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Sample records for acid methylester pcbm

  1. 40 CFR 721.10448 - Acetic acid, hydroxy- methoxy-, methylester, reaction products with substituted alkylamine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-, methylester, reaction products with substituted alkylamine (generic). 721.10448 Section 721.10448 Protection... Acetic acid, hydroxy- methoxy-, methylester, reaction products with substituted alkylamine (generic). (a... generically as acetic acid, hydroxymethoxy-, methyl ester, reaction products with substituted alkylamine...

  2. Electron Affinity of Phenyl-C61-Butyric Acid Methyl Ester (PCBM)

    SciTech Connect

    Larson, Bryon W.; Whitaker, James B.; Wang, Xue B.; Popov, Alexey A.; Rumbles, Garry; Kopidakis, Nikos; Strauss, Steven H.; Boltalina, Olga V.

    2013-07-25

    The gas-phase electron affinity (EA) of phenyl-C61-butyric acid methyl ester (PCBM), one of the best-performing electron acceptors in organic photovoltaic devices, is measured by lowtemperature photoelectron spectroscopy for the first time. The obtained value of 2.63(1) eV is only ca. 0.05 eV lower than that of C60 (2.68(1) eV), compared to a 0.09 V difference in their E1/2 values measured in this work by cyclic voltammetry. Literature E(LUMO) values for PCBM that are typically estimated from cyclic voltammetry, and commonly used as a quantitative measure of acceptor properties, are dispersed over a wide range between -4.3 and -3.62 eV; the reasons for such a huge discrepancy are analyzed here, and the protocol for reliable and consistent estimations of relative fullerene-based acceptor strength in solution is proposed.

  3. Combined enzymatic and colorimetric method for determining the uronic acid and methylester content of pectin: Application to tomato products.

    PubMed

    Anthon, Gordon E; Barrett, Diane M

    2008-09-01

    A simple procedure for determining the galacturonic acid and methanol contents of soluble and insoluble pectins, relying on enzymatic pectin hydrolysis and colorimetric quantification, is described. Pectin samples are incubated with a commercial pectinase preparation, Viscozyme, then the galacturonic acid content of the hydrolyzed pectin is quantified colorimetrically using a modification of the Cu reduction procedure originally described by Avigad and Milner. This modification, substituting the commonly used Folin-Ciocalteau reagent for the arsenic containing Nelson reagent, gives a response that is linear, sensitive, and selective for uronic acids over neutral sugars. This method also avoids the use of concentrated acids needed for the commonly used m-phenylphenol method. Methanol, released by the action of the pectin methylesterase found in the Viscozyme, is quantified using alcohol oxidase and Purpald. This combined enzymatic and colorimetric procedure correctly determined the galacturonic acid and methanol content of purified, soluble citrus pectin. Application of the procedure to water insoluble pectins was evaluated with water insoluble material from apples and oranges. In both cases good agreement was obtained between this method and commonly used methods based on chemical pectin hydrolysis. Good agreement between these procedures was also found in the analysis of both soluble and insoluble pectins from several tomato products.

  4. Origins of ultralow thermal conductivity in bulk [6,6]-phenyl-C61-butyric acid methyl ester (PCBM).

    PubMed

    Pöhls, Jan-Hendrik; Johnson, Michel B; White, Mary Anne

    2016-01-14

    Bulk PCBM has exceptionally low thermal conductivity, 0.07 W m(-1) K(-1) at room temperature. We show that its ultralow thermal conductivity is an intrinsic property. Based on results for thermal conductivity and heat capacity measurements down to <2 K, along with Raman spectroscopy and dilatometry, a new model for minimum thermal conductivity was developed. In the model the thermal energy is transferred between entities of phonons oscillating in a range of frequencies, and limited by the atomic density and the phonon mean speed. The model accurately represents the low thermal conductivity for both PCBM and C60/C70.

  5. Intermixing behaviors of PCBM with CuPc on Au(1 1 1) surface

    NASA Astrophysics Data System (ADS)

    Masui, Akane; Sakaue, Hiroyuki; Takahagi, Takayuki; Suzuki, Hitoshi

    2016-09-01

    The behavior of phenyl-C61-butyric acid methyl ester (PCBM) and copper-phthalocyanine (CuPc) on a Au(1 1 1) surface was investigated using scanning tunneling microscopy (STM). When CuPc was deposited in addition to PCBM it entered and disturbed the regularly spaced double row superstructure of the PCBM molecules. PCBM intermixed with CuPc to form a new square shaped superstructure that consisted of six to eight PCBM molecules with a CuPc molecule in its center. The intermixing of these materials that was observed indicated that they possessed an attractive interaction.

  6. Cocaine, norcocaine, ecgonine methylester and benzoylecgonine pharmacokinetics in the rat.

    PubMed

    Mets, B; Diaz, J; Soo, E; Jamdar, S

    1999-01-01

    We have compared the pharmacokinetics of bolus dose cocaine administration with that of its three most important metabolites; norcocaine, ecgonine methylester, and benzoylecgonine and assessed whether kinetics are dose dependent at two equimolar doses equivalent to cocaine hydrochloride 2.5 and 5 mg/kg respectively. Forty-nine male Sprague-Dawley rats were randomly divided into 8 groups to receive i.v. either high (14.7 umol/kg) (HI) or low (7.3 umol/kg) (LO) bolus doses of cocaine or one of its metabolites. Arterial blood samples for cocaine and metabolite analysis were taken repetitively over the next 3 h. Equimolar bolus doses of these congeners showed biexponential plasma concentration decay curves which were fitted to a two compartment model and subjected to noncompartmental analysis. The plasma concentration time profiles were significantly different for the HI and LO doses administered for each congener. The elimination half-lives of cocaine and norcocaine were similar (28-33 min), that for ecgonine methylester (60-71 min) was approximately twice this and for benzoylecgonine was 40-44 min. Cocaine clearance (155-158 ml/kg/min) was found to be in the range found in other rat studies. Ecgonine methylester clearance and benzoylecgonine clearance were found to be one quarter and one eighth of this value respectively. The pharmacokinetic profile of these congeners was not dose dependent when the two doses administered were compared.

  7. The photovoltaic efficiency of the fabrication of copolymer P3HT:PCBM on different thickness nano-anatase titania as solar cell.

    PubMed

    Lazim, Haidar Gazy; Ajeel, Khalid I; Badran, Hussain A

    2015-06-15

    Organic solar cells based on (3-hexylthiophene):[6,6]-phenyl C61-butyric acid methylester (P3HT:PCBM) bulk heterojunction (BHJ) with an inverted structure have been fabricated using nano-anatase crystalline titanium dioxide (TiO2) as their electron transport layer, which was prepared on the indium tin oxide coated glass (ITO-glass), silicon wafer and glass substrates by sol-gel method at different spin speed by using spin-coating (1000, 2000 and 3,000 rpm) for nano-thin film 58, 75 and 90 nm respectively. The effect of thickness on the surface morphology and optical properties of TiO2 layer were investigated by atomic force microscopy (AFM), X-ray diffraction and UV-visible spectrophotometer. The optical band gap of the films has been found to be in the range 3.63-3.96 eV for allowed direct transition and to be in the range 3.23-3.69 eV for forbidden direct transition to the different TiO2 thickness. The samples were examined to feature current and voltages darkness and light extraction efficiency of the solar cell where they were getting the highest open-circuit voltage, Voc, and power conversion efficiency were 0.66% and 0.39% fabricated with 90 nm respectively. PMID:25819135

  8. Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends.

    PubMed

    McLeod, John A; Pitman, Amy L; Kurmaev, Ernst Z; Finkelstein, Larisa D; Zhidkov, Ivan S; Savva, Achilleas; Moewes, Alexander

    2015-12-14

    The electronic structure of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and P3HT/PCBM blends is studied using soft X-ray emission and absorption spectroscopy and density functional theory calculations. We find that annealing reduces the HOMO-LUMO gap of P3HT and P3HT/PCBM blends, whereas annealing has little effect on the HOMO-LUMO gap of PCBM. We propose a model connecting torsional disorder in a P3HT polymer to the HOMO-LUMO gap, which suggests that annealing helps to decrease the torsional disorder in the P3HT polymers. Our model is used to predict the characteristic length scales of the flat P3TH polymer segments in P3HT and P3HT/PCBM blends before and after annealing. Our approach may prove useful in characterizing organic photovoltaic devices in situ or even in operando.

  9. Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

    NASA Astrophysics Data System (ADS)

    McLeod, John A.; Pitman, Amy L.; Kurmaev, Ernst Z.; Finkelstein, Larisa D.; Zhidkov, Ivan S.; Savva, Achilleas; Moewes, Alexander

    2015-12-01

    The electronic structure of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and P3HT/PCBM blends is studied using soft X-ray emission and absorption spectroscopy and density functional theory calculations. We find that annealing reduces the HOMO-LUMO gap of P3HT and P3HT/PCBM blends, whereas annealing has little effect on the HOMO-LUMO gap of PCBM. We propose a model connecting torsional disorder in a P3HT polymer to the HOMO-LUMO gap, which suggests that annealing helps to decrease the torsional disorder in the P3HT polymers. Our model is used to predict the characteristic length scales of the flat P3TH polymer segments in P3HT and P3HT/PCBM blends before and after annealing. Our approach may prove useful in characterizing organic photovoltaic devices in situ or even in operando.

  10. Influences of thermal annealing on P3HT/PCBM interfacial properties and charge dynamics in polymer solar cells

    NASA Astrophysics Data System (ADS)

    Cheng, Cheng-En; Dinelli, Franco; Yu, Chen-Te; Shih, Hwa-Wei; Pei, Zingway; Chang, Chen-Shiung; Shih-Sen Chien, Forest

    2015-12-01

    The effects of thermal annealing on the interfacial properties of poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl C61 butyric acid methyl ester (PCBM) and on the charge dynamics in P3HT:PCBM polymer solar cells (PSCs) are investigated. This study determines that an effective phase separation of the P3HT and PCBM caused by thermal annealing achieves a larger interfacial area for efficient exciton dissociation and a well-defined pn junction with few defect levels at the P3HT/PCBM interface. Additionally, thermal annealing creates a compositional gradient across the P3HT:PCBM films, which enhances the charge transit ability significantly. These improved interfacial properties and efficiency in charge transit ability account for the better power conversion efficiency of P3HT:PCBM PSCs treated with thermal annealing.

