These results are consistent with the presence of an anion binding pocket in the active site of nitronate monooxygenase that interacts with the nitro group of the substrate, and suggest a minimal contribution of the hydrocarbon chain of the nitronates to the binding of the ligands to the enzyme. PMID:19683782

  19. Nitrones are able to release nitric oxide in aqueous environment under hydroxyl free radical attack.

    PubMed

    Croitoru, Mircea Dumitru; Ibolya, Fülöp; Pop, Maria Cristiana; Dergez, Timea; Mitroi, Brânduşa; Dogaru, Maria Titica; Tokés, Béla

    2011-10-30

    Importance of a nitric oxide donor that can act as a spin trap might bring some new therapeutic possibilities regarding the treatment of ischemic diseases by reducing the intensity of free radical produced reperfusion lesions. These substances might be also used as a new type of photo protectors since they can absorb UV radiation, capture free radicals formed by interaction of UV radiation with tissue constituents, and tanning of the skin will be permitted due to nitric oxide release. The purpose of this work was to measure the ability of nitrones to release nitric oxide and how different factors (temperature, nitrone concentration, and free radicals) influence the releasing ability. Mostly, indirect determination of nitric oxide was carried out, by measuring nitrite and nitrate amounts (as decomposition products of nitric oxide), all nitrones proved to release significant amounts of nitric oxide. Nitrite measurements were made based on an HPLC-VIS method that uses pre-column derivatization of nitrite by forming an azo dye (limit of quantification: 5ng/ml). No good correlation was found between the amount of nitric oxide and temperature for most studied nitrones but between the formation of nitric oxide and nitrone concentration an asymptotic correlation was found. Fenton reagent also yielded formation of nitric oxide from nitrones and formed amounts were not different from those recorded for UV irradiation. Most of the nitrones effectively released about 0.5% of the maximum amount of nitric oxide that is chemically possible and estimated concentrations of 0.1μM were present in the solutions during decomposition. PMID:21645628

  20. Oxygen radicals in experimental shock: effects of spin-trapping nitrones in ameliorating shock pathophysiology (see comments)

    SciTech Connect

    Novelli, G.P. )

    1992-04-01

    Circulatory shock is accepted as a consequence of an acute oxygen radical overgeneration. Spin-trapping nitrones inactivate free radicals by forming relatively stable adducts. Three spin-trapping nitrones (N-tert-phenyl-butyl-nitrone; alpha-4-pyridyl-oxide-N-tert-butyl-nitrone; 5-5,dimethyl,1,pyrroline-N-oxide) were tested regarding their role in the pathophysiology and evolution of circulatory shock in rats. A prospective, randomized, controlled trial of spin-trapping nitrones in rats experiencing three different models of circulatory shock was designed. In the first group, endotoxic, traumatic, and mesenteric artery occlusion shock (all 100% lethal in control experiments) was prevented by the ip administration of N-tert-phenyl-butyl-nitrone (150 mg/kg); alpha-4-pyridyl-oxide-N-tert-butyl-nitrone (100 mg/kg); or 5-5,dimethyl,1,pyrroline-N-oxide (100 mg/kg). However, the evolution of shock was unaffected by the same compounds when all three nitrones had been previously inactivated by exposure to light and air. In the second group, microcirculatory derangements that were provoked by endotoxin and were observed in the mesocecum of rats were completely prevented by pretreatment with either peritoneal administration of each of the three nitrones or by their topical application to the microscopic field. While the rats survived after systemic treatment, those rats receiving topical nitrones died from endotoxic shock. In the third group, cell-membrane stiffness (a sign of peroxidative damage) was measured by spin-probes and electron-spin resonance in mitochondrial and microsomal membranes. Cell membranes obtained from shocked rats were more rigid than those membranes of controls. However, the membranes obtained from rats that were submitted to trauma or endotoxin after pretreatment with N-tert-phenyl-butyl-nitrone had normal stiffness.

  1. Anti-Cancer Activity of Nitrones and Observations on Mechanism of Action

    PubMed Central

    Floyd, Robert A.; Chandru, Hema K.; He, Ting; Towner, Rheal

    2011-01-01

    The nitrone compound PBN, α-phenyl-tert-butylnitrone, and closely related nitrones have anti-cancer activity in several experimental cancer models. The three experimental models most extensively studied include A) the rat choline deficiency liver cancer model, B) the rat C6 glioma model and C) the mouse APCMin/+ colon cancer model. The two PBN-nitrones mostly studied are PBN and a PBN derivative 2,4-disulfophenyl-tert-butylnitrone, referred as OKN-007. OKN-007 is a proprietary compound that has had extensive commercial development (designated as NXY-059) for another indication, acute ischemic stroke, and after extensive clinical studies was shown to lack efficacy for this indication but was shown to be very safe for human use. This compound administered orally in the rat glioma model has potent activity in treating fully formed gliomas. In this report observations made on the PBN-nitrones in experimental cancer models will be summarized. In addition the experimental results will be discussed in the general framework of the properties of the compounds with a view to try to understand the mechanistic basis of how the PBN-nitrones act as anti-cancer agents. Possible mechanisms related to the suppression of NO production, S-nitrosylation of critical proteins and inhibition of NF-κB activation are discussed. PMID:21651461

  2. Evaluation of nitrone spin-trapping agents as radioprotectors.

    PubMed

    Young, H K; Floyd, R A; Maidt, M L; Dynlacht, J R

    1996-08-01

    The focus of this investigation was to determine whether the nitrone spin-trapping compounds alpha-phenyl-N-tert-butylnitrone (PBN), 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) are radioprotectors. Two methods were used to assess for radioprotection: measurement of oxidative damage to DNA bases and mammalian cell survival assays. Oxidative damage to DNA was quantified by measuring the relative amounts of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) produced by the reaction of hydroxyl radicals (OH.) with 2-deoxyguanosine (dG) after irradiation. PBN, DMPO and POBN, when dissolved in aqueous solutions of either dG or naked salmon sperm DNA, reduced the formation of 8-OH-dG by 137Cs gamma irradiation significantly. The spin-trapping agents, especially PBN at lower concentrations, were more effective in preventing radiation-induced formation of 8-OH-dG in naked DNA than in free dG. These data suggest that PBN, DMPO and POBN act as free radical scavengers which may associate with DNA and afford protection against gamma rays. However, no enhancement of survival was observed when Chinese hamster ovary (CHO) cells were exposed to high non-toxic concentrations of PBN or POBN prior to and during irradiation with 60Co gamma rays and scored for clonogenic survival. DMPO provided only minimal protection from radiation-induced cell killing. PMID:8693073

  3. The Combined Structural and Kinetic Characterization of a Bacterial Nitronate Monooxygenase from Pseudomonas aeruginosa PAO1 Establishes NMO Class I and II*

    PubMed Central

    Salvi, Francesca; Agniswamy, Johnson; Yuan, Hongling; Vercammen, Ken; Pelicaen, Rudy; Cornelis, Pierre; Spain, Jim C.; Weber, Irene T.; Gadda, Giovanni

    2014-01-01

    Nitronate monooxygenase (NMO) oxidizes the mitochondrial toxin propionate 3-nitronate (P3N) to malonate semialdehyde. The enzyme has been previously characterized biochemically in fungi, but no structural information is available. Based on amino acid similarity 4,985 genes are annotated in the GenBankTM as NMO. Of these, 4,424 (i.e. 89%) are bacterial genes, including several Pseudomonads that have been shown to use P3N as growth substrate. Here, we have cloned and expressed the gene pa4202 of Pseudomonas aeruginosa PAO1, purified the resulting protein, and characterized it. The enzyme is active on P3N and other alkyl nitronates, but cannot oxidize nitroalkanes. P3N is the best substrate at pH 7.5 and atmospheric oxygen with kcatapp/Kmapp of 12 × 106 m−1 s−1, kcatapp of 1300 s−1, and Kmapp of 110 μm. Anerobic reduction of the enzyme with P3N yields a flavosemiquinone, which is formed within 7.5 ms, consistent with this species being a catalytic intermediate. Absorption spectroscopy, mass spectrometry, and x-ray crystallography demonstrate a tightly, non-covalently bound FMN in the active site of the enzyme. Thus, PA4202 is the first NMO identified and characterized in bacteria. The x-ray crystal structure of the enzyme was solved at 1.44 Å, showing a TIM barrel-fold. Four motifs in common with the biochemically characterized NMO from Cyberlindnera saturnus are identified in the structure of bacterial NMO, defining Class I NMO, which includes bacterial, fungal, and two animal NMOs. Notably, the only other NMO from Neurospora crassa for which biochemical evidence is available lacks the four motifs, defining Class II NMO. PMID:25002579

  4. OxaD: A Versatile Indolic Nitrone Synthase from the Marine-Derived Fungus Penicillium oxalicum F30.

    PubMed

    Newmister, Sean A; Gober, Claire M; Romminger, Stelamar; Yu, Fengan; Tripathi, Ashootosh; Parra, Lizbeth Lorena L; Williams, Robert M; Berlinck, Roberto G S; Joullié, Madeleine M; Sherman, David H

    2016-09-01

    Indole alkaloids are a diverse class of natural products known for their wide range of biological activities and complex chemical structures. Rarely observed in this class are indolic nitrones, such as avrainvillamide and waikialoid, which possess potent bioactivities. Herein the oxa gene cluster from the marine-derived fungus Penicillium oxalicum F30 is described along with the characterization of OxaD, a flavin-dependent oxidase that generates roquefortine L, a nitrone-bearing intermediate in the biosynthesis of oxaline. Nitrone functionality in roquefortine L was confirmed by spectroscopic methods and 1,3-dipolar cycloaddition with methyl acrylate. OxaD is a versatile biocatalyst that converts an array of semisynthetic roquefortine C derivatives bearing indoline systems to their respective nitrones. This work describes the first implementation of a nitrone synthase as a biocatalyst and establishes a novel platform for late-stage diversification of a range of complex natural products. PMID:27505044

  5. Nitronate monooxygenase, a model for anionic flavin semiquinone intermediates in oxidative catalysis.

    PubMed

    Gadda, Giovanni; Francis, Kevin

    2010-01-01

    Nitronate monooxygenase (NMO), formerly referred to as 2-nitropropane dioxygenase, is an FMN-dependent enzyme that uses molecular oxygen to oxidize (anionic) alkyl nitronates and, in the case of the enzyme from Neurospora crassa, (neutral) nitroalkanes to the corresponding carbonyl compounds and nitrite. Over the past 5 years, a resurgence of interest on the enzymology of NMO has driven several studies aimed at the elucidation of the mechanistic and structural properties of the enzyme. This review article summarizes the knowledge gained from these studies on NMO, which has been emerging as a model system for the investigation of anionic flavosemiquinone intermediates in the oxidative catalysis of organic molecules, and for the effect that branching of reaction intermediates has on both the kinetic parameters and isotope effects associated with enzymatic reactions. A comparison of the catalytic mechanism of NMO with other flavin-dependent enzymes that oxidize nitroalkane and nitronates is also presented. PMID:19577534

  6. Intramolecular nitrone dipolar cycloadditions: control of regioselectivity and synthesis of naturally-occurring spirocyclic alkaloids.

    PubMed

    Hodges, Alastair J; Adams, Joseph P; Bond, Andrew D; Holmes, Andrew B; Press, Neil J; Roughley, Stephen D; Ryan, John H; Saubern, Simon; Smith, Catherine J; Turnbull, Michael D; Newton, Annabella F

    2012-12-01

    The intramolecular nitrone dipolar cycloaddition of in situ-generated nitrones such as compound 26 has been used for the synthesis of cyclic isoxazolidines 27 and 29. The regioselectivity of the intramolecular cycloaddition depends on the nature of the terminal substituent on the dipolarophile. The influence of the substituent on the regioselectivity of the cycloaddition has been examined using several model systems and two methods of nitrone formation. These studies demonstrated that the cyano-substituent plays a special role in favouring the formation of the 6,6,5-ring fused adduct 27 under thermodynamically controlled conditions. The utility of the cyclo-adduct 57 (see Scheme 12) as a precursor for the naturally occurring histrionicotoxins is illustrated by the synthesis of three "unsymmetrical" (i.e. with each side chain bearing different functional groups) members of the histrionicotoxin family HTX-259A, HTX-285C and HTX-285E (2, 3 and 4 respectively). PMID:23051904

  7. Nitrones reverse hyperglycemia-induced endothelial dysfunction in bovine aortic endothelial cells.

    PubMed

    Headley, Colwyn A; DiSilvestro, David; Bryant, Kelsey E; Hemann, Craig; Chen, Chun-An; Das, Amlan; Ziouzenkova, Ouliana; Durand, Grégory; Villamena, Frederick A

    2016-03-15

    Hyperglycemia has been implicated in the development of endothelial dysfunction through heightened ROS production. Since nitrones reverse endothelial nitric oxide synthase (eNOS) dysfunction, increase antioxidant enzyme activity, and suppress pro-apoptotic signaling pathway and mitochondrial dysfunction from ROS-induced toxicity, the objective of this study was to determine whether nitrone spin traps DMPO, PBN and PBN-LA were effective at duplicating these effects and improving glucose uptake in an in vitro model of hyperglycemia-induced dysfunction using bovine aortic endothelial cells (BAEC). BAEC were cultured in DMEM medium with low (5.5mM glucose, LG) or high glucose (50mM, HG) for 14 days to model in vivo hyperglycemia as experienced in humans with metabolic disease. Improvements in cell viability, intracellular oxidative stress, NO and tetrahydrobiopterin (BH4)​ levels, mitochondrial membrane potential, glucose transport, and activity of antioxidant enzymes were measured from single treatment of BAEC with nitrones for 24h after hyperglycemia. Chronic hyperglycemia significantly increased intracellular ROS by 50%, decreased cell viability by 25%, reduced NO bioavailability by 50%, and decreased (BH4) levels by 15% thereby decreasing NO production. Intracellular glucose transport and superoxide dismutase (SOD) activity were also decreased by 50% and 25% respectively. Nitrone (PBN and DMPO, 50 μM) treatment of BAEC grown in hyperglycemic conditions resulted in the normalization of outcome measures except for SOD and catalase activities. Our findings demonstrate that the nitrones reverse the deleterious effects of hyperglycemia in BAEC. We believe that in vivo testing of these nitrone compounds in models of cardiometabolic disease is warranted. PMID:26774452

  8. 15.5 Million Americans Now Surviving Cancer

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_159164.html 15.5 Million Americans Now Surviving Cancer: Report But better ... United States reached record numbers this year -- 15.5 million -- and the American Cancer Society predicts they' ...

  9. 15.5 Million Americans Now Surviving Cancer

    MedlinePlus

    ... medlineplus/news/fullstory_159164.html 15.5 Million Americans Now Surviving Cancer: Report But better tools needed ... numbers this year -- 15.5 million -- and the American Cancer Society predicts they'll total more than ...

  10. 46 CFR 72.15-5 - Structural fire protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Structural fire protection. 72.15-5 Section 72.15-5... ARRANGEMENT Ventilation § 72.15-5 Structural fire protection. See § 72.05-50 for ventilation requirements pertaining to structural fire protection....

  11. 46 CFR 188.15-5 - Design of vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Design of vessels. 188.15-5 Section 188.15-5 Shipping... PROVISIONS Equivalents § 188.15-5 Design of vessels. (a) In order not to inhibit design and application the Commandant may accept vessels of unusual, unique, special, or exotic design, both new and for...

  12. 46 CFR 188.15-5 - Design of vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Design of vessels. 188.15-5 Section 188.15-5 Shipping... PROVISIONS Equivalents § 188.15-5 Design of vessels. (a) In order not to inhibit design and application the Commandant may accept vessels of unusual, unique, special, or exotic design, both new and for...

  13. 46 CFR 188.15-5 - Design of vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Design of vessels. 188.15-5 Section 188.15-5 Shipping... PROVISIONS Equivalents § 188.15-5 Design of vessels. (a) In order not to inhibit design and application the Commandant may accept vessels of unusual, unique, special, or exotic design, both new and for...

  14. 46 CFR 168.15-5 - Location of crew spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Location of crew spaces. 168.15-5 Section 168.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-5 Location of crew spaces. (a) Quarters must be located so that...

  15. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  16. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  17. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  18. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  19. 46 CFR 61.15-5 - Steam piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main...

  20. 46 CFR 46.15-5 - Engineering requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Engineering requirements. 46.15-5 Section 46.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Subdivision Load Lines for Passenger Vessels Engaged in Foreign, Coastwise, and Great Lakes Voyages § 46.15-5 Engineering...

  1. 46 CFR 46.15-5 - Engineering requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Engineering requirements. 46.15-5 Section 46.15-5... Lakes Voyages § 46.15-5 Engineering requirements. (a) Bilge and ballast systems, piping, inlets and... subchapter F (Marine Engineering) of this chapter....

  2. 46 CFR 46.15-5 - Engineering requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Engineering requirements. 46.15-5 Section 46.15-5... Lakes Voyages § 46.15-5 Engineering requirements. (a) Bilge and ballast systems, piping, inlets and... subchapter F (Marine Engineering) of this chapter....

  3. 46 CFR 46.15-5 - Engineering requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Engineering requirements. 46.15-5 Section 46.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Subdivision Load Lines for Passenger Vessels Engaged in Foreign, Coastwise, and Great Lakes Voyages § 46.15-5 Engineering...

  4. 47 CFR 15.5 - General conditions of operation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false General conditions of operation. 15.5 Section 15.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15.5 General conditions of operation. (a) Persons operating intentional or unintentional radiators shall not be deemed to have any vested...

  5. 47 CFR 15.5 - General conditions of operation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false General conditions of operation. 15.5 Section 15.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15.5 General conditions of operation. (a) Persons operating intentional or unintentional radiators shall not be deemed to have any vested...

  6. 46 CFR 46.15-5 - Engineering requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Engineering requirements. 46.15-5 Section 46.15-5... Lakes Voyages § 46.15-5 Engineering requirements. (a) Bilge and ballast systems, piping, inlets and... subchapter F (Marine Engineering) of this chapter....

  7. 46 CFR 167.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Authority of marine inspectors. 167.15-5 Section 167.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Inspections § 167.15-5 Authority of marine inspectors. Marine inspectors may at any...

  8. 46 CFR 91.15-5 - Alternate compliance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CFR 8.110(b). ... 46 Shipping 4 2013-10-01 2013-10-01 false Alternate compliance. 91.15-5 Section 91.15-5 Shipping... CERTIFICATION Inspection of Vessels § 91.15-5 Alternate compliance. (a) In place of compliance with...

  9. 46 CFR 72.15-5 - Structural fire protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Structural fire protection. 72.15-5 Section 72.15-5... ARRANGEMENT Ventilation § 72.15-5 Structural fire protection. See § 72.05-50 for ventilation requirements pertaining to structural fire protection....

  10. 46 CFR 72.15-5 - Structural fire protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Structural fire protection. 72.15-5 Section 72.15-5... ARRANGEMENT Ventilation § 72.15-5 Structural fire protection. See § 72.05-50 for ventilation requirements pertaining to structural fire protection....

  11. 46 CFR 167.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Authority of marine inspectors. 167.15-5 Section 167.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Inspections § 167.15-5 Authority of marine inspectors. Marine inspectors may at any...

  12. 46 CFR 167.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Authority of marine inspectors. 167.15-5 Section 167.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Inspections § 167.15-5 Authority of marine inspectors. Marine inspectors may at any...

  13. 46 CFR 167.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Authority of marine inspectors. 167.15-5 Section 167.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Inspections § 167.15-5 Authority of marine inspectors. Marine inspectors may at any...

  14. 46 CFR 167.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Authority of marine inspectors. 167.15-5 Section 167.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS Inspections § 167.15-5 Authority of marine inspectors. Marine inspectors may at any...

  15. 25 CFR 15.5 - May I revoke my will?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false May I revoke my will? 15.5 Section 15.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR PROBATE PROBATE OF INDIAN ESTATES, EXCEPT FOR MEMBERS OF THE OSAGE NATION AND THE FIVE CIVILIZED TRIBES Introduction § 15.5 May I revoke my will? Yes. You may...

  16. 46 CFR 188.15-5 - Design of vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Design of vessels. 188.15-5 Section 188.15-5 Shipping... PROVISIONS Equivalents § 188.15-5 Design of vessels. (a) In order not to inhibit design and application the Commandant may accept vessels of unusual, unique, special, or exotic design, both new and for...

  17. 46 CFR 168.15-5 - Location of crew spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Location of crew spaces. 168.15-5 Section 168.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-5 Location of crew spaces. (a) Quarters must be located so that...

  18. 46 CFR 168.15-5 - Location of crew spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Location of crew spaces. 168.15-5 Section 168.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-5 Location of crew spaces. (a) Quarters must be located so that...

  19. 46 CFR 168.15-5 - Location of crew spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Location of crew spaces. 168.15-5 Section 168.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-5 Location of crew spaces. (a) Quarters must be located so that...

  20. 46 CFR 111.15-5 - Battery installation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Battery installation. 111.15-5 Section 111.15-5 Shipping... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-5 Battery installation. (a) Large batteries. Each large battery installation must be in a room that is only for...

  1. 46 CFR 111.15-5 - Battery installation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Battery installation. 111.15-5 Section 111.15-5 Shipping... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-5 Battery installation. (a) Large batteries. Each large battery installation must be in a room that is only for...

  2. 46 CFR 111.15-5 - Battery installation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Battery installation. 111.15-5 Section 111.15-5 Shipping... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-5 Battery installation. (a) Large batteries. Each large battery installation must be in a room that is only for...

  3. 46 CFR 111.15-5 - Battery installation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Battery installation. 111.15-5 Section 111.15-5 Shipping... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-5 Battery installation. (a) Large batteries. Each large battery installation must be in a room that is only for...

  4. 46 CFR 111.15-5 - Battery installation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Battery installation. 111.15-5 Section 111.15-5 Shipping... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-5 Battery installation. (a) Large batteries. Each large battery installation must be in a room that is only for...

  5. 46 CFR 42.15-5 - Superstructure end bulkheads.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Superstructure end bulkheads. 42.15-5 Section 42.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Conditions of Assignment of Freeboard § 42.15-5 Superstructure end bulkheads. (a) Bulkheads at exposed ends of enclosed...

  6. 46 CFR 71.15-5 - Alternate compliance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 3 2010-10-01 2010-10-01 false Alternate compliance. 71.15-5 Section 71.15-5 Shipping... Inspection of Vessels § 71.15-5 Alternate compliance. (a) In place of compliance with other...

  7. 46 CFR 71.15-5 - Alternate compliance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 3 2012-10-01 2012-10-01 false Alternate compliance. 71.15-5 Section 71.15-5 Shipping... Inspection of Vessels § 71.15-5 Alternate compliance. (a) In place of compliance with other...

  8. 46 CFR 91.15-5 - Alternate compliance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... Approved classification society rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 4 2012-10-01 2012-10-01 false Alternate compliance. 91.15-5 Section 91.15-5 Shipping... CERTIFICATION Inspection of Vessels § 91.15-5 Alternate compliance. (a) In place of compliance with...

  9. 46 CFR 91.15-5 - Alternate compliance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... Approved classification society rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 4 2011-10-01 2011-10-01 false Alternate compliance. 91.15-5 Section 91.15-5 Shipping... CERTIFICATION Inspection of Vessels § 91.15-5 Alternate compliance. (a) In place of compliance with...

  10. 46 CFR 91.15-5 - Alternate compliance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... Approved classification society rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 4 2010-10-01 2010-10-01 false Alternate compliance. 91.15-5 Section 91.15-5 Shipping... CERTIFICATION Inspection of Vessels § 91.15-5 Alternate compliance. (a) In place of compliance with...

  11. 46 CFR 71.15-5 - Alternate compliance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 3 2011-10-01 2011-10-01 false Alternate compliance. 71.15-5 Section 71.15-5 Shipping... Inspection of Vessels § 71.15-5 Alternate compliance. (a) In place of compliance with other...

  12. 46 CFR 168.15-5 - Location of crew spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Location of crew spaces. 168.15-5 Section 168.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-5 Location of crew spaces. (a) Quarters must be located so that...

  13. Stilbazulenyl nitrone, a novel antioxidant, is highly neuroprotective in focal ischemia.

    PubMed

    Ginsberg, Myron D; Becker, David A; Busto, Raul; Belayev, Andrey; Zhang, Yongbo; Khoutorova, Larissa; Ley, James J; Zhao, Weizhao; Belayev, Ludmila

    2003-09-01

    Azulenyl nitrones are novel chain-breaking antioxidants with low oxidation potentials and high lipophilicity-properties favoring their efficacy as neuroprotectants. We tested the second-generation azulenyl nitrone, stilbazunenlyl nitrone (STAZN), in focal ischemic stroke. Physiologically monitored rats received 2 hours of middle cerebral artery occlusion by intraluminal suture, resulting in substantial cortical and striatal infarcation. Neurobehavior was quantified on a standard battery, and brains were perfusion-fixed for quantitative histopathology at 3 days. In 3 independent series, rats were treated at either 2h + 4h, or 2h + 4h + 24h + 48h, after onset of ischemia; vehicle-treated rats received dimethylsulfoxide or saline. All animals (n = 52) developed high-grade neurological deficits (score 11 of 12) during ischemia, which improved, in STAZN-treated rats, within 1-1.5 h of the initial dose and fell to a median score of 3 at 72 h, compared to 8 in vehicle rats. STAZN treatment reduced mean cortical infarct volume by 64-97%, and total infarct volume by 42-72%. In over one-half of STAZN-treated animals, cortical infarction was virtually abolished. Regression analysis predicted that STAZN would confer approximately 50% cortical neuroprotection even in the most severely affected cases. The potency of STAZN was orders-of-magnitude greater than other nitrones such as NXY-059. These results suggest that STAZN has great promise for ischemic stroke. PMID:12953265

  14. Metallurgical studies of NITRONIC 40 with reference to its use for cryogenic wind tunnel models

    NASA Technical Reports Server (NTRS)

    Wigley, D. A.

    1983-01-01

    The characterstics of NITRONIC 40 were investigated in connection with its use in cryogenic wind tunnel models. In particular, the effects of carbide and sigma-phase precipitation resulting from heat treatment and the presence of delta ferrite were evaluated in relation to their effects on mechanical properties and the potential consequences of such degradation. Methods were examined for desensitizing the material and for possible removal of delta ferrite as a means of restoring the material to its advertised properties. It was found that heat treatment followed by cryogenic quenching is a technique capable of desensitizing NITRONIC 40. However, it was concluded that it is extremely difficult, if not impossible, to remove the delta ferrite from the existing stock of material. Furthermore, heat treatments for removing delta ferrite have to take place at temperatures that cause very large grain growth. The implications of using the degraded NITRONIC 40 material for cryogenic model testing were reviewed, and recommendations were submitted with regard to the acceptability of the material. The experience gained from the study of NITRONIC 40 clearly identifies the need to implement a policy for purchasing top-quality materials for cryogenic wind tunnel model applications.

  15. 25 CFR 15.5 - May I revoke my will?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false May I revoke my will? 15.5 Section 15.5 Indians BUREAU OF... OSAGE NATION AND THE FIVE CIVILIZED TRIBES Introduction § 15.5 May I revoke my will? Yes. You may revoke your will at any time. You may revoke your will by any means authorized by tribal or Federal...

  16. 46 CFR 32.15-5 - Whistles-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Whistles-T/ALL. 32.15-5 Section 32.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-5 Whistles—T/ALL. (a) (b) On tankships contracted for on and after November 19, 1955 means shall be provided...

  17. 46 CFR 32.15-5 - Whistles-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Whistles-T/ALL. 32.15-5 Section 32.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS Navigation Equipment § 32.15-5 Whistles—T/ALL. (a) (b) On tankships contracted for on and after November 19, 1955 means shall be provided...

  18. 46 CFR 12.15-5 - Physical and medical requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Physical and medical requirements. 12.15-5 Section 12.15... REQUIREMENTS FOR RATING ENDORSEMENTS Qualified Member of the Engine Department § 12.15-5 Physical and medical requirements. The physical and medical requirements for an endorsement as QMED are found in § 10.215 of...

  19. 33 CFR 67.15-5 - Seismographic and surveying operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Seismographic and surveying operations. 67.15-5 Section 67.15-5 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES...

  20. 46 CFR 105.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Authority of marine inspectors. 105.15-5 Section 105.15... COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Inspection Required § 105.15-5 Authority of marine inspectors. (a) Marine inspectors may at any time lawfully inspect any vessel subject to the requirements...

  1. 46 CFR 12.15-5 - Physical and medical requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Physical and medical requirements. 12.15-5 Section 12.15... REQUIREMENTS FOR RATING ENDORSEMENTS Qualified Member of the Engine Department § 12.15-5 Physical and medical requirements. The physical and medical requirements for an endorsement as QMED are found in § 10.215 of...

  2. 46 CFR 12.15-5 - Physical and medical requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Physical and medical requirements. 12.15-5 Section 12.15... REQUIREMENTS FOR RATING ENDORSEMENTS Qualified Member of the Engine Department § 12.15-5 Physical and medical requirements. The physical and medical requirements for an endorsement as QMED are found in § 10.215 of...

  3. 46 CFR 105.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Authority of marine inspectors. 105.15-5 Section 105.15... COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Inspection Required § 105.15-5 Authority of marine inspectors. (a) Marine inspectors may at any time lawfully inspect any vessel subject to the requirements...

  4. 46 CFR 105.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Authority of marine inspectors. 105.15-5 Section 105.15... COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Inspection Required § 105.15-5 Authority of marine inspectors. (a) Marine inspectors may at any time lawfully inspect any vessel subject to the requirements...

  5. 46 CFR 105.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Authority of marine inspectors. 105.15-5 Section 105.15... COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Inspection Required § 105.15-5 Authority of marine inspectors. (a) Marine inspectors may at any time lawfully inspect any vessel subject to the requirements...

  6. 46 CFR 105.15-5 - Authority of marine inspectors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Authority of marine inspectors. 105.15-5 Section 105.15... COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Inspection Required § 105.15-5 Authority of marine inspectors. (a) Marine inspectors may at any time lawfully inspect any vessel subject to the requirements...

  7. 46 CFR 189.15-5 - Alternate compliance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... with the Alternate Compliance Program provisions of 46 CFR part 8. (b) For the purposes of this section... rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 7 2012-10-01 2012-10-01 false Alternate compliance. 189.15-5 Section 189.15-5...

  8. 46 CFR 189.15-5 - Alternate compliance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... with the Alternate Compliance Program provisions of 46 CFR part 8. (b) For the purposes of this section... rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 7 2011-10-01 2011-10-01 false Alternate compliance. 189.15-5 Section 189.15-5...

  9. 46 CFR 189.15-5 - Alternate compliance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... with the Alternate Compliance Program provisions of 46 CFR part 8. (b) For the purposes of this section... rules and supplements are incorporated by reference into 46 CFR 8.110(b). ... 46 Shipping 7 2010-10-01 2010-10-01 false Alternate compliance. 189.15-5 Section 189.15-5...

  10. Survey of physical property data for several alloys. [Nitronic 33; copper C10400; copper C17510

    SciTech Connect

    Pawel, R.E.; Williams, R.K.

    1985-08-01

    This report summarizes an examination of physical property data available in the literature for six alloys of potential interest to the Toroidal Fusion Core Experiment in the Fusion Energy Program. The properties of thermal expansion, density, specific heat, electrical resistivity, and thermal conductivity were compiled for six alloys: Nitronic 33, a low-nickel, high manganese stainless steel; nickel-base Inconnel Alloys 625, 718, and X-750; and copper alloys C10400 and C17510. The temperatures of interest were 4-500 K for the Nitronic 33 and the Inconels, and 250-400 K for the copper alloys. Where data were lacking, estimates were made based on theory or comparisons with similar materials.

  11. 44 CFR 15.5 - Preservation of property.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... HOMELAND SECURITY GENERAL CONDUCT AT THE MT. WEATHER EMERGENCY ASSISTANCE CENTER AND AT THE NATIONAL EMERGENCY TRAINING CENTER § 15.5 Preservation of property. At both Mt. Weather and NETC we prohibit: (a)...

  12. Highly diastereoselective and enantioselective formal [4 + 3] cycloaddition of donor-acceptor cyclobutanes with nitrones.

    PubMed

    Hu, Jiang-Lin; Wang, Lijia; Xu, Hao; Xie, Zuowei; Tang, Yong

    2015-06-01

    The first highly diastereoselective and enantioselective catalytic formal [4 + 3] cycloaddition of 1,1-cyclobutane diester with nitrone has been developed. Sterically hindered chiral SaBOX/Cu(II) complex promotes the reaction efficiently with a broad substrate scope, producing a range of multifunctionalized optically active 1,2-oxazepanes with excellent stereocontrol (up to >99/1 dr and 97% ee). PMID:25974724

  13. Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps.

    PubMed

    Bézière, Nicolas; Hardy, Micael; Poulhès, Florent; Karoui, Hakim; Tordo, Paul; Ouari, Olivier; Frapart, Yves-Michel; Rockenbauer, Antal; Boucher, Jean-Luc; Mansuy, Daniel; Peyrot, Fabienne

    2014-02-01

    Reactive oxygen species are by-products of aerobic metabolism involved in the onset and evolution of various pathological conditions. Among them, the superoxide radical is of special interest as the origin of several damaging species such as H2O2, hydroxyl radical, or peroxynitrite (ONOO(-)). Spin trapping coupled with ESR is a method of choice to characterize these species in chemical and biological systems and the metabolic stability of the spin adducts derived from reaction of superoxide and hydroxyl radicals with nitrones is the main limit to the in vivo application of the method. Recently, new cyclic nitrones bearing a triphenylphosphonium or permethylated β-cyclodextrin moiety have been synthesized and their spin adducts demonstrated increased stability in buffer. In this article, we studied the stability of the superoxide adducts of four new cyclic nitrones in the presence of liver subcellular fractions and biologically relevant reductants using an original setup combining a stopped-flow device and an ESR spectrometer. The kinetics of disappearance of the spin adducts were analyzed using an appropriate simulation program. Our results highlight the interest of the new spin trapping agents CD-DEPMPO and CD-DIPPMPO for specific detection of superoxide with high stability of the superoxide adducts in the presence of liver microsomes. PMID:24161442

  14. Structural Manipulation of Ruthenium(II) Polypyridine Nitrone Complexes to Generate Phosphorogenic Bioorthogonal Reagents for Selective Cellular Labeling.

    PubMed

    Tang, Tommy Siu-Ming; Liu, Hua-Wei; Lo, Kenneth Kam-Wing

    2016-07-01

    We report a new class of ruthenium(II) polypyridine complexes functionalized with a nitrone group as phosphorogenic bioorthogonal probes. These complexes were very weakly emissive owing to rapid C=N isomerization of the nitrone moiety, but exhibited significant emission enhancement upon strain-promoted alkyne-nitrone cycloaddition (SPANC) reaction with bicyclo[6.1.0]nonyne (BCN)-modified substrates. The modification of nitrone with a dicationic ruthenium(II) polypyridine unit at the α-C-position and a phenyl ring at the N-position led to remarkably accelerated reaction kinetics, which are substantially greater (up to ≈278 fold) than those of other acyclic nitrone-BCN systems. Interestingly, the complexes achieved specific cell membrane/cytosol staining upon specific labeling of an exogenous substrate, BCN-modified decane (BCN-C10), in live cells. Importantly, the in situ generation of the more lipophilic isoxazoline adduct in the cytoplasm resulted in increased cytotoxicity, highlighting a novel approach to apply the SPANC labeling technique in drug activation. PMID:27273833

  15. Catalytic oxidation of imines based on methyltrioxorhenium/urea hydrogen peroxide: a mild and easy chemo- and regioselective entry to nitrones.

    PubMed

    Soldaini, Gianluca; Cardona, Francesca; Goti, Andrea

    2007-02-01

    [reaction: see text] The first successful catalytic oxidation procedure for the chemoselective conversion of imines to nitrones is reported. The reaction is general, high yielding, and user and environmentally friendly, and furnishes a solution to the yet unanswered issue of regioselective access to nitrones by oxidation of nitrogen derivatives. PMID:17249790

  16. 33 CFR 67.15-5 - Seismographic and surveying operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Seismographic and surveying... Marking Requirements § 67.15-5 Seismographic and surveying operations. All stakes, casings, pipes, and... facilitate seismographic or surveying operations shall be marked, in the manner prescribed by the...

  17. 33 CFR 67.15-5 - Seismographic and surveying operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Seismographic and surveying... Marking Requirements § 67.15-5 Seismographic and surveying operations. All stakes, casings, pipes, and... facilitate seismographic or surveying operations shall be marked, in the manner prescribed by the...

  18. 33 CFR 67.15-5 - Seismographic and surveying operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Seismographic and surveying... Marking Requirements § 67.15-5 Seismographic and surveying operations. All stakes, casings, pipes, and... facilitate seismographic or surveying operations shall be marked, in the manner prescribed by the...

  19. 33 CFR 67.15-5 - Seismographic and surveying operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Seismographic and surveying... Marking Requirements § 67.15-5 Seismographic and surveying operations. All stakes, casings, pipes, and... facilitate seismographic or surveying operations shall be marked, in the manner prescribed by the...

  20. 14 CFR 15.5 - Administrative claim, who may file.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Administrative claim, who may file. 15.5... claim, who may file. (a) A claim for injury to, or loss of, property may be presented by the owner of... assert such a claim under applicable State law. (d) A claim for loss wholly compensated by an...

  1. 47 CFR 15.5 - General conditions of operation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 15.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15... radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator. (c) The operator of a radio frequency device shall...

  2. 47 CFR 15.5 - General conditions of operation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 15.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15... radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator. (c) The operator of a radio frequency device shall...

  3. 47 CFR 15.5 - General conditions of operation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 15.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15... radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator. (c) The operator of a radio frequency device shall...

  4. 46 CFR 112.15-5 - Final emergency loads.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... lubrication. (h) Each rudder angle indicator. (i) Each radio or global maritime distress and safety system (GMDSS) component. (j) Each radio direction finder, radar, gyrocompass, depth sounder, global positioning... AND POWER SYSTEMS Emergency Loads § 112.15-5 Final emergency loads. On vessels required to have...

  5. 46 CFR 112.15-5 - Final emergency loads.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... lubrication. (h) Each rudder angle indicator. (i) Each radio or global maritime distress and safety system (GMDSS) component. (j) Each radio direction finder, radar, gyrocompass, depth sounder, global positioning... AND POWER SYSTEMS Emergency Loads § 112.15-5 Final emergency loads. On vessels required to have...

  6. 46 CFR 112.15-5 - Final emergency loads.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... lubrication. (h) Each rudder angle indicator. (i) Each radio or global maritime distress and safety system (GMDSS) component. (j) Each radio direction finder, radar, gyrocompass, depth sounder, global positioning... AND POWER SYSTEMS Emergency Loads § 112.15-5 Final emergency loads. On vessels required to have...

  7. 46 CFR 112.15-5 - Final emergency loads.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... lubrication. (h) Each rudder angle indicator. (i) Each radio or global maritime distress and safety system (GMDSS) component. (j) Each radio direction finder, radar, gyrocompass, depth sounder, global positioning... AND POWER SYSTEMS Emergency Loads § 112.15-5 Final emergency loads. On vessels required to have...

  8. 46 CFR 112.15-5 - Final emergency loads.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... lubrication. (h) Each rudder angle indicator. (i) Each radio or global maritime distress and safety system (GMDSS) component. (j) Each radio direction finder, radar, gyrocompass, depth sounder, global positioning... AND POWER SYSTEMS Emergency Loads § 112.15-5 Final emergency loads. On vessels required to have...

  9. Comparison of Performance and Oxidation of Nitronic-50 and Stainless Steel 316 in Subcritical and Supercritical Water Environments

    NASA Astrophysics Data System (ADS)

    Karmiol, Zachary; Chidambaram, Dev

    2016-05-01

    This work investigates two austenitic stainless steels, Nitronic-50 and stainless steel 316, for use in both subcritical and supercritical water (SCW) conditions. The mechanical characteristics of the materials were investigated using slow strain rate testing in a SCW test loop under the following conditions: nitrogen at ambient temperature and pressure, liquid water at 473 K (200 °C) and 8 MPa, liquid water at 573 K (300 °C) and 15 MPa, and SCW at 698 K (425 °C) and 27 MPa. The surfaces of the failed samples were characterized using Raman spectroscopy, and X-ray photoelectron spectroscopy. Nitronic-50 was found to have superior mechanical strength characteristics at all conditions compared to stainless steel 316. At all elevated temperature conditions, stainless steel 316 was found to have a surface film consisting of iron oxides, while the surface film of Nitronic-50 predominantly consisted of nickel-iron spinel.

  10. [1,4]-sigmatropic rearrangement of chiral nitrones and their utilization in the synthesis of new iminosugars.

    PubMed

    Malinowski, Maciej; Rowicki, Tomasz; Guzik, Patrycja; Gryszel, Maciej; Łapczyński, Sebastian; Wielechowska, Monika; Czerwińska, Karolina; Madura, Izabela; Sas, Wojciech

    2016-01-14

    Reflection on the epimerization of the α-stereocenter of sugar nitrones leads to the conclusion that the process may occur through [1,4]-sigmatropic rearrangement. Participation of an ionic mechanism was excluded by a deuterium labeling experiment, and DFT calculations showed a reasonable energy barrier for the proposed [1,4]-shift. Products of the intramolecular 1,3-dipolar cycloaddition of the studied nitrones were utilized in the diversity-oriented synthesis of polyhydroxy derivatives of piperidine, indolizidine and quinolizidine. Minimal activity against the screened glucosidases and human melanoma cell lines was observed for some of the obtained compounds. PMID:26563609

  11. Nitrone-based Therapeutics for Neurodegenerative Diseases. Their use alone or in Combination with Lanthionines

    PubMed Central

    Floyd, Robert A.; Castro Faria Neto, Hugo C.; Zimmerman, Guy A.; Hensley, Kenneth; Towner, Rheal A.