  11. Nanostructure-Driven Ion Transport in PCBM-Based Polymer Electrolytes

    SciTech Connect

    Sun, Che-Nan; Zawodzinski, Thomas A; Ren, Fei; Keum, Jong Kahk; Chen, Jihua

    2014-01-01

    Nanostructure-Driven Ion Transport in PCBM-Based Polymer Electrolytes Che-Nan Sun1, Thomas A. Zawodzinski1,2, Fei Ren3, Jong Kahk Keum1 and Jihua Chen1, (1)Oak Ridge National Laboratory, (2)The University of Tennessee, (3)Temple University Polyethylene oxide or PEO is an extensively-examined candidate for solid polymer electrolyte materials of lithium ion batteries, and its composite electrolytes has promising ion conductivities.[1-3] Oxide nanoparticles with sizes of 5-10 nm are often introduced into these polymer-based composite electrolytes in order to suppress their room-temperature crystallite formation.1-9 The size, geometry and surface functionality of the added particles were known to largely affect the structure and performance of the blended electrolytes.5,10 In this study, we examined a functionalized-fullerene-based composite electrolytes, providing details in their self-assembled nanostructures, modulus, hardness, as well as temperature-dependent ion-conducting behaviors. To the best of our knowledge, no fullerene-based, lithium conducting, composite electrolyte has been reported previously. Herein we used a bench-mark fullerene derivative, phenyl-C61-butyric acid methyl ester (PCBM) as a model fullerene compound and performed impedance spectroscopy, equivalent circuit modeling, nanoscale elemental mapping (in transmission electron microscope), wide-angle X-ray diffraction, as well as nanoindentation to shed light on a 6-fold enhancement in low temperature (less than 50oC) ion conductivity of PEO - lithium bis(trifluoromethanesulfonyl) imide (LiTFSI)-PCBM electrolytes, along with the underlying changes in nanomorphology , mechanical properties, and crystal structures. Based on a previous density functional theory (DFT) calculation, 11 the interaction energies Ei among PEO polymers is estimated to be 2.58 kcal mol-1 per monomer, the Ei between PCBM and PEO is 3.50 kcal mol-1 per monomer (PCBM is taken as 1 repeat unit), and the Ei among PCBMs themselves

  12. Study of the P3HT/PCBM interface using photoemission yield spectroscopy

    NASA Astrophysics Data System (ADS)

    Grzibovskis, Raitis; Vembris, Aivars

    2016-04-01

    Photogeneration efficiency and charge carrier extraction from active layer are the parameters that determine the efficiency of organic photovoltaics (OPVs). Devices made of organic materials often consist of thin (up to 100nm) layers. At this thickness different interface effects become more pronounced. The electron affinity and ionization energy shift can affect the charge carrier transport across metal-organic interface which can affect the performance of the entire device. In the case of multilayer OPVs, energy level compatibility at the organic-organic interface is as important. Photoemission yield spectroscopy was used for organic-organic interface study by ionization energy measurements. In this work we studied "sandwich" type samples of two well-known organic photovoltaic materials- poly(3- hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). Ionization energy changes at the P3HT/PCBM interface depending on PCBM layer thickness were studied. P3HT layer was obtained by spin-coating while PCBM was deposited on the P3HT by thermal evaporation in vacuum. No ionization energy shift of P3HT was observed. On the contrary, PCBM at the interface with P3HT created additional 0.40eV barrier for hole transport from PCBM to P3HT.

  13. Spin-dependent charge carrier recombination in PCBM

    NASA Astrophysics Data System (ADS)

    Morishita, Hiroki; Baker, William; Waters, David; Baarda, Rachel; Lupton, John; Boehme, Christoph; Utah Spin Electronics Group Collaboration; Lupton Group Collaboration

    2013-03-01

    We present room temperature pulsed electrically detected magnetic resonance (pEDMR) measurements on [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) (electron acceptor) thin film unipolar and bipolar devices. Our study aimed at identifying the dominating spin-dependent transport and recombination processes therein. Experimentally, the devices were operated under a constant positive bias, and the resultant transient current response was then monitored after the application of a short resonant microwave pulse excitation. The measurements did not reveal any observable signal for unipolar electron devices which suggests that spin-dependent transport mechanisms are not dominant in PCBM. However, under bipolar injection, at least two pronounced spin-dependent signals were detected whose magnitudes increased as the devices degraded upon exposure to air. Electrical detection of spin-Rabi beat oscillation revealed that one of these two signals is due to weakly coupled pairs of spins with s =1/2. We therefore attribute this signal to electron-hole recombination. This observation shows that while PCBM is a poor hole conductor, hole injection can be significant.

  14. Electronic excitation induced modifications of optical and morphological properties of PCBM thin films

    NASA Astrophysics Data System (ADS)

    Sharma, T.; Singhal, R.; Vishnoi, R.; Sharma, P.; Patra, A.; Chand, S.; Lakshmi, G. B. V. S.; Biswas, S. K.

    2016-07-01

    Phenyl C61 butyric acid methyl ester (PCBM) is a fullerene derivative and most commonly used in organic photovoltaic devices both as electron acceptor and transporting material due to high electron mobility. PCBM is easy to spin caste on some substrate as it is soluble in chlorobenzene. In this study, the spin coated thin films of PCBM (on two different substrate, glass and double sided silicon) were irradiated using 90 MeV Ni7+ swift heavy ion beam at low fluences ranging from 1 × 109 to 1 × 1011 ions/cm2 to study the effect of ion beam irradiation. The pristine and irradiated PCBM thin films were characterized by UV-visible absorption spectroscopy and fourier transform infrared spectroscopy (FTIR) to investigate the optical properties before and after irradiation. These thin films were further analyzed using atomic force microscopy (AFM) to investigate the morphological modifications which are induced by energetic ions. The variation in optical band gap after irradiation was measured using Tauc's relation from UV-visible absorption spectra. A considerable change was observed with increasing fluence in optical band gap of irradiated thin films of PCBM with respect to the pristine film. The decrease in FTIR band intensity of C60 cage reveals the polymerization reaction due to high energy ion impact. The roughness is also found to be dependent on incident fluences. This study throws light for the application of PCBM in organic solar cells in form of ion irradiation induced nanowires of PCBM for efficient charge carrier transportation in active layer.

  15. Synthesis, Characterization and Performance of P3HT-Azide-PCBM Microgel.

    PubMed

    Wei, Guangmin; Li, Xinxin; Jia, Di; Cheng, He

    2016-06-01

    Spherical Poly(3-hexylthiophene)-azide-[6,61-phenyl-C61-butyric acid methyl ester (P3HT-azide-PCBM) microgel was synthesized by introducing an azide cross-linkable group into the conjugated polymer. Its UV-vis spectrum shifts blue as a result of the systematic disruption of planarity along the P3HT backbone and a reduction in long range conjugation. And the corresponding fluorescence spectrum also indicates that a strong intra-molecular photo-induced electron transfer is originated from the covalent linkage of PCBM moiety to the P3HT backbone via the hexyl bridge upon photoexcitation. Combined Gel Permeation Chromatography (GPC), dynamic and static light scattering (DLS and SLS) measurements prove that the resultant P3HT-azide-PCBM copolymer is a uniform spherical microgel with a hydrodynamic radius of 130 nm at room temperature. The spherical P3HT-azide-PCBM microgel can be used as electron donor or compatibilizer in bulk-heterojunction (BHJ) devices, but its introduction reduces the photovoltaic performance compared with the blend of P3HT/PCBM, because the hole mobility in the crosslinked polythiophene backbones is largely decreased. PMID:27427609

  16. Linking the HOMO-LUMO gap to torsional disorder in P3HT/PCBM blends

    SciTech Connect

    McLeod, John A.; Pitman, Amy L.; Moewes, Alexander; Kurmaev, Ernst Z.; Finkelstein, Larisa D.; Zhidkov, Ivan S.; Savva, Achilleas

    2015-12-14

    The electronic structure of [6,6]-phenyl C{sub 61} butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and P3HT/PCBM blends is studied using soft X-ray emission and absorption spectroscopy and density functional theory calculations. We find that annealing reduces the HOMO-LUMO gap of P3HT and P3HT/PCBM blends, whereas annealing has little effect on the HOMO-LUMO gap of PCBM. We propose a model connecting torsional disorder in a P3HT polymer to the HOMO-LUMO gap, which suggests that annealing helps to decrease the torsional disorder in the P3HT polymers. Our model is used to predict the characteristic length scales of the flat P3TH polymer segments in P3HT and P3HT/PCBM blends before and after annealing. Our approach may prove useful in characterizing organic photovoltaic devices in situ or even in operando.

  17. A QTAIM topological analysis of the P3HT-PCBM dimer

    NASA Astrophysics Data System (ADS)

    Rodríguez, Juan I.; Matta, Chérif F.; Uribe, Emilbus A.; Götz, Andreas W.; Castillo-Alvarado, F. L.; Molina-Brito, Bertha

    2016-01-01

    In order to cast some light onto the nature of the chemical bonding between a 8-unit oligomer of the poly(3-hexylthiophene) (P3HT) and the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in the two stables isomers reported recently [I. Gutiérrez-González, B. Molina-Brito, A.W. Götz, F.L. Castillo-Alvarado, J.I. Rodríguez, Chem. Phys. Lett. 612, 234 (2014)], we have performed a Bader's quantum theory of atoms in molecules (QTAIM) analysis. According to QTAIM, no covalent bonds are formed between P3HT and PCBM, and hydrogen and stacking interactions account for about 90% and 10% of the total number of bonds between P3HT and PCBM, respectively.

  18. Photo-response of a P3HT:PCBM blend in metal-insulator-semiconductor capacitors

    SciTech Connect

    Devynck, M.; Rostirolla, B.; Watson, C. P.; Taylor, D. M.

    2014-11-03

    Metal-insulator-semiconductor capacitors are investigated, in which the insulator is cross-linked polyvinylphenol and the active layer a blend of poly(3-hexylthiophene), P3HT, and the electron acceptor [6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM). Admittance spectra and capacitance-voltage measurements obtained in the dark both display similar behaviour to those previously observed in P3HT-only devices. However, the photo-capacitance response is significantly enhanced in the P3HT:PCBM case, where exciton dissociation leads to electron transfer into the PCBM component. The results are consistent with a network of PCBM aggregates that is continuous through the film but with no lateral interconnection between the aggregates at or near the blend/insulator interface.

  19. Fabrication of organic solar cells with design blend P3HT: PCBM variation of mass ratio

    NASA Astrophysics Data System (ADS)

    Supriyanto, Agus; Mustaqim, Amrina; Agustin, Maya; Ramelan, Ari H.; Suyitno; Septa Rosa, Erlyta; Yofentina; Nurosyid, Fahru

    2016-02-01

    Organic solar cells of FTO/PEDOT: PSS/P3HT: PCBM/Al has been fabricated, and its performance has been tested in dark and under various illumination of light intensity 1000 W/m2. The active materials used in this study are poly (3- hexylthiophene) (P3HT) and [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM). P3HT is the donor while PCBM acts as an acceptor. Variation of PCBM and P3HT are 1:1, 1:2, 1:3, 1:4 and 1:5. P3HT: PCBM was mixed by chlorobenzene solvents. The mixing was done by using the ultrasonic cleaner. The absorbance characterization using by UV-Visible Spectrometer Lambda 25 instrument and I-V characterization has been tested using a set of 2602A Keithley instrument. Absorbance characterization shows that two peaks are formed. The first peak in the range of 300 to 350 nm which is a range of PCBM and the second peak range from 450 to 600 nm which is a range of P3HT. As the mass ratio increases, the second peak of P3HT increases while the first peak does not change. The gap energy estimated by the Tauc method is 2.0 eV. I-V characterization of the efficiency was obtained. The efficiency of sample 1, 2, 3, 4, and 5 are 5.80x10-2%; 6.46x10-2%; 7.72x10-2%; 8.25x10-2% and 9.81x10-2%, respectively. The highest value of efficiency was obtained at mass ratio 1:5.

  20. A faux hawk fullerene with PCBM-like properties

    DOE PAGES

    San, Long K.; Bukovsky, Eric V.; Larson, Bryon W.; Whitaker, James B.; Deng, S. H.M.; Kopidakis, Nikos; Rumbles, Garry; Popov, Alexey A.; Chen, Yu-Sheng; Wang, Xue-Bin; et al

    2014-12-16

    Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion ofmore » 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)- can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F-. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/-) values of 2 and C60, -0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/-) of PCBM is -0.09 V). Time-resolved microwave conductivity charge-carrier yield × mobility values for organic photovoltaic active-layer-type blends of 2 and poly-3-hexylthiophene (P3HT) were comparable to those for equimolar blends of PCBM and P3HT. The structure of solvent-free crystals of 2 was determined by single-crystal X-ray diffraction. The number of nearest-neighbor fullerene–fullerene interactions with centroid

  1. A faux hawk fullerene with PCBM-like properties

    SciTech Connect

    San, Long K.; Bukovsky, Eric V.; Larson, Bryon W.; Whitaker, James B.; Deng, S. H.M.; Kopidakis, Nikos; Rumbles, Garry; Popov, Alexey A.; Chen, Yu-Sheng; Wang, Xue-Bin; Boltalina, Olga V.; Strauss, Steven H.

    2014-12-16

    Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion of 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)- can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F-. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/-) values of 2 and C60, -0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/-) of PCBM is -0.09 V). Time-resolved microwave conductivity charge-carrier yield × mobility values for organic photovoltaic active-layer-type blends

  2. A faux hawk fullerene with PCBM-like properties

    DOE PAGES

    San, Long K.; Bukovsky, Eric V.; Larson, Bryon W.; Whitaker, James B.; Deng, Shihu; Kopidakis, Nikos; Rumbles, Garry; Popov, Alexey A.; Chen, Yu-Sheng; Wang, Xue B.; et al

    2014-12-16

    Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion ofmore » 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)- can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F-. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/-) values of 2 and C60, -0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/-) of PCBM is -0.09 V). Time-resolved microwave conductivity charge-carrier yield x mobility values for organic photovoltaic active-layer-type blends of 2 and poly-3-hexylthiophene (P3HT) were comparable to those for equimolar blends of PCBM and P3HT. The structure of solvent-free crystals of 2 was determined by single-crystal X-ray diffraction. The number of nearest-neighbor fullerene–fullerene interactions with centroid

  3. A faux hawk fullerene with PCBM-like properties

    SciTech Connect

    San, Long K.; Bukovsky, Eric V.; Larson, Bryon W.; Whitaker, James B.; Deng, Shihu; Kopidakis, Nikos; Rumbles, Garry; Popov, Alexey A.; Chen, Yu-Sheng; Wang, Xue B.; Boltalina, Olga V.; Strauss, Steven H.

    2014-12-16

    Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion of 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)- can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F-. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/-) values of 2 and C60, -0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/-) of PCBM is -0.09 V). Time-resolved microwave conductivity charge-carrier yield x mobility values for organic

  4. Morphology Evolution of Molecular Weight Dependent P3HT: PCBM Solar Cells

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Chen, Dian; Briseno, Alejandro; Russell, Thomas

    2011-03-01

    Effective strategies to maximize the performance of bulk heterojunction (BHJ) photovoltaic devices have to be developed and understood to realize their full potential. In BHJ solar cells, the morphology of the active layer is a critical issue to improve device efficiency. In this work, we choose poly(3-hexyl-thiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) system to study the morphology evolution. Different molecular weight P3HTs were synthesized by using Grignard Metathesis (GRIM)~method. In device optimization, polymer with a molecular weight between 20k-30k shows the highest efficiency. It was observed that the as-spun P3HT: PCBM (1:1) blends do not have high order by GISAXS. Within a few seconds of thermal annealing at 150& circ; the crystallinity of P3HT increaased substantially and the polymer chains adopted an edge-on orientation. An-bicontinous morphology was also developed within this short thermal treatment. The in situ GISAXS experiment showed that P3HT of high molecular weight was more easily crystallized from a slowly evaporated chlorobenzene solution and their edge-on orientation is much more obvious than for the lower molecular weight P3HTs. DSC was used to study the thermal properties of P3HTs and P3HT: PCBM blend. The χ of P3HT-PCBM was also calculated by using melting point depression method.

  5. Absorption Mechanism of a Physical Complex of Monomeric Insulin and Deoxycholyl-l-lysyl-methylester in the Small Intestine.

    PubMed

    Mahmud, Foyez; Jeon, Ok-Cheol; Al-Hilal, Taslim A; Kweon, Seho; Yang, Victor C; Lee, Dong Soo; Byun, Youngro

    2015-06-01

    Currently, oral administration of insulin still remains the best option to avoid the burden of repeated subcutaneous injections and to improve its pharmacokinetics. The objective of the present investigation was to demonstrate the absorption mechanism of insulin in the physical complexation of deoxycholyl-l-lysyl-methylester (DCK) for oral delivery. The oral insulin/DCK complex was prepared by making a physical complex of insulin aspart with DCK through ion-pair interaction in water. For the cellular uptake study, fluorescein-labeled insulin or DCK were prepared according to a standard protocol and applied to Caco-2 or MDCK cell lines. For the PK/PD studies, we performed intrajejunal administration of different formulation of insulin/DCK complex to diabetic rats. The resulting insulin and DCK complex demonstrated greatly enhanced lipophilicity as well as increased permeation across Caco-2 monolayers. The immunofluorescence study revealed the distribution of the complex in the cytoplasm of Caco-2 cells. Moreover, in the apical sodium bile acid transporter (ASBT) transfected MDCK, the insulin/DCK complex showed interaction with ASBT, and also demonstrated absorption through passive diffusion. We could not find that any evidence of endocytosis in relation to the uptake of insulin complex in vitro. In the rat intestine model, the highest absorption of insulin complex was observed in the jejunum at 1 h and then in the ileum at 2-4 h. In PK/PD study, the complex showed a similar PK profile to that of SC insulin. Overall, the study showed that the effect of DCK on enhancing the absorption of insulin resulted from transcellular processes as well as bile acid transporter activity.

  6. New Insights into Dynamics and Morphology of P3HT:PCBM Active Layers in Bulk Heterojunctions

    SciTech Connect

    Carrillo, Jan-Michael Y.; Kumar, Rajeev; Goswami, Monojoy; Sumpter, Bobby G.; Brown, W. Michael

    2013-08-30

    Organic photovoltaics (OPVs) are topic of extensive research for their potential application in solar cells. Recent work has led to the development of a coarse-grained model for studying poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blends with molecular simulations. Here we provide further validation of the force field and use it to study the thermal annealing process of P3HT:PCBM blends. A key finding of our study is that, in contrast to a previous report, the annealing process does not converge at the short time scales reported. Rather, we find that the self assembly of the blends is characterized by three rate dependent stages that require much longer simulations to approach convergence. Using state-of-the- art high performance computing, we are able to study annealing at length and time scales commensurate with devices used in experiments. Our simulations show different phase segregated morphologies dependent on the P3HT chain length and PCBM volume fraction in the blend. For short chain lengths, we observed a smectic morphology containing alternate P3HT and PCBM domains. In contrast, a phase segregated morphology containing domains of P3HT and PCBM distributed randomly in space is found for longer chain lengths. Theoretical arguments justifying stabilization of these morphologies due to shape anisotropy of P3HT (rod-like) and PCBM (sphere-like) are presented. Furthermore, results on structure factor, miscibility of P3HT and PCBM, domain spacing and kinetics of phase segregation in the blends are presented in detail. Qualitative comparison of these results with small-angle neutron scattering experiments from literature is presented and an excellent agreement is found.

  7. Solubility of C60 and PCBM in Organic Solvents.

    PubMed

    Wang, Chun I; Hua, Chi C

    2015-11-12

    The ability to correlate fullerene solubility with experimentally or computationally accessible parameters can significantly facilitate nanotechnology nowadays for a wide range of applications, while providing crucial insight into optimum design of future fullerene species. To date, there has been no single relationship that satisfactorily describes the existing data clearly manifesting the effects of solvent species, system temperature, and isomer. Using atomistic molecular dynamics simulations on two standard fullerene species, C60 and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), in a representative series of organic solvent media (i.e., chloroform, toluene, chlorobenzene, 1,3-dichlorobenzene, and 1,2-dichlorobenzene), we show that a single time constant characterizing the dynamic stability of a tiny (angstrom-sized) solvation shell encompassing the fullerene particle can be utilized to effectively capture the known trends of fullerene solubility as reported in the literature. The underlying physics differs substantially between the two fullerene species, however. Although C60 was previously shown to be dictated by a diffusion-limited aggregation mechanism, the side-chain-substituted PCBM is demonstrated herein to proceed with an analogous reaction-limited aggregation with the "reaction rate" set by the fullerene rotational diffusivity in the medium. The present results suggest that dynamic quantities-in contrast to the more often employed, static ones-may provide an excellent means to characterize the complex (entropic and enthalpic) interplay between fullerene species and the solvent medium, shed light on the factors determining the solvent quality of a nanoparticle solution, and, in particular, offer a practical pathway to foreseeing optimum fullerene design and fullerene-solvent interactions. PMID:26488132

  8. Field-effect transistor structures on the basis of poly(3-hexylthiophene), fullerene derivatives [60]PCBM, [70]PCBM, and nickel nanoparticles

    NASA Astrophysics Data System (ADS)

    Aleshin, A. N.; Shcherbakov, I. P.; Trapeznikova, I. N.; Petrov, V. N.

    2016-09-01

    Organic field-effect transistor (OFET) structures with the active layers on the basis of composite films of semiconductor polymer poly(3-hexylthiophene) (P3HT), fullerene derivatives [60]PCBM, [70]PCBM, and nickel (Ni) nanoparticles are obtained, and their optical, electrical, and photoelectrical properties are studied. It is shown that introducing Ni nanoparticles into P3HT: [60]PCBM and P3HT: [70]PCBM films leads to an increase in the absorption and to quenching of photoluminescence of the composite in the 400-600 nm spectral band due to the plasmon effect. In P3HT: [60]PCBM: Ni and P3HT: [70]PCBM: Ni OFET structures at the P3HT: [60]PCBM and P3HT: [70]PCBM concentrations of ~1: 1 and Ni concentrations of ~3-5 wt %, current-voltage ( I-V) characteristics typical of ambipolar OFETs with the dominant hole conduction are observed. The charge-carrier (hole) mobilities calculated from the I-V characteristic at V G =-10 V were found to be ~0.46 cm2/(V s) for P3HT: [60]PCBM: Ni and ~4.7 cm2/(V s) for P3HT: [70]PCBM: Ni, which means that the mobility increases if [60]PCBM in the composition is replaced with [70]PCBM. The effect of light on the I-V characteristics of P3HT: [60]PCBM: Ni and P3HT: [70]PCBM: Ni OFETs is studied.