    2013-01-01

    The possibility of free radical reactions occurring in biological processes led to the development and employment of novel methods and techniques focused on determining their existence and importance in normal and pathological conditions. For this reason the use of Nitrones for spin trapping free radicals came into widespread use in the 1970s and 1980s when surprisingly the first evidence of their potent biological properties was first noted. Since then wide-spread exploration and demonstration of the potent biological properties of phenyl-tert-butylnitrone (PBN) and derivatives were shown in preclinical models of septic shock and then in experimental stroke. The most extensive commercial effort done in order to capitalize on the potent properties of the PBN-Nitrones was for acute ischemic stroke. This occurred during the 1993–2006 time interval where the 2,4-disulfonyl-phenyl PBN derivative, called NXY-059 in the stroke studies, was shown to be safe in humans and was taken all the way through clinical phase 3 trials and was deemed to be ineffective. As summarized in this review because of its excellent human safety profile 2,4-disulfonyl-phenyl PBN, now called OKN-007 in the cancer studies, was tested as an anti-cancer agent in several preclinical glioma models and shown to be very effective. Based on these studies this compound is now scheduled to enter into early clinical trials for astrocytoma/glioblastoma multiform this year. The potential use of OKN-007 in combination with neurotropic compounds such as the lanthionine ketamine esters (LKE) is discussed for glioblastoma multiform as well as for various other indications leading to dementia such as aging, septic shock, and malaria infections. There is much more research and development activity on-going for various indications with the nitrones alone or in combination with other active compounds as briefly noted in this review. PMID:23419732

  12. Detection of superoxide production in stimulated and unstimulated living cells using new cyclic nitrone spin traps.

    PubMed

    Abbas, Kahina; Hardy, Micael; Poulhès, Florent; Karoui, Hakim; Tordo, Paul; Ouari, Olivier; Peyrot, Fabienne

    2014-06-01

    Reactive oxygen species (ROS), including superoxide anion and hydrogen peroxide (H2O2), have a diverse array of physiological and pathological effects within living cells depending on the extent, timing, and location of their production. For measuring ROS production in cells, the ESR spin trapping technique using cyclic nitrones distinguishes itself from other methods by its specificity for superoxide and hydroxyl radical. However, several drawbacks, such as the low spin trapping rate and the spontaneous and cell-enhanced decomposition of the spin adducts to ESR-silent products, limit the application of this method to biological systems. Recently, new cyclic nitrones bearing a triphenylphosphonium (Mito-DIPPMPO) or a permethylated β-cyclodextrin moiety (CD-DIPPMPO) have been synthesized and their spin adducts demonstrated increased stability in buffer. In this study, a comparison of the spin trapping efficiency of these new compounds with commonly used cyclic nitrone spin traps, i.e., 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and analogs BMPO, DEPMPO, and DIPPMPO, was performed on RAW 264.7 macrophages stimulated with phorbol 12-myristate 13-acetate. Our results show that Mito-DIPPMPO and CD-DIPPMPO enable a higher detection of superoxide adduct, with a low (if any) amount of hydroxyl adduct. CD-DIPPMPO, especially, appears to be a superior spin trap for extracellular superoxide detection in living macrophages, allowing measurement of superoxide production in unstimulated cells for the first time. The main rationale put forward for this extreme sensitivity is that the extracellular localization of the spin trap prevents the reduction of the spin adducts by ascorbic acid and glutathione within cells. PMID:24662195

  13. Catalytic Asymmetric Synthesis of Dihydropyrido[1,2-a]indoles from Nitrones and Allenoates.

    PubMed

    Pace, Wiktoria H; Mo, Dong-Liang; Reidl, Tyler W; Wink, Donald J; Anderson, Laura L

    2016-08-01

    An asymmetric method for the synthesis of dihydropyrido[1,2-a]indoles from mixtures of nitrones and allenoates has been developed. This transformation showcases the use of squaramide catalysis in a complicated cascade system that has been shown to be highly sensitive to reaction conditions and substituent effects. The new method provides access to enantiomerically enriched dihydropyridoindoles from modular, non-indole reagents. The optimization and scope of the new transformation is discussed in addition to initial mechanistic experiments that indicate the role of the catalyst. PMID:27346675

  14. Revealing Stepwise Mechanisms in Dipolar Cycloaddition Reactions: Computational Study of the Reaction between Nitrones and Isocyanates.

    PubMed

    Darù, Andrea; Roca-López, David; Tejero, Tomás; Merino, Pedro

    2016-01-15

    The mechanism of cycloaddition reactions of nitrones with isocyanates has been studied using density functional theory (DFT) methods at the M06-2X/cc-pVTZ level of theory. The exploration of the potential energy surfaces associated with two reactive channels leading to 1,2,4-oxadiazolidin-5-ones and 1,4,2-dioxazolidines revealed that the cycloaddition reaction takes place through a concerted mechanism in gas phase and in apolar solvents but a stepwise mechanism in polar solvents. In stepwise mechanisms, the first step of the reaction is a rare case in which the nitrone oxygen acts as a nucleophile by attacking the central carbon atom of the isocyanate (interacting with the π-system of the C═O bond) to give an intermediate. The corresponding transition structure is stabilized by an attractive electrostatic interaction favored in a polar medium. The second step of the reaction is the rate-limiting one in which the formation of 1,2,4-oxadiazolidin-5-ones or 1,4,2-dioxazolidines is decided. Calculations indicate that formation of 1,2,4-oxadiazolidin-5-ones is favored both kinetically and thermodynamically independently of the solvent, in agreement with experimental observations. Noncovalent interactions (NCI) and topological analysis of the gradient field of electron localization function (ELF) bonding confirmed the observed interactions. PMID:26682934

  15. The metallurgical structure and mechanical properties at low temperature of Nitronic 40 with particular reference to its use in the construction of models for cryogenic wind tunnels

    NASA Technical Reports Server (NTRS)

    Wigley, D. A.

    1982-01-01

    Nitronic 40 was chosen for the construction of Pathfinder I, an R & D model for use in the National Transonic Facility, because of its good mechanical properties at cryogenic temperatures. Nitronic 40 contains delta ferrite and is in a sensitized condition. Heat treatments carried out to remove residual stresses also caused further sensitization. Experiments showed that heat treatment followed by cryoquenching removed the sensitization without creating residual stresses. Heat treatment at temperatures of 2200 F was used to remove the delta ferrite but with little success and at the cost of massive grain growth. The implications of using degraded Nitronic 40 for cryogenic wind tunnel models are discussed, together with possible acceptance criteria.

  16. Rv1894c Is a Novel Hypoxia-Induced Nitronate Monooxygenase Required for Mycobacterium tuberculosis Virulence

    PubMed Central

    Klinkenberg, Lee G.; Karakousis, Petros C.

    2013-01-01

    Tuberculosis is difficult to cure, requiring a minimum of 6 months of treatment with multiple antibiotics. Small numbers of organisms are able to tolerate the antibiotics and persist in the lungs of infected humans, but they still require some metabolic activity to survive. We studied the role of the hypoxia-induced Rv1894c gene in Mycobacterium tuberculosis virulence in guinea pigs, which develop hypoxic, necrotic granulomas histologically resembling those in humans and found this gene to be necessary for full bacillary growth and survival. We characterized the function of the encoded enzyme as a nitronate monooxygenase, which is needed to prevent the buildup of toxic products during hypoxic metabolism and is negatively regulated by the transcriptional repressor KstR. Future studies will focus on developing small-molecule inhibitors that target Rv1894c and its homologs, with the goal of killing persistent bacteria, thereby shortening the time needed to treat tuberculosis. PMID:23408846

  17. Fracture temperature and flaw growth in nitronic 40 at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Domack, M. S.

    1984-01-01

    The fracture resistance and fatigue response of Armco Nitronic 40 austenitic stainless steel were evaluated under cryogenic conditions. Tensile, fracture toughness and fatigue crack growth properties were measured at -275 F. The tensile yield strength was approximately 120 ksi and the fracture toughness was estimated to be 350 ksi-in /2 on the basis of fracture toughness measurements. Testing was conducted to evaluate the behavior of a simulated section of the wing of the Pathfinder 1 model subject to a load and temperature history typical of that for testing in the National Transonic Facility. The wing section model incorporated a proposed brazing technique for pressure-transducer attachment. The simulated wing section performed satisfactorily at stress levels of nearly 60 percent of the material yield strength. The brazing technique proved to be an effective method of transducer attachment under conditions of high stress levels and large temperature excursions.

  18. Comparison of Nitronic 50 and Stainless Steel 316 for use in Supercritical Water Environments

    NASA Astrophysics Data System (ADS)

    Karmiol, Zachary

    Increased efficiency can greatly benefit any mode of power production. Many proposed coal, natural gas, and nuclear reactors attempt to realize this goal through the use of increased operating temperatures and pressures, and as such require materials capable of withstanding extreme conditions. One such design employs supercritical water, which in addition to high temperatures and pressures is also highly oxidizing. A critical understanding of both mechanical and oxidation characteristics of candidate materials are required to determine the viability of materials for these reactors. This work investigates two potential materials, austenitic stainless steels, namely, Nitronic-50 and stainless steel 316, for use in these conditions. The supercritical water loop at the University of Nevada, Reno allowed for the study of materials at both subcritical and supercritical conditions. The materials were investigated mechanically using slow strain rate tests under conditions ranging from an inert nitrogen atmosphere, to both subcritical and supercritical water, with the failed samples surface characterized by optical microscopy, scanning electron microscopy, and Raman spectroscopy. Electrochemical studies were performed via potentiodynamic polarization in subcritical water only, and characterized using Raman spectroscopy. The samples were also exposed to supercritical water, and characterized using Raman spectroscopy. Nitronic-50 was found to have superior mechanical characteristics to stainless steel 316. SS-316 was found to have a surface film consisting of iron oxides, while the surface film of N-50 consisted predominantly of nickel-iron spinel. The crack interior of the sample was different from the exterior, indicating that the time and temperature of the exposure might play a defining role in determining the chemistry of the film.

  19. Synthesis of Isoxazoline/Cyclic Nitrone-Featured Methylenes Using Unsaturated Ketoximes: A Dual Role of TEMPO.

    PubMed

    Chen, Fei; Yang, Xiu-Long; Wu, Zhi-Wei; Han, Bing

    2016-04-01

    A novel, metal-free, and regioselective approach for the synthesis of isoxazoline/cyclic nitrone-featured methylenes has been developed by the reaction of readily accessible β,γ- and γ,δ-unsaturated ketoximes with TEMPO via tandem iminoxyl radical-promoted cyclization/TEMPO-mediated Cope-like elimination, respectively. This protocol utilizes commercially available TEMPO as the iminoxyl radical initiator as well as the β-hydrogen acceptor in the Cope-like elimination. PMID:26954339

  20. Inhibition of ROS-induced apoptosis in endothelial cells by nitrone spin traps via induction of phase II enzymes and suppression of mitochondria-dependent pro-apoptotic signaling

    PubMed Central

    Das, Amlan; Gopalakrishnan, Bhavani; Voss, Oliver H.; Doseff, Andrea I.; Villamena, Frederick A.

    2012-01-01

    Oxidative stress is the main etiological factor behind the pathogenesis of various diseases including inflammation, cancer, cardiovascular and neurodegenerative disorders. Due to the spin trapping abilities and various pharmacological properties of nitrones, their application as therapeutic agent has been gaining attention. Though the antioxidant properties of the nitrones are well known, the mechanisms by which they modulate the cellular defense machinery against oxidative stress is not well investigated and requires further elucidation. Here, we have investigated the mechanisms of cytoprotection of the nitrone spin traps against oxidative stress in bovine aortic endothelial cells (BAEC). Cytoprotective properties of both the cyclic nitrone 5,5-dimethyl-pyrroline N-oxide (DMPO) and linear nitrone alpha-phenyl N-tert-butyl nitrone (PBN) against H2O2-induced cytoxicity were investigated. Preincubation of BAEC with PBN or DMPO resulted in the inhibition of H2O2–mediated cytotoxicity and apoptosis. Nitrone-treatment resulted in the induction and restoration of phase II antioxidant enzymes via nuclear translocation of NF-E2-related factor 2 (Nrf-2) in oxidatively-challenged cells. Furthermore, the nitrones were found to inhibit the mitochondrial depolarization and subsequent activation of caspase-3 induced by H2O2. Significant down-regulation of the pro-apoptotic proteins p53 and Bax, and up-regulation of the anti-apoptotic proteins Bcl-2 and p-Bad were observed when the cells were preincubated with the nitrones prior to H2O2–treatment. It was also observed that Nrf-2 silencing completely abolished the protective effects of nitrones. Hence, these findings suggest that nitrones confer protection to the endothelial cells against oxidative stress by modulating phase II antioxidant enzymes and subsequently inhibiting mitochondria-dependent apoptotic cascade. PMID:22580046

  1. The stress corrosion resistance and the cryogenic temperature mechanical properties of annealed Nitronic 60 bar material

    NASA Technical Reports Server (NTRS)

    Montano, J. W. L.

    1977-01-01

    Ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of annealed, straightened, and centerless ground Nitronic 60 stainless steel alloy bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing strength with decreasing temperature to -196 C. Below liquid nitrogen temperature the smooth tensile and notched tensile strengths decreased slightly while the elongation and reduction of area decreased drastically. The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens and transverse C-ring specimens exposed to: alternate immersion in a 3.5% NaCl bath; humidity cabinet; and a 5% salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack. Approximately 3/4 of the transverse C-rings exposed to alternate immersion and to salt spray experienced a pitting attack on the top and bottom ends. Additional stress corrosion tests were performed on transverse tensile specimens. No failures occurred in the 90% stressed specimens exposed for 90 days in the alternate immersion and salt spray environments

  2. 46 CFR 95.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Quantity, pipe sizes, and discharge rates. 95.15-5 Section 95.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-5 Quantity, pipe sizes, and discharge rates. (a) General....

  3. 46 CFR 193.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Quantity, pipe sizes, and discharge rates. 193.15-5 Section 193.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-5 Quantity, pipe sizes, and discharge...

  4. 46 CFR 38.15-5 - Cargo hose-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Cargo hose-TB/ALL. 38.15-5 Section 38.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Special Requirements § 38.15-5 Cargo hose—TB/ALL. (a) When the liquid and vapor line hoses used for loading and...

  5. An Unprecedented Formal [5 + 2] Cycloaddition of Nitrones with o-Carboryne via Tandem [3 + 2] Cycloaddition/Oxygen Migration/Aromatization Sequence.

    PubMed

    Zhao, Da; Zhang, Jiji; Xie, Zuowei

    2015-11-01

    Heterocyclic skeletons are widespread among natural products as well as bioactive molecules. Cycloaddition reaction has created new opportunities to access heterocycles of great complexity due to its advantage of multiple bond formation in a single step. Here, we describe an unprecedented formal [5 + 2] cycloaddition of nitrone with o-carboryne to afford carborane-fused seven-membered heterocycles. Experimental and theoretical data suggest that a sequence of [3 + 2] cycloaddition, N-O bond cleavage, oxygen migration and rearomatization is involved in this unprecedented reaction. In this process, the nitrone moieties serve as five-atom coupling partners with both heteroatoms being incorporated into the framework of the final products. This new methodology also offers new insight into the chemistry of nitrones. PMID:26467943

  6. Highly sensitive free radical detection by nitrone-functionalized gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Du, Libo; Huang, Saipeng; Zhuang, Qianfen; Jia, Hongying; Rockenbauer, Antal; Liu, Yangping; Liu, Ke Jian; Liu, Yang

    2014-01-01

    The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems, has been greatly limited partially due to the low reaction rate between the currently available spin traps with biological radicals. To overcome this drawback, we herein report the first example of nitrone functionalized gold nanoparticles (Au@EMPO) as highly efficient spin traps in which the thiolated EMPO (2-(ethoxycarbonyl)-2-methyl-3,4-dihydro-2H-pyrrole 1-oxide) derivative was self-assembled on gold nanoparticles. Kinetic studies showed that Au@EMPO has a 137-fold higher reaction rate constant with &z.rad;OH than PBN (N-tert-butyl-α-phenylnitrone). Owing to the high rate of trapping &z.rad;OH by Au@EMPO as well as the high stability of the resulting spin adduct (t1/2 ~ 56 min), Au@EMPO affords 124-fold higher sensitivity for &z.rad;OH than EMPO. Thus, this new nanospin trap shows great potential in trapping the important radicals such as &z.rad;OH in various biological systems and provides a novel strategy to design spin traps with much improved properties.The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems

  7. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5 Section 52.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11). (a) Tubes, pipe and nipples shall be...

  8. Erosion behaviour of WC-10Co-4Cr coating on 23-8-N nitronic steel by HVOF thermal spraying

    NASA Astrophysics Data System (ADS)

    kumar, Avnish; Sharma, Ashok; Goel, S. K.

    2016-05-01

    WC-10Co-4Cr coating was deposited by high-velocity oxy-fuel (HVOF) process on cast and solution treated (1220 °C/150 min) 23-8-N nitronic steel substrates. Solution treated substrate has shown higher toughness, ductility and impact energy with a marginal reduction in hardness as compared to cast substrate. This influence the coating deposition efficiency and erosion behaviour. Erosion resistance of coatings was evaluated by air jet erosion tester on two different impact angles (30° and 90°). Phases, microstructure and eroded surface of the coating were characterised by X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FESEM) respectively. It is observed that coating on solution treated substrate was superior to cast substrate. The reason being that coating has dense and well-bonded structure with low porosity, less decarburization and inter-splat oxidation. Higher erosion resistance of coated solution treated 23-8-N nitronic steel was attributed to combination of high fracture toughness and hardness of coating including optimum mechanical properties of the substrate. FESEM analysis reveals that erosion response of WC-10Co-4Cr coating also dependent on the relative size of the impact crater with respect to the WC grain size. Coating is removed by combined mode of ductile and brittle erosion.

  9. Understanding bond formation in polar one-step reactions. Topological analyses of the reaction between nitrones and lithium ynolates.

    PubMed

    Roca-López, David; Polo, Victor; Tejero, Tomás; Merino, Pedro

    2015-04-17

    The mechanism of the reaction between nitrones and lithium ynolates has been studied using DFT methods at the M06-2X/cc-pVTZ/PCM=THF level. After the formation of a starting complex an without energy barrier, in which the lithium atom is coordinated to both nitrone and ynolate, the reaction takes place in one single kinetic step through a single transition structure. However, the formation of C-C and C-O bonds takes place sequentially through a typical two-stage, one-step process. A combined study of noncovalent interactions (NCIs) and electron localization function (ELFs) of selected points along the intrinsic reaction coordinate (IRC) of the reaction confirmed that, in the transition structure, only the C-C bond is being formed to some extent, whereas an electrostatic interaction is present between carbon and oxygen atoms previous to the formation of the C-O bond. Indeed, the formation of the second C-O bond only begins when the first C-C bond is completely formed without formation of any intermediate. Once the C-C bond is formed and before the C-O bond formation starts the RMS gradient norm dips, approaching but not reaching 0, giving rise to a hidden intermediate. PMID:25803829

  10. Characterization of nitrogen effects in high energy density weldments of Nitronic 40 stainless steel

    NASA Astrophysics Data System (ADS)

    Pfeif, Erik Andrew

    Variation in the welding environment for laser beam welding and electron beam welding can alter the resulting weld chemical composition, microstructure and therefore the mechanical properties. The room temperature mechanical properties of Nitronic 40 stainless steel weld metal from three different heats containing 0.24, 0.28, and 0.31 wt. pct. nitrogen were evaluated for continuous mode Ytterbium doped Fiber laser welds conducted with argon and nitrogen shielding gases, and for electron beam welds. The bulk nitrogen contents were monitored and the resulting properties were then related to microstructural features measured using Electron BackScatter Diffraction (EBSD). Traditional tensile testing of weld metal is conducted on composite tensile bars consisting of base metal and weld metal often leading to failure in the region adjacent to the weld due to strength mismatch at the weld interface. These tests provide composite strength but do not specifically determine the mechanical properties of the heterogeneous weld metal. In this research, microtensile testing was conducted to characterize the properties of the different regions of the weld. The microtensile testing procedures were developed using two geometries of tensile bars measuring the properties through the thickness of 3 mm full penetration welds. In all cases an increase in the strength of the weld metal was found to occur, though the electron beam welds exhibited a higher strength than the laser welds. Standard predictive equations were found to under-predict the strength of the laser welds, even when average grain size or intercept distances were measured. The contribution of nitrogen solid solution strengthening was consistent at approximately 513 MPa per wt. pct. nitrogen. Similar cooling rates and heat inputs allow for a comparison across high energy density welding techniques. Though microstructural differences through the depth of the weld metal were observed as nitrogen vaporization decreased and

  11. 46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Miscellaneous Boiler Repairs § 59.15-5 Stayed furnaces and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or...

  12. 46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Miscellaneous Boiler Repairs § 59.15-5 Stayed furnaces and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or...

  13. 46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Miscellaneous Boiler Repairs § 59.15-5 Stayed furnaces and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or...

  14. 46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Miscellaneous Boiler Repairs § 59.15-5 Stayed furnaces and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or...

  15. 46 CFR 59.15-5 - Stayed furnaces and combustion chambers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Stayed furnaces and combustion chambers. 59.15-5 Section... TO BOILERS, PRESSURE VESSELS AND APPURTENANCES Miscellaneous Boiler Repairs § 59.15-5 Stayed furnaces and combustion chambers. (a) Where the plate forming the walls of stayed furnaces or...

  16. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... 46 Shipping 2 2010-10-01 2010-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11)....

  17. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... 46 Shipping 2 2014-10-01 2014-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11)....

  18. 46 CFR 52.15-5 - Tube connections (modifies PWT-9 and PWT-11).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of section I of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 52.01... 46 Shipping 2 2011-10-01 2011-10-01 false Tube connections (modifies PWT-9 and PWT-11). 52.15-5... BOILERS Requirements for Watertube Boilers § 52.15-5 Tube connections (modifies PWT-9 and PWT-11)....

  19. 46 CFR 54.15-5 - Protective devices (modifies UG-125).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... allowable working pressure, except when the excess pressure is caused by exposure to fire or other....15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Pressure-Relief Devices § 54.15-5 Protective devices (modifies UG-125). (a) All pressure...

  20. 46 CFR 54.15-5 - Protective devices (modifies UG-125).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... allowable working pressure, except when the excess pressure is caused by exposure to fire or other....15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Pressure-Relief Devices § 54.15-5 Protective devices (modifies UG-125). (a) All pressure...

  1. 46 CFR 54.15-5 - Protective devices (modifies UG-125).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... allowable working pressure, except when the excess pressure is caused by exposure to fire or other....15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Pressure-Relief Devices § 54.15-5 Protective devices (modifies UG-125). (a) All pressure...

  2. 46 CFR 54.15-5 - Protective devices (modifies UG-125).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... allowable working pressure, except when the excess pressure is caused by exposure to fire or other....15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Pressure-Relief Devices § 54.15-5 Protective devices (modifies UG-125). (a) All pressure...

  3. 46 CFR 54.15-5 - Protective devices (modifies UG-125).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... allowable working pressure, except when the excess pressure is caused by exposure to fire or other....15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Pressure-Relief Devices § 54.15-5 Protective devices (modifies UG-125). (a) All pressure...

  4. Synthesis of densely functionalized enantiopure indolizidines by ring-closing metathesis (RCM) of hydroxylamines from carbohydrate-derived nitrones

    PubMed Central

    Bonanni, Marco; Marradi, Marco; Cardona, Francesca; Cicchi, Stefano; Goti, Andrea

    2007-01-01

    Background Indolizidine alkaloids widely occur in nature and display interesting biological activity. This is the reason for which their total synthesis as well as the synthesis of non-natural analogues still attracts the attention of many research groups. To establish new straightforward accesses to these molecules is therefore highly desirable. Results The ring closing metathesis (RCM) of enantiopure hydroxylamines bearing suitable unsaturated groups cleanly afforded piperidine derivatives in good yields. Further cyclization and deprotection of the hydroxy groups gave novel highly functionalized indolizidines. The synthesis of a pyrroloazepine analogue is also described. Conclusion We have developed a new straightforward methodology for the synthesis of densely functionalized indolizidines and pyrroloazepine analogues in 6 steps and 30–60% overall yields from enantiopure hydroxylamines obtained straightforwardly from carbohydrate-derived nitrones. PMID:18076753

  5. Computational Investigation of the Photochemical Reaction Path of Some Synthesized and Experimentally Analyzed Small-Chain Conjugated Nitrones.

    PubMed

    Saini, Praveen; Banerjee, Mainak; Chattopadhyay, Anjan

    2016-01-28

    This combined theoretical and experimental study has revealed the photochemistry of two small open-chain conjugated N-methylnitrone systems with phenyl substitutions at the C-terminal positions. The UV spectra of these synthesized nitrones have shown intense peaks around 330 nm while the new bands formed near 260 nm after their photoirradiation are predicted to be arising from the photoproduct oxaziridine. Photoexcitation of α-styryl N-methylnitrone populates the first excited singlet state which relaxes by 8 kcal/mol from the vertically excited state and subsequently goes toward the lowest-energy conical intersection (CI) geometry (situated 27-30 kcal/mol below) with a terminal CNO-kink. Following the gradient difference vectors of this CI, we have located the oxaziridine structure with its characteristic geometry at roughly 14 kcal/mol above the ground state. This whole process is triggered by a transfer of electronic cloud from oxygen to the conjugated chain side. On the other hand, the photoexcitation of the nonplanar 3,3-diphenylethylene N-methylnitrone has two strong singlet-singlet absorptions with almost 5 D transition moment values. Here the initial S2-S1 relaxation is followed by oxaziridine formation through the terminally twisted CI. However, the initially photoexcited S1 state in this nitrone is found to head toward some other direction with transfer of huge amount of nonbonding electron cloud of oxygen to the π* orbital, creating a stable excited state geometry with an elongated N-O bond which gets involved in a sloped CI with the ground state. PMID:26697926

  6. Diesterified Nitrone Rescues Nitroso-Redox Levels and Increases Myocyte Contraction Via Increased SR Ca2+ Handling

    PubMed Central

    Traynham, Christopher J.; Roof, Steve R.; Wang, Honglan; Prosak, Robert A.; Tang, Lifei; Viatchenko-Karpinski, Serge; Ho, Hsiang-Ting; Racoma, Ira O.; Catalano, Dominic J.; Huang, Xin; Han, Yongbin; Kim, Shang-U; Gyorke, Sandor; Billman, George E.

    2012-01-01

    Nitric oxide (NO) and superoxide (O2−) are important cardiac signaling molecules that regulate myocyte contraction. For appropriate regulation, NO and O2.− must exist at defined levels. Unfortunately, the NO and O2.− levels are altered in many cardiomyopathies (heart failure, ischemia, hypertrophy, etc.) leading to contractile dysfunction and adverse remodeling. Hence, rescuing the nitroso-redox levels is a potential therapeutic strategy. Nitrone spin traps have been shown to scavenge O2.− while releasing NO as a reaction byproduct; and we synthesized a novel, cell permeable nitrone, 2–2–3,4-dihydro-2H-pyrrole 1-oxide (EMEPO). We hypothesized that EMEPO would improve contractile function in myocytes with altered nitroso-redox levels. Ventricular myocytes were isolated from wildtype (C57Bl/6) and NOS1 knockout (NOS1−/−) mice, a known model of NO/O2.− imbalance, and incubated with EMEPO. EMEPO significantly reduced O2.− (lucigenin-enhanced chemiluminescence) and elevated NO (DAF-FM diacetate) levels in NOS1−/− myocytes. Furthermore, EMEPO increased NOS1−/− myocyte basal contraction (Ca2+ transients, Fluo-4AM; shortening, video-edge detection), the force-frequency response and the contractile response to β-adrenergic stimulation. EMEPO had no effect in wildtype myocytes. EMEPO also increased ryanodine receptor activity (sarcoplasmic reticulum Ca2+ leak/load relationship) and phospholamban Serine16 phosphorylation (Western blot). We also repeated our functional experiments in a canine post-myocardial infarction model and observed similar results to those seen in NOS1−/− myocytes. In conclusion, EMEPO improved contractile function in myocytes experiencing an imbalance of their nitroso-redox levels. The concurrent restoration of NO and O2.− levels may have therapeutic potential in the treatment of various cardiomyopathies. PMID:23300588

  7. Medium-throughput ESR detection of superoxide production in undetached adherent cells using cyclic nitrone spin traps.

    PubMed

    Abbas, K; Hardy, M; Poulhès, F; Karoui, H; Tordo, P; Ouari, O; Peyrot, F

    2015-01-01

    Spin trapping with cyclic nitrones coupled to electron spin resonance (ESR) is recognized as a specific method of detection of oxygen free radicals in biological systems, especially in culture cells. In this case, the detection is usually performed on cell suspensions, which is however unsuitable when adhesion influences free radical production. Here, we performed ESR detection of superoxide with four spin traps (5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide, DEPMPO; 5-diisopropoxyphosphoryl-5-methyl-1-pyrroline N-oxide, DIPPMPO; (4R*, 5R*)-5-(diisopropyloxyphosphoryl)-5-methyl-4-[({[2-(triphenylphosphonio)ethyl]carbamoyl}oxy)methyl]pyrroline N-oxide bromide, Mito-DIPPMPO; and 6-monodeoxy-6-mono-4-[(5-diisopropoxyphosphoryl-5-methyl-1-pyrroline-N-oxide)-ethylenecarbamoyl-(2,3-di-O-methyl) hexakis (2,3,6-tri-O-methyl)]-β-cyclodextrin, CD-DIPPMPO) directly on RAW 264.7 macrophages cultured on microscope coverslip glasses after phorbol 12-myristate 13-acetate (PMA) stimulation. Distinct ESR spectra were obtained with each spin trap using this method. CD-DIPPMPO, a recently published phosphorylated cyclic nitrone bearing a permethylated β-cyclodextrin moiety, was confirmed as the most specific spin trap of the superoxide radical, with exclusive detection of the superoxide adduct. ESR detection performed on cells attached to coverslips represents significant advances over other methods in terms of simplicity, speed, and measurement under near-physiological conditions. It thus opens the way for numerous applications, such as medium-throughput screening of antioxidants and reactive oxygen species (ROS)-modulating agents. PMID:25968949

  8. Azomethine Ylides from Nitrones: Using Catalytic nBuLi for the Totally Stereoselective Synthesis of trans-2-Alkyl-3-oxazolines.

    PubMed

    Juste-Navarro, Veronica; Delso, Ignacio; Tejero, Tomás; Merino, Pedro

    2016-08-01

    The cycloaddition of azomethine ylide N-oxides (nitrone ylides) with aldehydes provides 3-oxazolines in a completely stereoselective manner in the presence of a catalytic amount of n-butyllithium. The process involves an initial nucleophilic attack on the aldehyde, followed by intramolecular oxygen addition to the nitrone moiety and lithium-assisted elimination of water, regenerating the catalytic species. Various Li-based catalytic systems are possible and the in situ generated water is required for continuing the catalytic cycle. The best results are observed with 20 mol % of n-butyllithium, whereas the use of stoichiometric amounts inhibit the rate of catalysis. Experimental, spectroscopic, and computational mechanistic studies have provided evidence of lithium-ion catalysis and rationalized several competing catalytic pathways. PMID:27258625

  9. 46 CFR 193.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-5 Quantity, pipe sizes, and discharge rates. (a) General. The amount of carbon dioxide required for each.... A separate supply of carbon dioxide need not be provided for each space protected. The...

  10. 46 CFR 76.15-5 - Quantity, pipe sizes, and discharge rate.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 76.15-5 Quantity, pipe sizes, and discharge rate. (a) General. The amount of carbon dioxide required for each space shall be as determined by... the purpose of determining the amount of carbon dioxide required, a cargo compartment will...

  11. 46 CFR 34.15-5 - Quantity, pipe sizes, and discharge rates-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Carbon Dioxide Extinguishing Systems, Details § 34.15-5 Quantity, pipe sizes, and discharge rates—T/ALL. (a) General. (1) The amount of carbon dioxide required for each space shall be as determined by... carbon dioxide required for each space shall be equal to the gross volume of the space in cubic...

  12. 46 CFR 34.15-5 - Quantity, pipe sizes, and discharge rates-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Carbon Dioxide Extinguishing Systems, Details § 34.15-5 Quantity, pipe sizes, and discharge rates—T/ALL. (a) General. (1) The amount of carbon dioxide required for each space shall be as determined by... carbon dioxide required for each space shall be equal to the gross volume of the space in cubic...

  13. 46 CFR 76.15-5 - Quantity, pipe sizes, and discharge rate.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 76.15-5 Quantity, pipe sizes, and discharge rate. (a) General. The amount of carbon dioxide required for each space shall be as determined by... the purpose of determining the amount of carbon dioxide required, a cargo compartment will...

  14. 46 CFR 193.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 193.15-5 Quantity, pipe sizes, and discharge rates. (a) General. The amount of carbon dioxide required for each space shall be... supply of carbon dioxide need not be provided for each space protected. The total available supply...

  15. 46 CFR 193.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 193.15-5 Quantity, pipe sizes, and discharge rates. (a) General. The amount of carbon dioxide required for each space shall be... supply of carbon dioxide need not be provided for each space protected. The total available supply...

  16. 46 CFR 76.15-5 - Quantity, pipe sizes, and discharge rate.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 76.15-5 Quantity, pipe sizes, and discharge rate. (a) General. The amount of carbon dioxide required for each space shall be as determined by... the purpose of determining the amount of carbon dioxide required, a cargo compartment will...

  17. 46 CFR 34.15-5 - Quantity, pipe sizes, and discharge rates-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Carbon Dioxide Extinguishing Systems, Details § 34.15-5 Quantity, pipe sizes, and discharge rates—T/ALL. (a) General. (1) The amount of carbon dioxide required for each space shall be as determined by... carbon dioxide required for each space shall be equal to the gross volume of the space in cubic...

  18. 46 CFR 76.15-5 - Quantity, pipe sizes, and discharge rate.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 76.15-5 Quantity, pipe sizes, and discharge rate. (a) General. The amount of carbon dioxide required for each space shall be as determined by... the purpose of determining the amount of carbon dioxide required, a cargo compartment will...

  19. 46 CFR 76.15-5 - Quantity, pipe sizes, and discharge rate.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 76.15-5 Quantity, pipe sizes, and discharge rate. (a) General. The amount of carbon dioxide required for each space shall be as determined by... the purpose of determining the amount of carbon dioxide required, a cargo compartment will...

  20. 46 CFR 34.15-5 - Quantity, pipe sizes, and discharge rates-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Carbon Dioxide Extinguishing Systems, Details § 34.15-5 Quantity, pipe sizes, and discharge rates—T/ALL. (a) General. (1) The amount of carbon dioxide required for each space shall be as determined by... carbon dioxide required for each space shall be equal to the gross volume of the space in cubic...

  1. 46 CFR 95.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-5 Quantity, pipe sizes, and discharge rates. (a) General. The amount of carbon dioxide required for each space shall be... supply of carbon dioxide need not be provided for each space protected. The total available supply...

  2. 46 CFR 95.15-5 - Quantity, pipe sizes, and discharge rates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... VESSELS FIRE PROTECTION EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-5 Quantity, pipe sizes, and discharge rates. (a) General. The amount of carbon dioxide required for each space shall be... supply of carbon dioxide need not be provided for each space protected. The total available supply...

  3. 46 CFR 34.15-5 - Quantity, pipe sizes, and discharge rates-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Carbon Dioxide Extinguishing Systems, Details § 34.15-5 Quantity, pipe sizes, and discharge rates—T/ALL. (a) General. (1) The amount of carbon dioxide required for each space shall be as determined by... carbon dioxide required for each space shall be equal to the gross volume of the space in cubic...

  4. 29 CFR 15.5 - Administrative claim; evidence or information to substantiate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Administrative claim; evidence or information to... § 15.5 Administrative claim; evidence or information to substantiate. (a) Personal injury. In support... following evidence or information: (1) A written report by the attending physician or dentist setting...

  5. A comparison of E15.5 fetus and newborn rat serum proteomes

    PubMed Central

    2012-01-01

    Background Serum proteins carry out several functions in the circulation, including transfer, immunological functions, messenger functions, coagulation, and regulation of homeostasis. To investigate changes in serum proteins that occur during development, the serum proteomes of embryonic 15.5 (E15.5) fetuses and newborn rats were compared using LC-MS/MS. Results A total of 958 proteins were identified in the serum of rats at both developmental stages. The serum proteome pattern of newborn rats was compared to E15.5 fetuses by relative quantitation. The expression patterns of hemoglobin subunits were different at the two stages, with most of the subunits having decreased expression in newborn rats compared to E15.5 fetuses. In addition, 8 of 12 apolipoproteins were significantly decreased and 10 of 11 identified complement molecules were increased, with 4 exhibiting a significant increase. Moreover, 11 of 14 of the significantly increased enzyme regulators were inhibitors. The serum proteome patterns of different littermates from both developmental stages were also compared. We found that the levels of many highly abundant serum proteins varied between littermates, and the variations were larger than the variations of the technical control. Conclusions The serum proteomes of newborn rats and E15.5 fetuses were compared. The expression patterns of hemoglobin subunits were different at the two developmental stages, with most of the subunits having decreased expression. The majority of apolipoproteins had significantly decreased expression, while almost all identified complement proteins had increased expression. The levels of several highly abundant serum proteins also varied among littermates at these two developmental stages. This is the first study using LC-MS/MS to investigate serum proteome development. PMID:23134622

  6. 41 CFR 302-15.5 - Is my agency required to authorize payment for property management services?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 4 2011-07-01 2011-07-01 false Is my agency required to authorize payment for property management services? 302-15.5 Section 302-15.5 Public Contracts and Property...-ALLOWANCE FOR PROPERTY MANAGEMENT SERVICES General Rules for the Employee § 302-15.5 Is my agency...

  7. 41 CFR 302-15.5 - Is my agency required to authorize payment for property management services?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 4 2014-07-01 2014-07-01 false Is my agency required to authorize payment for property management services? 302-15.5 Section 302-15.5 Public Contracts and Property...-ALLOWANCE FOR PROPERTY MANAGEMENT SERVICES General Rules for the Employee § 302-15.5 Is my agency...

  8. 41 CFR 302-15.5 - Is my agency required to authorize payment for property management services?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true Is my agency required to authorize payment for property management services? 302-15.5 Section 302-15.5 Public Contracts and Property...-ALLOWANCE FOR PROPERTY MANAGEMENT SERVICES General Rules for the Employee § 302-15.5 Is my agency...

  9. 41 CFR 302-15.5 - Is my agency required to authorize payment for property management services?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false Is my agency required to authorize payment for property management services? 302-15.5 Section 302-15.5 Public Contracts and Property...-ALLOWANCE FOR PROPERTY MANAGEMENT SERVICES General Rules for the Employee § 302-15.5 Is my agency...

  10. 41 CFR 302-15.5 - Is my agency required to authorize payment for property management services?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false Is my agency required to authorize payment for property management services? 302-15.5 Section 302-15.5 Public Contracts and Property...-ALLOWANCE FOR PROPERTY MANAGEMENT SERVICES General Rules for the Employee § 302-15.5 Is my agency...

  11. The stress corrosion resistance and the cryogenic temperature mechanical properties of hot rolled Nitronic 32 bar material

    NASA Technical Reports Server (NTRS)

    Montano, J. W. L.

    1977-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to: alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray.

  12. Paternally inherited duplications of 11p15.5 and Beckwith-Wiedemann syndrome.

    PubMed Central

    Slavotinek, A; Gaunt, L; Donnai, D

    1997-01-01

    We present a three generation family in which a father and son have a balanced chromosome translocation between the short arms of chromosomes 5 and 11 (karyotype 46,XY,t(5;11)(p15.3;p15.3)). Two family members have inherited the unbalanced products of this translocation and are trisomic for chromosome 11p15.3-->pter and monosomic for chromosome 5p15.3-->pter (karyotype 46,XY,der(5)t(5;11)(p15.3;p15.3)pat). Paternally derived duplications of 11p15.5 are associated with Beckwith-Wiedemann syndrome (BWS) and both family members trisomic for 11p15.5 had prenatal overgrowth (birth weights >97th centile), macroglossia, coarse facial features, and broad hands. We review the clinical features of BWS patients who have a paternally derived duplication of 11p15.5 and provide evidence for a distinct pattern of dysmorphic features in those with this chromosome duplication. Interestingly, our family is the fifth unrelated family to be reported with a balanced reciprocal translocation between the short arms of chromosomes 5 and 11. The apparently non-random nature of this particular chromosome translocation is suggestive of sequence homology between the two chromosome regions involved in the translocation. Images PMID:9350814

  13. Metal-assisted addition of a nitrate anion to bis(oxy)enamines. A general approach to the synthesis of α-nitroxy-oxime derivatives from nitronates.

    PubMed

    Naumovich, Yana A; Buckland, Victoria Emily; Sen'ko, Dmitry A; Nelyubina, Yulia V; Khoroshutina, Yulia A; Sukhorukov, Alexey Yu; Ioffe, Sema L

    2016-04-28

    The synthesis of α-nitroxy-substituted oxime derivatives has been achieved by an unprecedented metal-assisted addition of a nitrate anion to bis(oxy)enamines, which are readily available from nitronates or nitroalkanes. The method has a broad scope and provides access to α-nitroxy-oximes and their cyclic ethers including nitroxy-substituted isoxazolines and dihydro-1,2-oxazines, which are of interest as potential NO-donors and intermediates in the synthesis of bioactive molecules. PMID:27050291

  14. alpha-Phenyl-n-tert-butyl-nitrone attenuates hypoxic-ischemic white matter injury in the neonatal rat brain.

    PubMed

    Lin, Shuying; Rhodes, Philip G; Lei, Manping; Zhang, Feng; Cai, Zhengwei

    2004-05-01

    White matter of the neonatal brain is highly sensitive to hypoxic-ischemic insult. The susceptibility of premature oligodendrocytes (OLs) to free radicals (FRs) produced during hypoxia-ischemia (HI) has been proposed as one of the mechanisms involved. To test this hypothesis, and to further investigate if the FR scavenger alpha-phenyl-N-tert-butyl-nitrone (PBN) attenuates hypoxic-ischemic white matter damage (WMD), postnatal day 4 (P4) SD rats were subjected to bilateral common carotid artery ligation (BCAL), followed by 8% oxygen exposure for 20 min. Pathological changes were evaluated on P6 and P9, 2 and 5 days after the HI insult. HI caused severe WMD including rarefaction, necrosis and cavity formation in the corpus callosum, external and internal capsule areas. OL injury was evidenced by degeneration of O4 positive OLs on P6. Disrupted myelination was verified by decreased immunostaining of myelin basic protein (MBP) on P9. Axonal injury was demonstrated by increased amyloid precursor protein (APP) immunostaining on both P6 and P9. Two lipid peroxidation end products, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), showed a one-fold elevation within 1-24 h following HI. 4-HNE immunostaining was found to specifically localize in the white matter area. Furthermore, pyknotic O4+ OLs were double-labeled with 4-HNE. These findings suggest that FRs are involved in the pathogenesis of neonatal WMD. PBN (100 mg/kg, i.p.) treatment alleviated the pathological changes of WMD following HI. It improved the survival of O4 positive OLs, attenuated hypomyelination and reduced axonal damage. PBN treatment also decreased the brain concentration of MDA/4-HNE and positive 4-HNE staining in the white matter area. These findings indicate that in the current WMD model, PBN protects both OLs and axons, the two main components in the white matter, from neonatal HI insult. FR scavenging appears to be the primary mechanism underlying its neuroprotective effect. PMID:15064144

  15. Aryl radical involvement in amiodarone-induced pulmonary toxicity: Investigation of protection by spin-trapping nitrones

    SciTech Connect

    Nicolescu, Adrian C.; Comeau, Jeannette L.; Hill, Bruce C.; Bedard, Leanne L.; Takahashi, Takashi; Brien, James F.; Racz, William J.; Massey, Thomas E. . E-mail: masseyt@post.queensu.ca

    2007-04-01

    Amiodarone (AM), an antidysrrhythmic drug, can produce serious adverse effects, including potentially fatal AM-induced pulmonary toxicity (AIPT). AM-induced cytotoxicity and pulmonary fibrosis are well recognized, but poorly understood mechanistically. The hypothesis of aryl radical involvement in AM toxicity was tested in non-biological and biological systems. Photolysis of anaerobic aqueous solutions of AM, or N-desethylamiodarone (DEA) resulted in the formation of an aryl radical, as determined by spin-trapping and electron paramagnetic resonance (EPR) spectroscopy experiments. The non-iodinated AM analogue, didesiodoamiodarone (DDIA), did not form aryl radicals under identical conditions. The toxic susceptibility of human lung epithelioid HPL1A cells to AM, DEA, and DDIA showed time- and concentration-dependence. DEA had a more rapid and potent toxic effect (LC{sub 50} = 8 {mu}M) than AM (LC{sub 50} = 146 {mu}M), whereas DDIA cytotoxicity was intermediate (LC{sub 50} = 26 {mu}M) suggesting a minor contribution of the iodine atoms. Incubation of human lung epithelial cells with the spin-trapping nitrones {alpha}-phenyl-N-t-butylnitrone (PBN, 10 mM) or {alpha}-(4-pyridyl N-oxide)-N-t-butylnitrone (POBN, 5.0 mM) did not significantly protect against AM, DEA, or DDIA cytotoxicity. Intratracheal administration of AM to hamsters produced pulmonary fibrosis at day 21, which was not prevented by 4 days of treatment with 150 mg/kg/day PBN or 164 mg/kg/day POBN. However, the body weight loss in AM-treated animals was counteracted by PBN. These results suggest that, although AM can generate an aryl radical photochemically, its in vivo formation may not be a major contributor to AM toxicity, and that spin-trapping reagents do not halt the onset of AM toxicity.