  9. Exceptionally low thermal conductivities of films of the fullerene derivative PCBM.

    PubMed

    Duda, John C; Hopkins, Patrick E; Shen, Yang; Gupta, Mool C

    2013-01-01

    We report on the thermal conductivities of microcrystalline [6,6]-phenyl C(61)-butyric acid methyl ester (PCBM) thin films from 135 to 387 K as measured by time domain thermoreflectance. Thermal conductivities are independent of temperature above 180 K and less than 0.030 ± 0.003 W m(-1) K(-1) at room temperature. The longitudinal sound speed is determined via picosecond acoustics and is found to be 30% lower than that in C(60)/C(70) fullerite compacts. Using Einstein's model of thermal conductivity, we find the Einstein characteristic frequency of microcrystalline PCBM is 2.88 × 10(12) rad s(-1). By comparing our data to previous reports on C(60)/C(70) fullerite compacts, we argue that the molecular tails on the fullerene moieties in our PCBM films are responsible for lowering both the apparent sound speeds and characteristic vibrational frequencies below those of fullerene films, thus yielding the exceptionally low observed thermal conductivities.

  10. Exceptionally low thermal conductivities of films of the fullerene derivative PCBM.

    PubMed

    Duda, John C; Hopkins, Patrick E; Shen, Yang; Gupta, Mool C

    2013-01-01

    We report on the thermal conductivities of microcrystalline [6,6]-phenyl C(61)-butyric acid methyl ester (PCBM) thin films from 135 to 387 K as measured by time domain thermoreflectance. Thermal conductivities are independent of temperature above 180 K and less than 0.030 ± 0.003 W m(-1) K(-1) at room temperature. The longitudinal sound speed is determined via picosecond acoustics and is found to be 30% lower than that in C(60)/C(70) fullerite compacts. Using Einstein's model of thermal conductivity, we find the Einstein characteristic frequency of microcrystalline PCBM is 2.88 × 10(12) rad s(-1). By comparing our data to previous reports on C(60)/C(70) fullerite compacts, we argue that the molecular tails on the fullerene moieties in our PCBM films are responsible for lowering both the apparent sound speeds and characteristic vibrational frequencies below those of fullerene films, thus yielding the exceptionally low observed thermal conductivities. PMID:23383810

  11. Studies on stability of bi-functional P3HT:PCBM:rubrene optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Gaur, Ankita; Kumar, Pankaj

    2013-06-01

    Investigations are carried out for stability in photovoltaic response of bifunctional electroluminescent and photovoltaic devices, based on ternary blend of poly(3-hexylthiophene) (P3HT), phenyl [6,6']C61 butyric acid methyl ester (PCBM), and 5,6,11,12-tetraphenylnaphthacene (rubrene). P3HT and PCBM are important and the most frequent materials used for photovoltaic applications, therefore, for relative comparison, photovoltaic cells were also prepared using a binary mixture of P3HT and PCBM. Devices based on the ternary blend exhibited better stability in all photovoltaic parameters and the lifetime was almost doubled, but their photovoltaic efficiency was lower than that of those based on the binary blend. Longer lifetime of ternary blend devices is because of a relatively better thermal, electrochemical, and morphological stabilities of the ternary blend system. However, the lower efficiencies are because of the reduced photo-current and low fill factor ( FF) due to an increased recombination and introduction of defects/trapping sites by rubrene molecules.

  12. Enhanced Charge Separation in Ternary P3HT/PCBM/CuInS2 Nanocrystals Hybrid Solar Cells

    PubMed Central

    Lefrançois, Aurélie; Luszczynska, Beata; Pepin-Donat, Brigitte; Lombard, Christian; Bouthinon, Benjamin; Verilhac, Jean-Marie; Gromova, Marina; Faure-Vincent, Jérôme; Pouget, Stéphanie; Chandezon, Frédéric; Sadki, Saïd; Reiss, Peter

    2015-01-01

    Geminate recombination of bound polaron pairs at the donor/acceptor interface is one of the major loss mechanisms in organic bulk heterojunction solar cells. One way to overcome Coulomb attraction between opposite charge carriers and to achieve their full dissociation is the introduction of high dielectric permittivity materials such as nanoparticles of narrow band gap semiconductors. We selected CuInS2 nanocrystals of 7.4 nm size, which present intermediate energy levels with respect to poly(3-hexylthiophene) (P3HT) and Phenyl-C61-butyric acid methyl ester (PCBM). Efficient charge transfer from P3HT to nanocrystals takes place as evidenced by light-induced electron spin resonance. Charge transfer between nanocrystals and PCBM only occurs after replacing bulky dodecanethiol (DDT) surface ligands with shorter 1,2-ethylhexanethiol (EHT) ligands. Solar cells containing in the active layer a ternary blend of P3HT:PCBM:CuInS2-EHT nanocrystals in 1:1:0.5 mass ratio show strongly improved short circuit current density and a higher fill factor with respect to the P3HT:PCBM reference device. Complementary measurements of the absorption properties, external quantum efficiency and charge carrier mobility indicate that enhanced charge separation in the ternary blend is at the origin of the observed behavior. The same trend is observed for blends using the glassy polymer poly(triarylamine) (PTAA). PMID:25588811

  13. Enhanced Charge Separation in Ternary P3HT/PCBM/CuInS2 Nanocrystals Hybrid Solar Cells

    NASA Astrophysics Data System (ADS)

    Lefrançois, Aurélie; Luszczynska, Beata; Pepin-Donat, Brigitte; Lombard, Christian; Bouthinon, Benjamin; Verilhac, Jean-Marie; Gromova, Marina; Faure-Vincent, Jérôme; Pouget, Stéphanie; Chandezon, Frédéric; Sadki, Saïd; Reiss, Peter

    2015-01-01

    Geminate recombination of bound polaron pairs at the donor/acceptor interface is one of the major loss mechanisms in organic bulk heterojunction solar cells. One way to overcome Coulomb attraction between opposite charge carriers and to achieve their full dissociation is the introduction of high dielectric permittivity materials such as nanoparticles of narrow band gap semiconductors. We selected CuInS2 nanocrystals of 7.4 nm size, which present intermediate energy levels with respect to poly(3-hexylthiophene) (P3HT) and Phenyl-C61-butyric acid methyl ester (PCBM). Efficient charge transfer from P3HT to nanocrystals takes place as evidenced by light-induced electron spin resonance. Charge transfer between nanocrystals and PCBM only occurs after replacing bulky dodecanethiol (DDT) surface ligands with shorter 1,2-ethylhexanethiol (EHT) ligands. Solar cells containing in the active layer a ternary blend of P3HT:PCBM:CuInS2-EHT nanocrystals in 1:1:0.5 mass ratio show strongly improved short circuit current density and a higher fill factor with respect to the P3HT:PCBM reference device. Complementary measurements of the absorption properties, external quantum efficiency and charge carrier mobility indicate that enhanced charge separation in the ternary blend is at the origin of the observed behavior. The same trend is observed for blends using the glassy polymer poly(triarylamine) (PTAA).

  14. Monitoring the dynamics of miscible P3HT:PCBM blends: A quasi elastic neutron scattering study of organic photovoltaic active layers

    DOE PAGES

    Etampawala, Thusitha; Ratnaweera, Dilru; Morgan, Brian; Diallo, Souleymane; Mamontov, Eugene; Dadmun, Mark

    2015-02-02

    Our work reports on the detailed molecular dynamic behavior of miscible blends of Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and their pure counterparts by quasi-elastic neutron scattering measurements (QENS). The study provides the measure of relaxation processes on pico-to-nanosecond time scales. A single relaxation process was observed in pure P3HT and PCBM while two relaxation processes, one fast and one slow, were observed in the blends. The fast process was attributed to the dynamics of P3HT while the slow process was correlated to the dynamics of PCBM. The results show that the relaxation process is a balance betweenmore » two opposing effects: increased mobility due to thermal activation of P3HT molecules and decrease mobility due to the presence of PCBM which is correlated to the percent crystallinity of P3HT and local packing density of PCBM in the amorphous phase. The threshold for the domination of the thermally activated relaxation is between 5 and 9 vol.% of PCBM loading. Two distinct spatial dependences of the relaxation processes, in which the crossover length scale depends neither on temperature nor composition, were observed for all the samples. They were attributed to the collective motions of the hexyl side chains and the rotational motions of the C-C single bonds of the side chains. Finally, these results provide an understanding of the effects of PCBM loading and temperature on the dynamics of the polymer-fullerene blends which provides a tool to optimize the efficiency of charge carrier and exciton transport within the organic photovoltaic (OPV) active layer to improve the high performance of organic solar cells.« less

  15. Monitoring the dynamics of miscible P3HT:PCBM blends: A quasi elastic neutron scattering study of organic photovoltaic active layers

    SciTech Connect

    Etampawala, Thusitha; Ratnaweera, Dilru; Morgan, Brian; Diallo, Souleymane; Mamontov, Eugene; Dadmun, Mark

    2015-02-02

    Our work reports on the detailed molecular dynamic behavior of miscible blends of Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and their pure counterparts by quasi-elastic neutron scattering measurements (QENS). The study provides the measure of relaxation processes on pico-to-nanosecond time scales. A single relaxation process was observed in pure P3HT and PCBM while two relaxation processes, one fast and one slow, were observed in the blends. The fast process was attributed to the dynamics of P3HT while the slow process was correlated to the dynamics of PCBM. The results show that the relaxation process is a balance between two opposing effects: increased mobility due to thermal activation of P3HT molecules and decrease mobility due to the presence of PCBM which is correlated to the percent crystallinity of P3HT and local packing density of PCBM in the amorphous phase. The threshold for the domination of the thermally activated relaxation is between 5 and 9 vol.% of PCBM loading. Two distinct spatial dependences of the relaxation processes, in which the crossover length scale depends neither on temperature nor composition, were observed for all the samples. They were attributed to the collective motions of the hexyl side chains and the rotational motions of the C-C single bonds of the side chains. Finally, these results provide an understanding of the effects of PCBM loading and temperature on the dynamics of the polymer-fullerene blends which provides a tool to optimize the efficiency of charge carrier and exciton transport within the organic photovoltaic (OPV) active layer to improve the high performance of organic solar cells.

  16. Formation of P3KHT:PCBM bulk-heterojunction using orthogonal solvents by ultrasonic spray method

    NASA Astrophysics Data System (ADS)

    Mahajan, Mrunal S.; Lonkar, Ganesh S.; Ghosh, Sanjay S.; Patil, Mahendra B.; Dalal, Dipak S.; Sali, Jaydeep V.

    2015-07-01

    Bulk-heterojunction (BHJ) morphologies with pure domains and sharp interfaces can lead to a more pronounced photovoltaic performance in organic solar cells. In this paper we report the formation of bulk-heterojunction of P3KHT (poly [3-(sodium-6 hexanoate) thiophene-2, 5-diyl]) and PCBM (phenyl-C61-butyric acid methyl ester) using orthogonal solvents by the ultrasonic spray method, which can lead to pure phases and sharp interfaces. P3KHT and PCBM are soluble in water and chlorobenzene respectively, which are orthogonal solvents. The modelling and simulation of the ultrasonic spray method is reported, and shows the possibility of formation of interconnecting phases of the two components in P3KHT:PCBM BHJ, formed using orthogonal solvents, if specific process parameters are chosen. The modelling and simulation also presents a way to determine optimum parameter space in an intermittent spray deposition method using orthogonal solvents. P3KHT:PCBM BHJ has been prepared using three different approaches. Significant photoluminescence quenching, suggesting efficient excitons separation before recombination has been observed in BHJ prepared by the ‘emulsion of solutions’ method. The study of the optical properties of P3KHT:PCBM BHJ suggests that the BHJ may contain bilayer type structures embedded in the BHJ morphology, which is further confirmed by complementary experiments. This new approach to preparing BHJ with pure phase domains and sharp donor/acceptor interfaces may find applications in optoelectronic devices such as organic thin-film transistors, photodetectors, organic light emitting diodes and organic solar cells.

  17. Charge generation and morphology in P3HT : PCBM nanoparticles prepared by mini-emulsion and reprecipitation methods

    NASA Astrophysics Data System (ADS)

    Schwarz, Kyra N.; Farley, Sam B.; Smith, Trevor A.; Ghiggino, Kenneth P.

    2015-11-01

    Organic semiconductor nanoparticles provide a potentially scalable approach for photovoltaics that can be processed from aqueous media. Particles of poly(3-hexylthiophene) (P3HT) : phenyl-C61-butyric acid methyl ester (PCBM) were prepared using two techniques; those produced by a mini-emulsion method contained greater amounts of crystalline P3HT domains with charge generation resembling phase-separated annealed solvent-cast films.Organic semiconductor nanoparticles provide a potentially scalable approach for photovoltaics that can be processed from aqueous media. Particles of poly(3-hexylthiophene) (P3HT) : phenyl-C61-butyric acid methyl ester (PCBM) were prepared using two techniques; those produced by a mini-emulsion method contained greater amounts of crystalline P3HT domains with charge generation resembling phase-separated annealed solvent-cast films. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06244f

  18. Thermally induced vertical phase separation and photovoltaic characteristics of polymer solar cells for P3HT/PCBM composites

    NASA Astrophysics Data System (ADS)

    Nagai, Masaru; Wei, Huang; Yoshida, Yuji

    2016-06-01

    The occurrence of vertical phase separation has been reported for various spin-cast polymer films, including bulk-heterojunction films of polymer solar cells (PSCs). Focusing on real-space analysis, we conducted a study on the relationship between the morphology and processing conditions of PSCs for typical poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) cells. Our results demonstrated that spin-casting caused a localized reduction in the P3HT concentration in the bulk center. Thermal annealing after cathode formation enhanced the unevenness in concentration and created a multilayered vertical phase-separated morphology in which the P3HT domains were gathered near the electrodes, leaving only PCBM domains at the center of the film. Cells with this morphology had good power conversion efficiency (∼3%).

  19. Phonon-assisted ultrafast charge separation in the PCBM band structure

    NASA Astrophysics Data System (ADS)

    Smith, Samuel L.; Chin, Alex W.

    2015-05-01

    Organic solar cells separate strongly bound electron-hole pairs into free charges at interfaces between electron donor and acceptor organic semiconductors. Recently, electron-hole separation was observed on femtosecond time scales near crystallite phases of the fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PCBM), which is incompatible with conventional Marcus theories of organic transport. Here we show that ultrafast charge transport in PCBM arises from its broad range of electronic eigenstates, provided by three closely spaced electronic bands near the lowest unoccupied molecular orbital. The highest band provides a charge transfer state resonant with delocalized states of the lower two bands away from the interface. This state acts as a bridge between the donor phase and the acceptor bulk, bypassing the trapped charge-transfer (CT) states below. Vibrational fluctuations enable rapid electronic transitions across this bridge, which can drive the electron more than 4 nm away from the interface within 100 fs. All this is demonstrated within a simple tight-binding Hamiltonian containing transfer integrals no larger than 8 meV.

  20. Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with Nonlinear Quantum Corrections

    DOE PAGES

    Wang, Lei; Jakowski, Jacek; Garashchuk, Sophya; Sumpter, Bobby G.

    2016-08-09

    The experimentally observed effect of selective deuterium substitution on the open circuit voltage for a blend of poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C61- butyric acid methyl ester (PCBM) (Nat. Commun. 5:3180, 2014) is explored using a 221-atom model of a polymer-wrapped PCBM molecule. We describe the protonic and deuteronic wavefunctions for the H/D isotopologues of the hexyl side chains within a Quantum Trajectory/Electronic Structure approach where the dynamics is performed with newly developed nonlinear corrections to the quantum forces, necessary to describe the nuclear wavefunctions; the classical forces are generated with a Density Functional Tight Binding method. We used the resulting protonic andmore » deuteronic time-dependent wavefunctions to assess the effects of isotopic substitution (deuteration) on the energy gaps relevant to the charge transfer for the donor and acceptor electronic states. Furthermore, while the isotope effect on the electronic energy levels is found negligible, the quantum-induced fluctuations of the energy gap between the charge transfer and charge separated states due to nuclear wavefunctions may account for experimental trends by promoting charge transfer in P3HT/PCBM and increasing charge recombination on the donor in the deuterium substituted P3HT/PCBM.« less

  1. Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with Nonlinear Quantum Corrections.

    PubMed

    Wang, Lei; Jakowski, Jacek; Garashchuk, Sophya; Sumpter, Bobby G

    2016-09-13

    The experimentally observed effect of selective deuterium substitution on the open circuit voltage for a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM; Nat. Commun. 2014, 5, 3180) is explored using a 221-atom model of a polymer-wrapped PCBM molecule. The protonic and deuteronic wave functions for the H/D isotopologues of the hexyl side chains are described within a quantum trajectory/electronic structure approach where the dynamics is performed with newly developed nonlinear corrections to the quantum forces, necessary to describe the nuclear wave functions; the classical forces are generated with a density functional tight binding method. The resulting protonic and deuteronic time-dependent wave functions are used to assess the effects of isotopic substitution (deuteration) on the energy gaps relevant to the charge transfer for the donor and acceptor electronic states. While the isotope effect on the electronic energy levels is found negligible, the quantum-induced fluctuations of the energy gap between the charge transfer and charge separated states due to nuclear wave functions may account for experimental trends by promoting charge transfer in P3HT:PCBM and increasing charge recombination on the donor in the deuterium substituted P3HT:PCBM.

  2. Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with Nonlinear Quantum Corrections.

    PubMed

    Wang, Lei; Jakowski, Jacek; Garashchuk, Sophya; Sumpter, Bobby G

    2016-09-13

    The experimentally observed effect of selective deuterium substitution on the open circuit voltage for a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM; Nat. Commun. 2014, 5, 3180) is explored using a 221-atom model of a polymer-wrapped PCBM molecule. The protonic and deuteronic wave functions for the H/D isotopologues of the hexyl side chains are described within a quantum trajectory/electronic structure approach where the dynamics is performed with newly developed nonlinear corrections to the quantum forces, necessary to describe the nuclear wave functions; the classical forces are generated with a density functional tight binding method. The resulting protonic and deuteronic time-dependent wave functions are used to assess the effects of isotopic substitution (deuteration) on the energy gaps relevant to the charge transfer for the donor and acceptor electronic states. While the isotope effect on the electronic energy levels is found negligible, the quantum-induced fluctuations of the energy gap between the charge transfer and charge separated states due to nuclear wave functions may account for experimental trends by promoting charge transfer in P3HT:PCBM and increasing charge recombination on the donor in the deuterium substituted P3HT:PCBM. PMID:27504981

  3. Mechanistic insights into UV-induced electron transfer from PCBM to titanium oxide in inverted-type organic thin film solar cells using AC impedance spectroscopy.

    PubMed

    Kuwabara, Takayuki; Iwata, Chiaki; Yamaguchi, Takahiro; Takahashi, Kohshin

    2010-08-01

    An inverted organic bulk-heterojunction solar cell containing amorphous titanium oxide (TiOx) as an electron collection electrode with the structure ITO/TiO(x)/[6,6]-phenyl C(61) butyric acid methyl ester (PCBM): regioregular poly(3-hexylthiophene) (P3HT)/poly(3,4-ethylenedioxylenethiophene):poly(4-styrene sulfonic acid)/Au (TiO(x) cell) was fabricated. Its complicated photovoltaic properties were investigated by photocurrent-voltage and alternating current impedance spectroscopy measurements. The TiO(x) cell required a significant amount of time (approximately 60 min) to reach its maximum power conversion efficiency (PCE) of 2.6%. To investigate the reason for this slow photoresponse, we investigated the influences of UV light and water molecules adsorbed on the TiO(x) layer. Surface treatment of the TiO(x) cell with water induced a rapid photoresponse and enhanced the performance, giving a PCE of 2.97%. However, the durability of the treated cell was considerably inferior that of the untreated cell because of UV-induced photodegradation. The cause of the rapid photoresponse of the treated cell was attributed to the formation of hydrogen bonds between adsorbed water molecules and carbonyl oxygen atoms in PCBM close to the TiO(x) surface. When the TiO(x) surface was positively charged by UV-induced holes, the carbonyl oxygen in PCBM close to the TiO(x) surface can quickly join to the TiO(x) surface, rapidly transporting photogenerated electrons from PCBM to TiO(x) in competition with the photocatalyzed degradation. The experimental results suggested that the slow photoresponse of the untreated TiO(x) cell was because the morphology of the photoactive organic layer changed gradually upon irradiation to improve the transport of photocarriers at the TiO(x)/PCBM:P3HT interface.

  4. Photodegradation of the electronic structure of PCBM and C60 films in air

    NASA Astrophysics Data System (ADS)

    Anselmo, Ana S.; Dzwilewski, Andrzej; Svensson, Krister; Moons, Ellen

    2016-05-01

    Fullerenes are common electron acceptors in organic solar cells. Here the photostability in air of the electronic structures of spin-coated PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and evaporated C60 films are studied using ultraviolet photoelectron spectroscopy (UPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. After exposing these materials in air to simulated sunlight, the filled and empty molecular orbitals are strongly altered, indicating that the conjugated π-system of the C60-cage has degraded. Even a few minutes in normal lab light induces changes. These results stress the importance of protecting fullerene-based films from light and air during processing, operation, and storage.