  16. 46 CFR 190.15-5 - Vessels using fuel having a flashpoint of 110 °F. or lower.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Vessels using fuel having a flashpoint of 110 °F. or lower. 190.15-5 Section 190.15-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-5 Vessels using fuel having a flashpoint of 110 °F. or lower. (a)...

  17. Beckwith-Wiedemann syndrome and imprinted genes on chromosome 11p15.5

    SciTech Connect

    Weksberg, R.; Perlikowski, S.; Squire, J.

    1994-09-01

    Beckwith-Wiedemann syndrome (BWS) is a syndrome characterized by generalized and regional overgrowth as well as a predisposition to specific embryonal tumors. We have previously reported biallelic expression of insulin like growth factor 2 (IGF2) in fibroblasts from sporadic cases of BWS. In these cells, the normal expression pattern for IGF2 is allele-specific and derived from the paternal allele. To determine whether biallelic expression of IGF2 in BWS patients results from aberrant regulation of a single gene or multiple genes in an imprinted domain, we undertook the study of a second gene in the 11p15.5 imprinted region. H19 is normally stringently regulated, expressed primarily from the maternal allele, and in many tissues reciprocal expression of H19 and IGF2 has been documented. Since no protein product for H19 has been identified, the RNA itself may be biologically active and it may have a tumor suppressor function. Moreover, H19 has been suggested as a candidate gene in BWS, especially in autosomal dominant pedigrees. Using an Rsa1 polymorphism in the transcribed region of H19, we found that the expression of H19 in 8 patients with sporadic BWS is consistently nonallelic and in the informative cases is always from the maternal allele. This is also true for the two cases of BWS where biallelic IGF2 expression has been documented. We conclude that IGF2 biallelic expression does not represent a general loss of imprint control. If H19 and IGF2 do normally respond to common signals within an imprinted domain at 11p15.5, we suggest that BWS patients with biallelic IGF2 expression can escape from such imprinting constraints. To study this region in more detail, we have developed a replication timing assay for IGF2 and H19 to determine whether loss of asynchronous replication accompanies biallelic IGF2 expression.

  18. On the Feasibility of Wireless Multimedia Sensor Networks over IEEE 802.15.5 Mesh Topologies

    PubMed Central

    Garcia-Sanchez, Antonio-Javier; Losilla, Fernando; Rodenas-Herraiz, David; Cruz-Martinez, Felipe; Garcia-Sanchez, Felipe

    2016-01-01

    Wireless Multimedia Sensor Networks (WMSNs) are a special type of Wireless Sensor Network (WSN) where large amounts of multimedia data are transmitted over networks composed of low power devices. Hierarchical routing protocols typically used in WSNs for multi-path communication tend to overload nodes located within radio communication range of the data collection unit or data sink. The battery life of these nodes is therefore reduced considerably, requiring frequent battery replacement work to extend the operational life of the WSN system. In a wireless sensor network with mesh topology, any node may act as a forwarder node, thereby enabling multiple routing paths toward any other node or collection unit. In addition, mesh topologies have proven advantages, such as data transmission reliability, network robustness against node failures, and potential reduction in energy consumption. This work studies the feasibility of implementing WMSNs in mesh topologies and their limitations by means of exhaustive computer simulation experiments. To this end, a module developed for the Synchronous Energy Saving (SES) mode of the IEEE 802.15.5 mesh standard has been integrated with multimedia tools to thoroughly test video sequences encoded using H.264 in mesh networks. PMID:27164106

  19. On the Feasibility of Wireless Multimedia Sensor Networks over IEEE 802.15.5 Mesh Topologies.

    PubMed

    Garcia-Sanchez, Antonio-Javier; Losilla, Fernando; Rodenas-Herraiz, David; Cruz-Martinez, Felipe; Garcia-Sanchez, Felipe

    2016-01-01

    Wireless Multimedia Sensor Networks (WMSNs) are a special type of Wireless Sensor Network (WSN) where large amounts of multimedia data are transmitted over networks composed of low power devices. Hierarchical routing protocols typically used in WSNs for multi-path communication tend to overload nodes located within radio communication range of the data collection unit or data sink. The battery life of these nodes is therefore reduced considerably, requiring frequent battery replacement work to extend the operational life of the WSN system. In a wireless sensor network with mesh topology, any node may act as a forwarder node, thereby enabling multiple routing paths toward any other node or collection unit. In addition, mesh topologies have proven advantages, such as data transmission reliability, network robustness against node failures, and potential reduction in energy consumption. This work studies the feasibility of implementing WMSNs in mesh topologies and their limitations by means of exhaustive computer simulation experiments. To this end, a module developed for the Synchronous Energy Saving (SES) mode of the IEEE 802.15.5 mesh standard has been integrated with multimedia tools to thoroughly test video sequences encoded using H.264 in mesh networks. PMID:27164106

  20. 46 CFR 190.15-5 - Vessels using fuel having a flashpoint of 110 °F. or lower.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... water in the bilge will not close off the ducts. (g) All ducts shall be of steel construction and...) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-5 Vessels using fuel having...

  1. On the vasoprotective mechanisms underlying novel β-phosphorylated nitrones: Focus on free radical characterization, scavenging and NO-donation in a biological model of oxidative stress.

    PubMed

    Cassien, Mathieu; Petrocchi, Consuelo; Thétiot-Laurent, Sophie; Robin, Maxime; Ricquebourg, Emilie; Kandouli, Chouaib; Asteian, Alice; Rockenbauer, Antal; Mercier, Anne; Culcasi, Marcel; Pietri, Sylvia

    2016-08-25

    A series of new hybrid 2-(diethoxyphosphoryl)-N-(benzylidene)propan-2-amine oxide derivatives with different aromatic substitution (PPNs) were synthesized. These molecules were evaluated for their EPR spin trapping potential on eleven different radicals and NO-donation properties in vitro, cytotoxicity and vasoprotective effect on precontracted rat aortic rings. A subfamily of the new PPNs featured an antioxidant moiety occurring in natural phenolic acids. From the experimental screening of these hydroxyphenyl- and methoxyphenyl-substituted PPNs, biocompatible nitrones 4d, and 4g-4i deriving from caffeic, gallic, ferulic and sinapic acids, which combined improved EPR probing of ROS formation, vasorelaxant action and antioxidant potency, might be potential drug candidate alternatives to PBN and its analogues. PMID:27162124

  2. Neuroprotective effects of pterin-6-aldehyde in gerbil global brain ischemia: comparison with those of alpha-phenyl-N-tert-butyl nitrone.

    PubMed

    Mori, H; Arai, T; Ishii, H; Adachi, T; Endo, N; Makino, K; Mori, K

    1998-01-30

    The superoxide (O2.-) scavenging activity and the neuroprotective effects of pterin-6-aldehyde (P6A), a xanthine oxidase inhibitor, were examined and compared with those of alpha-phenyl-N-tert-butyl nitrone (PBN), a spin trapping agent. The scavenging activity of P6A was more potent than that of PBN by 150-fold in neutrophil/phorbol myristate acetate O2.- generating system. P6A attenuated the neuronal damage with a much smaller dose and a greater efficiency than PBN in global brain ischemia in gerbils. These findings suggest that P6A is a more potent neuroprotective agent than PBN and has possible therapeutic effects against various diseases in which O2.- is involved. PMID:9507930

  3. Assignment of the cysteinyl-tRNA synthetase gene (CARS) to 11p15. 5

    SciTech Connect

    Cruzen, M.E.; Bengtsson, U.; McMahon, J.; Wasmuth, J.J.; Arfin, S.M. )

    1993-03-01

    The attachment of each of the 20 naturally occurring amino acids to their cognate tRNA isoaccepting families is catalyzed by a specific aminoacyl-tRNA synthetase. The structural genes encoding 10 of these enzymes have been assigned to specific human chromosomes. The HARS, LARS, RARS, and TARS genes, encoding histidyl-, leucyl-, arginyl-, and threonyl-tRNA synthetases, respectively, are all located on chromosome 5( 1, 5, 7, 9, 14). The MARS (methionyl-tRNA synthetase), NARS (asparaginyl-tRNA synthetase), VARS (valyl-tRNA synthetase), and WARS (tryptophanyl-tRNA synthetase) genes have been assigned to chromosomes 12, 18, 6, and 14, respectively (3, 4, 6, 8). A gene originally identified as encoding glutaminyl-tRNA synthetase was mapped to chromosome 1q32-q42 (10). However, a recent study suggests that the product of this gene is, in fact, a multifunctional enzyme with both glutamyl- and prolyl-tRNA synthetase activities (2). The fact that 4 of the 10 aminoacyl-tRNA synthetase genes already mapped are located on chromosome 5 may be fortuitous but might also indicate an evolutionary or regulatory relatedness. It is therefore, of interest to map genes encoding other aminoacyl-tRNA synthetases to determine if additional examples of synteny exist. The recent isolation of cDNA and genomic DNA clones for human cysteinyl-tRNA synthetase has now enabled us to map the CARS gene to segment p15.5 on chromosome 11 by fluorescence in situ hybridization.

  4. Fibroadenoma in Beckwith-Wiedemann syndrome with paternal uniparental disomy of chromosome 11p15.5.

    PubMed

    Takama, Yuichi; Kubota, Akio; Nakayama, Masahiro; Higashimoto, Ken; Jozaki, Kosuke; Soejima, Hidenobu

    2014-12-01

    Herein is described a case of breast fibroadenomas in a 16-year-old girl with Beckwith-Wiedemann syndrome (BWS) and uniparental disomy (UPD) of chromosome 11p15.5. She was clinically diagnosed with BWS and direct closure was performed for an omphalocele at birth. Subtotal and 90% pancreatectomy were performed for nesidioblastosis at the ages 2 months and 8 years, respectively. Bilateral multiple breast fibroadenomas were noted at the age of 16 and 17 years. In this case, paternal UPD of chromosome 11p15.5 was identified on microsatellite marker analysis. The relevant imprinted chromosomal region in BWS is 11p15.5, and UPD of chromosome 11p15 is a risk factor for BWS-associated tumorigenicity. Chromosome 11p15.5 consists of imprinting domains of IGF2, the expression of which is associated with the tumorigenesis of various breast cancers. This case suggests that fibroadenomas occurred in association with BWS. PMID:25521982

  5. 46 CFR 190.15-5 - Vessels using fuel having a flashpoint of 110 °F. or lower.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Vessels using fuel having a flashpoint of 110 °F. or...) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-5 Vessels using fuel having a flashpoint of 110 °F. or lower. (a) Spaces containing machinery which uses, or tanks which contain,...

  6. 46 CFR 190.15-5 - Vessels using fuel having a flashpoint of 110 °F. or lower.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Vessels using fuel having a flashpoint of 110 °F. or...) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-5 Vessels using fuel having a flashpoint of 110 °F. or lower. (a) Spaces containing machinery which uses, or tanks which contain,...

  7. 46 CFR 190.15-5 - Vessels using fuel having a flashpoint of 110 °F. or lower.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... having a flashpoint of 110 °F. or lower shall have natural supply and mechanical exhaust ventilation as required by this section. (b) The mechanical exhaust system shall be such as to assure the air changes as...) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-5 Vessels using fuel having...

  8. The Stress Corrosion Resistance and the Cryogenic Temperature Mechanical Behavior of 18-3 Mn (Nitronic 33) Stainless Steel Parent and Welded Material

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1976-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion results of 18-3 Mn (Nitronic 33)stainless steel, longitudinal and transverse, as received and as welded (TIG) material specimens manufactured from 0.063 inch thick sheet material, were described. The tensile test results indicate an increase in ultimate tensile and yield strengths with decreasing temperature. The elongation remained fairly constant to -200 F, but below that temperature the elongation decreased to less than 6.0% at liquid hydrogen temperature. The notched tensile strength (NTS) for the parent metal increased with decreasing temperature to liquid nitrogen temperature. Below -320 F the NTS decreased rapidly. The notched/unnotched (N/U) tensile ratio of the parent material specimens remained above 0.9 from ambient to -200 F, and decreased to approximately 0.65 and 0.62, respectively, for the longitudinal and transverse directions at liquid hydrogen temperature. After 180 days of testing, only those specimens exposed to the salt spray indicated pitting and some degradation of mechanical properties.

  9. Reduced losses in rolled Fe73.5Si15.5Nb3B7Cu1 nanocrystalline ribbon

    NASA Astrophysics Data System (ADS)

    Kernion, S. J.; Lucas, M. S.; Horwath, J.; Turgut, Z.; Michel, E.; Keylin, V.; Huth, J. F.; Leary, A. M.; Shen, S.; McHenry, M. E.

    2013-05-01

    Eddy currents in magnetic components undergoing high frequency switching can be mitigated by reducing the thickness of the component. Planar flow cast Fe73.5Si15.5Nb3B7Cu1 ribbon was plastically deformed by cold rolling, resulting in a thickness reduction of 38%. Shear band formation was seen and the coercivity was dramatically higher in the rolled ribbon. After crystallization, the hysteresis loop of the rolled ribbon was nearly identical to a non-rolled ribbon and losses were lower in the rolled ribbon above 25 kHz. Reductions in thickness by this method can lead to increases in operating frequency for power conversion applications.

  10. Interleukin-1β-induced brain injury in the neonatal rat can be ameliorated by α-phenyl-n-tert-butyl-nitrone

    PubMed Central

    Fan, Lir-Wan; Mitchell, Helen J.; Tien, Lu-Tai; Rhodes, Philip G.; Cai, Zhengwei

    2009-01-01

    To examine the possible role of inflammatory cytokines in mediating perinatal brain injury, we investigated effects of intracerebral injection of interleukin-1beta (IL-1β) on brain injury in the neonatal rat and the mechanisms involved. Intracerebral administration of IL-1β (1 μg/kg) resulted in acute brain injury, as indicated by enlargement of ventricles bilaterally, apoptotic death of oligodendrocytes (OLs) and loss of OL immunoreactivity in the neonatal rat brain. IL-1β also induced axonal and neuronal injury in the cerebral cortex as indicated by elevated expression of β-amyloid precursor protein, short beaded axons and dendrites, and loss of tyrosine hydroxylase positive neurons in the substantia nigra and the ventral tegmental areas. Administration of α-phenyl-n-tert-butyl-nitrone (PBN, 100 mg/kg i.p.) immediately after the IL-1β injection protected the brain from IL-1β-induced injury. Protection of PBN was linked with the attenuated oxidative stress induced by IL-1β, as indicated by decreased elevation of 8-isoprostane content and by the reduced number of 4-hydroxynonenal or malondialdehyde or nitrotyrosine positive cells following IL-1β exposure. PBN also attenuated IL-1β-stimulated inflammatory responses as indicated by the reduced activation of microglia. The finding that IL-1β induced perinatal brain injury was very similar to that induced by lipopolysaccharide (LPS), as we previously reported and that PBN was capable to attenuate the injury induced by either LPS or IL-1β suggests that IL-1β may play a critical role in mediating brain injury associated with perinatal infection/inflammation. PMID:19682987

  11. Protection against oxidative damage to CNS by alpha-phenyl-tert-butyl nitrone (PBN) and other spin-trapping agents: A novel series of nonlipid free radical scavengers

    SciTech Connect

    Carney, J.M.; Floyd, R.A. )

    1991-01-01

    Brain is extremely susceptible to oxidative damage. Utilizing a series of novel approaches, the authors have demonstrated that oxidative damage occurs during an ischemia/reperfusion insult (IRI) to brain. Thus, they have demonstrated that an IRI to Mongolian gerbil brain results in: (1) an enhanced rate of salicylate hydroxylation, implicating an increased flux of hydroxyl free radicals; (2) an enhanced flux of free radicals as determined by spin-trapping; (3) an enhanced level of endogenous protein oxidation; (4) a decrease in glutamine synthetase (GS) activity, an enzyme very sensitive to oxidative damage; and (5) demonstration of protection from an IRI by administering the spin-trapping agent alpha-phenyl-tert-butyl nitrone (PBN). The novel observation that PBN offers protection from the lethality brought on by a brain IRI appears to be clearly linked to the ability of the administered spin-trap to inhibit oxidative damage as evidenced by the decreased amount of brain protein oxidation and the prevention of an IRI-mediated loss of GS activity in treated animals. Aged gerbils are more sensitive to the lethal action of a brain IRI than younger animals, but they are protected by PBN administration as are the younger animals. Older gerbils have a significantly higher level of oxidized protein in the brain. Older gerbils have decreased activities of GS and neutral protease, the enzyme that removes oxidized protein, than younger animals. Chronic twice daily administration of PBN (32 mg/kg) for 14 days to older animals significantly lowered brain oxidized protein levels and raised GS and neutral protease activity to those observed in younger animals. Cessation of PBN administration resulted in a time-dependent restoration of protein oxidation levels and enzyme activities back to those observed prior to spin-trap administration.

  12. Premartensitic transition and relevant magnetic effects in Ni50Mn34In15.5Al0.5 alloy

    PubMed Central

    Wu, Yuqin; Guo, Shaopu; Yu, Shuyun; Cheng, Hui; Wang, Ruilong; Xiao, Haibo; Xu, Lingfang; Xiong, Rui; Liu, Yong; Xia, Zhengcai; Yang, Changping

    2016-01-01

    Resistance measurement, in situ optical microscopic observation, thermal and magnetic measurements have been carried out on Ni50Mn34In15.5Al0.5 alloy. The existence of a pronounced premartensitic transition prior to martensitic transition can be characterized by microstructure evolution as well as exothermic peak and smooth decrease of resistance and magnetization with obvious hysteresis over a wide temperature range upon cooling. Consequently, the alloy undergoes two successive magneto-structural transitions consisting of premartensitic and martensitic transitions. Magnetoelastic coupling between magnetic and structural degrees of freedom would be responsible for the appearance of premartensitic transition, as evinced by the distinct shift of transitions temperatures to lower temperature with external applied field of 50 kOe. The inverse premartensitic transition induced by magnetic field results in large magnetoresistance, and contributes to the enhanced inverse magnetocaloric effect through enlarging the peak value and temperature interval of magnetic entropy change ΔSm. PMID:27183331

  13. Premartensitic transition and relevant magnetic effects in Ni50Mn34In15.5Al0.5 alloy

    NASA Astrophysics Data System (ADS)

    Wu, Yuqin; Guo, Shaopu; Yu, Shuyun; Cheng, Hui; Wang, Ruilong; Xiao, Haibo; Xu, Lingfang; Xiong, Rui; Liu, Yong; Xia, Zhengcai; Yang, Changping

    2016-05-01

    Resistance measurement, in situ optical microscopic observation, thermal and magnetic measurements have been carried out on Ni50Mn34In15.5Al0.5 alloy. The existence of a pronounced premartensitic transition prior to martensitic transition can be characterized by microstructure evolution as well as exothermic peak and smooth decrease of resistance and magnetization with obvious hysteresis over a wide temperature range upon cooling. Consequently, the alloy undergoes two successive magneto-structural transitions consisting of premartensitic and martensitic transitions. Magnetoelastic coupling between magnetic and structural degrees of freedom would be responsible for the appearance of premartensitic transition, as evinced by the distinct shift of transitions temperatures to lower temperature with external applied field of 50 kOe. The inverse premartensitic transition induced by magnetic field results in large magnetoresistance, and contributes to the enhanced inverse magnetocaloric effect through enlarging the peak value and temperature interval of magnetic entropy change ΔSm.

  14. Premartensitic transition and relevant magnetic effects in Ni50Mn34In15.5Al0.5 alloy.

    PubMed

    Wu, Yuqin; Guo, Shaopu; Yu, Shuyun; Cheng, Hui; Wang, Ruilong; Xiao, Haibo; Xu, Lingfang; Xiong, Rui; Liu, Yong; Xia, Zhengcai; Yang, Changping

    2016-01-01

    Resistance measurement, in situ optical microscopic observation, thermal and magnetic measurements have been carried out on Ni50Mn34In15.5Al0.5 alloy. The existence of a pronounced premartensitic transition prior to martensitic transition can be characterized by microstructure evolution as well as exothermic peak and smooth decrease of resistance and magnetization with obvious hysteresis over a wide temperature range upon cooling. Consequently, the alloy undergoes two successive magneto-structural transitions consisting of premartensitic and martensitic transitions. Magnetoelastic coupling between magnetic and structural degrees of freedom would be responsible for the appearance of premartensitic transition, as evinced by the distinct shift of transitions temperatures to lower temperature with external applied field of 50 kOe. The inverse premartensitic transition induced by magnetic field results in large magnetoresistance, and contributes to the enhanced inverse magnetocaloric effect through enlarging the peak value and temperature interval of magnetic entropy change ΔSm. PMID:27183331

  15. Plant Habitat (PH)

    NASA Technical Reports Server (NTRS)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  16. pH optrode

    DOEpatents

    Northrup, M. Allen; Langry, Kevin C.

    1993-01-01

    A process is provided for forming a long-lasting, stable, pH-sensitive dye-acrylamide copolymer useful as a pH-sensitive material for use in an optrode or other device sensitive to pH. An optrode may be made by mechanically attaching the copolymer to a sensing device such as an optical fiber.

  17. pH Basics

    ERIC Educational Resources Information Center

    Lunelli, Bruno; Scagnolari, Francesco

    2009-01-01

    The exposition of the pervasive concept of pH, of its foundations and implementation as a meaningful quantitative measurement, in nonspecialist university texts is often not easy to follow because too many of its theoretical and operative underpinnings are neglected. To help the inquiring student we provide a concise introduction to the depth just…

  18. Ph.D. shortage

    NASA Astrophysics Data System (ADS)

    The late 1990s will see a shortage of Ph.D. graduates, according to the Association of American Universities, Washington, D.C. AAU's new comprehensive study, “The Ph.D. Shortage: The Federal Role,” reports that competition for new Ph.D.s is already intense and can only intensify because demand is greater than supply in both academic and nonacademic markets.Doctoral education plays an increasingly important role in U.S. research and development programs. Students have a pivotal part in doing research and enriching it with new ideas. The AAU report says that graduate students are “major determinants of the creativity and productivity of U.S. academic research, the source of more than 50% of the nation's basic research.’ The market for doctoral education extends beyond the university. In 1985, about 43% of all Ph.D.s employed in this country were working outside higher education; the demand for doctorate recipients in nonacademic sectors continues to grow.

  19. Preliminary results on the development of vacuum-brazed joints for cyrogenic wind tunnel aerofoil models

    SciTech Connect

    Wigley, D.A.; Lawing, P.L.; Sandefur, P.G.

    1982-01-01

    Initial trials carried out at the NASA Langley Research Center in the investigation of cryogenic wind tunnel joint construction demonstrated that diffusion-assisted brazed joints could be formed in 17-4 PH, 15-5 PH, AISI-type 347, and Nitronic 40 stainless steels using electrodeposited copper as the bonding agent. Subsequent work has concentrated on 15-5 PH and Nitronic 40 using thin foils of pure copper and Nicrobraz LM, a commercially available nickel-based alloy containing boron and silicon melting point depressants. This paper summarizes the work carried out to understand and evaluate these bonds and their metallurgical characteristics. The results indicate that a high-strength void-free bond can be formed by the vacuum brazing of stainless steels using copper- and nickel-based filler alloys. The Nitronic 40 brazed joints show strengths in excess of the yield strengths of the parent metal. The poor toughness of 15-5 PH stainless steel at cryogenic temperatures tends to disqualify its use in critical areas of low-temperature aerofoil models.

  20. Exclusive interaction of the 15.5 kD protein with the terminal box C/D motif of a methylation guide snoRNP.

    PubMed

    Szewczak, Lara B Weinstein; DeGregorio, Suzanne J; Strobel, Scott A; Steitz, Joan A

    2002-10-01

    Box C/D small nucleolar RNAs (snoRNAs) direct site-specific methylation of ribose 2'-hydroxyls in ribosomal and spliceosomal RNAs. To identify snoRNA functional groups contributing to assembly of an active box C/D snoRNP in Xenopus oocytes, we developed an in vivo nucleotide analog interference mapping procedure. Deleterious substitutions consistent with requirements for binding the 15.5 kD protein clustered within the terminal box C/D motif only. In vitro analyses confirmed a single interaction site for recombinant 15.5 kD protein and identified the exocyclic amine of A89 in box D as essential for binding. Our results argue that the 15.5 kD protein interacts asymmetrically with the two sets of conserved box C/D elements and that its binding is primarily responsible for the stability of box C/D snoRNAs in vivo. PMID:12401494

  1. A cryptic familial rearrangement of 11p15.5, involving both imprinting centers, in a family with a history of short stature.

    PubMed

    Brown, Lindsay A; Rupps, Rosemarie; Peñaherrera, Maria S; Robinson, Wendy P; Patel, Millan S; Eydoux, Patrice; Boerkoel, Cornelius F

    2014-06-01

    Silver-Russell syndrome (SRS) is a heterogeneous disorder characterized by intrauterine and postnatal growth retardation, dysmorphic facial features and body asymmetry. Both hypomethylation of the telomeric imprinting control region 1 (ICR1) at 11p15.5 and maternal duplication of 11p15.5 have been implicated in the etiology of this disorder. Here we report the origin and segregation of the first reported between-arm intrachromosomal insertion of 11p15.5 that encompasses both ICR1 and ICR2 in a multigenerational family with a history of short stature. One (or any odd number) crossover within the centromeric segment during meiosis would produce recombinant chromosomes; one with a duplication of the inserted segment and the other a deletion. In this 4-generation family, there were six instances of transmission of the recombinant chromosome with duplication of the11p15.5 segment, which leads to a SRS phenotype when maternally inherited and a Beckwith-Wiedemann phenotype when paternally transmitted. The size of the duplicated region is ~1.9 Mb as determined by microarray analysis. This study provides further evidence that maternally inherited duplications of 11p15.5 result in a SRS phenotype that includes short stature and other variable features. The methylation status of the extra copy of the duplicated region of 11p15.5 ultimately predicts the resulting phenotype. Thus, the different phenotype based on parental mode of transmission is of importance in the genetic counseling of these patients. PMID:24668696

  2. Urine pH test

    MedlinePlus

    A urine pH test measures the level of acid in urine. ... pH - urine ... meat products, or cheese can decrease your urine pH. ... to check for changes in your urine acid levels. It may be done to ... more effective when urine is acidic or non-acidic (alkaline).

  3. Synthesis, spectroscopic (FT-IR, FT-Raman, 13C, 1H, UV) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone.

    PubMed

    Sheela, N R; Sampathkrishnan, S; Thirumalai Kumar, M; Muthu, S

    2013-05-15

    The title compound, 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone (2HPN4MPN) was synthesized and characterized by FT-IR, FT-Raman, UV-Vis and (1)HNMR, (13)CNMR spectral analysis. The molecular geometry, harmonic vibrational frequencies and bonding features of the title compound in the ground state are computed at three parameter hybrid functional Lee-Yang-Parr/6-311++G(d,p) levels of theory. The most stable conformer of 2HPN4MPN is identified from the computational results. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMF). The UV-Vis spectrum was recorded in chloroform solution. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) complements the experimental findings. The calculated HOMO and LUMO energies confirm that charge transfer occurs within the molecule. In addition, DFT calculations of the compound, Molecular Electrostatic Potential (MEP), Natural Bond Orbital analysis (NBO) and non-linear optical (NLO) properties are performed at B3LYP/6-311++G(d,p) level of theory. Finally, the calculations are applied to simulated FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra. PMID:23542518

  4. Synthesis, spectroscopic (FT-IR, FT-Raman, 13C, 1H, UV) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone

    NASA Astrophysics Data System (ADS)

    Sheela, N. R.; Sampathkrishnan, S.; Thirumalai Kumar, M.; Muthu, S.

    2013-05-01

    The title compound, 2(2-Hydroxyphenyl)-N-(4-Methylphenyl) Nitrone (2HPN4MPN) was synthesized and characterized by FT-IR, FT-Raman, UV-Vis and 1HNMR, 13CNMR spectral analysis. The molecular geometry, harmonic vibrational frequencies and bonding features of the title compound in the ground state are computed at three parameter hybrid functional Lee-Yang-Parr/6-311++G(d,p) levels of theory. The most stable conformer of 2HPN4MPN is identified from the computational results. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMF). The UV-Vis spectrum was recorded in chloroform solution. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) complements the experimental findings. The calculated HOMO and LUMO energies confirm that charge transfer occurs within the molecule. In addition, DFT calculations of the compound, Molecular Electrostatic Potential (MEP), Natural Bond Orbital analysis (NBO) and non-linear optical (NLO) properties are performed at B3LYP/6-311++G(d,p) level of theory. Finally, the calculations are applied to simulated FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra.

  5. Probing the chemical steps of nitroalkane oxidation catalyzed by 2-nitropropane dioxygenase with solvent viscosity, pH, and substrate kinetic isotope effects.

    PubMed

    Francis, Kevin; Gadda, Giovanni

    2006-11-21

    Among the enzymes that catalyze the oxidative denitrification of nitroalkanes to carbonyl compounds, 2-nitropropane dioxygenase is the only one known to effectively utilize both the neutral and anionic (nitronate) forms of the substrate. A recent study has established that the catalytic pathway is common to both types of substrates, except for the initial removal of a proton from the carbon of the neutral substrates [Francis, K., Russell, B., and Gadda, G. (2005) J. Biol. Chem. 280, 5195-5204]. In the present study, the mechanistic properties of the enzyme have been investigated with solvent viscosity, pH, and kinetic isotope effects. With nitroethane or ethylnitronate, the kcat/Km and kcat values were independent of solvent viscosity, consistent with the substrate and product binding to the enzyme in rapid equilibrium. The abstraction of the proton from the alpha carbon of neutral substrates was investigated by measuring the pH dependence of the D(kcat/KNE) value with 1,1-[2H2]-nitroethane. The formation of the enzyme-bound flavosemiquinone formed during catalysis was examined by determining the pH dependence of the kcat/Km values with ethylnitronate and nitroethane and the inhibition by m-nitrobenzoate. Finally, alpha-secondary kinetic isotope effects with 1-[2H]-ethylnitronate were used to propose a non-oxidative tautomerization pathway, in which the enzyme catalyzes the interconversion of nitroalkanes between their anionic and neutral forms. The data presented suggest that enzymatic turnover of 2-nitropropane dioxygenase with neutral substrates is limited by the cleavage of the substrate CH bond at low pH, whereas that with anionic substrates is limited by the non-oxidative tautomerization of ethylnitroante to nitroethane at high pH. PMID:17105207

  6. The pH Game.

    ERIC Educational Resources Information Center

    Chemecology, 1996

    1996-01-01

    Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

  7. Stereo-, Regio-, and Chemoselective [3 + 2]-Cycloaddition of (2E,4E)-Ethyl 5-(Phenylsulfonyl)penta-2,4-dienoate with Various Azomethine Ylides, Nitrones, and Nitrile Oxides: Synthesis of Pyrrolidine, Isoxazolidine, and Isoxazoline Derivatives and a Computational Study.

    PubMed

    Sankar, Ulaganathan; Surya Kumar, Ch Venkata; Subramanian, V; Balasubramanian, K K; Mahalakshimi, S

    2016-03-18

    One-pot chemo-, regio-, and stereoselective synthesis of series of heterocyclic and spiroheterocyclic compounds was accomplished through mono- and bis[3 + 2]-cycloaddition reactions of (2E,4E)-ethyl 5-(phenylsulfonyl)penta-2,4-dienoate as a dipolarophile with azomethine ylides, nitrones, and nitrile oxides in good yields. The structures of the products were established by spectroscopic techniques as well as by single-crystal XRD study, and DFT calculations were performed to further understand the mechanism of this [3 + 2]-cycloaddition reaction. PMID:26886393

  8. Structural and relative energy assessments of DFT functionals and the MP2 method to describe the gas phase methylation of nitronates: [R(1)R(2)CNO2](-) + CH3I.

    PubMed

    Mahmood, Ayyaz; Longo, Ricardo L

    2016-06-22

    The performances of 26 combinations of density-functional theory (DFT) functionals or second-order Møller-Plesset (MP2) methods and basis sets were evaluated for the calculation of the activation energy (Δ(‡)E), the energy available (ΔRCE) to the reactant complex, the energy of reaction (ΔrE), and rotational constants of the main structures involved in the methylation reactions of nitronates, [R(1)R(2)CNO2](-) + CH3I, in the gas phase, where R(1) = R(2) = H, R(1) = H and R(2) = CH3, R(1) = R(2) = CH3, and R(1) + R(2) = c-(CH2)2. The separated reactants and products, the reactant and product complexes, and the transition states were considered, leading to 43 data points for the statistical analysis for each method under assessment. Five statistical quantifiers: the mean signed error (MSE), the mean unsigned error (MUE), the percent mean relative error (% MRE), best and worse (BW), and the confidence interval (CI) were used to assess the performance of methods relative to the CCSD(T)/CBS//MP2/aug-cc-pVTZ reference method. The DFT functionals included the widely applied B3LYP and M06-2X global-hybrids and the recently available DSD-PBEP86, DSD-PBEP86-D3BJ and PWPB95 double-hybrids. The basis sets involved an effective core potential (ECP) for describing the inner electrons of iodine such as LANL2DZdp and aug-cc-pVXZ-PP (X = D, T, and Q), and all-electron basis sets for the remaining atoms. The energy available to the reactant complex is described quite well by all methods, however, only the MP2/aug-cc-pVTZ-PP method provided values within 2 kcal mol(-1) (8.4 kJ mol(-1)) from the reference method for Δ(‡)E and ΔrE. Amongst the DFT methods, the global-hybrid M06-2X functional produced the best overall results including BW and CI. Notice that all methods yielded the smallest Δ(‡)E for the C-methylation pathway. The rotational constants of the reactant complexes and the transition state structures were compared, for which the MP2 method and the M06-2X

  9. Esophageal pH monitoring

    MedlinePlus

    pH monitoring - esophageal; Esophageal acidity test ... esophagitis You may need to have the following tests if your doctor suspects esophagitis : Barium swallow Esophagogastroduodenoscopy (also called upper GI endoscopy)

  10. Familial 1.3-Mb 11p15.5p15.4 Duplication in Three Generations Causing Silver-Russell and Beckwith-Wiedemann Syndromes

    PubMed Central

    Vals, Mari-Anne; Kahre, Tiina; Mee, Pille; Muru, Kai; Kallas, Eha; Žilina, Olga; Tillmann, Vallo; Õunap, Katrin

    2015-01-01

    Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS) are 2 opposite growth-affecting disorders. The common molecular cause for both syndromes is an abnormal regulation of genes in chromosomal region 11p15, where 2 imprinting control regions (ICR) control fetal and postnatal growth. Also, many submicroscopic chromosomal disturbances like duplications in 11p15 have been described among SRS and BWS patients. Duplications involving both ICRs cause SRS or BWS, depending on which parent the aberration is inherited from. We describe to our knowledge the smallest familial pure 1.3-Mb duplication in chromosomal region 11p15.5p15.4 that involves both ICRs and is present in 3 generations causing an SRS or BWS phenotype. PMID:26732610

  11. The crystallization, magnetic and magnetocaloric properties in Fe 76.5-xNb xSi 15.5B 7Au 1 ribbons

    NASA Astrophysics Data System (ADS)

    Hoa, N. Q.; Gam, D. T. H.; Chau, N.; The, N. D.; Yu, S.-C.

    2007-03-01

    Fe 76.5-xNb xSi 15.5B 7Au 1 ribbons ( x=0.0, 1.5, 3.0, 4.5) have been fabricated by rapid quenching technique. The DSC measurements indicated that both first exothermal peak Tp1 (of α-Fe(Si) phase) and second peak Tp2 (of boride phase) as well as crystallization activation energy increase with increasing Nb content substituted, whereas saturation magnetization of samples decreases with x, due to ferromagnetic dilution. Besides, Curie temperature of amorphous phase decreases with x, i.e. Nb stabilizes amorphous structure of ribbons. The investigation of magnetic entropy change of studied samples showed that it may lead to magnetocaloric effect around respective Curie temperature of amorphous phase.

  12. Familial 1.3-Mb 11p15.5p15.4 Duplication in Three Generations Causing Silver-Russell and Beckwith-Wiedemann Syndromes.

    PubMed

    Vals, Mari-Anne; Kahre, Tiina; Mee, Pille; Muru, Kai; Kallas, Eha; Žilina, Olga; Tillmann, Vallo; Õunap, Katrin

    2015-09-01

    Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS) are 2 opposite growth-affecting disorders. The common molecular cause for both syndromes is an abnormal regulation of genes in chromosomal region 11p15, where 2 imprinting control regions (ICR) control fetal and postnatal growth. Also, many submicroscopic chromosomal disturbances like duplications in 11p15 have been described among SRS and BWS patients. Duplications involving both ICRs cause SRS or BWS, depending on which parent the aberration is inherited from. We describe to our knowledge the smallest familial pure 1.3-Mb duplication in chromosomal region 11p15.5p15.4 that involves both ICRs and is present in 3 generations causing an SRS or BWS phenotype. PMID:26732610

  13. PhEDEx Data Service

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the "SiteDB" service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  14. Voltammetric pH Nanosensor.

    PubMed

    Michalak, Magdalena; Kurel, Malgorzata; Jedraszko, Justyna; Toczydlowska, Diana; Wittstock, Gunther; Opallo, Marcin; Nogala, Wojciech

    2015-12-01

    Nanoscale pH evaluation is a prerequisite for understanding the processes and phenomena occurring at solid-liquid, liquid-liquid, and liquid-gas interfaces, e.g., heterogeneous catalysis, extraction, partitioning, and corrosion. Research on the homogeneous processes within small volumes such as intracellular fluids, microdroplets, and microfluidic chips also requires nanometer scale pH assessment. Due to the opacity of numerous systems, optical methods are useless and, if applicable, require addition of a pH-sensitive dye. Potentiometric probes suffer from many drawbacks such as potential drift and lack of selectivity. Here, we present a voltammetric nanosensor for reliable pH assessment between pH 2 and 12 with high spatial resolution. It consists of a pyrolytic carbon nanoelectrode obtained by chemical vapor deposition (CVD) inside a quartz nanopipette. The carbon is modified by adsorption of syringaldazine from its ethanolic solution. It exhibits a stable quasi-reversible cyclic voltammogram with nearly Nernstian dependency of midpeak potentials (-54 mV/pH). This sensor was applied as a probe for scanning electrochemical microscopy (SECM) in order to map pH over a platinum ultramicroelectrode (UME), generating hydroxide ions (OH(-)) by the oxygen reduction reaction (ORR) at a diffusion-controlled rate in aerated phosphate buffered saline (PBS). The results reveal the alkalization of the electrolyte close to the oxygen reducing electrode, showing the insufficient buffer capacity of PBS to maintain a stable pH at the given conditions. PMID:26516786

  15. Comparative Analysis of the 15.5kD Box C/D snoRNP Core Protein in the Primitive Eukaryote Giardia lamblia Reveals Unique Structural and Functional Features

    SciTech Connect

    Biswas, Shyamasri; Buhrman, Greg; Gagnon, Keith; Mattos, Carla; Brown, II, Bernard A.; Maxwell, E. Stuart

    2012-07-11

    Box C/D ribonucleoproteins (RNP) guide the 2'-O-methylation of targeted nucleotides in archaeal and eukaryotic rRNAs. The archaeal L7Ae and eukaryotic 15.5kD box C/D RNP core protein homologues initiate RNP assembly by recognizing kink-turn (K-turn) motifs. The crystal structure of the 15.5kD core protein from the primitive eukaryote Giardia lamblia is described here to a resolution of 1.8 {angstrom}. The Giardia 15.5kD protein exhibits the typical {alpha}-{beta}-{alpha} sandwich fold exhibited by both archaeal L7Ae and eukaryotic 15.5kD proteins. Characteristic of eukaryotic homologues, the Giardia 15.5kD protein binds the K-turn motif but not the variant K-loop motif. The highly conserved residues of loop 9, critical for RNA binding, also exhibit conformations similar to those of the human 15.5kD protein when bound to the K-turn motif. However, comparative sequence analysis indicated a distinct evolutionary position between Archaea and Eukarya. Indeed, assessment of the Giardia 15.5kD protein in denaturing experiments demonstrated an intermediate stability in protein structure when compared with that of the eukaryotic mouse 15.5kD and archaeal Methanocaldococcus jannaschii L7Ae proteins. Most notable was the ability of the Giardia 15.5kD protein to assemble in vitro a catalytically active chimeric box C/D RNP utilizing the archaeal M. jannaschii Nop56/58 and fibrillarin core proteins. In contrast, a catalytically competent chimeric RNP could not be assembled using the mouse 15.5kD protein. Collectively, these analyses suggest that the G. lamblia 15.5kD protein occupies a unique position in the evolution of this box C/D RNP core protein retaining structural and functional features characteristic of both archaeal L7Ae and higher eukaryotic 15.5kD homologues.

  16. Hemoglobins, Hemorphins, and 11p15.5 Chromosomal Region in Cancer Biology and İmmunity with Special Emphasis for Brain Tumors.

    PubMed

    Altinoz, Meric Adil; Elmaci, Ilhan; Ince, Bahri; Ozpinar, Aysel; Sav, Aydin Murat

    2016-05-01

    In systemic cancers, increased hemolysis leads to extracellular hemoglobin (HB), and experimental studies have shown its provoking role on tumor growth and metastasis. However, investigations have shown that HB chains presented by tumor vascular pericytes or serum protein complexes of HB could also induce antitumor immunity, which may be harnessed to treat refractory cancers and brain tumors. Mounting recent evidence shows that expression of HBs is not restricted to erythrocytes and that HBs exist in the cells of lung and kidney, in macrophages, and in neurons and glia of the central nervous system (CNS). HBs mediate coping with hypoxia and free radical stress in normal and tumor cells, and they are increased in certain tumors including breast, lung, colon, and squamous cell cancers. Recent studies showed HBs in meningioma, in the cyst fluid of craniopharyngioma, in the cerebrospinal fluid (CSF) of pediatric patients with posterior fossa tumors, and in glioblastoma cell lines. Hemorphins, abundant brain peptides formed via HB-chain cleavage, exert opioid activity and antiproliferative and immunomodifier effects. Hence mutations in HBs may modify brain tumorigenesis via influencing hemorphins and perturbing regulations of immune surveillance and cell growth in the neuroectodermal tissues. The β-globin gene cluster resides in the chromosome region 11p15.5, harboring important immunity genes and IGF2, H19, PHLDA2/TSSC3, TRIM3, and SLC22A18 genes associated with cancers and gliomas. 11p15.5 is a prominent region subject to epigenetic regulation. Thus the β-globin loci may exert haplotypal interactions with these. Some clues support this theory. It is well established that iron load induces liver cancer in thalassemia major; however iron load-independent associations also exist. Enhanced rates of hematologic malignancies are associated with HB Lepore, association of hemoglobin E with cholangiocarcinoma, and enhanced gastric cancer rates in the thalassemia trait. In

  17. pH Optrode Instrumentation

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Zhou, Quan

    1995-01-01

    pH-sensitive chromophoric reagents immobilized in porous optical fibers. Optoelectronic instrumentation system measures acidity or alkalinity of aqueous nutrient solution. Includes one or more optrodes, which are optical-fiber chemical sensors, in sense, analogous to electrodes but not subject to some of spurious effects distorting readings taken by pH electrodes. Concept of optrodes also described in "Ethylene-Vapor Optrodes" (KSC-11579). pH optrode sensor head, with lead-in and lead-out optical fibers, convenient for monitoring solutions located away from supporting electronic equipment.