  5. Sequentially Different AB Diblock and ABA Triblock Copolymers as P3HT:PCBM Interfacial Compatibilizers for Bulk-Heterojunction Photovoltaics.

    PubMed

    Fujita, Hiroyuki; Michinobu, Tsuyoshi; Fukuta, Seijiro; Koganezawa, Tomoyuki; Higashihara, Tomoya

    2016-03-01

    The P3HT:PCBM (P3HT = poly(3-hexylthiophene, PCBM = phenyl-C61-butyric acid methyl ester) bulk-heterojunction (BHJ) organic photovoltaic (OPV) cells using the AB diblock and ABA triblock copolymers (A = polystyrene derivative with donor-acceptor units (PTCNE) and B = P3HT) as compatibilizers were fabricated. Under the optimized blend ratio of the block copolymer, the power conversion efficiency (PCE) was enhanced. This PCE enhancement was clearly related to the increased short-circuit current (J(sc)) and fill factor (FF). The incident photon to current efficiency (IPCE) measurement suggested that the P3HT crystallinity was improved upon addition of the block copolymers. The increased P3HT crystallinity was consistent with the increased photovoltaic parameters, such as J(sc), FF, and consequently the PCE. The surface energies of these block copolymers suggested their thermodynamically stable location at the interface of P3HT:PCBM, showing the efficient compatibilizing performance, resulting in enlarging and fixing the interfacial area and suppressing the recombination of the generated carriers. Grazing incidence X-ray scattering (GIXS) results confirmed the superior compatibilizing performance of the ABA triblock copolymer when compared to the AB diblock copolymer by the fact that, after blending the ABA triblock copolymer in the P3HT:PCBM system, the enhanced crystallinity of matrix P3HT was observed in the excluded areas of the less-aggregated PCBM domains, changing the P3HT crystalline domain orientation from "edge-on" to "isotropic". This is, to the best of our knowledge, the first sequential effect (AB vs ABA) of the block copolymers on the compatibilizing performances based on BHJ OPV device systems. PMID:26864393

  6. Sequentially Different AB Diblock and ABA Triblock Copolymers as P3HT:PCBM Interfacial Compatibilizers for Bulk-Heterojunction Photovoltaics.

    PubMed

    Fujita, Hiroyuki; Michinobu, Tsuyoshi; Fukuta, Seijiro; Koganezawa, Tomoyuki; Higashihara, Tomoya

    2016-03-01

    The P3HT:PCBM (P3HT = poly(3-hexylthiophene, PCBM = phenyl-C61-butyric acid methyl ester) bulk-heterojunction (BHJ) organic photovoltaic (OPV) cells using the AB diblock and ABA triblock copolymers (A = polystyrene derivative with donor-acceptor units (PTCNE) and B = P3HT) as compatibilizers were fabricated. Under the optimized blend ratio of the block copolymer, the power conversion efficiency (PCE) was enhanced. This PCE enhancement was clearly related to the increased short-circuit current (J(sc)) and fill factor (FF). The incident photon to current efficiency (IPCE) measurement suggested that the P3HT crystallinity was improved upon addition of the block copolymers. The increased P3HT crystallinity was consistent with the increased photovoltaic parameters, such as J(sc), FF, and consequently the PCE. The surface energies of these block copolymers suggested their thermodynamically stable location at the interface of P3HT:PCBM, showing the efficient compatibilizing performance, resulting in enlarging and fixing the interfacial area and suppressing the recombination of the generated carriers. Grazing incidence X-ray scattering (GIXS) results confirmed the superior compatibilizing performance of the ABA triblock copolymer when compared to the AB diblock copolymer by the fact that, after blending the ABA triblock copolymer in the P3HT:PCBM system, the enhanced crystallinity of matrix P3HT was observed in the excluded areas of the less-aggregated PCBM domains, changing the P3HT crystalline domain orientation from "edge-on" to "isotropic". This is, to the best of our knowledge, the first sequential effect (AB vs ABA) of the block copolymers on the compatibilizing performances based on BHJ OPV device systems.

  7. Human macrophage colony-stimulating factor induces macrophage colonies after L-phenylalanine methylester treatment of human marrow.

    PubMed

    Rosenfeld, C S; Evans, C; Shadduck, R K

    1990-11-01

    Macrophage-colony stimulating factor (M-CSF) has well-known effects on murine bone marrow, but its colony stimulating activity for human bone marrow is controversial. After treatment of human bone marrow with L-phenylalanine methylester (PME), macrophage-colonies (CFU-M) were induced by M-CSF in a dose-dependent fashion. The optimal concentration of recombinant human-macrophage colony stimulating factor (rhM-CSF) was 1,000 U/mL. Purified human urine M-CSF had colony stimulating activity similar to rhM-CSF. Further studies were performed to determine the factors responsible for the enhanced CFU-M formation from PME treated marrow. Compared with nylon wool and carbonyl iron monocyte depletion methods, PME eliminated significantly more monocytes and myeloid cells. This observation suggested that these cells may release hematopoietic inhibitory factors for CFU-M. Low concentrations (1%) but not normal (10%) concentrations of blood monocytes were inhibitory (mean inhibition, 48%) to CFU-M. High concentrations of monocytes (50%) augmented CFU-M colonies. HL-60 conditioned media was used to simulate secretory products of early myeloid cells. HL-60 conditioned media (1%) inhibited CFU-M formation but not granulocyte macrophage or granulocyte colonies. We conclude that M-CSF has colony stimulating activity for human marrow that can be recognized after removal of inhibitory cells by PME treatment. PMID:2224128

  8. M&B 28,767: a potent anti-secretory and anti-ulcer PG analogue. A comparative study with 16, 16' dimethyl PGE2 methylester.

    PubMed

    Banerjee, A K; Christmas, A J; Crowshaw, K; Heazell, M A; Ivers-Read, G C; Saunders, L C; Wyatt, D

    1984-12-17

    M&B 28,767 [(+/-)11-deoxy-16-phenoxy-omega-tetranor PGE1] and 16, 16'-dimethyl PGE2 methylester (DMPG) were compared for their effects on gastric acid secretion (GAS) and gastric ulceration (GU), employing various laboratory models. In anaesthetised rats, GAS was stimulated by a continuous i.v. infusion of pentagastrin (30 micrograms/kg/h), and PG analogues were perfused through the stomach for 1 h. M&B 28,767 (3-15 micrograms/kg/h) and DMPG (3-60 micrograms/kg/h) reduced GAS in a dose-related manner, the ED50 values being 4 and 15 micrograms/kg/h respectively. In conscious rats possessing indwelling gastric cannulae, oral doses of M&B 28,767 (0.025-0.1 microgram/kg) and DMPG (0.50-1.0 microgram/kg) caused a prolonged inhibition of pentagastrin-stimulated GAS. M&B 28,767 was 17 times more potent than DMPG; the respective ED50 values were 0.036 and 0.6 microgram/kg. Indomethacin-induced ulceration in rats, was reduced by both M&B 28,767 and DMPG; the respective ED50 values being 3.0 and 0.8 micrograms/kg. Both compounds given orally increased gastrointestinal motility in mice; M&B 28,767 (1-3 mg/kg) and DMPG (0.1-0.3 mg/kg) caused diarrhoea, the former being about 0.1 times as potent as the latter. In another test, M&B 28,767 (0.5-5.0 mg/kg) and DMPG (10-40 micrograms/kg) overcame morphine-induced constipation in a dose-related manner, the respective ED50s being 0.9-1.4 mg/kg and 20-40 micrograms/kg. Thus, M&B 28,767 had a better profile of activity than DMPG as an antisecretory and antiulcer agent.

  9. Photoinduced charge generation rates in soluble P3HT : PCBM nano-aggregates predict the solvent-dependent film morphology

    NASA Astrophysics Data System (ADS)

    Roy, Palas; Jha, Ajay; Dasgupta, Jyotishman

    2016-01-01

    The device efficiency of bulk heterojunction (BHJ) solar cells is critically dependent on the nano-morphology of the solution-processed polymer : fullerene blend. Active control on blend morphology can only emanate from a detailed understanding of solution structures during the film casting process. Here we use photoinduced charge transfer (CT) rates to probe the effective length scale of the pre-formed solution structures and their energy disorder arising from a mixture of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in three different organic solvents. The observed solvent-dependent ultrafast biphasic rise of the transient polaron state in solution along with changes detected in the C&z.dbd;C stretching frequency of bound PCBM provides direct evidence for film-like P3HT : PCBM interfaces in solution. Using the diffusive component of the charge transfer rate, we deduce ~3-times larger functional nano-domain size in toluene than in chlorobenzene thereby correctly predicting the relative polymer nanofiber widths observed in annealed films. We thus provide first experimental evidence for the postulated polymer : fullerene : solvent ternary phase that seeds the eventual morphology in spin-cast films. Our work motivates the design of new chemical additives to tune the grain size of the evolving polymer : fullerene domains within the solution phase.The device efficiency of bulk heterojunction (BHJ) solar cells is critically dependent on the nano-morphology of the solution-processed polymer : fullerene blend. Active control on blend morphology can only emanate from a detailed understanding of solution structures during the film casting process. Here we use photoinduced charge transfer (CT) rates to probe the effective length scale of the pre-formed solution structures and their energy disorder arising from a mixture of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in three

  10. New Insights into the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction: A Time-of-Flight Quasi-Elastic Neutron Scattering Study.

    PubMed

    Guilbert, Anne A Y; Zbiri, Mohamed; Jenart, Maud V C; Nielsen, Christian B; Nelson, Jenny

    2016-06-16

    The molecular dynamics of organic semiconductor blend layers are likely to affect the optoelectronic properties and the performance of devices such as solar cells. We study the dynamics (5-50 ps) of the poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) blend by time-of-flight quasi-elastic neutron scattering, at temperatures in the range 250-360 K, thus spanning the glass transition temperature region of the polymer and the operation temperature of an OPV device. The behavior of the QENS signal provides evidence for the vitrification of P3HT upon blending, especially above the glass transition temperature, and the plasticization of PCBM by P3HT, both dynamics occurring on the picosecond time scale. PMID:27192930

  11. Surface plasmon enhanced P3HT:PCBM photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Zivanovic, Sandra; Thapa, Anil; Koorie, Mark; Animilli, Shravanrakesh; Gunasekaran, A.; Melancon, Justin; Genov, Dentcho

    2012-10-01

    A reduction of material consumption in thin-film photovoltaic devices can make solar energy economically more viable. However, since thin films essentially absorb less light, there is an imminent need for existing technology to improve light harvesting. We present an effective approach of better light absorption, enhanced photocurrent generation and therefore higher quantum efficiency of poly (3-hexylthiophene): 1-(3-methoxycarbonyl) propyl-1-phenyl-[6, 6]-methanofullerene (P3HT:PCBM) bulk heterojunction photovoltaic/photodetector devices. We have integrated a thin semi-continuous gold film (SCGF) (~20nm) sputtered at percolation threshold between the active P3HT:PCBM layer and the indium-tin-oxide (ITO) electrode. At critical metal concentrations, i.e. percolation threshold, the light reaching the SCGF undergoes a broadband trapping with characteristic time of 200 fs, through complex interactions with fractal gold clusters. This thin SCGF together with the ITO serves as an anode. The interface between SCGF and the polymer represents the metaldielectric composite (MDC) that supports broad-band surface plasmon resonances that store electromagnetic radiation at the nanoscale and acts as an effective bulk type of concentrator without the need of increasing the photovoltaic device physical collection area. Here we report a six-fold enhancement in the integral quantum efficiency over the solar spectrum for device employing plasmon-active gold layer. Such enhancement is an important contribution for the future design of more efficient photodetecting/photovoltaic devices. The experimental results are supported by the theoretical modeling of metal-dielectric composites by block elimination method in 3D. The AC and DC responses of MDC, local field distribution, broad optical response and photon trapping in the percolating MDC were numerically calculated.

  12. Deposit heterogeneity and the dynamics of the organic semiconductors P3HT and PCBM solution under evaporation

    NASA Astrophysics Data System (ADS)

    Yu, H. P.; Luo, H.; Liu, T. T.; Jing, G. Y.

    2015-04-01

    The formation of organic semiconductor layer is the key procedure in the manufacture of organic photovoltaic solar cell, in which the natural evaporation of the solvent from the polymer solution plays the essential role for the conversion efficiency. Here, poly(3-hexylthiophene) (P3HT) and fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), as two types of semiconductor polymers, were selected as the active layer to form the deposit by drying the blend solution drops on the substrate. We explored the influences of droplet size and solute concentration on the homogeneity of the deposit. Additionally, the spatial distribution of molecular chains and grains and the instability of the droplet morphology during the drying were investigated. The results showed that the "coffee-ring" phenomenon occurred forming an annular deposit at the outermost edge and the width of the annular ring increased linearly with the concentration of the P3HT solution, until a saturation plateau is approached. On the other hand, the PCBM deposition presented a circular disk at low concentration, but displayed a sudden instability for an irregular perimeter at a critical concentration and there existed a second critical concentration above which the deposit exhibited the return of the stable circular shape. The results have an instructive impact on the performance of the device and the formation of fine structures during the process of printing, film preparation and painting.

  13. The Miscibility and Depth Profile of PCBM in P3HT: Thermodynamic Information to Improve Organic Photovoltaics

    SciTech Connect

    Dadmun, Mark D

    2012-01-01

    Recent work has shown that poly(3-hexylthiophene) (P3HT) and the surface functionalized fullerene 1-(3-methyloxycarbonyl)propy(1-phenyl [6,6]) C61 (PCBM) are much more miscible than originally thought, and the evidence of this miscibility requires a return to understanding the optimal morphology and structure of organic photovoltaic active layers. This manuscript describes the results of experiments that were designed to provide quantitative thermodynamic information on the miscibility, interdiffusion, and depth profile of P3HT:PCBM thin films that are formed by thermally annealing initial bilayers. It is found that the resultant thin films consist of a bulk layer that is not influenced by the air or substrate surface. The composition of PCBM in this bulk layer increases with increased PCBM loading in the original bilayer until the bulk layer contains 22 vol% PCBM. The introduction of additional PCBM into the sample does not increase the amount of PCBM dispersed in this bulk layer. This observation is interpreted to indicate that the miscibility limit of PCBM in P3HT is 22 vol%, while the precise characterization of the depth profiles in these films shows that the PCBM selectively segregates to the silicon and near air surface. The selective segregation of the PCBM near the air surface is ascribed to an entropic driving force.

  14. Photoinduced charge generation rates in soluble P3HT : PCBM nano-aggregates predict the solvent-dependent film morphology.

    PubMed

    Roy, Palas; Jha, Ajay; Dasgupta, Jyotishman

    2016-02-01

    The device efficiency of bulk heterojunction (BHJ) solar cells is critically dependent on the nano-morphology of the solution-processed polymer : fullerene blend. Active control on blend morphology can only emanate from a detailed understanding of solution structures during the film casting process. Here we use photoinduced charge transfer (CT) rates to probe the effective length scale of the pre-formed solution structures and their energy disorder arising from a mixture of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in three different organic solvents. The observed solvent-dependent ultrafast biphasic rise of the transient polaron state in solution along with changes detected in the C=C stretching frequency of bound PCBM provides direct evidence for film-like P3HT : PCBM interfaces in solution. Using the diffusive component of the charge transfer rate, we deduce ∼3-times larger functional nano-domain size in toluene than in chlorobenzene thereby correctly predicting the relative polymer nanofiber widths observed in annealed films. We thus provide first experimental evidence for the postulated polymer : fullerene : solvent ternary phase that seeds the eventual morphology in spin-cast films. Our work motivates the design of new chemical additives to tune the grain size of the evolving polymer : fullerene domains within the solution phase. PMID:26763690

  15. The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C{sub 60} derivative PCBM

    SciTech Connect

    Brumboiu, Iulia Emilia Eriksson, Olle; Brena, Barbara; Ericsson, Leif; Hansson, Rickard; Moons, Ellen

    2015-02-07

    Fullerenes have been a main focus of scientific research since their discovery due to the interesting possible applications in various fields like organic photovoltaics (OPVs). In particular, the derivative [6,6]-phenyl-C{sub 60}-butyric acid methyl ester (PCBM) is currently one of the most popular choices due to its higher solubility in organic solvents compared to unsubstituted C{sub 60}. One of the central issues in the field of OPVs is device stability, since modules undergo deterioration (losses in efficiency, open circuit voltage, and short circuit current) during operation. In the case of fullerenes, several possibilities have been proposed, including dimerization, oxidation, and impurity related deterioration. We have studied by means of density functional theory the possibility of oxygen adsorption on the C{sub 60} molecular moiety of PCBM. The aim is to provide guidelines for near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) measurements which can probe the presence of atomic or molecular oxygen on the fullerene cage. By analysing several configurations of PCBM with one or more adsorbed oxygen atoms, we show that a joint core level XPS and O1s NEXAFS investigation could be effectively used not only to confirm oxygen adsorption but also to pinpoint the bonding configuration and the nature of the adsorbate.

  16. Role of donor-acceptor domain formation and interface states in initial degradation of P3HT:PCBM-based solar cells

    NASA Astrophysics Data System (ADS)

    Arora, Swati; Rajouria, Satish Kumar; Kumar, Pankaj; Bhatnagar, P. K.; Arora, Manoj; Tandon, R. P.

    2011-03-01

    This work is devoted to identifying the degradation mechanism in various structures of a poly(3-hexylthiophene) (P3HT):6,6-phenyl C61-butyric acid methyl ester (PCBM)-based solar cell. We have tried to identify the dominant initial degradation mechanism on the basis of experimental studies carried out on different structures of an organic solar cell. It is known that many of these problems can be solved by means of the following: using proper electrodes and a suitable annealing temperature and duration, improving the morphology of the active film and maintaining a donor-acceptor phase-segregated ordered network as far as possible. The present studies have been carried out both in the dark and under illumination, and it is suggested that initial degradation plays a key role in device performance. The dominant degradation mechanism is the growth of the donor-acceptor complex with time, which not only reduces the effective surface area but also hampers the charge separation. The little change in VOC and the significant change in JSC suggest that once the LiF/Al electrode is improved, one must modify the structure either by introducing a thin layer of high-molecular-weight P3HT between PEDOT:PSS (poly(3,4-ethylenedioxythiopene) poly(styrenesulfonate)) and photoactive P3HT:PCBM layers or by introducing an optimized content of P3HT nanofibrils/nanoparticles into the P3HT:PCBM blend. The best structure was found to be ITO/PEDOT:PSS/P3HT:PCBM/LiF/Al and it can be improved by the above two methods.

  17. A mechanistic investigation of morphology evolution in P3HT-PCBM films induced by liquid crystalline molecules under external electric field.

    PubMed

    Zhou, Weihua; Shi, Jiangman; Lv, Lingjian; Chen, Lie; Chen, Yiwang

    2015-01-01

    We demonstrate that the morphology of poly(3-hexyl thiophene) and [6,6]-phenyl-C61-butyric acid methyl ester (P3HT-PCBM) bulk heterojunctions (BHJ) could be tuned by the 4-cyano-4'-pentylterphenyl (5CT) liquid crystalline molecules under electric field assisted treatment for enhanced solar cell performance. The miscibility and interactions between the components were carefully studied, showing that 5CT could induce the crystallization of P3HT to form edge-on structures in ternary blends after electric field assisted treatment as revealed by grazing-incidence wide-angle X-ray diffraction (GIXRD). The PCBM and 5CT are supposed to form the rod-like complexes, and the nanorods could orient to the direction of electric field, accompanied by the homogeneous distribution of nanorods in diameters of about 30 nm at an electric field of 600 V mm(-1). The sizes of PCBM clusters and complexes are dependent on the 5CT doping ratios and intensity of electric field according to grazing-incidence small-angle X-ray scattering (GISAXS) analysis. When the active layers were processed under the atmospheric environment, the power conversion efficiency (PCE) could reach 3.5% at 5CT weight fraction of 6 wt% after treatment by an electric field of 600 V mm(-1), in contrast to the PCE value of 2.4% for a pristine P3HT-PCBM blend. This work provides an attractive strategy for manipulating the nanostructure of BHJ layers and also increases insight into morphology evolution when liquid crystalline molecules are incorporated into BHJs. PMID:25407082

  18. Ultrafast Dynamics of Localized and Delocalized Polaron Transitions in P3HT/PCBM Blend Materials: The Effects of PCBM Concentration

    PubMed Central

    2009-01-01

    Nowadays, organic solar cells have the interest of engineers for manufacturing flexible and low cost devices. The considerable progress of this nanotechnology area presents the possibility of investigating new effects from a fundamental science point of view. In this letter we highlight the influence of the concentration of fullerene molecules on the ultrafast transport properties of charged electrons and polarons in P3HT/PCBM blended materials which are crucial for the development of organic solar cells. Especially, we report on the femtosecond dynamics of localized (P2at 1.45 eV) and delocalized (DP2at 1.76 eV) polaron states of P3HT matrix with the addition of fullerene molecules as well as the free-electron relaxation dynamics of PCBM-related states. Our study shows that as PCBM concentration increases, the amplified exciton dissociation at bulk heterojunctions leads to increased polaron lifetimes. However, the increase in PCBM concentration can be directly related to the localization of polarons, creating thus two competing trends within the material. Our methodology shows that the effect of changes in structure and/or composition can be monitored at the fundamental level toward optimization of device efficiency. PMID:20652147

  19. Morphological origin for the stratification of P3HT:PCBM blend film studied by neutron reflectometry

    SciTech Connect

    Keum, Jong Kahk; Browning, James F.; Halbert, Candice E.; Xiao, Kai; Shao, Ming; Hong, Kunlun

    2013-11-25

    Understanding the origin for the film stratification of electron donor/acceptor blend is crucial for high efficiency organic photovoltaic cell. In this study, P3HT:PCBM blend is deposited onto hydrophilic and hydrophobic substrate to examine the film stratifications. The neutron reflectivity results show that, on the different surfaces, PCBM diffuses toward the two interfacial regions in an identical fashion during thermal annealing. This evidences that the film stratification is not affected by the substrates. Instead, since P3HT remains more amorphous in the interfacial regions and PCBM is miscible with amorphous P3HT, PCBM preferentially diffuses to the interfacial regions, resulting in the stratification.