  18. 973 nm wavelength stabilized hybrid ns-MOPA diode laser system with 15.5 W peak power and a spectral line width below 10 pm

    NASA Astrophysics Data System (ADS)

    Vu, Thi N.; Klehr, Andreas; Sumpf, Bernd; Wenzel, Hans; Erbert, Götz; Tränkle, Günther

    2014-05-01

    A master oscillator power amplifier (MOPA) system for the generation of ns-pulses with high peak power, narrow spectral line width, and stabilized emission wavelength will be presented. The master oscillator is a distributed feedback (DFB) ridge waveguide (RW) laser. The tapered amplifier consists of one RW section and one flared gain-guided section. The DFB laser is operated in continuous wave mode and emits at 973.5 nm with a spectral line width below 10 pm. The RW section of the amplifier acts as an optical gate. The tapered section amplifies the generated optical pulse. An optical peak power of 15.5 W for a pulse width of 8 ns is obtained. The emission wavelength remains constant at all output power levels of the MOPA system for a fixed current into the DFB laser. The spectral power density of the ASE is 37 dB smaller than the lasing spectral power density. The spectral line width is smaller than 10 pm, limited by the resolution of the optical spectrum analyzer.

  19. Urine pH test

    MedlinePlus

    ... J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team. Related MedlinePlus Health Topics Kidney Stones Urinalysis Browse the Encyclopedia A. ...

  20. Making pH Tangible.

    ERIC Educational Resources Information Center

    McIntosh, Elizabeth; Moss, Robert

    1995-01-01

    Presents a laboratory exercise in which students test the pH of different substances, study the effect of a buffer on acidic solutions by comparing the behavior of buffered and unbuffered solutions upon the addition of acid, and compare common over-the-counter antacid remedies. (MKR)

  1. Development of coccolithophore-based transfer functions in the western Mediterranean sea: a sea surface salinity reconstruction for the last 15.5 kyr

    NASA Astrophysics Data System (ADS)

    Ausín, B.; Hernández-Almeida, I.; Flores, J.-A.; Sierro, F.-J.; Grosjean, M.; Francés, G.; Alonso, B.

    2015-12-01

    A new data set of 88 marine surface sediment samples and related oceanic environmental variables (temperature, salinity, chlorophyll a, oxygen, etc.) was studied to quantify the relationship between assemblages of coccolithophore species and modern environmental conditions in the western Mediterranean Sea and the Atlantic Ocean, west of the Strait of Gibraltar. Multivariate statistical analyses revealed that coccolithophore species were primarily related to sea surface salinity (SSS), explaining an independent and significant proportion of variance in the coccolithophore data. A quantitative coccolithophore-based transfer function to estimate SSS was developed using the modern analog technique (MAT) and weighted-averaging partial least square regression (WA-PLS). The bootstrapped regression coefficient (R2boot) was 0.85MAT and 0.80WA-PLS, with a root-mean-square error of prediction (RMSEP) of 0.29MAT and 0.30WA-PLS (psu). The resulting transfer function was applied to fossil coccolithophore assemblages in the highly resolved (~ 65 years) sediment core CEUTA10PC08 from the Alboran Sea (western Mediterranean) in order to reconstruct SSS for the last 25 kyr. The reliability of the reconstruction was evaluated by assessing the degree of similarity between fossil and modern coccolithophore assemblages and by a comparison of reconstructions with fossil ordination scores. Analogs were poor for the stadials associated with Heinrich events 2 and 1 and part of the Last Glacial Maximum. Good analogs indicate a more reliable reconstruction of the SSS for the last 15.5 kyr. During this period, several millennial and centennial SSS changes were observed and associated with sea-level oscillations and variations in the Atlantic Water entering the Alboran.

  2. Increased messenger RNA for allograft inflammatory factor-1, LERK-5, and a novel gene in 17.5-day relative to 15.5-day bovine embryos.

    PubMed

    Glover, Michelle D; Seidel, George E

    2003-09-01

    Considerable embryonic loss occurs between Gestation Days 15 and 18 in cattle when critical cellular and molecular events occur, including maternal recognition of pregnancy. To gain insight into these events, mRNA differential display analysis was used to identify eight unique cDNA fragments present in greater abundance in 17.5-day than in 15.5-day bovine embryos. Four cDNA fragments, confirmed to be upregulated in 17.5-day embryos using Northern analysis, were cloned and sequenced. Three cDNA fragments shared sequence identities with known homologs: human allograft inflammatory factor-1 (AIF-1), human LERK-5, and bovine interferon-tau. One novel cDNA fragment did not share sequence identity to previously reported genes, except for a similar DNA sequence in the human genome. AIF-1 mRNA was present in developing placenta through Gestation Day 36, and abundant levels were observed in adult bovine spleen and lung. The novel gene, which we have named periattachment factor (PAF), was not detected in adult tissues using Northern analysis or in conceptuses between Days 30 and 36 of pregnancy. Additional sequence information for bPAF was obtained from a cDNA library constructed from a 25-day bovine embryo. The protein corresponding to the open reading frame has four protein kinase C phosphorylation sites, two casein kinase II phosphorylation sites, a nuclear targeting sequence, but no obvious DNA or RNA binding motifs. Abundant expression of this gene during a narrow but critical window of embryonic development makes it worthy of further study. PMID:12773430

  3. Transverse development of the human jaws between the ages of 8.5 and 15.5 years, studied longitudinally with use of implants.

    PubMed

    Korn, E L; Baumrind, S

    1990-06-01

    We report longitudinal data on the transverse widening of the maxilla and mandible from a sample of normal subjects (11 males and 20 females) with metallic implants of the Bjork type. Data were from measurements on lateral and frontal (posterior-anterior) cephalograms generated at annual intervals between the ages of 8.5 and 15.5 years (although data were not available for all subjects at all time points). The maxillary data were, in general, similar to those reported by Bjork and Skieller (1974, 1977) for a smaller sample of slightly younger boys. During the age interval studied, transverse widening was greater in the more posterior part of the palate. [The mean annual rate of change in the posterior-most (zygomatic) region was 0.43 mm, sd = 0.18 mm; p less than 0.001.] Although the rate of palatal widening was not large in absolute terms, widening appeared to continue throughout the age interval under study, and there was no evidence to support the conventionally accepted idea that palatal growth in the transverse dimension tapers off substantially or even ceases during the age interval under observation. Evidence of statistically significant widening of the mandibular arch by means of transverse rotation of the osseous matrix was noted in nine of the 29 subjects for whom three-dimensional mandibular information was available. For these nine subjects, the estimated annual increase in mandibular arch angle ranged from 0.52 degrees to 1.40 degrees. As far as we are aware, this is the first report of mandibular matrix rotation in the transverse direction from a sample of subjects with metallic implants. The finding that spontaneous changes in this dimension are relatively common raises the possibility that classical attitudes concerning the immutability of osseous relationships in the symphyseal region during growth may be inappropriate. PMID:2355125

  4. The Methods Behind PH WINS

    PubMed Central

    Leider, Jonathon P.; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers—a nationally representative data set for permanently employed state health agency central office employees comprising over 10 000 responses, and a pilot data set with approximately 12 000 local and regional health department staff responses. PMID:26422490

  5. The Methods Behind PH WINS.

    PubMed

    Leider, Jonathon P; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers--a nationally representative data set for permanently employed state health agency central office employees comprising over 10,000 responses, and a pilot data set with approximately 12,000 local and regional health department staff responses. PMID:26422490

  6. The pH of antiseptic cleansers

    PubMed Central

    Kulthanan, Kanokvalai; Varothai, Supenya; Nuchkull, Piyavadee

    2014-01-01

    Background Daily bathing with antiseptic cleansers are proposed by some physicians as an adjunctive management of atopic dermatitis (AD). As atopic skin is sensitive, selection of cleansing products becomes a topic of concern. Objective Our purpose is to evaluate the pH of various antiseptic body cleansers to give an overview for recommendation to patients with AD. Methods Commonly bar and liquid cleansers consisted of antiseptic agents were measured for pH using pH meter and pH-indicator strips. For comparison, mild cleansers and general body cleansers were also measured. Results All cleansing bars had pH 9.8-11.3 except syndet bar that had neutral pH. For liquid cleansers, three cleansing agents had pH close to pH of normal skin, one of antiseptic cleansers, one of mild cleansers and another one of general cleansers. The rest of antiseptic cleansers had pH 8.9-9.6 while mild cleansers had pH 6.9-7.5. Syndet liquid had pH 7 and general liquid cleansers had pH 9.6. Conclusion The pH of cleanser depends on composition of that cleanser. Adding antiseptic agents are not the only factor determining variation of pH. Moreover, benefit of antiseptic properties should be considered especially in cases of infected skin lesions in the selection of proper cleansers for patients with AD. PMID:24527408

  7. Synthesis, structure, and magnetic properties of the novel sodium cobalt tellurate Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36}

    SciTech Connect

    Shan, Yue Jin; Yoshioka, Yuta; Wakeshima, Makoto; Tezuka, Keitaro; Imoto, Hideo

    2014-03-15

    The novel single crystal oxide Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} had been successfully synthesized by a self-flux method. Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} crystallizes in hexagonal symmetry, space group P6{sub 3}/m (No.176), with lattice parameters a=9.359 (3) Å, c=9.096 (8) Å, and Z=1. The structure is composed of combining the edge-sharing chains of octahedra, [TeO{sub 6}]{sup 6−} and [Co(1)O{sub 6}]{sup 10−} with the face-sharing chains of triangular prisms, [Co(2)O{sub 6}]{sup 10−} and [Co(3)(Na(3))O{sub 6}]{sup 10−}. Sodium ions partially occupy hexagonal channels along the c-axis that are formed by the connection of the chains. The magnetic susceptibility data show a long-range antiferromagnetic ordering with a Neel temperature of 52 K along the c axis. At temperatures above 200 K, the susceptibility corrected for the diamagnetic contribution can be fit to the Curie–Weiss law for Co{sup 2+} (S=3/2). The anisotropic ferromagnetic and antiferromagnetic feature of Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} was obtained through field-dependent magnetization measurements at low temperature. The ferromagnetic and antiferromagnetic behaviors can be considered from the interactions between the Co ions in 1D zig-zag chains formed by sharing the edges of the Co(1)O{sub 6} octahedra, and the interactions between the interchain Co ions, respectively. -- Graphical abstract: The unit cell (a) and perspective view along [001] (b) of novel single crystal oxide, Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36}. Highlights: • A single crystal of Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} has been synthesized by a self-flux method. • Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} crystallizes in hexagonal symmetry with a space group P6{sub 3}/m. • Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} has an antiferromagnetic ordering with a Neel temperature of 52 K. • Na{sub 5}Co{sub 15.5}Te{sub 6}O{sub 36} shows anisotropic ferro- and antiferromagnetism at low temperatures.

  8. Acid loading test (pH)

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003615.htm Acid loading test (pH) To use the sharing features on this page, please enable JavaScript. The acid loading test (pH) measures the ability of the ...

  9. Functional photoacoustic microscopy of pH

    NASA Astrophysics Data System (ADS)

    Chatni, M. Rameez; Yao, Junjie; Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin I.; Wang, Lihong V.

    2012-02-01

    pH is a tightly regulated indicator of metabolic activity. In mammalian systems, imbalance of pH regulation may result from or result in serious illness. Even though the regulation system of pH is very robust, tissue pH can be altered in many diseases such as cancer, osteoporosis and diabetes mellitus. Traditional high-resolution optical imaging techniques, such as confocal microscopy, routinely image pH in cells and tissues using pH sensitive fluorescent dyes, which change their fluorescence properties with the surrounding pH. Since strong optical scattering in biological tissue blurs images at greater depths, high-resolution pH imaging is limited to penetration depths of 1mm. Here, we report photoacoustic microscopy (PAM) of commercially available pH-sensitive fluorescent dye in tissue phantoms. Using both opticalresolution photoacoustic microscopy (OR-PAM), and acoustic resolution photoacoustic microscopy (AR-PAM), we explored the possibility of recovering the pH values in tissue phantoms. In this paper, we demonstrate that PAM was capable of recovering pH values up to a depth of 2 mm, greater than possible with other forms of optical microscopy.

  10. pH Meter probe assembly

    DOEpatents

    Hale, Charles J.

    1983-01-01

    An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe.

  11. pH Meter probe assembly

    DOEpatents

    Hale, C.J.

    1983-11-15

    An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe. 1 fig.

  12. Inexpensive and Disposable pH Electrodes

    ERIC Educational Resources Information Center

    Goldcamp, Michael J.; Conklin, Alfred; Nelson, Kimberly; Marchetti, Jessica; Brashear, Ryan; Epure, Emily

    2010-01-01

    Inexpensive electrodes for the measurement of pH have been constructed using the ionophore tribenzylamine for sensing H[superscript +] concentrations. Both traditional liquid-membrane electrodes and coated-wire electrodes have been constructed and studied, and both exhibit linear, nearly Nernstian responses to changes in pH. Measurements of pH…

  13. CALCULATING THE PH OF CALCIUM CARBONATE SATURATION

    EPA Science Inventory

    Two new expressions for the pH of saturation (pH subs) were derived. One is a simplified equation developed from an aqueous carbonate equilibrium system in which correction for ionic strength was considered. The other is a more accurate quadratic formula that involves computerize...

  14. pH [Measure of Acidity].

    ERIC Educational Resources Information Center

    Henderson, Paula

    This autoinstructional program deals with the study of the pH of given substances by using litmus and hydrion papers. It is a learning activity directed toward low achievers involved in the study of biology at the secondary school level. The time suggested for the unit is 25-30 minutes (plus additional time for further pH testing). The equipment…

  15. pH. Agricultural Lesson Plans.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This lesson plan is intended for use in conducting classes on the effect of pH on plant growth. Presented first are an attention step/problem statement and a series of questions and answers designed to convey general information about soil pH and its effect on plants. The following topics are among those discussed: acidity and alkalinity; the…

  16. Acid loading test (pH)

    MedlinePlus

    The acid loading test (pH) measures the ability of the kidneys to send acid to the urine when there is too much acid in the ... Urine with a pH less than 5.3 is normal. Normal value ranges may vary slightly among different laboratories. Some labs use different ...

  17. Fetal scalp pH testing

    MedlinePlus

    ... Normal pH: 7.25 to 7.35 Borderline pH: 7.20 to 7.25 The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some ...

  18. Middle School and pH?

    ERIC Educational Resources Information Center

    Herricks, Susan

    2007-01-01

    A local middle school requested that the Water Center of Advanced Materials for Purification of Water With Systems (WaterCAMPWS), a National Science Foundation Science and Technology Center, provide an introduction to pH for their seventh-grade water-based service learning class. After sorting through a multitude of information about pH, a…

  19. Determination Of Ph Including Hemoglobin Correction

    DOEpatents

    Maynard, John D.; Hendee, Shonn P.; Rohrscheib, Mark R.; Nunez, David; Alam, M. Kathleen; Franke, James E.; Kemeny, Gabor J.

    2005-09-13

    Methods and apparatuses of determining the pH of a sample. A method can comprise determining an infrared spectrum of the sample, and determining the hemoglobin concentration of the sample. The hemoglobin concentration and the infrared spectrum can then be used to determine the pH of the sample. In some embodiments, the hemoglobin concentration can be used to select an model relating infrared spectra to pH that is applicable at the determined hemoglobin concentration. In other embodiments, a model relating hemoglobin concentration and infrared spectra to pH can be used. An apparatus according to the present invention can comprise an illumination system, adapted to supply radiation to a sample; a collection system, adapted to collect radiation expressed from the sample responsive to the incident radiation; and an analysis system, adapted to relate information about the incident radiation, the expressed radiation, and the hemoglobin concentration of the sample to pH.

  20. Parameters affecting downhole pH

    SciTech Connect

    Garber, J.D.; Jangama, V.R.; Willmon, J.

    1997-09-01

    The presence of acetic and formic acids in the produced water of gas condensate wells has been known for some time by the industry. In traditional water analysis, it has been titrated and reported as alkalinity. The calculation of accurate downhole pH values requires that these ions be analyzed separately in the water and that an organic acid material balance be performed on all three phases in the separator. In this manner, it is then possible to use phase distribution coefficients involving ionic equilibrium to determine how these acids distribute themselves between phases as the pH calculation proceeds downhole. In this paper, the above method of calculation of pH and {Delta}pH is used to examine the effect that various concentrations of these acids have on the downhole pH. Various concentrations of acids are examined, and two cases are calculated in which the effect of condensate on the pH is examined.

  1. A new amphiphilic derivative, N-{[4-(lactobionamido)methyl]benzylidene}-1,1-dimethyl-2-(octylsulfanyl)ethylamine N-oxide, has a protective effect against copper-induced fulminant hepatitis in Long-Evans Cinnamon rats at an extremely low concentration compared with its original form alpha-phenyl-N-(tert-butyl) nitrone.

    PubMed

    Asanuma, Taketoshi; Yasui, Hironobu; Inanami, Osamu; Waki, Kenji; Takahashi, Momoko; Iizuka, Daisuke; Uemura, Taketo; Durand, Grégory; Polidori, Ange; Kon, Yasuhiro; Pucci, Bernard; Kuwabara, Mikinori

    2007-09-01

    An amphiphilic alpha-phenyl-N-(tert-butyl) nitrone (PBN) derivative, N-{[4-(lactobionamido)methyl]benzylidene}-1,1-dimethyl-2-(octylsulfanyl)ethylamine N-oxide (LPBNSH), newly synthesized from its original form PBN in hopes of clinical use, was intraperitoneally administered to Long-Evans Cinnamon (LEC) rats every 2 days at the concentrations of 0.1, 0.5, 1.0, and 2.0 mg/kg. We found that LPBNSH protected against copper-induced hepatitis with jaundice in LEC rats at concentrations of 0.1 and 0.5 mg/kg, which were extremely low compared with that of PBN. It also effectively prevented the loss of body weight, reduced the death rate, and suppressed the increase in serum aspartate aminotransferase and alanine aminotransferase values arising from fulminant hepatitis with jaundice at the same concentrations. Similar results were observed when PBN was administered at the concentration of 150 mg/kg. Immunohistochemical analysis of 8-hydroxy-2'-deoxyguanosine and measurement of thiobarbituric acid-reactive substances in the liver showed that LPBNSH largely suppressed the formation of these oxidative products at same concentrations. No difference in the abnormal accumulation of copper in the liver between the LPBNSH administered and control groups was observed. From these results, it was concluded that LPBNSH exhibited liver-protective effects against fulminant hepatitis with jaundice at ca. 1/1000, 500 the molar concentration of PBN and, therefore, was clinically promising. PMID:17886845

  2. 46 CFR 196.15-5 - Drafts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... of the water in which the vessel is then floating. (1) When an allowance for draft is made for density of the water in which the vessel is floating, this density is to be noted in the official logbook....

  3. 46 CFR 196.15-5 - Drafts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of the water in which the vessel is then floating. (1) When an allowance for draft is made for density of the water in which the vessel is floating, this density is to be noted in the official logbook....

  4. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... The maximum safety relief valve setting shall not exceed the maximum allowable working pressure of the tank. For cargoes carried at ambient temperatures, the minimum safety relief valve setting shall... relief valve or safety relief valve normally protected by a rupture disk or breaking pin device...

  5. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Pressure-vacuum venting. A normally closed venting system fitted with a device to automatically limit the pressure or vacuum in the tank to design limits. Pressure-vacuum relief valves shall comply with the... devices in accordance with the requirements of § 54.15-13 of this chapter. (2) When a...

  6. 30 CFR 15.5 - Test samples.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... explosive units shall submit 140 units. (b) Condition and composition. Explosives and sheathed explosive... MINING PRODUCTS REQUIREMENTS FOR APPROVAL OF EXPLOSIVES AND SHEATHED EXPLOSIVE UNITS General Provisions... sheathed explosive units to be tested until requested to do so by MSHA. (2) The applicant shall submit...

  7. 30 CFR 15.5 - Test samples.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... explosive units shall submit 140 units. (b) Condition and composition. Explosives and sheathed explosive... MINING PRODUCTS REQUIREMENTS FOR APPROVAL OF EXPLOSIVES AND SHEATHED EXPLOSIVE UNITS General Provisions... sheathed explosive units to be tested until requested to do so by MSHA. (2) The applicant shall submit...

  8. 46 CFR 196.15-5 - Drafts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of the water in which the vessel is then floating. (1) When an allowance for draft is made for density of the water in which the vessel is floating, this density is to be noted in the official logbook....

  9. Characterization of the interaction between protein Snu13p/15.5K and the Rsa1p/NUFIP factor and demonstration of its functional importance for snoRNP assembly.

    PubMed

    Rothé, Benjamin; Back, Régis; Quinternet, Marc; Bizarro, Jonathan; Robert, Marie-Cécile; Blaud, Magali; Romier, Christophe; Manival, Xavier; Charpentier, Bruno; Bertrand, Edouard; Branlant, Christiane

    2014-02-01

    The yeast Snu13p protein and its 15.5K human homolog both bind U4 snRNA and box C/D snoRNAs. They also bind the Rsa1p/NUFIP assembly factor, proposed to scaffold immature snoRNPs and to recruit the Hsp90-R2TP chaperone complex. However, the nature of the Snu13p/15.5K-Rsa1p/NUFIP interaction and its exact role in snoRNP assembly remained to be elucidated. By using biophysical, molecular and imaging approaches, here, we identify residues needed for Snu13p/15.5K-Rsa1p/NUFIP interaction. By NMR structure determination and docking approaches, we built a 3D model of the Snup13p-Rsa1p interface, suggesting that residues R249, R246 and K250 in Rsa1p and E72 and D73 in Snu13p form a network of electrostatic interactions shielded from the solvent by hydrophobic residues from both proteins and that residue W253 of Rsa1p is inserted in a hydrophobic cavity of Snu13p. Individual mutations of residues in yeast demonstrate the functional importance of the predicted interactions for both cell growth and snoRNP formation. Using archaeal box C/D sRNP 3D structures as templates, the association of Snu13p with Rsa1p is predicted to be exclusive of interactions in active snoRNPs. Rsa1p and NUFIP may thus prevent premature activity of pre-snoRNPs, and their removal may be a key step for active snoRNP production. PMID:24234454

  10. Genome-wide association study identifies two novel regions at 11p15.5-p13 and 1p31 with major impact on acute-phase serum amyloid A.

    PubMed

    Marzi, Carola; Albrecht, Eva; Hysi, Pirro G; Lagou, Vasiliki; Waldenberger, Melanie; Tönjes, Anke; Prokopenko, Inga; Heim, Katharina; Blackburn, Hannah; Ried, Janina S; Kleber, Marcus E; Mangino, Massimo; Thorand, Barbara; Peters, Annette; Hammond, Christopher J; Grallert, Harald; Boehm, Bernhard O; Kovacs, Peter; Geistlinger, Ludwig; Prokisch, Holger; Winkelmann, Bernhard R; Spector, Tim D; Wichmann, H-Erich; Stumvoll, Michael; Soranzo, Nicole; März, Winfried; Koenig, Wolfgang; Illig, Thomas; Gieger, Christian

    2010-11-01

    Elevated levels of acute-phase serum amyloid A (A-SAA) cause amyloidosis and are a risk factor for atherosclerosis and its clinical complications, type 2 diabetes, as well as various malignancies. To investigate the genetic basis of A-SAA levels, we conducted the first genome-wide association study on baseline A-SAA concentrations in three population-based studies (KORA, TwinsUK, Sorbs) and one prospective case cohort study (LURIC), including a total of 4,212 participants of European descent, and identified two novel genetic susceptibility regions at 11p15.5-p13 and 1p31. The region at 11p15.5-p13 (rs4150642; p = 3.20×10(-111)) contains serum amyloid A1 (SAA1) and the adjacent general transcription factor 2 H1 (GTF2H1), Hermansky-Pudlak Syndrome 5 (HPS5), lactate dehydrogenase A (LDHA), and lactate dehydrogenase C (LDHC). This region explains 10.84% of the total variation of A-SAA levels in our data, which makes up 18.37% of the total estimated heritability. The second region encloses the leptin receptor (LEPR) gene at 1p31 (rs12753193; p = 1.22×10(-11)) and has been found to be associated with CRP and fibrinogen in previous studies. Our findings demonstrate a key role of the 11p15.5-p13 region in the regulation of baseline A-SAA levels and provide confirmative evidence of the importance of the 1p31 region for inflammatory processes and the close interplay between A-SAA, leptin, and other acute-phase proteins. PMID:21124955

  11. Colorimetric Determination of pH.

    ERIC Educational Resources Information Center

    Tucker, Sheryl; And Others

    1989-01-01

    Presented is an activity in which the pH of a solution can be quantitatively measured using a spectrophotometer. The theory, experimental details, sample preparation and selection, instrumentation, and results are discussed. (CW)

  12. Brenda K. Edwards, PhD

    Cancer.gov

    Brenda K. Edwards, PhD, has been with the Surveillance Research Program (SRP) and its predecessor organizations at the National Cancer Institute (NCI) since 1989, serving as SRP’s Associate Director from 1990-2011.

  13. MRF with adjustable pH

    NASA Astrophysics Data System (ADS)

    Jacobs, Stephen D.

    2011-10-01

    Deterministic final polishing of high precision optics using sub-aperture processing with magnetorheological finishing (MRF) is an accepted practice throughout the world. A wide variety of materials can be successfully worked with aqueous (pH 10), magnetorheological (MR) fluids, using magnetic carbonyl iron (CI) and either ceria or nanodiamond nonmagnetic abrasives. Polycrystalline materials like zinc sulfide (ZnS) and zinc selenide (ZnSe) are difficult to polish at pH 10 with MRF, due to their grain size and the relatively low stiffness of the MR fluid lap. If microns of material are removed, the grain structure of the material begins to appear. In 2005, Kozhinova et al. (Appl. Opt. 44 4671-4677) demonstrated that lowering pH could improve MRF of ZnS. However, magnetic CI particle corrosion rendered their low pH approach unstable and unsuitable for commercial implementation. In 2009, Shafrir et al. described a sol-gel coating process for manufacturing a zirconia-coated CI particle that protects the magnetic core from aqueous corrosion (Appl. Opt .48 6797-6810). The coating process produces free nanozirconia polishing abrasives during the coating procedure, thereby creating an MR polishing powder that is "self-charged" with the polishing abrasive. By simply adding water, it was possible to polish optical glasses and ceramics with good stability at pH 8 for three weeks. The development of a corrosion resistant, MR polishing powder, opens up the possibility for polishing additional materials, wherein the pH may be adjusted to optimize effectiveness. In this paper we describe the CI coating process, the characterization of the coated powder, and procedures for making stable MR fluids with adjustable pH, giving polishing results for a variety of optical glasses and crystalline ceramics.

  14. Eukaryotic diversity at pH extremes

    PubMed Central

    Amaral-Zettler, Linda A.

    2013-01-01

    Extremely acidic (pH < 3) and extremely alkaline (pH > 9) environments support a diversity of single-cell and to a lesser extent, multicellular eukaryotic life. This study compared alpha and beta diversity in eukaryotic communities from seven diverse aquatic environments with pH values ranging from 2 to 11 using massively-parallel pyrotag sequencing targeting the V9 hypervariable region of the 18S ribosomal RNA (rRNA) gene. A total of 946 operational taxonomic units (OTUs) were recovered at a 6% cut-off level (94% similarity) across the sampled environments. Hierarchical clustering of the samples segregated the communities into acidic and alkaline groups. Similarity percentage (SIMPER) analysis followed by indicator OTU analysis (IOA) and non-metric multidimensional scaling (NMDS) were used to determine which characteristic groups of eukaryotic taxa typify acidic or alkaline extremes and the extent to which pH explains eukaryotic community structure in these environments. Spain's Rio Tinto yielded the fewest observed OTUs while Nebraska Sandhills alkaline lakes yielded the most. Distinct OTUs, including metazoan OTUs, numerically dominated pH extreme sites. Indicator OTUs included the diatom Pinnularia and unidentified opisthokonts (Fungi and Filasterea) in the extremely acidic environments, and the ciliate Frontonia across the extremely alkaline sites. Inferred from NMDS, pH explained only a modest fraction of the variation across the datasets, indicating that other factors influence the underlying community structure in these environments. The findings from this study suggest that the ability for eukaryotes to adapt to pH extremes over a broad range of values may be rare, but further study of taxa that can broadly adapt across diverse acidic and alkaline environments, respectively present good models for understanding adaptation and should be targeted for future investigations. PMID:23335919

  15. pH. Training Module 5.305.2.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with pH, measurement of pH with a pH meter and maintenance of pH meter electrodes. Included are objectives, instructor guides, student handouts and transparency masters. This module considers the definition of pH, types of electrodes and…

  16. Low pH myoglobin photoproducts.

    PubMed Central

    Sage, J T; Morikis, D; Li, P; Champion, P M

    1992-01-01

    Recently, there has been interest in determining the conditions under which the iron-histidine bond ruptures in myoglobin at low pH, so that the effect of proximal heme ligation can be studied. A 220-cm-1 Raman mode, assigned to iron-histidine stretching, is clearly visible after photolysis of aqueous MbCO samples below pH4 at room temperature (Sage et al. Biochemistry. 30:1237-1247). In contrast, Iben et al. (Biophys. J. 59:908-919) do not observe this mode upon photolysis of a pH3 MbCO sample in a glycerol/water glass at low temperature. In order to account for both the low temperature and the room temperature experiments, Iben et al. suggest a scheme involving an unusual protonation state of the proximal histidine. Here, we discuss some inconsistencies in their explanation of the room temperature results and offer instead a simple modification of an earlier model. In addition, circular dichroism data are presented that indicate partial unfolding of MbCO in aqueous solution below pH4, and raise questions about the claim of Iben et al. that MbCO remains folded in 75% glycerol at pH3. PMID:1581497

  17. Fiber-Optic pH Sensor

    NASA Astrophysics Data System (ADS)

    Ganesh, A. Balaji; Radhakrishnan, T. K.

    The new enhancement in the determination of pH using optical fiber system is described here. This work uses the membrane made of cellulose acetate membrane for reagent immobilization and congo red (pKa 3.7) and neutral red (pKa 7.2) as pH indicators. An effective covalent chemical binding procedure is used to immobilize the indicatorsE The response time, reversibility, linear range, reproducibility, and long-term stability of fiber optic sensor with congo red as well as neutral red have been determined. The linear range measured for the sensor based on the congo red and neutral red is 4.2-6.3 and 4.1-9.0, respectively. The response time of sensor membrane is measured by varying the substance pH values between 11.0 and 2.0.

  18. Magnetic microstructure in a stress-annealed Fe73.5Si15.5B7Nb3Cu1 soft magnetic alloy observed using off-axis electron holography and Lorentz microscopy

    NASA Astrophysics Data System (ADS)

    Kovács, A.; Pradeep, K. G.; Herzer, G.; Raabe, D.; Dunin-Borkowski, R. E.

    2016-05-01

    Fe-Si-B-Nb-Cu alloys are attractive for high frequency applications due to their low coercivity and high saturation magnetization. Here, we study the effect of stress annealing on magnetic microstructure in Fe73.5Si15.5B7Nb3Cu1 using off-axis electron holography and the Fresnel mode of Lorentz transmission electron microscopy. A stress of 50 MPa was applied to selected samples during rapid annealing for 4 s, resulting in uniaxial anisotropy perpendicular to the stress direction. The examination of focused ion beam milled lamellae prepared from each sample revealed a random magnetic domain pattern in the sample that had been rapidly annealed in the absence of stress, whereas a highly regular domain pattern was observed in the stress-annealed sample. We also measured a decrease in domain wall width from ˜ 94 nm in the sample annealed without stress to ˜ 80 nm in the stress-annealed sample.

  19. Evaluation of fluorimetric pH sensors for bioprocess monitoring at low pH.

    PubMed

    Janzen, Nils H; Schmidt, Michael; Krause, Christian; Weuster-Botz, Dirk

    2015-09-01

    Optical chemical sensors are the standard for pH monitoring in small-scale bioreactors such as microtiter plates, shaking flasks or other single-use bioreactors. The dynamic pH range of the so far commercially available fluorescent pH sensors applied in small-scale bioreactors is restricted to pH monitoring around neutral pH, although many fermentation processes are performed at pH < 6 on industrial scale. Thus, two new prototype acidic fluorescence pH sensors immobilized in single-use stirred-tank bioreactors, one with excitation at 470 nm and emission at 550 nm (sensor 470/550) and the other with excitation at 505 nm and emission at 600 nm (sensor 505/600), were characterized with respect to dynamic ranges and operational stability in representative fermentation media. Best resolution and dynamic range was observed with pH sensor 505/600 in mineral medium (dynamic range of 3.9 < pH < 7.2). Applying the same pH sensors to complex medium results in a drastic reduction of resolution and dynamic ranges. Yeast extract in complex medium was found to cause background fluorescence at the sensors' operating wavelength combinations. Optical isolation of the sensor by adding a black colored polymer layer above the sensor spot and fixing an aperture made of adhesive photoresistant foil between the fluorescence reader and the transparent bottom of the polystyrene reactors enabled full re-establishment of the sensor's characteristics. Reliability and operational stability of sensor 505/600 was shown by online pH monitoring (4.5 < pH < 5.8) of parallel anaerobic batch fermentations of Clostridium acetobutylicum for the production of acetone, butanol and ethanol (ABE) with offline pH measurements with a standard glass electrode as reference. PMID:25969385

  20. Ph.D.'s and the Marketplace.

    ERIC Educational Resources Information Center

    Harvey, James

    Throughout the last decade, Ph.D. recipients were accustomed to a job market in which demand for their services far exceeded supply. During the same period, manpower experts predicted this situation would continue in the foreseeable future. However, when the 60's ended, the employment illusion had been rudely dispelled by frantic reports of a…

  1. First-Principles pH Theory

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hyun; Zhang, S. B.

    2006-03-01

    Despite being one of the most important macroscopic measures and a long history even before the quantum mechanics, the concept of pH has rarely been mentioned in microscopic theories, nor being incorporated computationally into first-principles theory of aqueous solutions. Here, we formulate a theory for the pH dependence of solution formation energy by introducing the proton chemical potential as the microscopic counterpart of pH in atomistic solution models. Within the theory, the general acid-base chemistry can be cast in a simple pictorial representation. We adopt density-functional molecular dynamics to demonstrate the usefulness of the method by studying a number of solution systems including water, small solute molecules such as NH3 and HCOOH, and more complex amino acids with several functional groups. For pure water, we calculated the auto- ionization constant to be 13.2 with a 95 % accuracy. For other solutes, the calculated dissociation constants, i.e., the so- called pKa, are also in reasonable agreement with experiments. Our first-principles pH theory can be readily applied to broad solution chemistry problems such as redox reactions.

  2. The Ph.D. Value Proposition

    ERIC Educational Resources Information Center

    Cooper, Kenneth J.

    2012-01-01

    Atlanta University launched its doctor of arts in humanities (DAH) programs almost 40 years ago, and, since the 1988 merger with Clark College, Clark Atlanta University has continued to award the degrees. This fall, for the first time, its students will be able to earn Ph.D.s in humanities instead. In DAH programs around the country, there's been…

  3. Optoelectronic pH Meter: Further Details

    NASA Technical Reports Server (NTRS)

    Jeevarajan, Antony S.; Anderson, Mejody M.; Macatangay, Ariel V.

    2009-01-01

    A collection of documents provides further detailed information about an optoelectronic instrument that measures the pH of an aqueous cell-culture medium to within 0.1 unit in the range from 6.5 to 7.5. The instrument at an earlier stage of development was reported in Optoelectronic Instrument Monitors pH in a Culture Medium (MSC-23107), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 4a. To recapitulate: The instrument includes a quartz cuvette through which the medium flows as it is circulated through a bioreactor. The medium contains some phenol red, which is an organic pH-indicator dye. The cuvette sits between a light source and a photodetector. [The light source in the earlier version comprised red (625 nm) and green (558 nm) light-emitting diodes (LEDs); the light source in the present version comprises a single green- (560 nm)-or-red (623 nm) LED.] The red and green are repeatedly flashed in alternation. The responses of the photodiode to the green and red are processed electronically to obtain the ratio between the amounts of green and red light transmitted through the medium. The optical absorbance of the phenol red in the green light varies as a known function of pH. Hence, the pH of the medium can be calculated from the aforesaid ratio.

  4. Teaching Physics Using PhET Simulations

    ERIC Educational Resources Information Center

    Wieman, C. E.; Adams, W. K.; Loeblein, P.; Perkins, K. K.

    2010-01-01

    PhET Interactive Simulations (sims) are now being widely used in teaching physics and chemistry. Sims can be used in many different educational settings, including lecture, individual or small group inquiry activities, homework, and lab. Here we will highlight a few ways to use them in teaching, based on our research and experiences using them in…

  5. The Economic Contribution of PhDs

    ERIC Educational Resources Information Center

    Casey, Bernard H.

    2009-01-01

    This paper looks at what the value of a doctorate is, both to employers in particular and to society and the economy at large. Given the emphasis many universities and funding agencies/governments are putting upon the development of PhD programmes, this is an issue deserving attention. The paper tries to show how two separate but interrelated…

  6. pH & Rate of Enzymatic Reactions.

    ERIC Educational Resources Information Center

    Clariana, Roy B.

    1991-01-01

    A quantitative and inexpensive way to measure the rate of enzymatic reaction is provided. The effects of different pH levels on the reaction rate of an enzyme from yeast are investigated and the results graphed. Background information, a list of needed materials, directions for preparing solutions, procedure, and results and discussion are…

  7. The effect of pH on growth of Clostridium botulinum type A and expression of bontA and botR during different growth stages.

    PubMed

    Li, Tao; Tian, Renmao; Cai, Kun; Wang, Qin; Chen, Fanghong; Fang, Huali; Luo, Sen; Li, Zhan; Wang, Dehui; Hou, Xiaojun; Wang, Hui

    2013-08-01

    In this study, the effects of pH on the growth, relative expressions of bontA and botR genes, and neurotoxin formation of foodborne pathogens Clostridium botulinum type A were systematically studied throughout its growth stage. As in the previous reports, no C. botulinum growth was observed at extremely acidic pH. However, the effect of alkaline pH on the growth and neurotoxin production of C. botulinum was first revealed in this study. The maximum growth rate at pH 9.0 was similar to that at other pH values, although the lag phase at pH 9.0 was 16 h longer than that at pH 8.0. The peak of bontA mRNA expression at pH 9.0 was only 15.5% compared with that at pH 7.0. However, the neurotoxin concentration quantified in the cultures did not differ significantly. BotR is a known regulatory protein of bontA. The quantitative relationship between bontA and botR at different growth stages was first determined in this study. The mRNA levels of bontA were found to be positively correlated with those of botR, and the ratio of the mRNA transcript varied with pH. All these findings provide important physiological information on C. botulinum and thereby contribute to the improvement of food safety. PMID:23767855

  8. Effect of electrolyte pH on CIEF with narrow pH range ampholytes.

    PubMed

    Páger, Csilla; Vargová, Andrea; Takácsi-Nagy, Anna; Dörnyei, Ágnes; Kilár, Ferenc

    2012-11-01

    CIEF of components following sequential injection of ampholytes and the sample zone offers unique advantages for analysis. The most important one of these is the efficient separation of amphoteric compounds having pIs outside the pH range of the ampholytes applied, but the resolution of the components can be increased by an adequate setup in the injection protocol. In this study, the effect of the pH of the anolyte and catholyte on the selectivity and speed of the isoelectric focusing was investigated. Changes in the pH values significantly influenced the resolution and the length of the pH gradient, while changes in the charge state of components were also observed. Three ampholyte solutions (from different suppliers) covering only two pH units were used for the analyses of substituted nitrophenol dyes in uncoated capillary. With appropriate setup, the components, with pIs not covered by the ampholyte pH range, migrated in charged state outside the pH gradient. This phenomenon is preferable for coupling isoelectric focusing to MS detection, by evading the undesirable ion suppression effect of ampholytes. PMID:23086725

  9. Relation between pH in the Trunk and Face: Truncal pH Can Be Easily Predicted from Facial pH

    PubMed Central

    Kim, Sung Ae; Kim, Bo Ri; Chun, Mi Young

    2016-01-01

    Background The clinical symptoms of facial and truncal acne differ. Skin surface acidity (pH), which is affected by sebum secretions, reflects the different clinical characteristics of the face and trunk. However, no studies have been conducted on truncal sebum production and skin pH. Objective We evaluated the differences and relationship between pH values of the face and trunk. We also evaluated the relationship between pH and the quantity of sebum produced in the trunk. Methods A total of 35 female patients clinically diagnosed with truncal acne were included. We measured pH on the face and truncal area using the Skin-pH-Meter PH 905®. We measured truncal sebum secretions using the Sebumeter SM 815®. Statistical analysis was performed to evaluate the correlations and differences between pH and sebum. Results Facial pH was significantly higher than chest and back pH values. The correlation between pH on the trunk and the face was significant. We used linear regression equations to estimate truncal pH using only measured pH from the chin. There was no significant relationship between truncal sebum secretion and pH. Conclusion This was the first study that evaluated the differences and correlations between facial and truncal pH. We found that facial pH can predict truncal pH. In addition, we conclude that differences in pH and sebum secretion between the face and trunk are one of the reasons for differences in acne symptom at those sites. PMID:27081270

  10. The pH of Enceladus' ocean

    NASA Astrophysics Data System (ADS)

    Glein, Christopher R.; Baross, John A.; Waite, J. Hunter

    2015-08-01

    Saturn's moon, Enceladus, is a geologically active waterworld. The prevailing paradigm is that there is a subsurface ocean that erupts to the surface, which leads to the formation of a plume of vapor and ice above the south polar region. The chemistry of the ocean is just beginning to be understood, but is of profound geochemical and astrobiological interest. Here, we determine the pH of the ocean using a thermodynamic model of carbonate speciation. Observational data from the Cassini spacecraft are used to make a chemical model of ocean water on Enceladus. The model suggests that Enceladus' ocean is a Na-Cl-CO3 solution with an alkaline pH of ∼11-12. The dominance of aqueous NaCl is a feature that Enceladus' ocean shares with terrestrial seawater, but the ubiquity of dissolved Na2CO3 suggests that soda lakes are more analogous to the Enceladus ocean. The high pH implies that the hydroxide ion should be relatively abundant, while divalent metals should be present at low concentrations owing to buffering by carbonates and phyllosilicates on the ocean floor. Carboxyl groups in dissolved organic species would be negatively charged, while amino groups would exist predominately in the neutral form. Knowledge of the pH improves our understanding of geochemical processes in Enceladus' ocean. The high pH is interpreted to be a key consequence of serpentinization of chondritic rock, as predicted by prior geochemical reaction path models; although degassing of CO2 from the ocean may also play a role depending on the efficiency of mixing processes in the ocean. Serpentinization leads to the generation of H2, a geochemical fuel that can support both abiotic and biological synthesis of organic molecules such as those that have been detected in Enceladus' plume. Serpentinization and H2 generation should have occurred on Enceladus, like on the parent bodies of aqueously altered meteorites; but it is unknown whether these critical processes are still taking place, or if

  11. What Is a pH Probe Study?

    MedlinePlus

    What is a pH Probe Study ? What is pH a probe study? M easuring the pH in the esophagus helps determine whether or not acid is coming up from the stomach. A pH probe study is usually done in patients where ...

  12. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  13. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  14. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  15. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  16. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  17. Sensing pH with TMCs.

    PubMed

    Spalthoff, Christian; Göpfert, Martin C

    2016-07-01

    Transmembrane channel-like (TMC) proteins have been implicated in hair cell mechanotransduction, Drosophila proprioception, and sodium sensing in the nematode C. elegans. In this issue of Neuron, Wang et al. (2016) report that C. elegans TMC-1 mediates nociceptor responses to high pH, not sodium, allowing the nematode to avoid strongly alkaline environments in which most animals cannot survive. PMID:27387645

  18. Complexation Key to a pH Locked Redox Reaction

    ERIC Educational Resources Information Center

    Rizvi, Masood Ahmad; Dangat, Yuvraj; Shams, Tahir; Khan, Khaliquz Zaman

    2016-01-01

    An unfavorable pH can block a feasible electron transfer for a pH dependent redox reaction. In this experiment, a series of potentiometric titrations demonstrate the sequential loss in feasibility of iron(II) dichromate redox reaction over a pH range of 0-4. The pH at which this reaction failed to occur was termed as a pH locked reaction. The…

  19. Reactivity of the isolable disilene R*PhSi=SiPhR* (R* = SitBu3).

    PubMed

    Wiberg, Nils; Niedermayer, Wolfgang; Polborn, Kurt; Mayer, Peter

    2002-06-17

    The disilene R*PhSi=SiPhR* (R* = supersilyl = SitBu3), which can be quantitatively prepared by dehalogenation of the disilane R*PhClSi-SiBrPhR* with NaR* (yellow, water- and air-sensitive crystals; decomp at ca. 70 degrees C; Si=Si distance 2.182 A), is comparatively reactive. It transforms 1) with Cl2, Br2, HCl, HBr, and HOH under 1,2-addition into disilanes R*PhXSi-SiX'PhR* (X/X' = Hal/Hal, H/Hal, H/OH), 2) with O2, S8, and Sen under insertion into 1,3-disiletanes R*PhSi(-Y-)2SiPhR* (Y = O, S, Se), 3) with Me2C=CH2 under ene reaction into the disilane R*PhRSi-SiHPhR* (R = CH2-CMe=CH2), 4) with N2O, Ten, tBuN identical to C, and Me3SiN=N=N under [2 + 1] cycloaddition into disiliranes -R*PhSi-Y-SiPhR*- (Y = O, Te, C=NtBu, NSiMe3; P4 adds 2 molecules of disilene), 5) with CO2, COS, PhCHO, and Ph2CS under [2 + 2] cycloaddition into disiletanes -R*PhSi-SiPhR*-Y-CO- (Y = O, S) as well as -R*PhSi-SiPhR*-Y-CRPh- (Y/R = O/H, S/Ph), 6) with CS2 and CSe2 under [2 + 3] cycloaddition into ethenes R*2Ph2Si2Y2C = CY2Si2Ph2R*2 (Y = S, Se), and 7) with CH2 = CMe-CMe=CH2 and Ph2CO under [2 + 4] cycloaddition into "Diels-Alder adducts". X-ray structure analyses of seven of these compounds are presented. PMID:12391651

  20. The Added Value of a PhD in Medicine--PhD Students' Perceptions of Acquired Competences

    ERIC Educational Resources Information Center

    Anttila, Henrika; Lindblom-Ylänne, Sari; Lonka, Kristi; Pyhältö, Kirsi

    2015-01-01

    PhD in the field of medicine is more common than in any other domain. Many medical doctors are driven towards PhD, but also students with other backgrounds (usually MSc) are conducting a PhD in medical schools. Higher education has invested a lot in developing generic and research competences. Still little is known about how PhD students…

  1. Effects of pH adjustment with phosphates on attributes and functionalities of normal and high pH beef.

    PubMed

    Young, O A; Zhang, S X; Farouk, M M; Podmore, C

    2005-05-01

    Longissimus dorsi muscles from six normal- and six high-ultimate pH bulls were selected for fine mincing and subsequent pH adjustment with acid and alkaline pyrophosphate. Four pH treatments were prepared: initially high remains high (mean of pH 6.37), high becomes normal (5.62); initially normal remains normal (5.65), and normal becomes high (6.21). The addition level of phosphate as P(2)O(5) was the same in all replicates. Before pH adjustment, colour and water holding capacity (WHC) values were strongly affected by higher (initial) pH in expected ways: darker, lower chroma, higher capacity. After pH adjustment, these values were affected only by the final pH, not the initial pH (the pH history). Total protein solubility was likewise affected by final pH but not initial pH. In contrast, the combination high initial pH-high final pH improved sarcoplasmic protein solubility by 20% over the combination normal initial pH-high final pH. Sarcoplasmic protein solubility is an indicator of strain required to fracture cooked batters made from the minced meats; in the event, the rank order of the four treatments for strain-to-fracture matched that of sarcoplasmic protein solubility. Statistically, sarcoplasmic protein solubility and strain-to-fracture were both affected by initial pH (P<0.01) and final pH (P<0.001). However, stress required to fracture cooked batters was entirely controlled by initial pH (P<0.01). In other words, the stress-to-fracture advantage of initially high pH meat was not matched by upward pH adjustment of initially normal pH meat. Emulsion stability, which is better with higher pH meat, was affected by initial and final pH (both P<0.01). Cook yield, like WHC of pH-adjusted raw meat, was more due to final pH than initial pH, similarly cooked batter colour, whereas final pH had a significant effect on quality attributes (generally better when higher). An initially high pH history conferred an enduring advantage on three important batter attributes

  2. Assignment of the human fast skeletal troponin T gene (TNNT3) to chromosome 11p15.5: Evidence for the presence of 11pter in a monochromosome 9 somatic cell hybrid in NIGMS mapping panel 2

    SciTech Connect

    Mao, Chengjian; Jha, P.K.; Sarkar, S.

    1996-02-01

    Human fast skeletal troponin T (TnT{sub f}), the tropomyosin binding component of the multisubunit troponin complex, plays an important role in the Ca{sup 2+} regulation of striated muscle contraction. Specific primers designed from the 3{prime} end of human TnT{sub f} cDNA were used to amplify an intronic region by polymerase chain reaction (PCR). This TnT{sub f}-specific PCR product was detected from two somatic cell hybrids containing human chromosomes 9 and 11, respectively, in NIGMS mapping panel 2. However, further studies with other somatic hybrid cell lines (Bios Laboratory) localized the TnT{sub f} genomic probe generated by extended PCR, showing the sublocalization of the gene to band p15.5 on chromosome 11. This locus is of specific interest, as Beckwith-Wiedemann syndrome and various childhood and adult tumor-related abnormalities have been mapped to this region. The study also indicates the presence of an 11pter region in the NIGMS cell hybrid GM10611, which has previously been reported to contain only human chromosome 9. 11 refs., 2 figs.

  3. The panacea toolbox of a PhD biomedical student.

    PubMed

    Skaik, Younis

    2014-01-01

    Doing a PhD (doctor of philosophy) for the sake of contribution to knowledge should give the student an immense enthusiasm through the PhD period. It is the time in one's life that one spends to "hit the nail on the head" in a specific area and topic of interest. A PhD consists mostly of hard work and tenacity; however, luck and genius might also play a little role. You can pass all PhD phases without having both luck and genius. The PhD student should have pre-PhD and PhD toolboxes, which are "sine quibus non" for getting successfully a PhD degree. In this manuscript, the toolboxes of the PhD student are discussed. PMID:25674150

  4. Recent Ph.D.s; Honors

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Recent Ph.D.s. Atmospheric Sciences. A study of atmospheric ammonia in coastal ecosystems utilizing relaxed eddy accumulation techniques and ion mobility spectrometry, LaToya Myles, Florida A&M University, December 2004, Advisor: Larry Robinson. Honors. Rana A. Fine has been awarded the 2005 Provost Award for Scholarly Activity, presented by the University of Miami. The award ``recognizes faculty for extraordinary research and scholarly pursuits.'' Charles David Keeling and Lonnie G. Thompson will receive the 2005 Tyler Prize for Environmental Achievement. The prize is given to individuals whose accomplishments in environmental science, policy, energy, and medicine confer great benefit upon mankind.

  5. Ultra-soft magnetic properties and correlated phase analysis by 57Fe Mössbauer spectroscopy of Fe74Cu0.8Nb2.7Si15.5B7 alloy

    NASA Astrophysics Data System (ADS)

    Manjura Hoque, S.; Liba, S. I.; Anirban, A.; Choudhury, Shamima; Akhter, Shireen

    2016-02-01

    A detailed study of magnetic softness has been performed on FINEMENT type of ribbons by investigating the BH loop with maximum applied field of 960 A/m. The ribbon with the composition of Fe74Cu0.8Nb2.7Si15.5B7 was synthesized by rapid solidification technique and the compositions volume fraction was controlled by changing the annealing condition. Detail phase analysis was performed through X-ray diffraction (XRD), Differential scanning calorimetry (DSC), Vibrating sample magnetometer (VSM) and Mössbauer spectroscopy in order to correlate the ultrasoft magnetic properties with the volume fraction of amorphous and α-Fe(Si) soft nano composites. Bright (BF) and dark field (DF) image with selective area diffraction (SAD) patterns by the transmission electron microscopy (TEM) of the sample annealed for the optimized annealed condition at 853 K for 3 min reveals nanocrystals with an average size between 10-15 nm possessing the bcc structure which matches with the grain size revealed by the X-ray diffraction. Kinetics of crystallization of α-Fe(Si) phases has been determined by DSC curves. Extremely small coercivity of 30.9 A/m and core loss of 2.5 W/Kg for the sample annealed at 853 K for 3 min was found. Similar values for other crystalline conditions were determined by using BH loop tracer with a maximum applied field of around 960 A/m. Mössbauer spectroscopy was used to determine chemical shift, hyperfine field distribution (HFD), and peak width of different phases. The volume fractions of the relative amount of amorphous and crystalline phases are also determined by Mössbauer spectroscopy. High saturation magnetization along with ultrasoft magnetic properties exhibits very high potentials technological applications.

  6. The pH of Mars

    NASA Technical Reports Server (NTRS)

    Plumb, R. C.; Bishop, J. L.; Edwards, J. O.

    1993-01-01

    The Viking labeled release (LR) experiments provided data that can be used to determine the acid-base characteristics of the regolith. Constraints on the acid-base properties and redox potentials of the Martian surface material would provide additional information for determining what reactions are possible and defining formation conditions for the regolith. Calculations devised to determine the pH of Mars must include the amount of soluble acid species or base species present in the LR regolith sample and the solubility product of the carbonate with the limiting solubility. This analysis shows that CaCO3, either as calcite or aragonite, has the correct K(sub sp) to have produced the Viking LR successive injection reabsorption effects. Thus CaCO3 or another MeCO3 with very similar solubility characteristics must have been present on Mars. A small amount of soluble acid, but no more than 4 micro-mol per sample, could also have been present. It is concluded that the pH of the regolith is 7.2 +/- 0.1.

  7. Histone Acetylation Regulates Intracellular pH

    PubMed Central

    McBrian, Matthew A.; Behbahan, Iman Saramipoor; Ferrari, Roberto; Su, Trent; Huang, Ta-Wei; Li, Kunwu; Hong, Candice S.; Christofk, Heather R.; Vogelauer, Maria; Seligson, David B.; Kurdistani, Siavash K.

    2014-01-01

    SUMMARY Differences in global levels of histone acetylation occur in normal and cancer cells, although the reason why cells regulate these levels has been unclear. Here we demonstrate a role for histone acetylation in regulating intracellular pH (pHi). As pHi decreases, histones are globally deacetylated by histone deacetylases (HDACs), and the released acetate anions are coexported with protons out of the cell by monocarboxylate transporters (MCTs), preventing further reductions in pHi. Conversely, global histone acetylation increases as pHi rises, such as when resting cells are induced to proliferate. Inhibition of HDACs or MCTs decreases acetate export and lowers pHi, particularly compromising pHi maintenance in acidic environments. Global deacetylation at low pH is reflected at a genomic level by decreased abundance and extensive redistribution of acetylation throughout the genome. Thus, acetylation of chromatin functions as a rheostat to regulate pHi with important implications for mechanism of action and therapeutic use of HDAC inhibitors. PMID:23201122

  8. The Job Market for Ph.D.s: Two Views.

    ERIC Educational Resources Information Center

    Barkume, Megan

    1997-01-01

    Offers both optimistic and pessimistic views of the labor market for those with Doctor of Philosophy (Ph.D.) degrees. Discusses postdoctoral appointments and jobs for Ph.D.s outside the university. (JOW)

  9. Catalytic Decomposition of PH3 on Heated Tungsten Wire Surfaces

    NASA Astrophysics Data System (ADS)

    Umemoto, Hironobu; Nishihara, Yushin; Ishikawa, Takuma; Yamamoto, Shingo

    2012-08-01

    The catalytic decomposition processes of PH3 on heated tungsten surfaces were studied to clarify the mechanisms governing phosphorus doping into silicon substrates. Mass spectrometric measurements show that PH3 can be decomposed by more than 50% over 2000 K. H, P, PH, and PH2 radicals were identified by laser spectroscopic techniques. Absolute density measurements of these radical species, as well as their PH3 flow rate dependence, show that the major products on the catalyst surfaces are P and H atoms, while PH and PH2 are produced in secondary processes in the gas phase. In other words, catalytic decomposition, unlike plasma decomposition processes, can be a clean source of P atoms, which can be the only major dopant precursors. In the presence of an excess amount of H2, the apparent decomposition efficiency is small. This can be explained by rapid cyclic reactions including decomposition, deposition, and etching to reproduce PH3.

  10. Microscopic measurement of pH with iridium oxide microelectrodes

    PubMed

    Wipf; Ge; Spaine; Baur

    2000-10-15

    Microscopic pH electrodes were produced by deposition of hydrous iridium oxide onto carbon fiber microelectrodes. The electrodes exhibit two linear regions of potentiometric response between pH 2-6 and pH 6-12. The electrodes respond to pH changes within 50 ms, and an equilibrium value is reached within 30 s. By using these electrodes as probes in the scanning electrochemical microscope, dynamic pH changes occurring at or near a surface can be measured and pH maps of the surface can be generated. Vertical pH profiles and images of pH were obtained at substrates where electrochemical (oxidation and reduction of H2O2, hydrogen evolution) or enzymatic (glucose oxidase) reactions involving proton transfers occur. PMID:11055710

  11. Development of a porous polymer pH optrode.

    PubMed

    Liu, J N; Shahriari, M R; Sigel, G H

    1992-12-15

    A novel fiber-optic pH sensor has been developed with long-term stability and high sensitivity. The sensor is based on a porous cellulose triacetate fiber immobilized with Congo Red (pH indicator). This intrinsic fiberoptic pH sensor has shown excellent sensitivity, reversibility, and stability. It has also been demonstrated that the pH optrode is immune to metal-ion interferences. PMID:19798326

  12. INFLUENCE OF PH AND REDOX CONDITIONS ON COPPER LEACHING

    EPA Science Inventory

    Leaching behavior of metals from a mineral processing waste at varying pH and redox conditions was studies. Effect of combinations of pH and Eh on leaching of copper is described. Leaching of copper was found to be dependent on both pH and Eh. Higher concentrations of Cu were ...

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

    ERIC Educational Resources Information Center

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

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

  14. pH of organ-culture-stored corneas.

    PubMed

    Lass, J H; Greiner, J V; Meneses, P; Morgan, D C; Medcalf, S K; Collie, D M; Skelnik, D L; Glonek, T

    1988-10-01

    Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea. PMID:3218477

  15. Ian Douglass Coulter, PhD

    PubMed Central

    Brown, Douglas M

    2004-01-01

    This paper focuses on Dr. Ian Coulter’s accomplishments from the time he became Executive Vice-President of CMCC in 1981, until he ended his presidency with a year’s administrative leave in 1990. Annual planning initiatives, pedagogy, scholarship, conflicts, and the quest for university affiliation are discussed as well as his legacy to the College and the chiropractic profession. The term “adventurous” was first attributed to Coulter by Oswald Hall, PhD, Professor Emeritus, University of Toronto who had worked closely with Coulter in a major investigation of the chiropractic profession from 1976 to 1979. Throughout this article the author tries to capture the spirit of daring, innovation and intellect that permeated Coulter’s presidency, enthralling his advocates and confounding his detractors. PMID:17549218

  16. Intracellular pH in Sperm Physiology

    PubMed Central

    Nishigaki, Takuya; José, Omar; González-Cota, Ana Laura; Romero, Francisco; Treviño, Claudia L.; Darszon, Alberto

    2014-01-01

    Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca2+ channel; Slo3, a K+ channel; the sperm-specific Na+/H+ exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction. PMID:24887564

  17. Understanding Non-Traditional PhD Students Habitus--Implications for PhD Programmes

    ERIC Educational Resources Information Center

    Naidoo, Devika

    2015-01-01

    Against the background of vast changes in doctoral education and the emergence of non-traditional doctoral programmes, this paper investigates the habitus of non-traditional PhD students at a South African university. Bourdieu's conceptual tool of habitus informed the study. In-depth and open-ended interviews were conducted with 10 non-traditional…

  18. Comparison of Rumen Fluid pH by Continuous Telemetry System and Bench pH Meter in Sheep with Different Ranges of Ruminal pH

    PubMed Central

    Reis, Leonardo F.; Minervino, Antonio H. H.; Araújo, Carolina A. S. C.; Sousa, Rejane S.; Oliveira, Francisco L. C.; Rodrigues, Frederico A. M. L.; Meira-Júnior, Enoch B. S.; Barrêto-Júnior, Raimundo A.; Mori, Clara S.; Ortolani, Enrico L.

    2014-01-01

    We aimed to compare the measurements of sheep ruminal pH using a continuous telemetry system or a bench pH meter using sheep with different degrees of ruminal pH. Ruminal lactic acidosis was induced in nine adult crossbred Santa Ines sheep by the administration of 15 g of sucrose per kg/BW. Samples of rumen fluid were collected at the baseline, before the induction of acidosis (T0) and at six, 12, 18, 24, 48, and 72 hours after the induction for pH measurement using a bench pH meter. During this 72-hour period, all animals had electrodes for the continuous measurement of pH. The results were compared using the Bland-Altman analysis of agreement, Pearson coefficients of correlation and determination, and paired analysis of variance with Student's t-test. The measurement methods presented a strong correlation (r = 0.94, P < 0.05) but the rumen pH that was measured continuously using a telemetry system resulted in lower values than the bench pH meter (overall mean of 5.38 and 5.48, resp., P = 0.0001). The telemetry system was able to detect smaller changes in rumen fluid pH and was more accurate in diagnosing both subacute ruminal lactic acidosis and acute ruminal lactic acidosis in sheep. PMID:24967422

  19. PhD Students' Work Conditions and Study Environment in University- and Industry-Based PhD Programmes

    ERIC Educational Resources Information Center

    Kolmos, A.; Kofoed, L. B.; Du, X. Y.

    2008-01-01

    During the last 10 years, new models of funding and training PhD students have been established in Denmark in order to integrate industry into the entire PhD education. Several programmes have been conducted where it is possible to co-finance PhD scholarships or to become an employee as an industrial PhD in a company. An important question is what…

  20. Proton Transport and pH Control in Fungi.

    PubMed

    Kane, Patricia M

    2016-01-01

    Despite diverse and changing extracellular environments, fungi maintain a relatively constant cytosolic pH and numerous organelles of distinct lumenal pH. Key players in fungal pH control are V-ATPases and the P-type proton pump Pma1. These two proton pumps act in concert with a large array of other transporters and are highly regulated. The activities of Pma1 and the V-ATPase are coordinated under some conditions, suggesting that pH in the cytosol and organelles is not controlled independently. Genomic studies, particularly in the highly tractable S. cerevisiae, are beginning to provide a systems-level view of pH control, including transcriptional responses to acid or alkaline ambient pH and definition of the full set of regulators required to maintain pH homeostasis. Genetically encoded pH sensors have provided new insights into localized mechanisms of pH control, as well as highlighting the dynamic nature of pH responses to the extracellular environment. Recent studies indicate that cellular pH plays a genuine signaling role that connects nutrient availability and growth rate through a number of mechanisms. Many of the pH control mechanisms found in S. cerevisiae are shared with other fungi, with adaptations for their individual physiological contexts. Fungi deploy certain proton transport and pH control mechanisms not shared with other eukaryotes; these regulators of cellular pH are potential antifungal targets. This review describes current and emerging knowledge proton transport and pH control mechanisms in S. cerevisiae and briefly discusses how these mechanisms vary among fungi. PMID:26721270

  1. Intracellular pH of acid-tolerant ruminal bacteria.

    PubMed Central

    Russell, J B

    1991-01-01

    Acid-tolerant ruminal bacteria (Bacteroides ruminicola B1(4), Selenomonas ruminantium HD4, Streptococcus bovis JB1, Megasphaera elsdenii B159, and strain F) allowed their intracellular pH to decline as a function of extracellular pH and did not generate a large pH gradient across the cell membrane until the extracellular pH was low (less than 5.2). This decline in intracellular pH prevented an accumulation of volatile fatty acid anions inside the cells. PMID:1781695

  2. The Role of pH Regulation in Cancer Progression.

    PubMed

    McIntyre, Alan; Harris, Adrian L

    2016-01-01

    Frequently observed phenotypes of tumours include high metabolic activity, hypoxia and poor perfusion; these act to produce an acidic microenvironment. Cellular function depends on pH homoeostasis, and thus, tumours become dependent on pH regulatory mechanisms. Many of the proteins involved in pH regulation are highly expressed in tumours, and their expression is often of prognostic significance. The more acidic tumour microenvironment also has important implications with regard to chemotherapeutic and radiotherapeutic interventions. In addition, we review pH-sensing mechanisms, the role of pH regulation in tumour phenotype and the use of pH regulatory mechanisms as therapeutic targets. PMID:27557536

  3. Time course of pH change in plant epidermis using microscopic pH imaging system

    NASA Astrophysics Data System (ADS)

    Dan, Risako; Shimizu, Megumi; Kazama, Haruko; Sakaue, Hirotaka

    2010-11-01

    We established a microscopic pH imaging system to track the time course of pH change in plant epidermis in vivo. In the previous research, we have found out that anthocyanin containing cells have higher pH. However, it was not clear whether the anthocyanin increased the pH or anthocyanin was synthesized result from the higher pH. Therefore, we further investigated the relationship between anthocyanin and pH change. To track the time course of pH change in plant epidermis, we established a system using luminescent imaging technique. We used HPTS (8-Hydroxypyrene-1,3,6-Trisulfonate) as pH indicator and applied excitation ratio imaging method. Luminescent image was converted to a pH distribution by obtained in vitro calibration using known pH solution. Cellular level observation was enabled by merging microscopic color picture of the same region to the pH change image. The established system was applied to epidermal cells of red-tip leaf lettuce, Lactuca Sativa L. and the time course was tracked in the growth process. We would discuss about the relationship between anthocyanin and pH change in plant epidermis.

  4. Tear pH, air pollution, and contact lenses

    SciTech Connect

    Andres, S.; Garcia, M.L.; Espina, M.; Valero, J.; Valls, O.

    1988-08-01

    We analyzed the tear pH of a random sample of 100 subjects, divided into 3 groups according to the stability of their precorneal tear film (normal eyes, borderline; and dry eyes). The average pH value obtained was 7.52. The pH for borderline and dry eyes was higher than for normal eyes. The purpose of this study was to determine the influence of air pollution, specifically sulfur dioxide (SO/sub 2/), on the tear pH. We found that air pollution affected the lacrimal pH, which decreased when the atmospheric SO/sub 2/ increased. Finally, we studied the effect of soft contact lens wear on tear pH after 7 days of contact lens adaptation by assessing the tear pH decrease. We took into account the influence of the sex and age of subjects on the results obtained.

  5. pH regulation of urease levels in Streptococcus salivarius.

    PubMed

    Sissons, C H; Perinpanayagam, H E; Hancock, E M; Cutress, T W

    1990-05-01

    Potential mechanisms for regulation of urease levels in Streptococcus salivarius were examined, including: induction by urea, nitrogen or carbon source repression, and effects of pH and CO2 (because CO2 enrichment enhanced urease detection on urea agar plates). Regulation by either pH or CO2 was confirmed by comparison of the urease accumulation pattern during anaerobic growth under CO2 with that under N2. Under CO2, there was an initial buffering plateau at pH 6.2 and a rate of Streptococcus salivarius urease accumulation three-fold that under N2, with a pH 7.6 plateau. With both gas phases there was also an increase in the rate of urease appearance coincident with the decrease in medium pH following the pH plateau. The effects of pH, CO2, and HCO3- on urease levels and on growth were separately assessed by culture in media containing 0, 25, 100 mmol/L KHCO3 buffered at different pH levels. There was an inverse relationship between the logarithm of the urease level after 24-hour growth and the pH during growth-the urease specific activity was 100-fold higher at pH 5.5, compared with pH 7.0 and above. HCO3-/CO2 (100 mmol/L) had little effect on urease levels, but was essential for growth at pH 5.5. There was no significant urease induction by urea, or repression by ammonia or glucose. There was also evidence of pH regulation of urease levels in some staphylococci, Klebsiella pneumonia, and Corynebacterium renale, but not in Actinomyces naeslundii and several other species. We conclude that the external pH is a major factor regulating urease levels in S. salivarius and possibly some other species-a mechanism equivalent to urease repression by OH-. PMID:2110582

  6. Intracellular pH of symbiotic dinoflagellates

    NASA Astrophysics Data System (ADS)

    Gibbin, E. M.; Davy, S. K.

    2013-09-01

    Intracellular pH (pHi) is likely to play a key role in maintaining the functional success of cnidarian-dinoflagellate symbiosis, yet until now the pHi of the symbiotic dinoflagellates (genus Symbiodinium) has never been quantified. Flow cytometry was used in conjunction with the ratiometric fluorescent dye BCECF to monitor changes in pHi over a daily light/dark cycle. The pHi of Symbiodinium type B1 freshly isolated from the model sea anemone Aiptasia pulchella was 7.25 ± 0.01 (mean ± SE) in the light and 7.10 ± 0.02 in the dark. A comparable effect of irradiance was seen across a variety of cultured Symbiodinium genotypes (types A1, B1, E1, E2, F1, and F5) which varied between pHi 7.21-7.39 in the light and 7.06-7.14 in the dark. Of note, there was a significant genotypic difference in pHi, irrespective of irradiance.

  7. Dipstick Spot urine pH does not accurately represent 24 hour urine PH measured by an electrode

    PubMed Central

    Omar, Mohamed; Sarkissian, Carl; Jianbo, Li; Calle, Juan; Monga, Manoj

    2016-01-01

    ABSTRACT Objectives To determine whether spot urine pH measured by dipstick is an accurate representation of 24 hours urine pH measured by an electrode. Materials and Methods We retrospectively reviewed urine pH results of patients who presented to the urology stone clinic. For each patient we recorded the most recent pH result measured by dipstick from a spot urine sample that preceded the result of a 24-hour urine pH measured by the use of a pH electrode. Patients were excluded if there was a change in medications or dietary recommendations or if the two samples were more than 4 months apart. A difference of more than 0.5 pH was considered an inaccurate result. Results A total 600 patients were retrospectively reviewed for the pH results. The mean difference in pH between spot urine value and the 24 hours collection values was 0.52±0.45 pH. Higher pH was associated with lower accuracy (p<0.001). The accuracy of spot urine samples to predict 24-hour pH values of <5.5 was 68.9%, 68.2% for 5.5 to 6.5 and 35% for >6.5. Samples taken more than 75 days apart had only 49% the accuracy of more recent samples (p<0.002). The overall accuracy is lower than 80% (p<0.001). Influence of diurnal variation was not significant (p=0.588). Conclusions Spot urine pH by dipstick is not an accurate method for evaluation of the patients with urolithiasis. Patients with alkaline urine are more prone to error with reliance on spot urine pH. PMID:27286119

  8. In vitro synthesis and purification of PhIP-deoxyguanosine and PhIP-DNA oligomer covalent complexes

    SciTech Connect

    Freeman, J.

    1994-12-01

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic amine compound formed when meats are cooked at high temperatures. PhIP damages DNA by forming covalent complexes with DNA carcinogen. In an effort to understand how the binding of PhIP to DNA may cause cancer, it is important to characterize the structures of PhIP-damaged DNA molecules. Our HPLC data support fluorescence and {sup 32}P Post-labeling studies which indicate the formation of several species of 2{prime}deoxyguanosine-(dG) or oligodeoxynucleotide-PhIP adducts. The reaction of PhIP with dG resulted in a reddish precipitate that was likely the major adduct, N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP) adduct, with a more polar adduct fraction remaining in the supernatant. Reversed-phase HPLC analysis of the adducts in the supernatant revealed the existence of species of much shorter retention times than the dG-C8-PhIP adduct, confirming that these species are more polar than dG-C8-PhIP. At least four adducts were formed in the reaction of PhIP with DNA oligomer. HPLC analysis of the PhIP-DNA oligomer supernatant after butanol extractions revealed four unresolved peaks which spectra had maximum wavelengths between 340 and 360 nm. Though adduct peaks were not completely resolved, there was {approximately}3 minutes interval between the DNA oligomer peak and the adduct peaks. Furthermore, fluorescence emission data of the DNA oligomer-PhIP adduct solution show heterogeneous binding. The more polar PhIP adducts were fraction-collected and their structures will be solved by nuclear magnetic resonance or x-ray crystallography.

  9. Impact of ruminal pH on enteric methane emissions.

    PubMed

    Hünerberg, M; McGinn, S M; Beauchemin, K A; Entz, T; Okine, E K; Harstad, O M; McAllister, T A

    2015-04-01

    The objective of this study was to determine the impact of ruminal pH on methane (CH4) emission from beef cattle. Ruminal pH and CH4 data were generated in 2 experiments using 16 beef heifers offered high-forage (55% barley silage) or high-grain (92% concentrate; DM basis) diets. Both experiments were designed as a replicated 4 × 4 Latin square with 4 periods and 4 dietary treatments. Methane was measured over 4 consecutive days using open-circuit respiratory chambers with each chamber housing 2 heifers. The ruminal pH of individual heifers was measured using indwelling pH loggers. The mean ruminal pH and CH4 emission (g/h) of 2 heifers in every chamber were summarized in 30-min blocks. Even though rumen methanogens have been described to be inhibited by a pH < 6.0 in vitro, in vivo CH4-production rates (g/h) did not decrease when ruminal pH declined to threshold levels for subacute (5.2 ≤ pH < 5.5) or acute ruminal acidosis (pH < 5.2; P > 0.05). Daily mean CH4 emission (g/d) and ruminal pH were only mildly correlated (r2 = 0.27; P < 0.05), suggesting that additional factors, such as increased propionate formation or passage rate, account for the lower CH4 emissions from cattle fed high-grain as compared to high-forage diets. Lowering ruminal pH alone is, therefore, not an effective CH4-mitigation strategy. Mechanisms permitting methanogens to survive episodes of low-ruminal pH might include changes in community structure toward more pH-tolerant strains or sequestration into microenvironments within biofilms or protozoa where methanogens are protected from low pH. PMID:26020197

  10. pH measurement of low-conductivity waters

    USGS Publications Warehouse

    Busenberg, Eurybiades; Plummer, L.N.

    1987-01-01

    pH is an important and commonly measured parameter of precipitation and other natural waters. The various sources of errors in pH measurement were analyzed and procedures for improving the accuracy and precision of pH measurements in natural waters with conductivities of < 100 uS/cm at 25 C are suggested. Detailed procedures are given for the preparation of dilute sulfuric acid standards to evaluate the performance of pH electrodes in low conductivity waters. A daily check of the pH of dilute sulfuric acid standards and deionized water saturated with a gas mixture of low carbon dioxide at partial pressure (air) prior to the measurement of the pH of low conductivity waters is suggested. (Author 's abstract)

  11. Cell wall pH and auxin transport velocity

    NASA Technical Reports Server (NTRS)

    Hasenstein, K. H.; Rayle, D.

    1984-01-01

    According to the chemiosmotic polar diffusion hypothesis, auxin pulse velocity and basal secretion should increase with decreasing cell wall pH. Experiments were designed to test this prediction. Avena coleoptile sections were preincubated in either fusicoccin (FC), cycloheximide, pH 4.0, or pH 8.0 buffer and subsequently their polar transport capacities were determined. Relative to controls, FC enhanced auxin (IAA) uptake while CHI and pH 8.0 buffer reduced IAA uptake. Nevertheless, FC reduced IAA pulse velocity while cycloheximide increased velocity. Additional experiments showed that delivery of auxin to receivers is enhanced by increased receiver pH. This phenomenon was overcome by a pretreatment of the tissue with IAA. Our data suggest that while acidic wall pH values facilitate cellular IAA uptake, they do not enhance pulse velocity or basal secretion. These findings are inconsistent with the chemiosmotic hypothesis for auxin transport.

  12. Cell wall pH and auxin transport velocity.

    PubMed Central

    Hasenstein, K H; Rayle, D

    1984-01-01

    According to the chemiosmotic polar diffusion hypothesis, auxin pulse velocity and basal secretion should increase with decreasing cell wall pH. Experiments were designed to test this prediction. Avena coleoptile sections were preincubated in either fusicoccin (FC), cycloheximide, pH 4.0, or pH 8.0 buffer and subsequently their polar transport capacities were determined. Relative to controls, FC enhanced auxin (IAA) uptake while CHI and pH 8.0 buffer reduced IAA uptake. Nevertheless, FC reduced IAA pulse velocity while cycloheximide increased velocity. Additional experiments showed that delivery of auxin to receivers is enhanced by increased receiver pH. This phenomenon was overcome by a pretreatment of the tissue with IAA. Our data suggest that while acidic wall pH values facilitate cellular IAA uptake, they do not enhance pulse velocity or basal secretion. These findings are inconsistent with the chemiosmotic hypothesis for auxin transport. PMID:11540807

  13. Computer model of unstirred layer and intracellular pH changes. Determinants of unstirred layer pH.

    PubMed

    Marrannes, Roger

    2013-06-01

    Transmembrane acid-base fluxes affect the intracellular pH and unstirred layer pH around a superfused biological preparation. In this paper the factors influencing the unstirred layer pH and its gradient are studied. An analytical expression of the unstirred layer pH gradient in steady state is derived as a function of simultaneous transmembrane fluxes of (weak) acids and bases with the dehydration reaction of carbonic acid in equilibrium. Also a multicompartment computer model is described consisting of the extracellular bulk compartment, different unstirred layer compartments and the intracellular compartment. With this model also transient changes and the influence of carbonic anhydrase (CA) can be studied. The analytical expression and simulations with the multicompartment model demonstrate that in steady state the unstirred layer pH and its gradient are influenced by the size and type of transmembrane flux of acids and bases, their dissociation constant and diffusion coefficient, the concentration, diffusion coefficient and type of mobile buffers and the activity and location of CA. Similar principles contribute to the amplitude of the unstirred layer pH transients. According to these models an immobile buffer does not influence the steady-state pH, but reduces the amplitude of pH transients especially when these are fast. The unstirred layer pH provides useful information about transmembrane acid-base fluxes. This paper gives more insight how the unstirred layer pH and its transients can be interpreted. Methodological issues are discussed. PMID:23860924

  14. Chapter A6. Section 6.4. pH

    USGS Publications Warehouse

    Wilde, Franceska D.; Busenberg, Eurybiades; Radtke, Dean B.

    2006-01-01

    Measurement of pH is critical to the understanding of the viability and vulnerability of environmental waters and is considered a master variable in determining the aqueous geochemistry of an aqueous system. pH is a measure that represents the hydrogen-ion concentration (activity) of a solution. This section of the National Field Manual (NFM) describes U.S. Geological Survey (USGS) guidance and protocols for measurement of pH in ground and surface waters.

  15. Fast optical pH manipulation and imaging.

    PubMed

    Filevich, Oscar; Carrone, Guillermo; Pavlovsky, Victoria Andino; Etchenique, Roberto

    2012-07-01

    We describe a complete system for optical pH manipulation and imaging. The system consists of a photoactive Ruthenium complex capable of inducing a change of more than 5 pH units at the nanosecond time scale. A compatible imaging system acquires microscopic pH images at 1200 fps using a nonexpensive commercial digital camera and an LED illumination system. We use the system as a superb tool to investigate flow in Flow Injection Analysis (FIA) models. PMID:22703044

  16. 4-Nitro-N-(3-nitro-phen-yl)benzamide.

    PubMed

    Johnston, Dean H; Taylor, Colin R

    2011-10-01

    The title compound, C(13)H(9)N(3)O(5), prepared as a solid derivative of 3-nitro-analine via reaction with 4-nitro-benzoyl chloride, crystallizes in a chiral space group. The mol-ecule is non-planar with a dihedral angle of 26.1 (1)° between the two benzene rings. Both nitro groups are twisted slightly out of the plane of their corresponding benzene rings, making dihedral angles of 10.7 (4) and 13.5 (4)°. The mol-ecules are stacked along the a axis with benzene ring centroid-centroid distances of 3.8878 (6) Å. In the crystal, inter-molecular benzene C-H⋯O inter-actions involving one nitro group and the carbonyl group link the mol-ecules, forming chains along [001]. An additional set of aromatic C-H⋯O inter-actions with the second nitro group form chains along [101], connecting adjacent chains to create layers perpendicular to the b axis. PMID:22065512

  17. Field measurement of alkalinity and pH

    USGS Publications Warehouse

    Barnes, Ivan

    1964-01-01

    The behavior of electrometric pH equipment under field conditions departs from the behavior predicted from Nernst's law. The response is a linear function of pH, and hence measured pH values may be corrected to true pH if the instrument is calibrated with two reference solutions for each measurement. Alkalinity titrations may also be made in terms of true pH. Standard methods, such as colorimetric titrations, were rejected as unreliable or too cumbersome for rapid field use. The true pH of the end point of the alkalinity titration as a function of temperature, ionic strength, and total alkalinity has been calculated. Total alkalinity in potable waters is the most important factor influencing the end point pH, which varies from 5.38 (0 ? C, 5 ppm (parts per million) HC0a-) to 4.32 (300 ppm HC0a-,35 ? C), for the ranges of variables considered. With proper precautions, the pH may be determined to =i:0.02 pH and the alkalinity to =i:0.6 ppm HCO3- for many naturally occurring bodies of fresh water.

  18. Nanosensor aided photoacoustic measurement of pH in vivo

    NASA Astrophysics Data System (ADS)

    Ray, Aniruddha; Yoon, Hyung Ki; Kopelman, Raoul; Wang, Xueding

    2013-03-01

    pH plays a critical role in many aspects of cell and tissues physiology. Lower pH is also a typical characteristic of arthritic joints and tumor tissues. These pH anomalies are also exploited in different drug delivery mechanisms. Here we present, a new method of pH sensing in vivo using spectroscopic photoacoustic measurements facilitated by pH sensitive nanosensors. The nanosensors consist of Seminaphtharhodafluor (SNARF), a pH sensitive dye, encapsulated in a specially designed polyacrylamide hydrogel matrix with a hydrophobic core. The photoacoustic intensity ratio between the excitation wavelengths of 585nm and 565nm increases in the pH range from 6.0 to 8.0 and is used to determine the pH of the local environment. These nanosensors are biodegradable, biocompatible, have a long plasma lifetime and can be targeted to any type of cells or tissues by surface modification using proper targeting moieties. The encapsulation of the dye prevents the interaction of the dye with proteins in plasma and also reduces the dye degradation. The SNARF dye in its free form loses 90% of its absorbance in presence of albumin, a protein found in abundance in plasma, and this has severely limited its adaptation to in vivo environments. In comparison, the SNARF nanosensors lose only 16% of their absorbance in the same environment. We employ these nanosensors to demonstrate the feasibility of pH sensing in vivo through photoacoustic measurements on a rat joint model.

  19. Molecular aspects of bacterial pH sensing and homeostasis

    PubMed Central

    Krulwich, Terry A.; Sachs, George; Padan, Etana

    2011-01-01

    Diverse mechanisms for pH-sensing and cytoplasmic pH homeostasis enable most bacteria to tolerate or grow at external pH values that are outside the cytoplasmic pH range they must maintain for growth. The most extreme cases are exemplified by the extremophiles that inhabit environments whose pH is below 3 or above 11. Here we describe how recent insights into the structure and function of key molecules and their regulators reveal novel strategies of bacterial pH-homeostasis. These insights may help us better target certain pathogens and better harness the capacities of environmental bacteria. PMID:21464825

  20. Gastric fluid pH in patients receiving sodium citrate.

    PubMed

    Viegas, O J; Ravindran, R S; Shumacker, C A

    1981-07-01

    Gastric fluid pH was measured following induction of anesthesia and placement of an endotracheal tube in 30 surgical patients undergoing elective operations. None of the patients received an anticholinergic drug before surgery. Fifteen patients who had been given 15 ml of sodium citrate 15 to 20 minutes before induction of anesthesia had a mean pH of 6.2 +/- 0.8. The control group, which also consisted of 15 patients, had a mean pH of 2.1 +/- 1.4. The increase in gastric pH noted following sodium citrate would result in reduced pulmonary reaction should aspiration occur. PMID:7195668

  1. The Semen pH Affects Sperm Motility and Capacitation

    PubMed Central

    Hong, Zhiwei; Xie, Min; Chen, Shengrong; Yao, Bing

    2015-01-01

    As the chemical environment of semen can have a profound effect on sperm quality, we examined the effect of pH on the motility, viability and capacitation of human sperm. The sperm in this study was collected from healthy males to avoid interference from other factors. The spermatozoa cultured in sperm nutrition solution at pH 5.2, 6.2, 7.2 and 8.2 were analyzed for sperm total motility, progressive motility (PR), hypo-osmotic swelling (HOS) rate, and sperm penetration. Our results showed that these parameters were similar in pH 7.2 and 8.2 sperm nutrition solutions, but decreased in pH 5.2 and 6.2 solutions. The HOS rate exhibited positive correlation with the sperm total motility and PR. In addition, the sperm Na+/K+-ATPase activity at different pHs was measured, and the enzyme activity was significantly lower in pH 5.2 and 6.2 media, comparing with that in pH 8.2 and pH 7.2 solutions. Using flow cytometry (FCM) and laser confocal scanning microscopy (LCSM) analysis, the intracellular Ca2+ concentrations of sperm cultured in sperm capacitation solution at pH 5.2, 6.2, 7.2 and 8.2 were determined. Compared with that at pH 7.2, the mean fluorescence intensity of sperm in pH 5.2 and 6.2 media decreased significantly, while that of pH 8.2 group showed no difference. Our results suggested that the declined Na+/K+-ATPase activity at acidic pHs result in decreased sperm movement and capacitation, which could be one of the mechanisms of male infertility. PMID:26173069

  2. Mapping Soil pH Buffering Capacity of Selected Fields

    NASA Technical Reports Server (NTRS)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

  3. Notes on the Measurement of pH Values

    SciTech Connect

    Carranza, R M; Rebak, R B

    2005-05-05

    The original definition of pH is: pH = -log a{sub H}. Where a{sub H} is the (relative) hydrogen ion activity. However, a single ion activity cannot be measured. Activities of individual ionic species are necessarily conventional. The pH number, of course, has in itself little absolute significance. As the negative of the logarithm of a product of a concentration (c or m) and an activity coefficient (y or {gamma}), it acquires its magnitude from the numerical scale adopted for the latter. Experimental pH measurements are nonetheless widely applied to the determination of thermodynamic equilibrium data such as pK values, on the assumption that they represent -log a{sub H} (or paH). The single ion activity coefficient approaches unity as the ionic strength goes to zero, so that activity becomes m or c and paH becomes pmH or pcH. pH is therefore defined operationally in terms of the operation or method used to measure it, that is, by means of a cell called an operational cell. The cell is standardized by solutions of assigned pH value (Reference Value pH Standard, Primary pH Standards and Operational Standards). Such standard reference solutions are buffer solutions whose pH values are assigned from measurements on cells with or without liquid junction. It must be emphasized that the definition of pH scale is quite different from the measurement of pH with glass-reference electrode-pH meter assemblies, where several standards are used in order to take into account possible deficiencies in the electrode and meter performance.

  4. Cooperative effects in pnicogen bonding: (PH2F)2-7 and (PH2Cl)2-7 clusters

    NASA Astrophysics Data System (ADS)

    Esrafili, Mehdi D.; Vakili, Mahshad; Solimannejad, Mohammad

    2014-08-01

    The cooperative effects between pnicogen bond interactions in open-chain clusters of (PH2F)n and (PH2Cl)n are studied by ab initio calculations, where n = 2-7. These effects are analyzed in terms of geometric and energetic properties of the clusters. The intermolecular distances observed in the PH2F clusters exhibit quite larger bond contractions than those found in the PH2Cl. The contribution of cooperative effects to the interaction energy is quite significant. In order to understand the mechanism of the cooperativity, interaction energy decomposition and molecular electrostatic potential analyses are performed.

  5. The PhD Viva: A Space for Academic Development

    ERIC Educational Resources Information Center

    Share, Michelle

    2016-01-01

    This study examined the viva experiences of 87 social science PhD graduates from three Irish higher education institutions through a questionnaire that assessed outcome, preparation, conduct and post-viva. The majority were awarded their PhD with minor corrections, considered their viva as a summative assessment, and emphasised its purpose as…

  6. The Early Development of Electronic pH Meters

    ERIC Educational Resources Information Center

    Hines, Wallis G.; de Levie, Robert

    2010-01-01

    A 19-year-old undergraduate at the University of Chicago, Kenneth Goode, in 1921 came up with the idea of an electronic pH meter, worked out some of its initial problems, and set in motion an international scientific effort that culminated in the current, wide availability of electronic pH meters. Except for the replacement of vacuum tubes by…

  7. Research Collaboration and Commercialization: The PhD Candidate Perspective

    ERIC Educational Resources Information Center

    Dooley, Lawrence; Kenny, Breda

    2015-01-01

    This paper explores PhD students' perceptions of their entrepreneurial and commercial capabilities, their attitude towards university supports and the extent to which they engage in external collaboration. The study concentrated on current PhD researchers at one university in Ireland as a unit of analysis and provides encouraging evidence from the…

  8. Rethinking PhD Learning Incorporating Communities of Practice

    ERIC Educational Resources Information Center

    Shacham, Miri; Od-Cohen, Yehudit

    2009-01-01

    This paper grows from research which focuses on the learning characteristics of PhD students, incorporating communities of practice both during their studies and beyond completion of their PhD, and drawing on theories of adult learning and lifelong learning. It shows how professional discourse enhances academic discourse through student engagement…

  9. PhDs in Australia, from the Beginning

    ERIC Educational Resources Information Center

    Dobson, Ian R.

    2012-01-01

    The Australian PhD is a relatively recent phenomenon, the first three being awarded in 1948. Before that, most Australian scholars typically went to Britain (predominantly) or the USA to undertake their doctoral studies. The aim of this research note is to provide a brief statistical history of the Australian PhD, noting changes over time between…

  10. Microscale pH Titrations Using an Automatic Pipet.

    ERIC Educational Resources Information Center

    Flint, Edward B.; Kortz, Carrie L.; Taylor, Max A.

    2002-01-01

    Presents a microscale pH titration technique that utilizes an automatic pipet. A small aliquot (1-5 mL) of the analyte solution is titrated with repeated additions of titrant, and the pH is determined after each delivery. The equivalence point is determined graphically by either the second derivative method or a Gran plot. The pipet can be…

  11. Jeanne Murphy, PhD, CNM | Division of Cancer Prevention

    Cancer.gov

    Jeanne Murphy, PhD, CNM is a postdoctoral Cancer Prevention Fellow in the Breast and Gynecologic Cancer Research Group in the Division of Cancer Prevention. She comes to BGCRG with a PhD from Johns Hopkins University School of Nursing. She also completed a graduate certificate in Health Disparities and Health Inequality at Johns Hopkins Bloomberg School of Public Health. |

  12. Photoreversible changes in pH of pea phytochrome solutions

    SciTech Connect

    Tokutomi, S.; Yamamoto, K.T.; Miyoshi, Y.; Furuya, M.

    1982-02-01

    Phytochrome is a chromoprotein that serves as the photoreceptor for a variety of photomorphogenic responses in plants. Phytochrome was isolated from etiolated pea seedlings. Photoinduced pH changes of an unbuffered solution of the phytochrome were monitored with a semimicrocombination pH electrode at pH 6.5. Red-light irradiation increased the pH of the medium. This alkalinization was reversed by a subsequent far-red-light irradiation. The magnitude and direction of the red-light-induced pH changes was dependent on the pH of the photocrome solution, and the maximum alkalinization was observed at pH 6.0, where the number of protons taken up per phytochrome monomer was 0.18. These results suggest that phytochrome is a multifunctional protein composed of a chromophoric domain and a hydrophobic domain. It is probable that the hydrophobic domain is responsible for the photoinduced change of hydrophobicity of phytochrome and that the ionizable groups responsible for the photoinduced pH changes are localized in the chromophoric domain. (JMT)

  13. The Ph.D. Surplus - Realities and Illusions.

    ERIC Educational Resources Information Center

    Hansen, Harold P.

    Every 6 years the number of Ph.D.'s produced doubles. At this point about 1 percent of the babies born 27 years ago gets a Ph.D. This production rate will probably increase to 6 percent of the adult population. With the present situation in higher education, which includes an average retirement after 40 years of service, the supply already…

  14. Thermal and pH stability of "beta-benzyme".

    PubMed Central

    D'Souza, V T; Lu, X L; Ginger, R D; Bender, M L

    1987-01-01

    The thermal and pH stability of "beta-benzyme", an artificial chymotrypsin based on beta-cyclodextrin, has been studied and compared with the stability of real chymotrypsin. Artificial chymotrypsin is vastly superior to real chymotrypsin with regard to both temperature and pH stability. The reasons for this increased stability are discussed. PMID:3468505

  15. The Undergraduate Origins of PhD Economists Revisited

    ERIC Educational Resources Information Center

    Stock, Wendy A.; Siegfried, John J.

    2015-01-01

    The authors update prior analyses of the undergraduate origins of individuals who earn a PhD in economics in the United States. They include the list of the top institutions worldwide graduating the largest number of undergraduates who subsequently earn an economics PhD from a U.S. university and lists of American institutions with the largest…

  16. The Importance of Having a Ph.D., Career Advice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A presentation on the importance of having a PhD to motivate Initiative to Maximize Student Diversity Program (IMSD) undergrads towards conducting research, pursuing careers in the biomedical field, applying to grad school, and getting a Ph.D., based upon ARS scientist's experiences as a student, a ...

  17. Earth & Space Science PhDs, Class of 2001.

    ERIC Educational Resources Information Center

    Claudy, Nicholas; Henly, Megan; Migdalski, Chet

    This study documents the employment patterns and demographic characteristics of recent PhDs in earth and space science. It summarizes the latest annual survey of recent earth and space science PhDs conducted by the American Geological Institute, the American Geophysical Union, and the Statistical Research Center of the American Institute of…

  18. Tracking the PhD Students' Daily Computer Use

    ERIC Educational Resources Information Center

    Sim, Kwong Nui; van der Meer, Jacques

    2015-01-01

    This study investigated PhD students' computer activities in their daily research practice. Software that tracks computer usage (Manic Time) was installed on the computers of nine PhD students, who were at their early, mid and final stage in doing their doctoral research in four different discipline areas (Commerce, Humanities, Health Sciences and…

  19. Consideration of Factors Affecting Strip Effluent PH and Sodium Content

    SciTech Connect

    Peters, T.

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  20. What if We Made Fewer Ph.D.'s?

    ERIC Educational Resources Information Center

    Cassuto, Leonard

    2012-01-01

    Whenever a discussion opens about nonacademic employment for Ph.D.s, it is not long before someone suggests reducing graduate-school admissions. "The market for full-time scholars has fallen off a cliff lately," this argument goes, "so why not just train fewer of them?" The strategy to reduce the number of Ph.D. students recurs in those…

  1. The Undergraduate Origins of PhD Economists

    ERIC Educational Resources Information Center

    Siegfried, John J.; Stock, Wendy A.; Walstad, William

    2007-01-01

    The authors document the types of undergraduate colleges and universities attended by those who earned a doctorate in economics from an American university from 1966 through 2003. They examine relationships between type of undergraduate institution and attrition and time-to-degree in PhD programs. The total number of new economics PhDs awarded to…

  2. [Stop the compulsive PhD trajectory for junior doctors].

    PubMed

    Clevers, J C Hans

    2014-01-01

    It has become the rule rather than the exception that junior doctors in training spend 3-4 years on a research project, culminating in a thesis. Without a PhD, clinical career prospects within and outside academia look rather bleak. Here I argue that PhD degrees should be pursued only by the most talented and motivated young clinicians. PMID:24893817

  3. Predicting Computer Science Ph.D. Completion: A Case Study

    ERIC Educational Resources Information Center

    Cox, G. W.; Hughes, W. E., Jr.; Etzkorn, L. H.; Weisskopf, M. E.

    2009-01-01

    This paper presents the results of an analysis of indicators that can be used to predict whether a student will succeed in a Computer Science Ph.D. program. The analysis was conducted by studying the records of 75 students who have been in the Computer Science Ph.D. program of the University of Alabama in Huntsville. Seventy-seven variables were…

  4. pH in atomic scale simulations of electrochemical interfaces.

    PubMed

    Rossmeisl, Jan; Chan, Karen; Ahmed, Rizwan; Tripković, Vladimir; Björketun, Mårten E

    2013-07-01

    Electrochemical reaction rates can strongly depend on pH, and there is increasing interest in electrocatalysis in alkaline solution. To date, no method has been devised to address pH in atomic scale simulations. We present a simple method to determine the atomic structure of the metal|solution interface at a given pH and electrode potential. Using Pt(111)|water as an example, we show the effect of pH on the interfacial structure, and discuss its impact on reaction energies and barriers. This method paves the way for ab initio studies of pH effects on the structure and electrocatalytic activity of electrochemical interfaces. PMID:23703376

  5. Continuous pH monitoring in a perfused bioreactor system using an optical pH sensor

    NASA Technical Reports Server (NTRS)

    Jeevarajan, Antony S.; Vani, Sundeep; Taylor, Thomas D.; Anderson, Melody M.

    2002-01-01

    Monitoring and regulating the pH of the solution in a bioprocess is one of the key steps in the success of bioreactor operation. An in-line optical pH sensor, based on the optical absorption properties of phenol red present in the medium, was developed and tested in this work for use in NASA space bioreactors based on a rotating wall-perfused vessel system supporting a baby hamster kidney (BHK-21) cell culture. The sensor was tested over three 30-day and one 124-day cell runs. The pH sensor initially was calibrated and then used during the entire cell culture interval. The pH reported by the sensor was compared to that measured by a fiber optically coupled Shimadzu spectrophotometer and a blood gas analyzer. The maximum standard error of prediction for all the four cell runs for development pH sensor against BGA was +/-0.06 pH unit and for the fiber optically coupled Shimadzu spectrophotometer against the blood gas analyzer was +/-0.05 pH unit. The pH sensor system performed well without need of recalibration for 124 days. Copyright 2002 Wiley Periodicals, Inc.

  6. A ph sensor based on a flexible substrate

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Ding

    pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on low-cost sol-gel fabrication process of iridium oxide (IrOx) sensing film (IROF). A pair of flexible miniature IrOx/AgCl electrode generated the action potential from the solution by electrochemical mechanism to obtain the pH level of the reagent. The fabrication process including sol-gel, thermal oxidation, and the electro-plating process of the silver chloride (AgCl) reference electrode were reported in the work. The IrOx film was verified and characterized using electron dispersive analysis (EDAX), scanning electron microscope (SEM), and x-ray diffraction (XRD). The flexible pH sensor's performance and characterization have been investigated with different testing parameters such as sensitivity, response time, stability, reversibility, repeatability, selectivity and temperature dependence. The flexible IrOx pH sensors exhibited promising sensing performance with a near-Nernstian response of sensitivity which is between --51.1mV/pH and --51.7mV/pH in different pH levels ranging from 1.5 to 12 at 25°C. Two applications including gastroesophageal reflux disease (GERD) diagnosis and food freshness wireless monitoring using our micro-flexible IrOx pH sensors were demonstrated. For the GERD diagnosing system, we embedded the micro flexible pH sensor on a 1.2cmx3.8cm of the capsule size of wireless sensor

  7. Mixed metal oxide films as pH sensing materials

    NASA Astrophysics Data System (ADS)

    Arshak, Khalil; Gill, Edric; Korostynska, Olga; Arshak, Arousian

    2007-05-01

    Due to the demand for accurate, reliable and highly sensitive pH sensors, research is being pursued to find novel materials to achieve this goal. Semiconducting metal oxides, such as TiO, SnO and SnO II and insulating oxides such as Nb IIO 5 and Bi IIO 3, and their mixtures in different proportions are being investigated for this purpose. The films of these materials mixtures are used in conjunction with an interdigitated electrode pattern to produce a conductimetric/capacitive pH sensor. The advantages of this approach include straightforward manufacturing, versatility and cost-effectiveness. It was noted that upon contact with a solution, the electrical parameters of the films, such as resistance etc., change. The correlation of these changes with pH values is the basis for the proposed system development. The ultimate goal is to find materials composition, which would have the highest sensitivity towards the pH level of the solutions. It was found that the materials that produced the highest sensitivity either had a long response time or were unstable over a wide pH range. Those exhibiting lower sensitivities were found to be more stable over a wide pH range. All oxide films tested demonstrated a change in electrical parameters upon contact with buffers of known pH value.

  8. pH in physiological salt solutions: direct measurements.

    PubMed

    Abrahamsen, J; Norrie, B; Andersen, P K; Stokke, D B; Nedergaard, O A

    1990-11-01

    Calculations of pH in modified Krebs solutions by inserting PCO2 and total-CO2 in the Henderson-Hasselbalch (H.-H.) equation are obvious as the equation originally served for this purpose. An exact calculation of the relation between pH and PCO2 is complicated as the concentration of bicarbonate, the dissociation constant and the solubility of CO2 change. Furthermore, the dissociation constant in the H.-H. equation is constant only if activities are used in the equation instead of stoichiometric concentrations. We therefore investigated the influence of different carbon dioxide tensions and bicarbonate concentrations on directly measured pH of organ baths aerated with mass-spectrometric analyzed O2-CO2 gases. For reference precision buffers were used. The measured pH values differed distinctly from calculated pH values in the acidic and alkaline parts of the pH interval investigated (6.57-8.15). Measurements of actual pH with proper calibration standards therefore seem mandatory. PMID:2177306

  9. Improved granular activated carbon for the stabilization of wastewater PH

    SciTech Connect

    Farmer, R.W.; Dussert, B.W.; Kovacic, S.L.

    1996-12-31

    Laboratory studies have identified the cause of the pH rise, which occurs during water treatment with activated carbon, as an interaction between the naturally occurring anions and protons in the water and the carbon surface. The interaction can be described as an ion exchange type of phenomenon, in which the carbon surface sorbs the anions and corresponding hydronium ions from the water. These studies have shown that the anion sorption and resulting pH increase is independent of the raw material used for the activated carbon production, e.g. bituminous or subbituminous coal, peat, wood or coconut. Also, the pH excursions occur with virgin, reactivated, and acid washed granular carbons. Current pH control technologies focus on adjustment of the wastewater pH prior to discharge or recycle of the initial effluent water until the pH increase abates. However, improved water pH control options have been realized by altering the carbon surface through controlled oxidation rather than the water chemistry or extended preprocessing at the treatment site.

  10. Titratable acidity of beverages influences salivary pH recovery.

    PubMed

    Tenuta, Livia Maria Andaló; Fernández, Constanza Estefany; Brandão, Ana Carolina Siqueira; Cury, Jaime Aparecido

    2015-01-01

    A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control) were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively) and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively). Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH. PMID:25715032

  11. Women Ph.D.'s Careers lag men's

    NASA Astrophysics Data System (ADS)

    Numerous studies of male and female Ph.D.'s have found wide differences in academic rank and pay. Now a study by a National Research Council committee debunks the traditional reasons given to explain the disparity. This study, which analyzed matched triads of Ph.D.'s, concluded that neither the perceived greater restraints on the career mobility of women nor the greater likelihood that women will interrupt their careers for child rearing explains adequately the differences between male and female Ph.D.'s. Discrimination appears to be the most likely root.

  12. Method for producing rapid pH changes

    DOEpatents

    Clark, John H.; Campillo, Anthony J.; Shapiro, Stanley L.; Winn, Kenneth R.

    1981-01-01

    A method of initiating a rapid pH change in a solution by irradiating the solution with an intense flux of electromagnetic radiation of a frequency which produces a substantial pK change to a compound in solution. To optimize the resulting pH change, the compound being irradiated in solution should have an excited state lifetime substantially longer than the time required to establish an excited state acid-base equilibrium in the solution. Desired pH changes can be accomplished in nanoseconds or less by means of picosecond pulses of laser radiation.

  13. Method for producing rapid pH changes

    DOEpatents

    Clark, J.H.; Campillo, A.J.; Shapiro, S.L.; Winn, K.R.

    A method of initiating a rapid pH change in a solution comprises irradiating the solution with an intense flux of electromagnetic radiation of a frequency which produces a substantial pK change to a compound in solution. To optimize the resulting pH change, the compound being irradiated in solution should have an excited state lifetime substantially longer than the time required to establish an excited state acid-base equilibrium in the solution. Desired pH changes can be accomplished in nanoseconds or less by means of picosecond pulses of laser radiation.

  14. [Ultrasonic study of nucleic acids. Effect of pH].

    PubMed

    Braginskaia, F I; Sadykhova, S Kh

    1979-01-01

    The ultrasonic absorption of nucleic acids in water solutions was studied by the pulse ultrasonic technique depending on pH, at frequency 12 mHz T = 20 dedrees C. The obtained data show the occurrence of structural relaxation in DNA solutions caused by the proton exchange and transfer reactions with the extremal pH at 2.5 and 11.7. Possible mechanisms of the excess ultrasonic absorption were discussed concerning the protolytic processes with the charged DNA groups (N--P1 exchange and the hydrolysis of lactam groups at acid and alkaline pH correspondingly). PMID:36177

  15. A ph sensor based on a flexible substrate

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Ding

    pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on low-cost sol-gel fabrication process of iridium oxide (IrOx) sensing film (IROF). A pair of flexible miniature IrOx/AgCl electrode generated the action potential from the solution by electrochemical mechanism to obtain the pH level of the reagent. The fabrication process including sol-gel, thermal oxidation, and the electro-plating process of the silver chloride (AgCl) reference electrode were reported in the work. The IrOx film was verified and characterized using electron dispersive analysis (EDAX), scanning electron microscope (SEM), and x-ray diffraction (XRD). The flexible pH sensor's performance and characterization have been investigated with different testing parameters such as sensitivity, response time, stability, reversibility, repeatability, selectivity and temperature dependence. The flexible IrOx pH sensors exhibited promising sensing performance with a near-Nernstian response of sensitivity which is between --51.1mV/pH and --51.7mV/pH in different pH levels ranging from 1.5 to 12 at 25°C. Two applications including gastroesophageal reflux disease (GERD) diagnosis and food freshness wireless monitoring using our micro-flexible IrOx pH sensors were demonstrated. For the GERD diagnosing system, we embedded the micro flexible pH sensor on a 1.2cmx3.8cm of the capsule size of wireless sensor

  16. In vitro alkaline pH resistance of Enterococcus faecalis.

    PubMed

    Weckwerth, Paulo Henrique; Zapata, Ronald Ordinola; Vivan, Rodrigo Ricci; Tanomaru Filho, Mário; Maliza, Amanda Garcia Alves; Duarte, Marco Antonio Hungaro

    2013-01-01

    Enterococcus faecalis is a bacterial species often found in root canals with failed endodontic treatment. Alkaline pastes are widely used in Endodontics because of their biocompatibility and antimicrobial activity, but this microorganism can resist alkalinity. The purpose of this study was to evaluate in vitro the alkaline pH resistance of E. faecalis for different periods up to 14 days. Samples were obtained from the oral cavity of 150 patients from the Endodontic clinic. The pH of the experimental tubes (n=84) was first adjusted with 6M NaOH to pH values of 9.5, 10.5, 11.5 and 12.5 (21 tubes per pH). Twenty clinical isolates and the ATCC 29212 strain were tested. The 5 positive controls and experimental tubes of each pH were inoculated with 10 µL of bacterial suspension and incubated at 36 °C for 24, 48 and 72 h, 7 and 14 days. For each period, the turbidity of the medium was visually compared with a 0.5 McFarland standard. The presence of the microorganism was confirmed by seeding on M-Enterococcus agar. Four tubes containing BHI broth adjusted to the tested pHs were incubated for 14 days to verify if pH changes occurred. The pH of inoculated BHI broth was also measured on day 14 to determine if the microorganism acidified the medium. The growth of all E. faecalis strains occurred at pH 9.5 to 11.5 in all periods. Although turbidity was not observed at pH 12.5, there was growth of 13 and 2 strains at 24 and 48 h, respectively, on M-Enterococcus agar. No tube showed growth at pH 12.5 after 72 h. It was concluded that E. faecalis can survive in highly alkaline pH, and some clinical isolates require 72 h at pH 12.5 to be killed. PMID:24474287

  17. Label-Free Carbon-Dots-Based Ratiometric Fluorescence pH Nanoprobes for Intracellular pH Sensing.

    PubMed

    Shangguan, Jingfang; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Xu, Fengzhou; Liu, Jinquan; Tang, Jinlu; Yang, Xue; Huang, Jin

    2016-08-01

    Measuring pH in living cells is of great importance for better understanding cellular functions as well as providing pivotal assistance for early diagnosis of diseases. In this work, we report the first use of a novel kind of label-free carbon dots for intracellular ratiometric fluorescence pH sensing. By simple one-pot hydrothermal treatment of citric acid and basic fuchsin, the carbon dots showing dual emission bands at 475 and 545 nm under single-wavelength excitation were synthesized. It is demonstrated that the fluorescence intensities of the as-synthesized carbon dots at the two emissions are pH-sensitive simultaneously. The intensity ratio (I475 nm/I545 nm) is linear against pH values from 5.2 to 8.8 in buffer solution, affording the capability as ratiometric probes for intracellular pH sensing. It also displays that the carbon dots show excellent reversibility and photostability in pH measurements. With this nanoprobe, quantitative fluorescence imaging using the ratio of two emissions (I475 nm/I545 nm) for the detection of intracellular pH were successfully applied in HeLa cells. In contrast to most of the reported nanomaterials-based ratiometric pH sensors which rely on the attachment of additional dyes, these carbon-dots-based ratiometric probes are low in toxicity, easy to synthesize, and free from labels. PMID:27334762

  18. Ecological Agriculture Research: Increasing Competence through PhD Courses.

    ERIC Educational Resources Information Center

    Lieblein, G.; Francis, C. A.; Salomonsson, L.; Sriskandarajah, N.

    1999-01-01

    A Ph.D. course in ecological agriculture included a weeklong intensive workshop and individual research projects. The course demonstrated the usefulness of multiple approaches to learning research methods and perspectives and increased networking among researchers. (SK)

  19. Commentary: PhDs in Biochemistry Education--5 Years Later

    ERIC Educational Resources Information Center

    Offerdahl, Erika G.; Momsen, Jennifer L.; Osgood, Marcy

    2014-01-01

    In this commentary, the discussion of PhDs in biochemistry education research is expanded to explore a number of diverse pathways leading to a competitive research program in biochemistry education research.

  20. Ashley Felix, Ph.D., M.P.H.

    Cancer.gov

    NCI Cancer Prevention Fellowship Program (CPFP) alumna, Ashley Felix, Ph.D., M.P.H., details her transition from pre-med student to an epidemiologist who focuses on studying the causes and prevention of disease.

  1. The Training and Work of Ph.D. Physical Scientists

    NASA Astrophysics Data System (ADS)

    Smith, S. J.; Schweitzer, A. E.

    2003-05-01

    Doctoral education has often been viewed as the pinnacle of the formal education system. How useful is doctoral training in one's later career? In an NSF-funded project, we set out to perform a study of the training, careers, and work activities of Ph.D. physical scientists. The study included both in-depth interviews and a survey sent out to a sample of Ph.D. holders 4-8 years after graduation. Come and find out the results of this study: What skills are most Ph.D. physical scientists using? What should graduate programs be teaching? Are Ph.D.'s who are working in their specific field of training happier than their counterparts working different jobs? What skills and preparation lead to future job satisfaction, perhaps the most important indicator of the "success" of graduate education? A preprint and further details can be found at the project web site at: spot.colorado.edu/ phdcarer.

  2. Stress-Corrosion Cracking in Martensitic PH Stainless Steels

    NASA Technical Reports Server (NTRS)

    Humphries, T.; Nelson, E.

    1984-01-01

    Precipitation-hardening alloys evaluated in marine environment tests. Report describes marine-environment stress-corrosion cracking (SCC) tests of three martensitic precipitation hardening (PH) stainless-steel alloys.

  3. Goli Samimi, PhD, MPH | Division of Cancer Prevention

    Cancer.gov

    Dr. Samimi received her PhD in Biomedical Sciences from the University of California, San Diego, focusing on molecular mechanisms in ovarian cancer that conferred resistance to platinum-based chemotherapy. |

  4. The bimodal pH distribution of volcanic lake waters

    NASA Astrophysics Data System (ADS)

    Marini, Luigi; Vetuschi Zuccolini, Marino; Saldi, Giuseppe

    2003-02-01

    Volcanic lake waters have a bimodal pH distribution with an acidic mode at pH 0.5-1.5 and a near neutral mode at pH 6-6.5, with relatively few samples having pH 3.5-5. To investigate the reasons for this distribution, the irreversible water-rock mass exchanges during the neutralization of acid SO 4-Cl waters with andesite, under both low- and high-temperature conditions, were simulated by means of the EQ3/6 software package, version 7.2. Reaction path modeling under low temperature and atmospheric P CO 2 and f O 2, suggests that several homogeneous and/or heterogeneous pH buffers exist both in the acidic and neutral regions, but no buffer is active in the intermediate, central pH region. Again, the same titration, under high-temperature, hydrothermal-magmatic conditions, is expected to produce comparatively infrequent aqueous solutions with pH values in the 3.5-5 range, upon their cooling below 100°C. Substantially different pH values are obtained depending on the cooling paths, either through boiling or conductive heat losses. These distinct pH values are governed by either HSO 4- and HCl (aq), in poorly neutralized aqueous solutions, or the CO 2(aq)/HCO 3- couple and the P CO 2 value as well, in neutralized aqueous solutions. Finally, mixing of the acid lake water with the aqueous solutions produced through high-temperature titration and cooled below 100°C is unlikely to generate mixtures with pH values higher than 3, unless the fraction of the acidic water originally present in the lake becomes very small, which means its virtually complete substitution. Summing up, the evidence gathered through reaction path modeling of the neutralization of acid lake waters with andesite, both at low and high temperatures, explains the scarcity of volcanic lake waters with measured pH values of 3.5-5.

  5. MD-PhD training: looking back and looking forward.

    PubMed

    Bonham, Ann C

    2014-01-01

    MD-PhD programs provide rigorous, integrated training for physician-scientists, enabling them to frame scientific questions in unique ways and to apply clinical insight to fundamental science. Few would question the influential contributions of MD-PhD physician-scientists in advancing medical science. In this issue of Academic Medicine, Jeffe et al affirm high levels of excellence in educational outcomes from MD-PhD training programs at U.S. MD-granting medical schools, especially programs that receive funding from the NIH Medical Scientist Training Program (MSTP). The author of this commentary observes that, in the face of current economic pressures, comprehensive, longitudinal national outcomes data from MSTP- and non-MSTP-funded MD-PhD programs will help verify the value provided by MD-PhD physician-scientists. She proposes that MD-PhD programs should better prepare the next generation of physician-scientists for future research environments, which will provide new technologies, venues, and modalities. These research environments will be more closely integrated within health care delivery systems, extend into diverse communities and regions, and employ complex technologies. MD-PhD physician-scientists also will train and gain expertise in broadening areas of research, such as health policy, health economics, clinical epidemiology, and medical informatics. Program leaders are ideally situated to foster innovative learning environments and methodologies. By sharing their innovations, they can help ensure production of a diverse MD-PhD physician-scientist workforce, prepared to engage in myriad research opportunities to meet patient and population needs in a new environment. PMID:24280863

  6. Transport mechanism of a glutamate transporter homologue GltPh.

    PubMed

    Ji, Yurui; Postis, Vincent L G; Wang, Yingying; Bartlam, Mark; Goldman, Adrian

    2016-06-15

    Glutamate transporters are responsible for uptake of the neurotransmitter glutamate in mammalian central nervous systems. Their archaeal homologue GltPh, an aspartate transporter isolated from Pyrococcus horikoshii, has been the focus of extensive studies through crystallography, MD simulations and single-molecule FRET (smFRET). Here, we summarize the recent research progress on GltPh, in the hope of gaining some insights into the transport mechanism of this aspartate transporter. PMID:27284058

  7. Dysregulated pH in Tumor Microenvironment Checkmates Cancer Therapy

    PubMed Central

    Barar, Jaleh; Omidi, Yadollah

    2013-01-01

    Introduction: The dysregulation of pH by cancerous cells of solid tumors is able to create a unique milieu that is in favor of progression, invasion and metastasis as well as chemo-/immuno-resistance traits of solid tumors. Bioelements involved in pH dysregulation provide new set of oncotargets, inhibition of which may result in better clinical outcome. Methods: To study the impacts of pH dysregulation, we investigated the tumor development and progression in relation with Warburg effect, glycolysis and formation of aberrant tumor microenvironment. Results: The upregulation of glucose transporter GLUT-1 and several enzymes involve in glycolysis exacerbates this phenomenon. The accumulation of lactic acids in cancer cells provokes upregulation of several transport machineries (MCT-1, NHE-1, CA IX and H+ pump V-ATPase) resulting in reinforced efflux of proton into extracellular fluid. This deviant event makes pH to be settled at 7.4 and 6.6 respectively in cancer cells cytoplasm and extracellular fluid within the tumor microenvironment, which in return triggers secretion of lysosomal components (various enzymes in acidic milieu with pH 5) into cytoplasm. All these anomalous phenomena make tumor microenvironment (TME) to be exposed to cocktail of various enzymes with acidic pH, upon which extracellular matrix (ECM) can be remodeled and even deformed, resulting in emergence of a complex viscose TME with high interstitial fluid pressure. Conclusion: It seems that pH dysregulation is able to remodel various physiologic functions and make solid tumors to become much more invasive and metastatic. It also can cause undesired resistance to chemotherapy and immunotherapy. Hence, cancer therapy needs to be reinforced using specific inhibitors of bioelements involved in pH dysregulation of TME in solid tumors. PMID:24455478

  8. Teaching Human Digestion and pH Using Technology

    ERIC Educational Resources Information Center

    Kim, Hanna

    2008-01-01

    Testing the pH of various liquids is one of the most popular activities in 5th- through 8th-grade classrooms. The author presents an extensive pH-testing lesson based on a 5E (engagement, exploration, explanation, extension, and evaluation) teaching model. The activity provides students with the opportunity to learn about pH and how it relates to…

  9. Transport mechanism of a glutamate transporter homologue GltPh

    PubMed Central

    Ji, Yurui; Postis, Vincent L.G.; Wang, Yingying; Bartlam, Mark; Goldman, Adrian

    2016-01-01

    Glutamate transporters are responsible for uptake of the neurotransmitter glutamate in mammalian central nervous systems. Their archaeal homologue GltPh, an aspartate transporter isolated from Pyrococcus horikoshii, has been the focus of extensive studies through crystallography, MD simulations and single-molecule FRET (smFRET). Here, we summarize the recent research progress on GltPh, in the hope of gaining some insights into the transport mechanism of this aspartate transporter. PMID:27284058

  10. Glucosylceramide modulates endolysosomal pH in Gaucher disease.

    PubMed

    Sillence, Dan J

    2013-06-01

    GlcCer accumulation causes Gaucher disease where GlcCer breakdown is inhibited due to a hereditary deficiency in glucocerebrosidase. Glycolipids are endocytosed and targeted to the Golgi apparatus in normal cells but in Gaucher disease they are mistargeted to lysosomes. To better understand the role of GlcCer in endocytic sorting RAW macrophages were treated with Conduritol B-epoxide to inhibit GlcCer breakdown. Lipid analysis found increases in GlcCer led to accumulation of both triacylglycerol and cholesterol consistent with increased lysosomal pH. Ratio imaging of macrophages using both acridine orange and lysosensor yellow/blue to measure endolysosomal pH revealed increases in Conduritol B-epoxide treated RAW macrophages and Gaucher patient lymphoblasts. Increased endolysosomal pH was restricted to Gaucher lymphoblasts as no significant increases in pH were seen in Fabry, Krabbe, Tay-Sachs and GM1-gangliosidosis lymphoblasts. Substrate reduction therapy utilises inhibitors of GlcCer synthase to reduce storage in Gaucher disease. The addition of inhibitors of GlcCer synthesis to RAW macrophages also led to increases in cholesterol and triacylglycerol and an endolysosomal pH increase of up to 1 pH unit. GlcCer modulation appears specific since glucosylsphingosine but not galactosylsphingosine reversed the effects of GlcCer depletion. Although no acute effects on glycolipid trafficking were observed using bafilomycin A the results are consistent with a multistep model whereby increases in pH lead to altered trafficking via cholesterol accumulation. GlcCer modulates endolysosomal pH in lymphocytes suggesting an important role in normal lysosomes which may be disrupted in Gaucher disease. PMID:23628459

  11. Mouthguard and sports drinks on tooth surface pH.

    PubMed

    Maeda, Y; Yang, T-C; Miyanaga, H; Tanaka, Y; Ikebe, K; Akimoto, N

    2014-09-01

    The influence of sports drinks and mouthguards on the pH level of tooth surface was examined. A custom-made mouthguard was fabricated for each subject. The pH level was measured by electric pH meter with sensitivity of 0.01 up to 30 min. Sports drinks (pH=3.75) containing 9.4% sugar were used in this study. Measurements were performed on a cohort of 23 female subjects without a mouthguard (control), wearing a mouthguard only (MG), wearing a mouthguard after 30 ml sports drink intake (SD+MG), wearing a mouthguard during a 5-min jogging exercise (MG+EX) and wearing a mouthguard during jogging after sports drink intake (SD+MG+EX). For 7 male subjects, the same measurements were performed while a sports drink was taken over the mouthguard (MG+SD, MD+EX+SD). MG showed statistically higher pH level than control (p<0.05). SD+MG exhibited a significant decrease in pH level, and SD+MG+EX exhibited even below the critical level of pH 5.5 in some subjects. When sports drinks were taken over the mouthguard, no significant differences in pH level were observed among the different conditions.Within the limitations of this study, it was suggested that wearing a mouthguard during exercise is in itself not a possible risk factor for dental caries, while wearing a mouthguard after consuming sports drinks is. PMID:24604353

  12. Automated high precision secondary pH measurements

    NASA Astrophysics Data System (ADS)

    Bastkowski, F.; Jakobsen, P. T.; Stefan, F.; Kristensen, H. B.; Jensen, H. D.; Kawiecki, R.; Wied, C. E.; Kauert, A.; Seidl, B.; Spitzer, P.; Eberhardt, R.; Adel, B.

    2013-04-01

    A new setup for high precision, automated secondary pH measurements together with a reference measurement procedure has been developed and tested in interlaboratory comparisons using buffers pH 4.005, pH 7.000, and pH 10.012 at 25 °C and 37 °C. Using primary buffers as standards, a standard uncertainty in pH better than 0.005 can be reached. The central measuring device is a one piece, thermostatted cell of PFA (perfluoroalkoxy) with a built-in Hamilton® Single Pore™ Glass electrode. Due to its flow-through principle this device allows pH measurements with low consumption of measurement solutions. The very hydrophobic and smooth PFA as construction material facilitates complete emptying of the cell. Furthermore, the tempering unit affords very precise temperature control and hence contributes to the low target uncertainty of the produced secondary buffer solutions. Use of a symmetric measurement sequence and the two point calibration was sufficient to reach high precision and accuracy.

  13. Monitoring pH and ORP in a SHARON reactor.

    PubMed

    Claros, J; Serralta, J; Seco, A; Ferrer, J; Aguado, D

    2011-01-01

    This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been achieved by adding methanol at the beginning of anoxic stages. Time evolution of pH and ORP along each cycle allows identifying the decrease in nitritation rate when ammonia is consumed during the aerobic phase and the end of the denitrification process during the anoxic phase. Therefore, monitoring pH and ORP can be used to develop a real-time control system aimed at optimizing the length of both aerobic and anoxic stages. Real-time control of methanol addition can be carried out by using the information provided by these probes: excessive methanol addition in the anoxic stage is clearly detected in the ORP profile of the following aerobic phase, while a deficit of methanol is detected in both pH and ORP profiles of that anoxic phase. Moreover, other valuable information such as the amount of ammonia nitrified, failures in DO measurements, excessive stirring during the anoxic stage and methanol dosage in the aerobic phase was also provided by the pH and ORP profiles. PMID:22049741

  14. pH sensing by intracellular Salmonella induces effector translocation.

    PubMed

    Yu, Xiu-Jun; McGourty, Kieran; Liu, Mei; Unsworth, Kate E; Holden, David W

    2010-05-21

    Salmonella enterica is an important intracellular bacterial pathogen of humans and animals. It replicates within host-cell vacuoles by delivering virulence (effector) proteins through a vacuolar membrane pore made by the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (T3SS). T3SS assembly follows vacuole acidification, but when bacteria are grown at low pH, effector secretion is negligible. We found that effector secretion was activated at low pH from mutant strains lacking a complex of SPI-2-encoded proteins SsaM, SpiC, and SsaL. Exposure of wild-type bacteria to pH 7.2 after growth at pH 5.0 caused dissociation and degradation of SsaM/SpiC/SsaL complexes and effector secretion. In infected cells, loss of the pH 7.2 signal through acidification of host-cell cytosol prevented complex degradation and effector translocation. Thus, intravacuolar Salmonella senses host cytosolic pH, resulting in the degradation of regulatory complex proteins and effector translocation. PMID:20395475

  15. Economical wireless optical ratiometric pH sensor

    NASA Astrophysics Data System (ADS)

    Vuppu, Sandeep; Kostov, Yordan; Rao, Govind

    2009-04-01

    The development and application of a portable, wireless fluorescence-based optical pH sensor is presented. The design incorporates the MSP430 microcontroller as the control unit, an RF transceiver for wireless communication, digital filters and amplifiers and a USB-based communication module for data transmission. The pH sensor is based on ratiometric fluorescence detection from pH sensitive dye incorporated in a peel-and-stick patch. The ability of the instrument to detect the pH of the solution with contact only between the sensor patch and the solution makes it partially non-invasive. The instrument also has the ability to transmit data wirelessly, enabling its use in processes that entail stringent temperature control and sterility. The use of the microcontroller makes it a reliable, low-cost and low-power device. The luminous intensity of the light source can be digitally controlled to maximize the sensitivity of the instrument. It has a resolution of 0.05 pH. The sensor is accurate and reversible over the pH range of 6.5-9.

  16. The potentiometric titration of fluoride using pH electrodes

    SciTech Connect

    Selig, W.S.

    1987-07-01

    Sodium fluoride solutions with an initial pH of 4.46 yielded poorly defined endpoint breaks with a pH electrode system and Ce(III) or La(III) as titrants. At this initial pH, however, the fluoride ISE yielded acceptable S-shaped titration curves. At an initial pH of 6.30, both electrode systems and titrant combinations yielded acceptable endpoint breaks and titration curves. While a partially nonaqueous medium (50% methanol) enhanced the steepness of the endpoint breaks, the standard deviation also increased. This was possibly caused by evaporation of some of the solvent. We therefore do not see the necessity for, nor recommend a partially nonaqueous medium. There is no advantage in using Ce(III) rather than La(III) as titrant. Increasing the initial pH from 4.46 to 6.3 decreased the mean normality of the titrant (or increased the titration volume) for both electrode systems and titrants. We therefore recommend that the sodium fluoride standard solutions be adjusted to the same pH as the samples to be determined. For the most accurate results, the standardization should be done with a good approximation of the salt content of the unknown solution.

  17. Structure of human saposin A at lysosomal pH

    SciTech Connect

    Hill, Chris H.; Read, Randy J.; Deane, Janet E.

    2015-06-27

    A 1.8 Å resolution structure of the sphingolipid activator protein saposin A has been determined at pH 4.8, the physiologically relevant lysosomal pH for hydrolase enzyme activation and lipid-transfer activity. The saposins are essential cofactors for the normal lysosomal degradation of complex glycosphingolipids by acid hydrolase enzymes; defects in either saposin or hydrolase function lead to severe metabolic diseases. Saposin A (SapA) activates the enzyme β-galactocerebrosidase (GALC), which catalyzes the breakdown of β-d-galactocerebroside, the principal lipid component of myelin. SapA is known to bind lipids and detergents in a pH-dependent manner; this is accompanied by a striking transition from a ‘closed’ to an ‘open’ conformation. However, previous structures were determined at non-lysosomal pH. This work describes a 1.8 Å resolution X-ray crystal structure determined at the physiologically relevant lysosomal pH 4.8. In the absence of lipid or detergent at pH 4.8, SapA is observeed to adopt a conformation closely resembling the previously determined ‘closed’ conformation, showing that pH alone is not sufficient for the transition to the ‘open’ conformation. Structural alignments reveal small conformational changes, highlighting regions of flexibility.

  18. Comparing Metal Leaching and Toxicity from High pH, Low pH, and High Ammonia Fly Ash

    SciTech Connect

    Palumbo, Anthony Vito; Phillips, Jana Randolph; Fagan, Lisa Anne; Drake, Meghan M; Ruther, Rose Emily; Fisher, L. Suzanne; Amonette, J. E.

    2007-01-01

    Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7-12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.

  19. Comparing metal leaching and toxicity from high pH, low pH, and high ammonia fly ash

    SciTech Connect

    Palumbo, Anthony V.; Tarver, Jana R.; Fagan, Lisa A.; McNeilly, Meghan S.; Ruther, Rose; Fisher, L. S.; Amonette, James E.

    2007-07-01

    Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7–12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox* system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.

  20. Characterisation and deployment of an immobilised pH sensor spot towards surface ocean pH measurements.

    PubMed

    Clarke, Jennifer S; Achterberg, Eric P; Rérolle, Victoire M C; Abi Kaed Bey, Samer; Floquet, Cedric F A; Mowlem, Matthew C

    2015-10-15

    The oceans are a major sink for anthropogenic atmospheric carbon dioxide, and the uptake causes changes to the marine carbonate system and has wide ranging effects on flora and fauna. It is crucial to develop analytical systems that allow us to follow the increase in oceanic pCO2 and corresponding reduction in pH. Miniaturised sensor systems using immobilised fluorescence indicator spots are attractive for this purpose because of their simple design and low power requirements. The technology is increasingly used for oceanic dissolved oxygen measurements. We present a detailed method on the use of immobilised fluorescence indicator spots to determine pH in ocean waters across the pH range 7.6-8.2. We characterised temperature (-0.046 pH/°C from 5 to 25 °C) and salinity dependences (-0.01 pH/psu over 5-35), and performed a preliminary investigation into the influence of chlorophyll on the pH measurement. The apparent pKa of the sensor spots was 6.93 at 20 °C. A drift of 0.00014 R (ca. 0.0004 pH, at 25 °C, salinity 35) was observed over a 3 day period in a laboratory based drift experiment. We achieved a precision of 0.0074 pH units, and observed a drift of 0.06 pH units during a test deployment of 5 week duration in the Southern Ocean as an underway surface ocean sensor, which was corrected for using certified reference materials. The temperature and salinity dependences were accounted for with the algorithm, R=0.00034-0.17·pH+0.15·S(2)+0.0067·T-0.0084·S·1.075. This study provides a first step towards a pH optode system suitable for autonomous deployment. The use of a short duration low power illumination (LED current 0.2 mA, 5 μs illumination time) improved the lifetime and precision of the spot. Further improvements to the pH indicator spot operations include regular application of certified reference materials for drift correction and cross-calibration against a spectrophotometric pH system. Desirable future developments should involve novel

  1. Local pH tracking in living cells

    NASA Astrophysics Data System (ADS)

    Tsou, Chieh-Jui; Hsia, Chih-Hao; Chu, Jia-Yin; Hung, Yann; Chen, Yi-Ping; Chien, Fan-Ching; Chou, Keng C.; Chen, Peilin; Mou, Chung-Yuan

    2015-02-01

    Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ~10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which provides much needed information for designing an efficient drug delivery nanosystem.Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ~10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which

  2. Effect of systemic pH on pH sub i and lactic acid generation in exhaustive forearm exercise

    SciTech Connect

    Hood, V.L.; Schubert, C.; Keller, U.; Mueller, S. Univ. of Vermont College of Medicine, Burlington )

    1988-09-01

    To investigate whether changes in systemic pH affect intracellular pH (pH{sub i}), energy-rich phosphates, and lactic acid generation in muscle, eight normal volunteers performed exhaustive forearm exercise with arterial blood flow occluded for 2 min on three occasions. Subjects ingested 4 mmol/kg NH{sub 4}Cl (acidosis; A) or NaHCO{sub 3} (alkalosis; B) or nothing (control; C) 3 h before the exercise. Muscle pH{sub i} and phosphocreatine (PCr) content were measured with {sup 31}P-nuclear magnetic resonance ({sup 31}P-NMR) spectroscopy during exercise and recovery. Lactate output during 0.5-7 min of recovery was calculated as deep venous-arterial concentration differences times forearm blood flow. Before exercise, blood pH and bicarbonate were lower in acidosis than alkalosis and intermediate in control. Lactic acid output during recovery was less with A than B and intermediate in C. PCr utilization and resynthesis were not affected by extracellular pH changes. pH{sub i} did not differ before exercise or at its end. Hence systemic acidosis inhibited and alkalosis stimulated lactic acid output. These findings suggest that systemic pH regulates cellular acid production, protecting muscle pH, at the expense of energy availability.

  3. Fluorescent pH Sensors for Broad-Range pH Measurement Based on a Single Fluorophore.

    PubMed

    Qi, Jing; Liu, Daying; Liu, Xiaoyan; Guan, Shiquan; Shi, Fengli; Chang, Hexi; He, Huarui; Yang, Guangming

    2015-06-16

    We constructed a series of novel optical sensors for determination of broad-range pH based on a single fluorophore and multi-ionophores with different pK(a) values. These optical sensors use photoinduced electron transfer (PET) as the signal transduction and follow the design concept of "fluorophore-spacer-receptor (ionophore)" which employs 4-amino-1,8-naphthalimide as the single fluorophore, ethyl moiety as the spacer, and a series of phenols and anilines as the receptors. Key to the successful development of this sensor system is that coupling the receptors with six different pK(a) values with a single fluorophore produces the correct optical properties. This rational design affords a series of optical pH sensors with unique fluorescence property and accurately tunable pH measurement ranging from 1 to 14 pH units. Because of covalent immobilization of the indicators, these sensors demonstrate excellent stability, adequate reversibility, and satisfactory dynamic range up to full pH ranges (pH 1-14). PMID:25893705

  4. A survey of beef muscle color and pH.

    PubMed

    Page, J K; Wulf, D M; Schwotzer, T R

    2001-03-01

    The objectives of this study were to define a beef carcass population in terms of muscle color, ultimate pH, and electrical impedance; to determine the relationships among color, pH, and impedance and with other carcasses characteristics; and to determine the effect of packing plant, breed type, and sex class on these variables. One thousand beef carcasses were selected at three packing plants to match the breed type, sex class, marbling score, dark-cutting discount, overall maturity, carcass weight, and yield grade distributions reported for the U.S. beef carcass population by the 1995 National Beef Quality Audit. Data collected on these carcasses included USDA quality and yield grade data and measurements of muscle color (L*, a*, b*), muscle pH, and electrical impedance of the longissimus muscle. About one-half (53.1%) of the carcasses fell within a muscle pH range of 5.40 to 5.49, and 81.3% of the carcasses fell within a longissimus muscle pH range of 5.40 to 5.59. A longissimus muscle pH of 5.87 was the approximate cut-off between normal and dark-cutting carcasses. Frequency distributions indicated that L* values were normally distributed, whereas a* and b* values were abnormally distributed (skewed because of a longer tail for lower values, a tail corresponding with dark-cutting carcasses). Electrical impedance was highly variable among carcasses but was not highly related to any other variable measured. Color measurements (L*, a*, b*) were correlated (P < 0.05) with lean maturity score (-.58, -.31, and -.43, respectively) and with muscle pH (-.40, -.58, and -.56, respectively). In addition, fat thickness was correlated with muscle pH and color (P < 0.05). There was a threshold at approximately .76 cm fat thickness, below which carcasses had higher muscle pH values and lower colorimeter readings. Steer carcasses (L* = 39.62, a* = 25.20, and b* = 11.03) had slightly higher colorimeter readings (P < 0.05) than heifer carcasses (L* = 39.20, a* = 24.78, and b

  5. Measuring Phagosome pH by Ratiometric Fluorescence Microscopy.

    PubMed

    Nunes, Paula; Guido, Daniele; Demaurex, Nicolas

    2015-01-01

    Phagocytosis is a fundamental process through which innate immune cells engulf bacteria, apoptotic cells or other foreign particles in order to kill or neutralize the ingested material, or to present it as antigens and initiate adaptive immune responses. The pH of phagosomes is a critical parameter regulating fission or fusion with endomembranes and activation of proteolytic enzymes, events that allow the phagocytic vacuole to mature into a degradative organelle. In addition, translocation of H(+) is required for the production of high levels of reactive oxygen species (ROS), which are essential for efficient killing and signaling to other host tissues. Many intracellular pathogens subvert phagocytic killing by limiting phagosomal acidification, highlighting the importance of pH in phagosome biology. Here we describe a ratiometric method for measuring phagosomal pH in neutrophils using fluorescein isothiocyanate (FITC)-labeled zymosan as phagocytic targets, and live-cell imaging. The assay is based on the fluorescence properties of FITC, which is quenched by acidic pH when excited at 490 nm but not when excited at 440 nm, allowing quantification of a pH-dependent ratio, rather than absolute fluorescence, of a single dye. A detailed protocol for performing in situ dye calibration and conversion of ratio to real pH values is also provided. Single-dye ratiometric methods are generally considered superior to single wavelength or dual-dye pseudo-ratiometric protocols, as they are less sensitive to perturbations such as bleaching, focus changes, laser variations, and uneven labeling, which distort the measured signal. This method can be easily modified to measure pH in other phagocytic cell types, and zymosan can be replaced by any other amine-containing particle, from inert beads to living microorganisms. Finally, this method can be adapted to make use of other fluorescent probes sensitive to different pH ranges or other phagosomal activities, making it a generalized

  6. PH5 for integrating and archiving different data types

    NASA Astrophysics Data System (ADS)

    Azevedo, Steve; Hess, Derick; Beaudoin, Bruce

    2016-04-01

    PH5 is IRIS PASSCAL's file organization of HDF5 used for seismic data. The extensibility and portability of HDF5 allows the PH5 format to evolve and operate on a variety of platforms and interfaces. To make PH5 even more flexible, the seismic metadata is separated from the time series data in order to achieve gains in performance as well as ease of use and to simplify user interaction. This separation affords easy updates to metadata after the data are archived without having to access waveform data. To date, PH5 is currently used for integrating and archiving active source, passive source, and onshore-offshore seismic data sets with the IRIS Data Management Center (DMC). Active development to make PH5 fully compatible with FDSN web services and deliver StationXML is near completion. We are also exploring the feasibility of utilizing QuakeML for active seismic source representation. The PH5 software suite, PIC KITCHEN, comprises in-field tools that include data ingestion (e.g. RefTek format, SEG-Y, and SEG-D), meta-data management tools including QC, and a waveform review tool. These tools enable building archive ready data in-field during active source experiments greatly decreasing the time to produce research ready data sets. Once archived, our online request page generates a unique web form and pre-populates much of it based on the metadata provided to it from the PH5 file. The data requester then can intuitively select the extraction parameters as well as data subsets they wish to receive (current output formats include SEG-Y, SAC, mseed). The web interface then passes this on to the PH5 processing tools to generate the requested seismic data, and e-mail the requester a link to the data set automatically as soon as the data are ready. PH5 file organization was originally designed to hold seismic time series data and meta-data from controlled source experiments using RefTek data loggers. The flexibility of HDF5 has enabled us to extend the use of PH5 in several

  7. Noninvasive Ph-telemetric Measurement of Gastrointestinal Function

    NASA Technical Reports Server (NTRS)

    Tietze, Karen J.

    1991-01-01

    The purpose of this study was to gain experience with and validate the Heidelberg pH-telemetric methodology in order to determine if the pH-telemetric methodology would be a useful noninvasive measure of gastrointestinal transit time for future ground-based and in-flight drug evaluation studies. The Heidelberg pH metering system is a noninvasive, nonradioactive telemetric system that, following oral ingestion, continuously measures intraluminal pH of the stomach, duodenum, small bowel, ileocecal junction, and large bowel. Gastrointestinal motility profiles were obtained in normal volunteers using the lactulose breath-hydrogen and Heidelberg pH metering techniques. All profiles were obtained in the morning after an overnight fast. Heidelberg pH profiles were obtained in the fasting and fed states; lactulose breath-hydrogen profiles were obtained after a standard breakfast. Mouth-to-cecum transit time was measured as the interval from administration of lactulose (30 ml; 20 g) to a sustained increase in breath-hydrogen of 10 ppm or more. Gastric emptying time was measured as the interval from the administration of the Heidelberg capsule to a sustained increase in pH of three units or more.

  8. pH responsive graft copolymers of chitosan.

    PubMed

    Yilmaz, Elvan; Yalinca, Zulal; Yahya, Kovan; Sirotina, Uliana

    2016-09-01

    Grafting suitable polymers onto chitosan can produce cationic or polyampholyte polymers or hydrogels that are potential smart biomedical materials. Chitosan-graft-[poly(diethylamino)ethyl methacrylate] has been prepared in three different physical forms as linear free chains in solution, chemical gels crosslinked with glutaraldehyde, and poly(diethylamino)ethyl methacrylate] grafted onto chitosan tripolyphosphate gel beads. In addition to chemical structure, the graft copolymers were characterized with respect to their dissolution and swelling behavior in aqueous solution. It has been established that solubility of the products is controlled by the grafting yield. While pH sensitive polymers, which collapse at a given pH value are obtained at lower grafting yields, hydrogels form at higher grafting yields with pH responsive swelling behavior. Glutaraldehyde crosslinked chitosan-graft-[poly(diethylamino)ethyl methacrylate] gels and chitosan tripolyphosphate gel beads grafted with poly[(diethylamino)ethyl methacrylate] exhibit pH sensitive swelling with highest equilibrium swelling capacity at pH=1.2. PMID:26500176

  9. The Production Rate and Employment of Ph.D. Astronomers

    NASA Astrophysics Data System (ADS)

    Metcalfe, Travis S.

    2008-02-01

    In an effort to encourage self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astronomy and astrophysics. The average new astronomer might expect to hold up to 3 jobs before finding a steady position.

  10. Near-infrared noninvasive spectroscopic determination of pH

    DOEpatents

    Alam, Mary K.; Robinson, Mark R.

    1998-08-11

    Methods and apparatus for, preferably, determining noninvasively and in vitro pH in a human. The non-invasive method includes the steps of: generating light at three or more different wavelengths in the range of 1000 nm to 2500 nm; irradiating blood containing tissue; measuring the intensities of the wavelengths emerging from the blood containing tissue to obtain a set of at least three spectral intensities v. wavelengths; and determining the unknown values of pH. The determination of pH is made by using measured intensities at wavelengths that exhibit change in absorbance due to histidine titration. Histidine absorbance changes are due to titration by hydrogen ions. The determination of the unknown pH values is performed by at least one multivariate algorithm using two or more variables and at least one calibration model. The determined pH values are within the physiological ranges observed in blood containing tissue. The apparatus includes a tissue positioning device, a source, at least one detector, electronics, a microprocessor, memory, and apparatus for indicating the determined values.

  11. The Role of Ph Fronts in Tissue Electroporation Based Treatments

    PubMed Central

    Maglietti, Felipe; Michinski, Sebastian; Olaiz, Nahuel; Castro, Marcelo; Suárez, Cecilia; Marshall, Guillermo

    2013-01-01

    Treatments based on electroporation (EP) induce the formation of pores in cell membranes due to the application of pulsed electric fields. We present experimental evidence of the existence of pH fronts emerging from both electrodes during treatments based on tissue EP, for conditions found in many studies, and that these fronts are immediate and substantial. pH fronts are indirectly measured through the evanescence time (ET), defined as the time required for the tissue buffer to neutralize them. The ET was measured through a pH indicator imaged at a series of time intervals using a four-cluster hard fuzzy-c-means algorithm to segment pixels corresponding to the pH indicator at every frame. The ET was calculated as the time during which the number of pixels was 10% of those in the initial frame. While in EP-based treatments such as reversible (ECT) and irreversible electroporation (IRE) the ET is very short (though enough to cause minor injuries) due to electric pulse characteristics and biological buffers present in the tissue, in gene electrotransfer (GET), ET is much longer, enough to denaturate plasmids and produce cell damage. When any of the electric pulse parameters is doubled or tripled the ET grows and, remarkably, when any of the pulse parameters in GET is halved, the ET drops significantly. Reducing pH fronts has relevant implications for GET treatment efficiency, due to a substantial reduction of plasmid damage and cell loss. PMID:24278257

  12. Computational Analysis of the Binding Specificities of PH Domains

    PubMed Central

    Jiang, Zhi; Liang, Zhongjie; Shen, Bairong; Hu, Guang

    2015-01-01

    Pleckstrin homology (PH) domains share low sequence identities but extremely conserved structures. They have been found in many proteins for cellular signal-dependent membrane targeting by binding inositol phosphates to perform different physiological functions. In order to understand the sequence-structure relationship and binding specificities of PH domains, quantum mechanical (QM) calculations and sequence-based combined with structure-based binding analysis were employed in our research. In the structural aspect, the binding specificities were shown to correlate with the hydropathy characteristics of PH domains and electrostatic properties of the bound inositol phosphates. By comparing these structure properties with sequence-based profiles of physicochemical properties, PH domains can be classified into four functional subgroups according to their binding specificities and affinities to inositol phosphates. The method not only provides a simple and practical paradigm to predict binding specificities for functional genomic research but also gives new insight into the understanding of the basis of diseases with respect to PH domain structures. PMID:26881206

  13. pH regulation of an egg cortex tyrosine kinase.

    PubMed

    Jiang, W P; Veno, P A; Wood, R W; Peaucellier, G; Kinsey, W H

    1991-07-01

    Fertilization of the echinoderm egg is known to result in the phosphorylation, on tyrosine, of a high-molecular-weight cortical protein (HMWCP) localized in the egg cortex. Studies using various parthenogenic agents indicate that this phosphorylation event occurs in response to the alkaline shift in cytoplasmic pHi which normally occurs 1 to 2 min after fertilization. In the present study, the purified egg cell surface complex was used as in vitro system to determine whether a small alkaline shift in pH, such as occurs upon fertilization, could stimulate the activity of the egg cortex-associated tyrosine kinase toward endogenous protein substrates. The results demonstrated that the cell surface complex is highly enriched in a tyrosine kinase activity which accounts for the majority of the protein kinase activity in this preparation. The activity of this tyrosine kinase toward the HMWCP and other cortical proteins was highly dependent on pH over the range pH 6.8 to 7.3. This indicates that the fertilization-associated change in cytoplasmic pH would be sufficient to trigger increased tyrosine phosphorylation of the high-molecular-weight cortical protein in vivo. The regulation of tyrosine phosphorylation by small changes in pH represents a novel control mechanism in which a tyrosine protein kinase may act as a pH-sensitive transducer. PMID:2060713

  14. Interfacial pH during mussel adhesive plaque formation.

    PubMed

    Martinez Rodriguez, Nadine R; Das, Saurabh; Kaufman, Yair; Israelachvili, Jacob N; Waite, J Herbert

    2015-01-01

    Mussel (Mytilus californianus) adhesion to marine surfaces involves an intricate and adaptive synergy of molecules and spatio-temporal processes. Although the molecules, such as mussel foot proteins (mfps), are well characterized, deposition details remain vague and speculative. Developing methods for the precise surveillance of conditions that apply during mfp deposition would aid both in understanding mussel adhesion and translating this adhesion into useful technologies. To probe the interfacial pH at which mussels buffer the local environment during mfp deposition, a lipid bilayer with tethered pH-sensitive fluorochromes was assembled on mica. The interfacial pH during foot contact with modified mica ranged from 2.2 to 3.3, which is well below the seawater pH of ~ 8. The acidic pH serves multiple functions: it limits mfp-Dopa oxidation, thereby enabling the catecholic functionalities to adsorb to surface oxides by H-bonding and metal ion coordination, and provides a solubility switch for mfps, most of which aggregate at pH ≥ 7-8. PMID:25875963

  15. Iron respiration by Acidiphilium cryptum at pH 5.

    PubMed

    Bilgin, Azize Azra; Silverstein, JoAnn; Jenkins, Joy D

    2004-07-01

    The growth of acidophilic iron respiring bacteria at pH > 4.5 may be a key to the transition from acidic to circumneutral conditions that would occur during restoration of acid mine drainage sites. Flasks containing Acidiphilium cryptum ATCC 33463 were incubated initially under aerobic conditions in liquid medium containing Fe(2)(SO(4))(3) and glucose at an initial pH of 5. Significant iron respiration was observed after flasks were sealed to prevent oxygenation; at the same time, medium pH increased from 4.5 to 6. No soluble Fe(III) was detected throughout the experiments, consistent with pH conditions, indicating that bacteria were able to respire using precipitated ferric iron species. In addition, the concentration of soluble Fe(2+) reached a plateau, even though iron respiration appeared to continue, possibly due to precipitation of mixed Fe (II)/Fe(III)-oxide as magnetite. Results suggest that A. cryptum has a wide range of pH tolerance, which may enable it to play a role in controlling acid generation by means of establishing growth conditions favorable to neutrophilic bacteria such as sulfate reduction. PMID:19712391

  16. Interfacial pH during mussel adhesive plaque formation

    PubMed Central

    Rodriguez, Nadine R. Martinez; Das, Saurabh; Kaufman, Yair; Israelachvili, Jacob N.; Waite, J. Herbert

    2015-01-01

    Mussel (Mytilus californianus) adhesion to marine surfaces involves an intricate and adaptive synergy of molecules and spatio-temporal processes. Although the molecules, such as mussel foot proteins (mfps), are well characterized, deposition details remain vague and speculative. Developing methods for the precise surveillance of conditions that apply during mfp deposition would aid both in understanding mussel adhesion and translating this adhesion into useful technologies. To probe the interfacial pH at which mussels buffer the local environment during mfp deposition, a lipid bilayer with tethered pH-sensitive fluorochromes was assembled on mica. The interfacial pH during foot contact with modified mica ranged from 2.2−3.3, which is well below the seawater pH of ~8. The acidic pH serves multiple functions: it limits mfp-Dopa oxidation, thereby enabling the catecholic functionalities to adsorb to surface oxides by H-bonding and metal ion coordination, and provides a solubility switch for mfps, most of which aggregate at pH ≥ 7-8. PMID:25875963

  17. Local pH tracking in living cells.

    PubMed

    Tsou, Chieh-Jui; Hsia, Chih-Hao; Chu, Jia-Yin; Hung, Yann; Chen, Yi-Ping; Chien, Fan-Ching; Chou, Keng C; Chen, Peilin; Mou, Chung-Yuan

    2015-03-01

    Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ∼10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which provides much needed information for designing an efficient drug delivery nanosystem. PMID:25672786

  18. Intracellular pH and the Control of Multidrug Resistance

    NASA Astrophysics Data System (ADS)

    Simon, Sanford; Roy, Deborshi; Schindler, Melvin

    1994-02-01

    Many anticancer drugs are classified as either weak bases or molecules whose binding to cellular structures is pH dependent. Accumulation of these drugs within tumor cells should be affected by transmembrane pH gradients. Indeed, development of multidrug resistance (MDR) in tumor cells has been correlated with an alkaline shift of cytosolic pH. To examine the role of pH in drug partitioning, the distribution of two drugs, doxorubicin and daunomycin, was monitored in fibroblasts and myeloma cells. In both cell types the drugs rapidly accumulated within the cells. The highest concentrations were measured in the most acidic compartments-e.g., lysosomes. Modifying the cellular pH in drug-sensitive cells to mimic reported shifts in MDR caused an immediate change in the cellular drug concentration. Drug accumulation was enhanced by acidic shifts and reversed by alkaline shifts. All of these effects were rapid and reversible. These results demonstrate that the alkaline shift observed in MDR is sufficient to prevent the accumulation of chemotherapeutic drugs independent of active drug efflux.

  19. PhIN: A Protein Pharmacology Interaction Network Database

    PubMed Central

    Wang, Z; Li, J; Dang, R; Liang, L; Lin, J

    2015-01-01

    Network pharmacology is a new and hot concept in drug discovery for its ability to investigate the complexity of polypharmacology, and becomes more and more important in drug development. Here we report a protein pharmacology interaction network database (PhIN), aiming to assist multitarget drug discovery by providing comprehensive and flexible network pharmacology analysis. Overall, PhIN contains 1,126,060 target–target interaction pairs in terms of shared compounds and 3,428,020 pairs in terms of shared scaffolds, which involve 12,419,700 activity data, 9,414 targets, 314 viral targets, 652 pathways, 1,359,400 compounds, and 309,556 scaffolds. Using PhIN, users can obtain interacting target networks within or across human pathways, between human and virus, by defining the number of shared compounds or scaffolds under an activity cutoff. We expect PhIN to be a useful tool for multitarget drug development. PhIN is freely available at http://cadd.pharmacy.nankai.edu.cn/phin/. PMID:26225242

  20. Ocean Acidification: Euphausia Pacifica's Response to Decreasing pH

    NASA Astrophysics Data System (ADS)

    Weber, H. N.; Cooper, H.

    2014-12-01

    The increasing rate of CO2 accumulating in Earth's oceans creates a threat to organisms that can lead to disturbances in their reproduction, survival and growth. Euphausia pacifica is the dominant species of krill in Monterey Bay, CA, and a keystone species in the bay's food web. Previous work on the effects of ocean acidification on the survival, growth and molting of E. pacifica have shown they are fairly tolerant to increased CO2 concentrations. However, less is known about energy costs associated with maintaining their internal pH levels which could affect food consumption, swimming behavior or growth activity. We hypothesized that krill exposed to high CO2 will increase their feeding rate on local species of phytoplankton to account for increased energy costs of pH buffering activity. We exposed experimental E. pacifica to waters of pH 7.6 (the expected pH surface waters in year 2100), and pH 8.0 (control) periods.test for acclimation or longer term stress. Feeding rates were calculated as changes in phytoplankton counts over 24 hours of feeding using Frost's equations (Frost 1972). Understanding the way E. pacifica is affected by ocean acidification is important because of the role they play as the primary food source for a variety of predators necessary to maintain the Pacific's ecology.

  1. Tin(IV) halide complexes of AsPh3) The structures of trans-SnCl4(AsPh3)2 and SnBr4(AsPh3).AsPh3.

    PubMed

    Mahon, Mary F; Moldovan, Natalia L; Molloy, Kieran C; Muresan, Alexandra; Silaghi-Dumitrescu, Ioan; Silaghi-Dumitrescu, Luminita

    2004-12-01

    The structures of two 1 : 2 adducts between tin(IV) halides and AsPh(3) have been determined. SnCl(4)(AsPh(3))(2) adopts a six-coordinate geometry at tin in which the two organoarsine donors are mutually trans. In contrast, SnBr(4)(AsPh(3))(2) is five-coordinate at tin and only one arsine is directly bonded to the metal, in an axial site of the trigonal bipyramid. The second AsPh(3) group has a close contact with the axially bound bromine [As...Br: 3.567(3) angstroms], which is a unique structural variation that depicts an intermediate in a halogen-transfer reaction between Group 14 and Group 15 elements. AACVD using SnCl(4)(AsPh(3))(2) generates a film containing SnO(2) and a second crystalline material which is possibly SnCl(2), but which contains no arsenic. PMID:15558128

  2. Plaque, plaque model systems and pH.

    PubMed

    Sissons, C

    1998-06-01

    Four interlocking lines of research carried out during the Directorship of Dr TW Cutress in the Dental Research Unit were: plaque urea metabolism, which led to the study of plaque pH responses and their control; development of plaque-like biofilm model systems; plaque mineralisation to calculus; and plaque demineralisation of tooth tissue in caries. New modes of regulation of oral bacterial urea metabolism and its role in the mouth were discovered, especially a role as a pH-rise factor and in mineralisation processes. The development of microcosm plaques, consortia of major plaque species, and of the multi-plaque artificial mouth with the ability to measure pH continuously, has substantiated the theory that plaque thickness and fluid flow are important in determining plaque pH. For the first time, formation of large pH gradients inside plaque have been demonstrated and plaque pH experimentally controlled. Plaque growth curves can be accurately measured and procedures established for measuring antiplaque and anticaries agents. These studies exemplify the value of the fundamental approach adopted by Dr Cutress--that integrated, basic, applied, and public-health lines of research reinforce each other. PMID:9676473

  3. Intracellular pH measurements using perfluorocarbon nanoemulsions

    PubMed Central

    Patrick, Michael J.; Janjic, Jelena M.; Teng, Haibing; O’Hear, Meredith R.; Brown, Cortlyn W.; Stokum, Jesse A.; Schmidt, Brigitte F.; Ahrens, Eric T.; Waggoner, Alan S.

    2014-01-01

    We report the synthesis and formulation of unique perfluorocarbon (PFC) nanoemulsions enabling intracellular pH measurements in living cells via fluorescent microscopy and flow cytometry. These nanoemulsions are formulated to readily enter cells upon co-incubation and contain two cyanine-based fluorescent reporters covalently bound to the PFC molecules, specifically Cy3-PFC and CypHer5-PFC conjugates. The spectral and pH-sensing properties of the nanoemulsions where characterized in vitro and showed the unaltered spectral behavior of dyes after formulation. In rat 9L glioma cells loaded with nanoemulsion, the local pH of nanoemulsions was longitudinally quantified using optical microscopy and flow cytometry, and displayed a steady decrease in pH to a level of 5.5 over 3 hours, indicating rapid uptake of nanoemulsion to acidic compartments. Overall, these reagents enable real-time optical detection of intracellular pH in living cells in response to pharmacological manipulations. Moreover, recent approaches for in vivo cell tracking using magnetic resonance imaging (MRI) employ intracellular PFC nanoemulsion probes to track cells using 19F MRI. However, the intracellular fate of these imaging probes is poorly understood. The pH sensing nanoemulsions allow the study of the fate of the PFC tracer inside the labeled cell, which is important for understanding the PFC cell loading dynamics and nanoemulsion stability and cell viability over time. PMID:24266634

  4. Chondrocytes, synoviocytes and dermal fibroblasts all express PH-20, a hyaluronidase active at neutral pH

    PubMed Central

    El Hajjaji, Hafida; Cole, Ada Asbury; Manicourt, Daniel-Henri

    2005-01-01

    Hyaluronan (HA), an important component of connective tissues, is highly metabolically active, but the mechanisms involved in its catabolism are still largely unknown. We hypothesized that a protein similar to sperm PH-20, the only mammalian hyaluronidase known to be active at neutral pH, could be expressed in connective tissue cells. An mRNA transcript similar to that of PH-20 was found in chondrocytes, synoviocytes, and dermal fibroblasts, and its levels were enhanced upon stimulation with IL-1. In cell layers extracted with Triton X-100 – but not with octylglucoside – and in culture media, a polyclonal antipeptide anti-PH-20 antibody identified protein bands with a molecular weight similar to that of sperm PH-20 (60 to 65 kDa) and exhibiting a hyaluronidase activity at neutral pH. Further, upon stimulation with IL-1, the amounts of the neutral-active hyaluronidase increased in both cell layers and culture media. These findings contribute potential important new insights into the biology of connective tissues. It is likely that PH-20 facilitates cell-receptor-mediated uptake of HA, while overexpression or uncontrolled expression of the enzyme can cause great havoc to connective tissues: not only does HA fragmentation compromise the structural integrity of tissues, but also the HA fragments generated are highly angiogenic and are potent inducers of proinflammatory cytokines. On the other hand, the enzyme activity may account for the progressive depletion of HA seen in osteoarthritis cartilage, a depletion that is believed to play an important role in the apparent irreversibility of this disease process. PMID:15987477

  5. IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY

    SciTech Connect

    Daniel P. Molloy

    2002-10-15

    The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics.

  6. PH and Electrochemical Responsive Materials for Corrosion Smart Coating Applications

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2008-01-01

    Corrosion is a costly issue for military operations and civil industries. While most corrosion initiates from localized corrosion form, such as pitting, failure directly caused by localized corrosion is the most dangerous kind, because it is difficult to anticipate and prevent, occurs very suddenly and can be catastrophic. One way of preventing these failures is with a coating that can detect and heal localized corrosion. pH and other electrochemical changes are often associated with localized corrosion, so it is expected that materials that are pH or otherwise electrochemical responsive can be used to detect and control corrosion. This paper will review various pH and electrochemical responsive materials and their potential applications in corrosion smart coatings. Current research results in this field will also be reported.

  7. Stabilization of Mercury in High pH Tank Sludges

    SciTech Connect

    Spence, R.; Barton, J.

    2003-02-24

    DOE complex contains many tank sludges contaminated with mercury. The high pH of these tank sludges typically fails to stabilize the mercury, resulting in these radioactive wastes also being characteristically hazardous or mixed waste. The traditional treatment for soluble inorganic mercury species is precipitation as insoluble mercuric sulfide. Sulfide treatment and a commercial mercury-stabilizing product were tested on surrogate sludges at various alkaline pH values. Neither the sulfide nor the commercial product stabilized the mercury sufficiently at the high pH of the tank sludges to pass the Toxicity Characteristic Leach Procedure (TCLP) treatment standards of the Resource Conservation and Recovery Act (RCRA). The commercial product also failed to stabilize the mercury in samples of the actual tank sludges.

  8. An analysis of Ph.D. examiners' reports in engineering

    NASA Astrophysics Data System (ADS)

    Prieto, Elena; Holbrook, Allyson; Bourke, Sid

    2016-03-01

    In recent years, there have been increasing calls for an overall transformation of the nature of engineering Ph.D. programs and the way theses are assessed. There exists a need to understand the examination process to ensure the best quality outcome for candidates in engineering. The work we present in this paper uses data collected between 2003 and 2010 for a total of 1220 Australian Ph.D. theses by analysing examiner reports. Our analysis indicates that Ph.D. theses in engineering, N = 106, differ considerably from those in other fields in areas such as gender of candidates and examiners and the examiners' geographical location. We also found that assessment areas such as significance and contribution of the thesis, publications arising from the thesis, breadth, depth and recency of the literature review and communication and editorial correctness are areas in which the proportion of text of engineering examiners' comments differs significantly from other fields.

  9. Designing pH induced fold switch in proteins

    NASA Astrophysics Data System (ADS)

    Baruah, Anupaul; Biswas, Parbati

    2015-05-01

    This work investigates the computational design of a pH induced protein fold switch based on a self-consistent mean-field approach by identifying the ensemble averaged characteristics of sequences that encode a fold switch. The primary challenge to balance the alternative sets of interactions present in both target structures is overcome by simultaneously optimizing two foldability criteria corresponding to two target structures. The change in pH is modeled by altering the residual charge on the amino acids. The energy landscape of the fold switch protein is found to be double funneled. The fold switch sequences stabilize the interactions of the sites with similar relative surface accessibility in both target structures. Fold switch sequences have low sequence complexity and hence lower sequence entropy. The pH induced fold switch is mediated by attractive electrostatic interactions rather than hydrophobic-hydrophobic contacts. This study may provide valuable insights to the design of fold switch proteins.

  10. Intracellular pH Modulates Autophagy and Mitophagy.

    PubMed

    Berezhnov, Alexey V; Soutar, Marc P M; Fedotova, Evgeniya I; Frolova, Maria S; Plun-Favreau, Helene; Zinchenko, Valery P; Abramov, Andrey Y

    2016-04-15

    The specific autophagic elimination of mitochondria (mitophagy) plays the role of quality control for this organelle. Deregulation of mitophagy leads to an increased number of damaged mitochondria and triggers cell death. The deterioration of mitophagy has been hypothesized to underlie the pathogenesis of several neurodegenerative diseases, most notably Parkinson disease. Although some of the biochemical and molecular mechanisms of mitochondrial quality control are described in detail, physiological or pathological triggers of mitophagy are still not fully characterized. Here we show that the induction of mitophagy by the mitochondrial uncoupler FCCP is independent of the effect of mitochondrial membrane potential but dependent on acidification of the cytosol by FCCP. The ionophore nigericin also reduces cytosolic pH and induces PINK1/PARKIN-dependent and -independent mitophagy. The increase of intracellular pH with monensin suppresses the effects of FCCP and nigericin on mitochondrial degradation. Thus, a change in intracellular pH is a regulator of mitochondrial quality control. PMID:26893374

  11. Controllable dissociations of PH3 molecules on Si(001)

    NASA Astrophysics Data System (ADS)

    Liu, Qin; Lei, Yanhua; Shao, Xiji; Ming, Fangfei; Xu, Hu; Wang, Kedong; Xiao, Xudong

    2016-04-01

    We demonstrate for the first time to our knowledge that controllable dissociation of PH3 adsorption products PH x (x = 2, 1) can be realized by STM (scanning tunneling microscope) manipulation techniques at room temperature. Five dissociative products and their geometric structures are identified via combining STM experiments and first-principle calculations and simulations. In total we realize nine kinds of controllable dissociations by applying a voltage pulse among the PH3-related structures on Si(001). The dissociation rates of the five most common reactions are measured by the I-t spectrum method as a function of voltage. The suddenly increased dissociation rate at 3.3 V indicates a transition from multivibrational excitation to single-step excitation induced by inelastic tunneling electrons. Our studies prove that selectively breaking the chemical bonds of a single molecule on semiconductor surface by STM manipulation technique is feasible.

  12. Earth and Space Science PhD Employment Trends

    NASA Astrophysics Data System (ADS)

    Giesler, J. L.

    2001-05-01

    A recent report by the American Geophysical Union and the American Geological Institute, "Earth and Space Science PhDs, Class of 1999" looked at employment trends of recent graduates. Demographically, our graduates are, as a population, older than those who graduated in any other physical science. While almost one-third of graduates are employed in a different subfield than that of their degree, more than 80% of Earth and space science PhDs secure initial employment in the geosciences. Graduates are finding employment in less than 6 months and the unemployment rate has dropped significantly below that of two years ago. The PhD classes of 1996, 1997, and 1998 had ~ 50% of their graduates taking postdoctoral appointments. In 1999, this declined to only 38% postdocs with an increase in permanent employment in both the education and government sectors. Perception of the job market is improving as well. Respondents are considerably happier than they were in 1996.

  13. Photonic porous silicon as a pH sensor

    NASA Astrophysics Data System (ADS)

    Pace, Stephanie; Vasani, Roshan B.; Zhao, Wei; Perrier, Sébastien; Voelcker, Nicolas H.

    2014-08-01

    Chronic wounds do not heal within 3 months, and during the lengthy healing process, the wound is invariably exposed to bacteria, which can colonize the wound bed and form biofilms. This alters the wound metabolism and brings about a change of pH. In this work, porous silicon photonic films were coated with the pH-responsive polymer poly(2-diethylaminoethyl acrylate). We demonstrated that the pH-responsive polymer deposited on the surface of the photonic film acts as a barrier to prevent water from penetrating inside the porous matrix at neutral pH. Moreover, the device demonstrated optical pH sensing capability visible by the unaided eye.

  14. Nanocrystalline hydroxyapatite prepared under various pH conditions

    NASA Astrophysics Data System (ADS)

    Palanivelu, R.; Mary Saral, A.; Ruban Kumar, A.

    2014-10-01

    Hydroxyapatite (HAP) has sovereign biomedical application due to its excellent biocompatibility, chemical and crystallographic similitude with natural human bone. In this present work, we discussed about the role of pH in the synthesis of calcium phosphate compound using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as starting materials by chemical precipitation method assisted with ultrasonic irradiation technique. 5% polyethylene glycol (PEG600) is added along with the precursors under various pH condition of 7, 9 and 11 respectively. The functional group analysis, crystallized size and fraction of crystallized size are confirmed using Fourier Transformation Infra-Red spectroscopy and X-ray diffraction pattern. Morphological observations are done by scanning electron microscope. The results revealed the presence of nanocrystalline hydroxyapatite at pH above 9.

  15. Photonic porous silicon as a pH sensor

    PubMed Central

    2014-01-01

    Chronic wounds do not heal within 3 months, and during the lengthy healing process, the wound is invariably exposed to bacteria, which can colonize the wound bed and form biofilms. This alters the wound metabolism and brings about a change of pH. In this work, porous silicon photonic films were coated with the pH-responsive polymer poly(2-diethylaminoethyl acrylate). We demonstrated that the pH-responsive polymer deposited on the surface of the photonic film acts as a barrier to prevent water from penetrating inside the porous matrix at neutral pH. Moreover, the device demonstrated optical pH sensing capability visible by the unaided eye. PMID:25177227

  16. The pH dependent Raman spectroscopic study of caffeine

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Gu, Huaimin; Zhong, Liang; Hu, Yongjun; Liu, Fang

    2011-02-01

    First of all the surface enhanced Raman spectroscopy (SERS) and normal Raman spectra of caffeine aqueous solution were obtained at different pH values. In order to obtain the detailed vibrational assignments of the Raman spectroscopy, the geometry of caffeine molecule was optimized by density functional theory (DFT) calculation. By comparing the SERS of caffeine with its normal spectra at different pH values; it is concluded that pH value can dramatically affect the SERS of caffeine, but barely affect the normal Raman spectrum of caffeine aqueous solution. It can essentially affect the reorientation of caffeine molecule to the Ag colloid surface, but cannot impact the vibration of functional groups and chemical bonds in caffeine molecule.

  17. Role of pH changes in primary uraninite mineralization

    SciTech Connect

    Shmariovich, Ye.M.; Zhil'tsova, I.G.; Pakul'nis, G.V.; Shugina, G.A.

    1982-10-01

    Uranyl minerals form a distinct series based on their solubilities in environments of different pH, beginning with the molybdenates, and proceeding through the arsenates, phosphates, vanadates, and silicates of the soddyite groups. Unlike exogenetic-epigenetic uranium deposits with pitchblende, infiltrational deposits with uranyl mineralization are primarily the result of changes in the pH of the environment. The model presented gives the precipitation of uranyl vanadates at an acidic geochemical barrier, and it can be used to explain the genesis of carnotite deposits in calcretes. A geochemically opposite model for the formation of uranyl minerals as the result of the neutralization of interstitial waters that have been strongly acidified (to pH 2) in conjunction with the oxidation of sulfide-bearing rocks must be adopted to explain the distribution and conditions of the formation of the uraninite deposits in black shales. (JMT)

  18. Manganese toxicity to fungi: influence of pH

    SciTech Connect

    Babich, H.; Stotzky, G.

    1981-10-01

    The effects of Mn on mycelial proliferation of fungi and the effect of pH on Mn toxicity were evaluated. Results indicated that the fungi exhibited wide differences in their sensitivities to Mn. Incipient inhibition (i.e., the level of Mn at which growth inhibition was noted initially, P < 0.05) for Scopulariopsis brevicaulis and Aspergillus giganteus occurred at 100 ppM Mn; for Rhizopus stolonifer, Arthrobotrys conoides, Aspergillus niger, Aspergillus flavus, Trichoderma viride, and Penicillium vermiculatum at 500 ppM Mn; for Cephalosporium sp. at 1000 ppM Mn; and for Gliocladium sp. at 1000 to 1500 ppM Mn; growth of Aspergillus clavatus was not inhibited even at 2000 ppM Mn. No growth of S. brevicaulis occurred at 500 ppM Mn and of R. stolonifer at 1500 ppM Mn. The levels of Mn causing incipient and/or total inhibition of mycelial growth of the fungi studied were comparable to the levels reported to inhibit mycelial proliferation of some phylloplane fungi. Only A. conoides showed significant (P < 0.5) stimulation of mycelial growth by Mn; 10, 50, and 100 ppM Mn increased growth rates over control (0 ppM Mn) values. There was no consistent trend in the effect of pH on Mn toxicity to the fungi. However, each fungus showed a definitive response to Mn at the different pH levels. Thus, increasing the pH from 5.5 to 8.5 did not significantly affect the toxicity of Mn to Gliocladium sp., P. vermiculatum, or A. niger. The toxicity of Mn to R. stolonifer and T. viride was not different at pH 5.5 and 6.5, but increasing the pH to 7.5 or 8.5 significantly enhanced the toxicity.

  19. pH sensing and regulation in cancer

    PubMed Central

    Damaghi, Mehdi; Wojtkowiak, Jonathan W.; Gillies, Robert J.

    2013-01-01

    Cells maintain intracellular pH (pHi) within a narrow range (7.1–7.2) by controlling membrane proton pumps and transporters whose activity is set by intra-cytoplasmic pH sensors. These sensors have the ability to recognize and induce cellular responses to maintain the pHi, often at the expense of acidifying the extracellular pH. In turn, extracellular acidification impacts cells via specific acid-sensing ion channels (ASICs) and proton-sensing G-protein coupled receptors (GPCRs). In this review, we will discuss some of the major players in proton sensing at the plasma membrane and their downstream consequences in cancer cells and how these pH-mediated changes affect processes such as migration and metastasis. The complex mechanisms by which they transduce acid pH signals to the cytoplasm and nucleus are not well understood. However, there is evidence that expression of proton-sensing GPCRs such as GPR4, TDAG8, and OGR1 can regulate aspects of tumorigenesis and invasion, including cofilin and talin regulated actin (de-)polymerization. Major mechanisms for maintenance of pHi homeostasis include monocarboxylate, bicarbonate, and proton transporters. Notably, there is little evidence suggesting a link between their activities and those of the extracellular H+-sensors, suggesting a mechanistic disconnect between intra- and extracellular pH. Understanding the mechanisms of pH sensing and regulation may lead to novel and informed therapeutic strategies that can target acidosis, a common physical hallmark of solid tumors. PMID:24381558

  20. Bicarbonate Increases Tumor pH and Inhibits Spontaneous Metastases

    PubMed Central

    Robey, Ian F.; Baggett, Brenda K.; Kirkpatrick, Nathaniel D.; Roe, Denise J.; Dosescu, Julie; Sloane, Bonnie F.; Hashim, Arig Ibrahim; Morse, David L.; Raghunand, Natarajan; Gatenby, Robert A.; Gillies, Robert J.

    2010-01-01

    The external pH of solid tumors is acidic as a consequence of increased metabolism of glucose and poor perfusion. Acid pH has been shown to stimulate tumor cell invasion and metastasis in vitro and in cells before tail vein injection in vivo. The present study investigates whether inhibition of this tumor acidity will reduce the incidence of in vivo metastases. Here, we show that oral NaHCO3 selectively increased the pH of tumors and reduced the formation of spontaneous metastases in mouse models of metastatic breast cancer. This treatment regimen was shown to significantly increase the extracellular pH, but not the intracellular pH, of tumors by 31P magnetic resonance spectroscopy and the export of acid from growing tumors by fluorescence microscopy of tumors grown in window chambers. NaHCO3 therapy also reduced the rate of lymph node involvement, yet did not affect the levels of circulating tumor cells, suggesting that reduced organ metastases were not due to increased intravasation. In contrast, NaHCO3 therapy significantly reduced the formation of hepatic metastases following intrasplenic injection, suggesting that it did inhibit extravasation and colonization. In tail vein injections of alternative cancer models, bicarbonate had mixed results, inhibiting the formation of metastases from PC3M prostate cancer cells, but not those of B16 melanoma. Although the mechanism of this therapy is not known with certainty, low pH was shown to increase the release of active cathepsin B, an important matrix remodeling protease. PMID:19276390

  1. Harvard College Observatory: Shapley's Factory for PhD Degrees?

    NASA Astrophysics Data System (ADS)

    Welther, B. L.

    2000-12-01

    When Harlow Shapley assumed the Directorship of Harvard College Observatory in 1921, there was no program in place there to train the next generation of astronomers. In 1923, using the Pickering Fund for women assistants, Shapley hired a young English woman, Cecilia Payne, to work on stellar spectra. Just two short years later, Payne completed her research and wrote a celebrated thesis on stellar atmospheres. Because Harvard University was not prepared to confer a PhD degree on a woman at that time, Payne presented her thesis to Radcliffe College. Thus, in 1925 she became the first person to receive a PhD in astronomy for a research project at HCO. By 1933, a PhD in Astronomy had been conferred on eight graduate students who had undertaken research projects at HCO: four men who received their degree from Harvard, and four women, from Radcliffe. In subsequent years, however, the equal distribution of degrees for men and women quickly changed. When the 30th degree was bestowed in 1943, only 10 of the candidates were women. By 1955, when the 60th degree was conferred, only 14 women had received a PhD. In just two decades, then, the ratio of women astronomers had steadily dropped from a solid 50% at the height of the Shapley era to slightly less than 25% at his retirement. Also, until the mid-1960s, the women astronomers still had to apply to Radcliffe for their PhD degrees. This paper will briefly examine the funding and research topics of some of the HCO PhD candidates in the Shapley Era (1921-1955). It will also highlight some of their subsequent contributions to 20th-century American Astronomy.

  2. pH sensitive quantum dot-anthraquinone nanoconjugates

    NASA Astrophysics Data System (ADS)

    Ruedas-Rama, Maria Jose; Hall, Elizabeth A. H.

    2014-05-01

    Semiconductor quantum dots (QDs) have been shown to be highly sensitive to electron or charge transfer processes, which may alter their optical properties. This feature can be exploited for different sensing applications. Here, we demonstrate that QD-anthraquinone conjugates can function as electron transfer-based pH nanosensors. The attachment of the anthraquinones on the surface of QDs results in the reduction of electron hole recombination, and therefore a quenching of the photoluminescence intensity. For some anthraquinone derivatives tested, the quenching mechanism is simply caused by an electron transfer process from QDs to the anthraquinone, functioning as an electron acceptor. For others, electron transfer and energy transfer (FRET) processes were found. A detailed analysis of the quenching processes for CdSe/ZnS QD of two different sizes is presented. The photoluminescence quenching phenomenon of QDs is consistent with the pH sensitive anthraquinone redox chemistry. The resultant family of pH nanosensors shows pKa ranging ˜5-8, being ideal for applications of pH determination in physiological samples like blood or serum, for intracellular pH determination, and for more acidic cellular compartments such as endosomes and lysosomes. The nanosensors showed high selectivity towards many metal cations, including the most physiologically important cations which exist at high concentration in living cells. The reversibility of the proposed systems was also demonstrated. The nanosensors were applied in the determination of pH in samples mimicking the intracellular environment. Finally, the possibility of incorporating a reference QD to achieve quantitative ratiometric measurements was investigated.

  3. Nuclear magnetic resonance studies of intracellular pH and pH homeostasis in the hog carotid artery

    SciTech Connect

    Grieder, T.A.

    1989-01-01

    Intracellular pH (pH{sub i}) is an important determinant of vascular smooth muscle (VSM) contractility and relaxation. Most NMR measurement of pH have been calculated from the chemical shift of inorganic phosphate (P{sub i}) in {sup 31}P spectra. An alternative approach is to calculate pH from the difference in chemical shifts of signals in the {sup 19}F spectrum of cells loaded with difluoromethylalanine. This technique has higher sensitivity to pH changes and provides better time resolution than other NMR methods. In this study we report simultaneous measurements of pH{sub i} and the contractile state of single, intact hog carotid arterial segments, closed at both ends and superfused with HCO{sub 3}{sup {minus}}-buffered Krebs solution at physiological pressures. At 28{degree}C, resting arteries maintained a pH{sub i} of 7.15 {+-} 0.03 units (n = 16). In a parallel study, helically cut strips studied with {sup 31}P NMR maintained a similar resting pH (7.18 {+-} 0.09).

  4. Lipid-conjugated fluorescent pH sensors for monitoring pH changes in reconstituted membrane systems.

    PubMed

    Kemmer, Gerdi Christine; Bogh, Sidsel Ammitzbøll; Urban, Michael; Palmgren, Michael G; Vosch, Tom; Schiller, Jürgen; Günther Pomorski, Thomas

    2015-09-21

    Accurate real-time measurements of the dynamics of proton concentration gradients are crucial for detailed molecular studies of proton translocation by membrane-bound enzymes. To reduce complexity, these measurements are often carried out with purified, reconstituted enzyme systems. Yet the most paramount problem to detect pH changes in reconstituted systems is that soluble pH reporters leak out of the vesicle system during the reconstitution procedure. This requires loading of substantial amounts of pH-sensors into the lumen of unilamellar liposomes during reconstitution. Here, we report the synthesis and detailed characterisation of two lipid-linked pH sensors employing amine-reactive forms of seminaphthorhodafluors (SNARF®-1 dye) and rhodamine probes (pHrodo™ Red dye). Lipid-conjugation of both dyes allowed for efficient detergent-based reconstitution of these pH indicators into liposomes. Vesicle-embedded pHrodo™ displayed excellent photostability and an optimal pH-response between 4 and 7. The suitability of the lipid-linked pHrodo™ probe as a pH reporter was demonstrated by assaying the activity of a plant plasma membrane H(+)-ATPase (proton pump) reconstituted in proteoliposomes. PMID:26280031

  5. CCD camera full range pH sensor array.

    PubMed

    Safavi, A; Maleki, N; Rostamzadeh, A; Maesum, S

    2007-01-15

    Changes in colors of an array of optical sensors that responds in full pH range were recorded using a CCD camera. The data of the camera were transferred to the computer through a capture card. Simple software was written to read the specific color of each sensor. In order to associate sensor array responses with pH values, a number of different mathematics and chemometrics methods were investigated and compared. The results show that the use of "Microsoft Excel's Solver" provides results which are in very good agreement with those obtained with chemometric methods such as artificial neural network (ANN) and partial least square (PLS) methods. PMID:19071333

  6. Metal/Metal Oxide Differential Electrode pH Sensors

    NASA Technical Reports Server (NTRS)

    West, William; Buehler, Martin; Keymeulen, Didier

    2007-01-01

    Solid-state electrochemical sensors for measuring the degrees of acidity or alkalinity (in terms of pH values) of liquid solutions are being developed. These sensors are intended to supplant older electrochemical pH sensors that include glass electrode structures and reference solutions. The older sensors are fragile and subject to drift. The present developmental solid-state sensors are more rugged and are expected to be usable in harsh environments. The present sensors are based on a differential-electrode measurement principle. Each sensor includes two electrodes, made of different materials, in equilibrium with the solution of interest.

  7. PhET: Interactive Simulations for Teaching and Learning Physics

    NASA Astrophysics Data System (ADS)

    Perkins, Katherine; Adams, Wendy; Dubson, Michael; Finkelstein, Noah; Reid, Sam; Wieman, Carl; LeMaster, Ron

    2006-01-01

    The Physics Education Technology (PhET) project creates useful simulations for teaching and learning physics and makes them freely available from the PhET website (http://phet.colorado.edu). The simulations (sims) are animated, interactive, and game-like environments in which students learn through exploration. In these sims, we emphasize the connections between real-life phenomena and the underlying science, and seek to make the visual and conceptual models of expert physicists accessible to students. We use a research-based approach in our design—incorporating findings from prior research and our own testing to create sims that support student engagement with and understanding of physics concepts.

  8. pH control in biological systems using calcium carbonate.

    PubMed

    Salek, S S; van Turnhout, A G; Kleerebezem, R; van Loosdrecht, M C M

    2015-05-01

    Due to its abundance, calcium carbonate (CaCO3) has high potentials as a source of alkalinity for biotechnological applications. The application of CaCO3 in biological systems as neutralizing agent is, however, limited due to potential difficulties in controlling the pH. The objective of the present study was to determine the dominant processes that control the pH in an acid-forming microbial process in the presence of CaCO3. To achieve that, a mathematical model was made with a minimum set of kinetically controlled and equilibrium reactions that was able to reproduce the experimental data of a batch fermentation experiment using finely powdered CaCO3. In the model, thermodynamic equilibrium was assumed for all speciation, complexation and precipitation reactions whereas, rate limited reactions were included for the biological fatty acid production, the mass transfer of CO2 from the liquid phase to the gas phase and the convective transport of CO2 out of the gas phase. The estimated pH-pattern strongly resembled the measured pH, suggesting that the chosen set of kinetically controlled and equilibrium reactions were establishing the experimental pH. A detailed analysis of the reaction system with the aid of the model revealed that the pH establishment was most sensitive to four factors: the mass transfer rate of CO2 to the gas phase, the biological acid production rate, the partial pressure of CO2 and the Ca(+2) concentration in the solution. Individual influences of these factors on the pH were investigated by extrapolating the model to a continuously stirred-tank reactor (CSTR) case. This case study indicates how the pH of a commonly used continuous biotechnological process could be manipulated and adjusted by altering these four factors. Achieving a better insight of the processes controlling the pH of a biological system using CaCO3 as its neutralizing agent can result in broader applications of CaCO3 in biotechnological industries. PMID:25425281

  9. Doping of germanium nanowires grown in presence of PH3

    NASA Astrophysics Data System (ADS)

    Tutuc, E.; Chu, J. O.; Ott, J. A.; Guha, S.

    2006-12-01

    The authors study the Au-catalyzed chemical vapor growth of germanium (Ge) nanowires in the presence of phosphine (PH3), used as a dopant precursor. The device characteristics of the ensuing nanowire field effect transistors (FETs) indicate n-type, highly doped nanowires. Using a combination of different nanowire growth sequences and their FET characteristics, the authors determine that phosphorus incorporates predominately via the conformal growth, which accompanies the acicular, nanowire growth. As such, the Ge nanowires grown in the presence of PH3 contain a phosphorus doped shell and an undoped core. The authors determine the doping level in the shell to be ≃(1-4)×1019cm-3.

  10. Measurement and control of pH in hydrothermal solutions

    SciTech Connect

    Wesolowski, D.J.; Palmer, D.A.; Mesmer, R.E.

    1995-12-31

    Hydrogen-electrode concentration cells with liquid junction are routinely used to measure the pH of aqueous solutions from 0 to 300 C. Results include the dissociation constants of common acids and bases and the hydrolysis and complexation of metal ions in aqueous electrolytes over a wide range of salinities. Recently, we have utilized these cells to examine the sorption of H{sup +} on mineral surfaces, the solubility of minerals with continuous in situ pH measurement, and the thermal decompositon rates of organic acids.

  11. Alkaline pH Homeostasis in Bacteria: New Insights

    PubMed Central

    Padan, Etana; Bibi, Eitan; Ito, Masahiro; Krulwich, Terry A.

    2011-01-01

    The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches. Alkali-tolerance and alkaliphily, in turn, strongly depend upon mechanisms for alkaline pH homeostasis, as shown in pH shift experiments and growth experiments in chemostats at different external pH values. Transcriptome and proteome analyses have recently complemented physiological and genetic studies, revealing numerous adaptations that contribute to alkaline pH homeostasis. These include elevated levels of transporters and enzymes that promote proton capture and retention (e.g. the ATP synthase and monovalent cation/proton antiporters), metabolic changes that lead to increased acid production, and changes in the cell surface layers that contribute to cytoplasmic proton retention. Targeted studies over the past decade have followed up the long-recognized importance of monovalent cations in active pH homeostasis. These studies show the centrality of monovalent cation/proton antiporters in this process while microbial genomics provides information about the constellation of such antiporters in individual strains. A comprehensive phylogenetic analysis of both eukaryotic and prokaryotic genome databases has identified orthologes from bacteria to humans that allow better understanding of the specific functions and physiological roles of the antiporters. Detailed information about the properties of multiple antiporters in individual strains is starting to explain how specific monovalent cation/proton antiporters play dominant roles in alkaline pH homeostasis in cells that have several additional antiporters catalyzing ostensibly similar reactions. New insights into the pH-dependent Na+/H+ antiporter NhaA that plays an important role in Escherichia coli have recently emerged from the determination of the structure

  12. An analysis of the UCF Optics Ph.D. curriculum

    NASA Astrophysics Data System (ADS)

    Hagan, David J.

    2005-10-01

    Graduate degrees specializing in optics have been offered at the University of Central Florida since 1987, with stand-alone Optics degrees being offered since 1998. In 2002, the Optics Ph.D. core was radically changed to allow students to take the PhD qualifying examination earlier in their studies, while still providing a broad and rigorous grounding in optics. This involved the creation of several new courses. We describe how this new system has worked over the first three years. We also discuss results of a study on how well typical admission criteria such as GRE exam results, grade point average, etc. predict student performance in our program.

  13. Plastic optical fiber sensor for gastric ph detection

    NASA Astrophysics Data System (ADS)

    Baldini, Francesco; Bracci, Susanna; Cosi, Franco

    1994-02-01

    An optical fiber sensor for gastric pH detection is described, making use of plastic fibers as light carriers and a proper electronic system for both source driving and signal processing. The use of a suitable microprocessor and an internal buffer allows the realization of a portable and reliable device, fed by batteries. The indicators, bromophenol blue (BPB) or thymol blue (TB), are immobilized on controlled pore glass (CPG) fixed at the end of plastic optical fibers following a proprietary process. The realized optrode, satisfying clinical requirements, was tested `in vitro.' A precision of pH units and a response time of (

  14. 46 CFR 189.15-5 - Alternate compliance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Engineering Systems, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593... with the Alternate Compliance Program provisions of 46 CFR part 8. (b) For the purposes of this section... are incorporated by reference into 46 CFR 8.110(b)....

  15. 46 CFR 71.15-5 - Alternate compliance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... King Jr. Avenue SE., Washington, DC 20593-7509; telephone 202-372-1372 or fax 202-372-1925. Approved classification society rules and supplements are incorporated by reference into 46 CFR 8.110(b)....

  16. 46 CFR 189.15-5 - Alternate compliance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... with the Alternate Compliance Program provisions of 46 CFR part 8. (b) For the purposes of this section...-7509; telephone 202-372-1371 or fax 202-372-1925. Approved classification society rules and supplements are incorporated by reference into 46 CFR 8.110(b)....

  17. 46 CFR 71.15-5 - Alternate compliance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... King Jr. Avenue SE., Washington, DC 20593-7509; telephone 202-372-1372 or fax 202-372-1925. Approved classification society rules and supplements are incorporated by reference into 46 CFR 8.110(b)....

  18. 46 CFR 32.15-5 - Whistles-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Engineering) of this chapter. Note: Appendix A in 33 CFR subchapter D contains the International Regulations... GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS..., 1955 means shall be provided to operate the whistle from a position adjacent to the main...

  19. 46 CFR 32.15-5 - Whistles-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Engineering) of this chapter. Note: Appendix A in 33 CFR subchapter D contains the International Regulations... GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS..., 1955 means shall be provided to operate the whistle from a position adjacent to the main...

  20. 46 CFR 32.15-5 - Whistles-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Engineering) of this chapter. Note: Appendix A in 33 CFR subchapter D contains the International Regulations... GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS..., 1955 means shall be provided to operate the whistle from a position adjacent to the main...

  1. 49 CFR 15.5 - Sensitive security information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... infrastructure asset information. Any list identifying systems or assets, whether physical or virtual, so vital... 49 CFR 1542.303, 1544.305, or other authority; (ii) Issued by the Coast Guard under the Maritime Transportation Security Act, 33 CFR part 6, or 33 U.S.C. 1221 et seq. related to maritime security; or (iii)...

  2. 49 CFR 15.5 - Sensitive security information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... infrastructure asset information. Any list identifying systems or assets, whether physical or virtual, so vital... 49 CFR 1542.303, 1544.305, or other authority; (ii) Issued by the Coast Guard under the Maritime Transportation Security Act, 33 CFR part 6, or 33 U.S.C. 1221 et seq. related to maritime security; or (iii)...

  3. 49 CFR 15.5 - Sensitive security information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... infrastructure asset information. Any list identifying systems or assets, whether physical or virtual, so vital... 49 CFR 1542.303, 1544.305, or other authority; (ii) Issued by the Coast Guard under the Maritime Transportation Security Act, 33 CFR part 6, or 33 U.S.C. 1221 et seq. related to maritime security; or (iii)...

  4. 49 CFR 15.5 - Sensitive security information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... infrastructure asset information. Any list identifying systems or assets, whether physical or virtual, so vital... 49 CFR 1542.303, 1544.305, or other authority; (ii) Issued by the Coast Guard under the Maritime Transportation Security Act, 33 CFR part 6, or 33 U.S.C. 1221 et seq. related to maritime security; or (iii)...

  5. 49 CFR 15.5 - Sensitive security information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... infrastructure asset information. Any list identifying systems or assets, whether physical or virtual, so vital... 49 CFR 1542.303, 1544.305, or other authority; (ii) Issued by the Coast Guard under the Maritime Transportation Security Act, 33 CFR part 6, or 33 U.S.C. 1221 et seq. related to maritime security; or (iii)...

  6. 46 CFR 56.15-5 - Fluid-conditioner fittings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... comparable to those of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2) or Section VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 56.01-2); (B) Subjecting a... the ASME Boiler and Pressure Vessel Code (incorporated by reference, see 46 CFR 56.01-2); or (C)...

  7. 46 CFR 56.15-5 - Fluid-conditioner fittings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... comparable to those of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2) or Section VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 56.01-2); (B) Subjecting a... the ASME Boiler and Pressure Vessel Code (incorporated by reference, see 46 CFR 56.01-2); or (C)...

  8. 46 CFR 56.15-5 - Fluid-conditioner fittings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... comparable to those of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2) or section VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 56.01-2); (B) Subjecting a... the ASME Boiler and Pressure Vessel Code (incorporated by reference, see 46 CFR 56.01-2); or (C)...

  9. 46 CFR 56.15-5 - Fluid-conditioner fittings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... comparable to those of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2) or section VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 56.01-2); (B) Subjecting a... the ASME Boiler and Pressure Vessel Code (incorporated by reference, see 46 CFR 56.01-2); or (C)...

  10. 46 CFR 56.15-5 - Fluid-conditioner fittings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... comparable to those of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2) or Section VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 56.01-2); (B) Subjecting a... the ASME Boiler and Pressure Vessel Code (incorporated by reference, see 46 CFR 56.01-2); or (C)...

  11. Covalent organic frameworks as pH responsive signaling scaffolds.

    PubMed

    Zhang, Yuwei; Shen, Xiaochen; Feng, Xiao; Xia, Hong; Mu, Ying; Liu, Xiaoming

    2016-09-25

    A β-ketoenamine based covalent organic framework, COF-JLU4, was synthesized by condensation of 2,5-dimethoxyterephthalohydrazide with triformylphloroglucinol under solvothermal conditions. This COF has strong crystallinity, good porosity, photoluminescence properties and wettability for water. It can serve as the first COF-based fluorescent pH sensor in aqueous solutions. PMID:27545686

  12. Online Ph.D. Program Delivery Models and Student Success

    ERIC Educational Resources Information Center

    Jorissen, Shari L.; Keen, James P.; Riedel, Eric S.

    2015-01-01

    The purpose of this study was to provide information to an online university that offers Ph.D. programs in three formats: knowledge area modules (or KAM, a type of faculty-led, self-directed doctoral study), course-based model, and mixed model (a combination of the KAM and course-based models). The investigators sought to determine why students…

  13. An Analysis of Ph.D. Examiners' Reports in Engineering

    ERIC Educational Resources Information Center

    Prieto, Elena; Holbrook, Allyson; Bourke, Sid

    2016-01-01

    In recent years, there have been increasing calls for an overall transformation of the nature of engineering Ph.D. programs and the way theses are assessed. There exists a need to understand the examination process to ensure the best quality outcome for candidates in engineering. The work we present in this paper uses data collected between 2003…

  14. Measures for Ph.D. Evaluation: The Recruitment Process

    ERIC Educational Resources Information Center

    D'Agostino, Antonella; Fruzzetti, Stefania; Ghellini, Giulio; Neri, Laura

    2011-01-01

    In the last years the quality of Higher Education (HE) system and its evaluation have been key issues of the political and scientific debate on education policies all over Europe. In the wide landscape that involves the entire HE system we draw attention on the third level of its organization, i.e. the Ph.D. In particular, this paper discusses the…

  15. Application of SERS Nanoparticles for Intracellular pH Measurements

    SciTech Connect

    Laurence, T; Talley, C; Colvin, M; Huser, T

    2004-10-21

    We present an alternative approach to optical probes that will ultimately allow us to measure chemical concentrations in microenvironments within cells and tissues. This approach is based on monitoring the surface-enhanced Raman scattering (SERS) response of functionalized metal nanoparticles (50-100 nm in diameter). SERS allows for the sensitive detection of changes in the state of chemical groups attached to individual nanoparticles and small clusters. Here, we present the development of a nanoscale pH meter. The pH response of these nanoprobes is tested in a cell-free medium, measuring the pH of the solution immediately surrounding the nanoparticles. Heterogeneities in the SERS signal, which can result from the formation of small nanoparticle clusters, are characterized using SERS correlation spectroscopy and single particle/cluster SERS spectroscopy. The response of the nanoscale pH meters is tested under a wide range of conditions to approach the complex environment encountered inside living cells and to optimize probe performance.

  16. Cytosolic pH: A conserved regulator of cell growth?

    PubMed Central

    Dechant, Reinhard; Peter, Matthias

    2014-01-01

    Although target of rapamycin (TOR) kinase and Ras are central regulators of cell growth in yeast and mammals, the molecular mechanisms underlying their regulation by nutrients are still poorly understood. Interestingly, recent studies identified cytosolic pH as a critical regulatory signal for both pathways, which might have widespread implications for tumor cell biology PMID:27308377

  17. The PhD Project: How Successful Is It?

    ERIC Educational Resources Information Center

    Schwartz, Bill N.; Williams, Satina V.; Walden, W. Darrell

    2011-01-01

    The PhD Project's mission to diversify the work force by increasing the diversity of business school faculty is quite admirable, but is the Project successful? To gather insights toward responding to that question and to offer suggestions, we reviewed three of the Project's objectives that relate most closely to minority doctoral students and…

  18. [Regulation effects of tourmaline on seawater pH value].

    PubMed

    Xia, Meisheng; Zhang, Hongmei; Hu, Caihong; Xu, Zirong

    2005-10-01

    In this paper, chemical analysis, X-ray diffraction and atomic force microscopy were employed to examine the characteristics of tourmaline produced in east Inner Mongolia Autonomous Region, and batch experiments were conducted to study its regulation effects on seawater pH value. The factors affecting the regulation, such as the dosage of tourmaline and the salinity and initial pH value of seawater, were also studied. The results showed that tourmaline could regulate the seawater pH value from its initial 3 and 10 to 7.1 and 8.9, respectively, and the regulation effect was greater in the seawater with lower salinity, e.g., after 120 minutes treatment, the initial pH value (5.0) of the seawater with a salinity of 5, 10, 15, 20 and 35 was increased by 3.24, 3.16, 3.06, 2.99 and 2.85 unit, respectively. Tourmaline had little effect on seawater conductivity. This study would provide an experimental base for the application of tourmaline in aquaculture. PMID:16422525

  19. PHYSICOCHEMICAL FACTORS AFFECTING TOXICITY IN FRESHWATER: HARDNESS, PH, AND TEMPERATURE

    EPA Science Inventory

    A search of the literature for effects of hardness, pH, or temperature on the toxicity of chemicals to freshwater organisms suggested that the amount of reliable and useful data is limited. uch of the disparity among results reported in the literature was caused by improperly des...

  20. The Production Rate and Employment of Ph.D. Astronomers

    NASA Astrophysics Data System (ADS)

    Metcalfe, Travis S.

    2007-05-01

    As in many sciences, the production rate of new Ph.D. astronomers is decoupled from the global demand for trained scientists. As noted by Thronson (1991, PASP, 103, 90), overproduction appears to be built into the system, making the mathematical formulation of surplus astronomer production similar to that for industrial pollution models -- an unintended side effect of the process. Following Harris (1994, ASP Conf., 57, 12), I document the production of Ph.D. astronomers from 1990 to 2005 using the online Dissertation Abstracts database. To monitor the changing patterns of employment, I examine the number of postdoctoral, tenure-track, and other jobs advertised in the AAS Job Register during this same period. Although the current situation is clearly unsustainable, it was much worse a decade ago with nearly 7 new Ph.D. astronomers in 1995 for every new tenure-track job. While the number of new permanent positions steadily increased throughout the late 1990's, the number of new Ph.D. recipients gradually declined. After the turn of the century, the production of new astronomers leveled off, but new postdoctoral positions grew dramatically. There has also been recent growth in the number of non-tenure-track lecturer, research, and support positions. This is just one example of a larger cultural shift to temporary employment that is happening throughout society -- it is not unique to astronomy.

  1. Promoting Creativity in PhD Supervision: Tensions and Dilemmas

    ERIC Educational Resources Information Center

    Whitelock, Denise; Faulkner, Dorothy; Miell, Dorothy

    2008-01-01

    In this paper we argue that the processes of collaborative creativity are just as important within the sociocultural context of PhD supervisory practice, as they are in other organizational and educational settings. In order to test this claim a series of interviews with supervisors and students were undertaken to uncover the pedagogic processes…

  2. Earth and Space Science PhDs: Class of 2000

    NASA Astrophysics Data System (ADS)

    Giesler, J.

    2001-12-01

    The American Geophysical Union (AGU) and the American Geological Institute (AGI) have been collecting data on recent PhDs in the geosciences for 5 years (1996-2000). Over these years continual improvement has been recorded in the job market through indicators such as time to find employment and starting salaries. As these indicators continue to improve, so too does the perception of the job market in general. There are several characteristics that are unique to PhDs in the geosciences. Unlike physical science graduates, there is a significant number who have been working full-time at least one year prior to earning their PhD. Recent graduates employed prior to graduation are heavily concentrated in Solid Earth Geology (41%) followed by Atmospheric Sciences (19%) and Oceanography (12%). A second distinguishable feature of Earth & space science PhDs is their age. Each year there is a higher percentage of recent graduates over the age of 40: 16% in 1998, 20% in 1999, and 23% in 2000. In 2000, the average time between earning a B.S. and starting a graduate program was 4.6 years. Both 1999 and 2000 show a drop in the overall numbers of postdoctoral appointments. This suggests that greater than 50% of the recent graduates are finding full-time permanent employment. Of the geoscience subfields, oceanography has greatest number of people obtaining employment outside the field.

  3. Gender Differences in Research Patterns among PhD Economists

    ERIC Educational Resources Information Center

    Barbezat, Debra A.

    2006-01-01

    This study is based on a 1996 survey of PhD economists working in the academic and nonacademic sectors since 1989. Despite a raw gender difference in all types of research output, the male dummy variable proves statistically significant in predicting only one publication measure. In a full sample and faculty subsample, number of years since…

  4. PH-sensitive fluorescence detection by diffuse fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Li, Jiao; Gao, Feng; Duan, Linjing; Wang, Xin; Zhang, Limin; Zhao, Huijuan

    2012-03-01

    The importance of cellular pH has been shown clearly in the study of cell activity, pathological feature, drug metabolism, etc. Monitoring pH changes of living cells and imaging the regions with abnormal pH values in vivo could provide the physiologic and pathologic information for the research of the cell biology, pharmacokinetics, diagnostics and therapeutics of certain diseases such as cancer. Thus, pH-sensitive fluorescence imaging of bulk tissues has been attracting great attention in the regime of near-infrared diffuse fluorescence tomography (DFT), an efficient small-animal imaging tool. In this paper, the feasibility of quantifying pH-sensitive fluorescence targets in turbid medium is investigated using both time-domain and steady-state DFT methods. By use of the specifically designed time-domain and continuous-wave systems and the previously proposed image reconstruction scheme, we validate the method through 2-dimensional imaging experiments on a small-animal-sized phantom with multiply targets of distinct pH values. The results show that the approach can localize the targets with reasonable accuracy and achieve quantitative reconstruction of the pH-sensitive fluorescent yield.

  5. Legitimate Peripheral Participation and Supervising Ph.D. Students

    ERIC Educational Resources Information Center

    Hasrati, Mostafa

    2005-01-01

    This article is part of a larger scale project on some aspects of the process of academic socialization of a group of Iranian Ph.D. students studying in five UK universities, particularly focusing on the relationship between these students and their supervisors. The study included eight engineering and five social sciences/humanities students, as…

  6. Lignocellulose pretreatment severity - relating pH to biomatrix opening.

    PubMed

    Pedersen, Mads; Meyer, Anne S

    2010-12-31

    In cellulose-to-ethanol processes a physico-chemical pretreatment of the lignocellulosic feedstock is a crucial prerequisite for increasing the amenability of the cellulose to enzymatic attack. Currently published pretreatment strategies span over a wide range of reaction conditions involving different pH values, temperatures, types of catalysts and holding times. The consequences of the pretreatment on lignocellulosic biomass are described with special emphasis on the chemical alterations of the biomass during pretreatment, especially highlighting the significance of the pretreatment pH. We present a new illustration of the pretreatment effects encompassing the differential responses to the pH and temperature. A detailed evaluation of the use of severity factor calculations for pretreatment comparisons signifies that the multiple effects of different pretreatment factors on the subsequent monosaccharide yields after enzymatic hydrolysis cannot be reliably compared by a one-dimensional severity factor, even within the same type of pretreatment strategy. However, a quantitative comparison of published data for wheat straw pretreatment illustrates that there is some correlation between the hydrolysis yields (glucose and xylose) and the pretreatment pH, but no correlation with the pretreatment temperature (90-200°C). A better recognition and understanding of the factors affecting biomatrix opening, and use of more standardized evaluation protocols, will allow for the identification of new pretreatment strategies that improve biomass utilization and permit rational enzymatic hydrolysis of the cellulose. PMID:20460178

  7. PhOLKS Lore: Learning from Photographs, Families, and Children.

    ERIC Educational Resources Information Center

    Allen, JoBeth; Fabregas, Vinette; Hankins, Karen Hale; Hull, Gregory; Labbo, Linda; Lawson, Hattie Spruill; Michalove, Barabara; Piazza, Steve; Piha, Cyndy; Sprague, Linda; Townsend, Sybil; Urdanivia-English, Carmen

    2002-01-01

    Considers how children can develop personal, social, and cultural connections through photography and narratives in order to envision other possibilities for their lives. Concludes that they found a "web of complex and engaging social relationships" that provided a solid foundation for learning with children and families. Describes the PhOLKS…

  8. Improved pH buffering agent for sodium hypochlorite

    NASA Technical Reports Server (NTRS)

    Nash, J. R.; Veeder, L. N.

    1969-01-01

    Sodium citrate/citric acid was found to be an effective buffer for pH control when used with sodium hypochlorite. The mixture does not corrode aluminum. The buffer appears to form a type of conversion coating that may provide corrosion-resistant properties to aluminum in other applications.

  9. Supervising the PhD: A Guide to Success.

    ERIC Educational Resources Information Center

    Delamont, Sara; Atkinson, Paul; Parry, Odette

    This handbook is a practical guide for the novice and experienced supervisor of Ph.D. students focusing on the British system. The book is organized to follow the progress of a student from starting out to a career after the viva voce examination. The chapters are: (1) "A Most Persuasive Piece of Argument"; (2) "Caught and Held by a Cobweb:…

  10. The pH tolerance of Chlamydomonas applanata (Volvocales, Chlorophyta).

    PubMed

    Visviki, I; Santikul, D

    2000-02-01

    The effects of hydrogen ions on the growth and ultrastructure of Chlamydomonas applanata Pringsheim were examined. This species exhibits wide tolerance growing at pH values ranging from 3.4 to 8.4, with optimum growth obtained at 7.4. Growth is noticeably depressed at pH 4.4 and 3.4. At the ultrastructural level, exposure to pH 4.4 results in a 10% decrease in cell volume of single vegetative cells, an increase in pyrenoidal volume, and reduction of starch reserves. Palmelloid colonies also appear. pH 3.4 induces excessive production of mucilage and leads to the preponderance of palmelloid colonies. Cell death of both colony and single cells is seen, as well as loss of motility and abnormal cell division. Surviving single cells are significantly larger than controls, with thicker cell walls, smaller chloroplasts, and larger vacuome. Such cells entering dormancy ensure the survival of the species in times of stress. PMID:10629274

  11. Miniaturized metal oxide pH sensors for bacteria detection.

    PubMed

    Uria, Naroa; Abramova, Natalia; Bratov, Andrey; Muñoz-Pascual, Francesc-Xavier; Baldrich, Eva

    2016-01-15

    It is well known that the metabolic activity of some microorganisms results in changes of pH of the culture medium, a phenomenon that can be used for detection and quantification of bacteria. However, conventional glass electrodes that are commonly used for pH measurements are bulky, fragile and expensive, which hinders their application in miniaturized systems and encouraged to the search for alternatives. In this work, two types of metal oxide pH sensors have been tested to detect the metabolic activity of the bacterium Escherichia coli (E. coli). These pH sensors were produced on silicon chips with platinum metal contacts, onto which thin layers of IrOx or Ta2O5 were incorporated by two different methods (electrodeposition and e-beam sputtering, respectively). In order to facilitate measurement in small sample volumes, an Ag/AgCl pseudo-reference was also screen-printed in the chip and was assayed in parallel to an external Ag/AgCl reference electrode. As it is shown, the developed sensors generated results indistinguishable from those provided by a conventional glass pH-electrode but could be operated in significantly smaller sample volumes. After optimization of the detection conditions, the metal oxide sensors are successfully applied for detection of increasing concentrations of viable E. coli, with detection of less than 10(3)cfu mL(-1) in undiluted culture medium in just 5h. PMID:26592620

  12. Karl Krueger, PhD | Division of Cancer Prevention

    Cancer.gov

    Dr. Karl Krueger received a PhD in biochemistry from Vanderbilt University and continued his research training at NIH as a postdoctoral fellow before joining the faculty at Georgetown University School of Medicine. His research throughout this period focused on different aspects of drug receptors and their role in the nervous system. |

  13. Vance Berger, PhD | Division of Cancer Prevention

    Cancer.gov

    Dr. Vance Berger completed his PhD in statistics at Rutgers University in 1995, and then began working at the FDA. This is where he developed his research focus on biases and threats to the validity of medical studies, especially clinical trials. In 1999, Dr. Berger joined the NCI, and has remained ever since. |

  14. Richard Mazurchuk, PhD | Division of Cancer Prevention

    Cancer.gov

    Dr. Richard Mazurchuk received a BS in Physics and MS and PhD in Biophysics from SUNY Buffalo. His research focused on developing novel multi-modality imaging techniques, contrast (enhancing) agents and methods to assess the efficacy of experimental therapeutics. |

  15. Christos Patriotis, PhD | Division of Cancer Prevention

    Cancer.gov

    Dr. Christos Patriotis obtained his MSc in Biochemistry from the University of Sofia, Bulgaria in 1985 and his PhD in Molecular Biology from the Bulgarian Academy of Sciences in 1990. Postdoctoral training focused on signal transduction and tumor cell biology. |

  16. 2D luminescence imaging of pH in vivo

    PubMed Central

    Schreml, Stephan; Meier, Robert J.; Wolfbeis, Otto S.; Landthaler, Michael; Szeimies, Rolf-Markus; Babilas, Philipp

    2011-01-01

    Luminescence imaging of biological parameters is an emerging field in biomedical sciences. Tools to study 2D pH distribution are needed to gain new insights into complex disease processes, such as wound healing and tumor metabolism. In recent years, luminescence-based methods for pH measurement have been developed. However, for in vivo applications, especially for studies on humans, biocompatibility and reliability under varying conditions have to be ensured. Here, we present a referenced luminescent sensor for 2D high-resolution imaging of pH in vivo. The ratiometric sensing scheme is based on time-domain luminescence imaging of FITC and ruthenium(II)tris-(4,7-diphenyl-1,10-phenanthroline). To create a biocompatible 2D sensor, these dyes were bound to or incorporated into microparticles (aminocellulose and polyacrylonitrile), and particles were immobilized in polyurethane hydrogel on transparent foils. We show sensor precision and validity by conducting in vitro and in vivo experiments, and we show the versatility in imaging pH during physiological and chronic cutaneous wound healing in humans. Implementation of this technique may open vistas in wound healing, tumor biology, and other biomedical fields. PMID:21262842

  17. Carbon Nanotube Chemiresistor for Wireless pH Sensing

    PubMed Central

    Gou, Pingping; Kraut, Nadine D.; Feigel, Ian M.; Bai, Hao; Morgan, Gregory J.; Chen, Yanan; Tang, Yifan; Bocan, Kara; Stachel, Joshua; Berger, Lee; Mickle, Marlin; Sejdić, Ervin; Star, Alexander

    2014-01-01

    The ability to accurately measure real-time pH fluctuations in-vivo could be highly advantageous. Early detection and potential prevention of bacteria colonization of surgical implants can be accomplished by monitoring associated acidosis. However, conventional glass membrane or ion-selective field-effect transistor (ISFET) pH sensing technologies both require a reference electrode which may suffer from leakage of electrolytes and potential contamination. Herein, we describe a solid-state sensor based on oxidized single-walled carbon nanotubes (ox-SWNTs) functionalized with the conductive polymer poly(1-aminoanthracene) (PAA). This device had a Nernstian response over a wide pH range (2–12) and retained sensitivity over 120 days. The sensor was also attached to a passively-powered radio-frequency identification (RFID) tag which transmits pH data through simulated skin. This battery-less, reference electrode free, wirelessly transmitting sensor platform shows potential for biomedical applications as an implantable sensor, adjacent to surgical implants detecting for infection. PMID:24667793

  18. Carbon Nanotube Chemiresistor for Wireless pH Sensing

    NASA Astrophysics Data System (ADS)

    Gou, Pingping; Kraut, Nadine D.; Feigel, Ian M.; Bai, Hao; Morgan, Gregory J.; Chen, Yanan; Tang, Yifan; Bocan, Kara; Stachel, Joshua; Berger, Lee; Mickle, Marlin; Sejdić, Ervin; Star, Alexander

    2014-03-01

    The ability to accurately measure real-time pH fluctuations in-vivo could be highly advantageous. Early detection and potential prevention of bacteria colonization of surgical implants can be accomplished by monitoring associated acidosis. However, conventional glass membrane or ion-selective field-effect transistor (ISFET) pH sensing technologies both require a reference electrode which may suffer from leakage of electrolytes and potential contamination. Herein, we describe a solid-state sensor based on oxidized single-walled carbon nanotubes (ox-SWNTs) functionalized with the conductive polymer poly(1-aminoanthracene) (PAA). This device had a Nernstian response over a wide pH range (2-12) and retained sensitivity over 120 days. The sensor was also attached to a passively-powered radio-frequency identification (RFID) tag which transmits pH data through simulated skin. This battery-less, reference electrode free, wirelessly transmitting sensor platform shows potential for biomedical applications as an implantable sensor, adjacent to surgical implants detecting for infection.

  19. Peer Mentorship and Transformational Learning: PhD Student Experiences

    ERIC Educational Resources Information Center

    Preston, Jane P.; Ogenchuk, Marcella J.; Nsiah, Joseph K.

    2014-01-01

    The purpose of the paper is to describe our peer mentorship experiences and explain how these experiences fostered transformational learning during our PhD graduate program in educational administration. As a literature backdrop, we discuss characteristics of traditional forms of mentorship and depict how our experiences of peer mentorship was…

  20. PhDs by Publications: An "Easy Way Out"?

    ERIC Educational Resources Information Center

    Niven, Penelope; Grant, Carolyn

    2012-01-01

    PhDs by publications are a relatively new model for doctoral research, especially in the context of the Humanities or Education. This paper describes two writers' experiences of conducting doctoral studies in this genre and in these faculties. Each discover alternative ways of employing a body of published research papers in development of an…