  20. Investigation of the magnetic nickel nanoparticle on performance improvement of P3HT:PCBM solar cell

    NASA Astrophysics Data System (ADS)

    Gong, Xiu; Jiang, Yurong; Zhang, Congcong; Yang, Lei; Li, Meng; Ma, Heng

    2016-04-01

    This work reports an investigation on the performance improvement of bulk heterojunction polymer solar cells made of poly(3-hexylthiophene) and [6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) blend system by introducing nickel nanoparticles (Ni NPs). Using the simplest cell structure, the addition ratio of 2 % of Ni NPs results in a remarkable increase in the light absorption and the short current, which brings an enhancement on power conversion efficiency with 25 % compared with the reference device. The analysis indicates that the electromagnetic surface wave generated from Ni NPs coupled with the photoactive layer forms surface plasmon resonance, which can result in a light trapping effect to increase the light absorption. As a conclusion, the inexpensive Ni NPs may provide an effect and alternative process on the performance improvement of the polymer solar devices.

  1. Fabrication and characterization of inverted organic solar cells using shuttle cock-type metal phthalocyanine and PCBM:P3HT

    SciTech Connect

    Suzuki, Atsushi Furukawa, Ryo Akiyama, Tsuyoshi Oku, Takeo

    2015-02-27

    Inverted organic solar cells using shuttle cock-type phthalocyanine, semiconducting polymer and fullerenes were fabricated and characterized. Photovoltaic and optical properties of the solar cells with inverted structures were investigated by optical absorption, current density-voltage characteristics. The photovoltaic properties of the tandem organic solar cell using titanyl phthalocyanine, vanadyl phthalocyanine, poly(3-hexylthiophene) (P3HT) and [6, 6]-phenyl C{sub 61}-butyric acid methyl ester (PCBM) were improved. Effect of annealing and solvent treatment on surface morphologies of the active layer was investigated. The photovoltaic mechanisms, energy levels and band gap of active layers were discussed for improvement of the photovoltaic performance.

  2. Improved charge transport in P3HT:PCBM bulk heterojunction PV cell under ambient environment

    NASA Astrophysics Data System (ADS)

    Bell, July T.; Mola, Genene T.

    2014-03-01

    Enhanced current density has been observed from P3HT:PCBM bulk heterojunction solar cell after a well sonicated solution was diluted with fresh chloroform solvent. The preparation of the devices was carried out in a simple laboratory environment without glove box and clean room. As the result of such current surge in the devices the efficiency has risen more than double compared to those devices without dilution of the P3HT:PCBM solution. We have recorded an average power conversion efficiency of 4.02(5)% under this condition. This is an encouraging development toward achieving low cost organic photovoltaic devices.

  3. P3HT:PCBM, best seller in polymer photovoltaic research.

    PubMed

    Dang, Minh Trung; Hirsch, Lionel; Wantz, Guillaume

    2011-08-16

    In the fi eld of polymer-based photovoltaic cells, poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C₆₁ (PCBM) are, to date, the most-studied active materials around the world for the bulk-heterojunction structure. Various power-conversion effi ciencies are reported up to approximately 5%. This Research News article is focused on a survey of the tremendous literature published between 2002 and 2010 that exhibits solar cells based on blends of P3HT and PCBM. PMID:21936074

  4. Amino acids and their Cu complexes covalently grafted onto a polystyrene resin A vibrational spectroscopic study

    NASA Astrophysics Data System (ADS)

    Korbély, B.; Kiss, J. T.; Hernadi, K.; Pálinkó, I.

    2007-05-01

    Immobilised Cu(II)- L-tyrosine methylester and Cu(II)-BOC- L-histidine complexes were prepared through covalently grafting the amino acid ligands onto chlorine-functionalised polystyrene. The steps of the syntheses were followed by IR spectroscopy. The ligand to central ion ratio was four in both anchored complexes, and the most probable coordination sites were the carboxylic, the amino and the phenolic OH groups and the imidazole nitrogens for the tyrosine methylester and the BOC- L-histidine, respectively.

  5. Enhancing the performances of P3HT:PCBM – MoS3 based H2-evolving photocathodes with interfacial layers

    PubMed Central

    Bourgeteau, Tiphaine; Tondelier, Denis; Geffroy, Bernard; Brisse, Romain; Cornut, Renaud; Artero, Vincent; Jousselme, Bruno

    2015-01-01

    Organic semiconductors have great potential for producing hydrogen in a durable and economically viable manner, as they rely on readily available materials and can be solution-processed over large areas. With the objective of building efficient hybrid organic-inorganic photo-electrochemical cells, we combined a noble metal-free and solution-processable catalyst for proton reduction, MoS3, and a poly-(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction (BHJ). Different interfacial layers were investigated to improve the charge transfer between P3HT:PCBM and MoS3. Metallic Al\\Ti interfacial layers led to an increase of the photocurrent up to 8 mA cm−2 at reversible hydrogen electrode (RHE) potential with a 0.6 V anodic shift of the HER onset potential, a value close to the open circuit potential of the P3HT:PCBM solar cell. A 50 nm thick C60 layer also works as interfacial layer, with current density reaching 1 mA cm−2 at RHE potential. Moreover, two recently highlighted1 figures-of-merit, measuring the ratio of power saved, Φsaved,ideal and Φsaved,NPAC, were evaluated and discussed to compare the performances of various photocathodes assessed in a three-electrode configuration. Φsaved,ideal and Φsaved,NPAC use the RHE and a non-photoactive electrode with identical catalyst as dark electrode, respectively. They provide different information especially for the differentiation of the role of the photogenerating layer and the role of the catalyst. Best results were obtained with the Al\\Ti metallic interlayer, with Φsaved,ideal and Φsaved,NPAC reaching 0.64 % and 2.05 % respectively. PMID:26151685

  6. Energy level alignment in polymer organic solar cells at donor-acceptor planar junction formed by electrospray vacuum deposition

    SciTech Connect

    Kim, Ji-Hoon; Hong, Jong-Am; Kwon, Dae-Gyeon; Seo, Jaewon; Park, Yongsup

    2014-04-21

    Using ultraviolet photoelectron spectroscopy (UPS), we have measured the energy level offset at the planar interface between poly(3-hexylthiophene) (P3HT) and C{sub 61}-butyric acid methylester (PCBM). Gradual deposition of PCBM onto spin-coated P3HT in high vacuum was made possible by using electrospray vacuum deposition (EVD). The UPS measurement of EVD-prepared planar interface resulted in the energy level offset of 0.91 eV between P3HT HOMO and PCBM LUMO, which is considered as the upper limit of V{sub oc} of the organic photovoltaic cells.

  7. Encapsulation of MEH-PPV:PCBM Hybrids in the Cores of Block Copolymer Micellar Assemblies: Photoinduced Electron Transfer in a Nanoscale Donor-Acceptor System.

    PubMed

    Wang, Suxiao; Ryan, James William; Singh, Amita; Beirne, Jason Gerard; Palomares, Emilio; Redmond, Gareth

    2016-01-12

    The objective of this work is to demonstrate that conjugated polymer:fullerene hybrid nanoparticles encapsulated in the hydrophobic cores of triblock copolymer micelles may successfully act as spatially confined donor-acceptor systems capable of facilitating photoinduced charge carrier separation. To this end, aqueous dispersions of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) nanoparticles were first prepared by solubilization of the polymer in the cores of poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) triblock copolymer, Pluronic F-127 micelles. A number of significant optical spectroscopic changes were observed on transfer of the conjugated polymer from a nonaqueous solvent to the aqueous micellar environment. These were primarily attributed to increased interchain interactions due to conjugated polymer chain collapse during encapsulation in the micellar cores. When prepared in buffer solution, the micelles exhibited good long-term collodial stability. When MEH-PPV micelles were blended by the addition of controlled amounts of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), the observed correspondence of photoluminescence emission quenching, quantum yield decreases, and emission lifetime shortening with increasing PCBM concentration indicated efficient photoinduced donor-to-acceptor charge transfer between MEH-PPV and the fullerenes in the cores of the micelles, an assignment that was confirmed by transient absorption spectroscopic monitoring of carrier photogeneration and recombination. PMID:26653672

  8. Promising Strategy To Improve Charge Separation in Organic Photovoltaics: Installing Permanent Dipoles in PCBM Analogues.

    PubMed

    de Gier, Hilde D; Jahani, Fatemeh; Broer, Ria; Hummelen, Jan C; Havenith, Remco W A

    2016-07-14

    A multidisciplinary approach involving organic synthesis and theoretical chemistry was applied to investigate a promising strategy to improve charge separation in organic photovoltaics: installing permanent dipoles in fullerene derivatives. First, a PCBM analogue with a permanent dipole in the side chain (PCBDN) and its reference analogue without a permanent dipole (PCBBz) were successfully synthesized and characterized. Second, a multiscale modeling approach was applied to investigate if a PCBDN environment around a central donor-acceptor complex indeed facilitates charge separation. Alignment of the embedding dipoles in response to charges present on the central donor-acceptor complex enhances charge separation. The good correspondence between experimentally and theoretically determined electronic and optical properties of PCBDN, PCBBz, and PCBM indicates that the theoretical analysis of the embedding effects of these molecules gives a reliable expectation for their influence on the charge separation process at a microscopic scale in a real device. This work suggests the following strategies to improve charge separation in organic photovoltaics: installing permanent dipoles in PCBM analogues and tuning the concentration of these molecules in an organic donor/acceptor blend.

  9. Charge carrier transport and photogeneration in P3HT:PCBM photovoltaic blends.

    PubMed

    Laquai, Frédéric; Andrienko, Denis; Mauer, Ralf; Blom, Paul W M

    2015-06-01

    This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano-fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10(-4) cm(2) V(-1) s(-1) after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea-sured in P3HT:PCBM photovoltaic devices.

  10. Shanzhiside methylester, the principle effective iridoid glycoside from the analgesic herb Lamiophlomis rotata, reduces neuropathic pain by stimulating spinal microglial β-endorphin expression.

    PubMed

    Fan, Hui; Li, Teng-Fei; Gong, Nian; Wang, Yong-Xiang

    2016-02-01

    Lamiophlomis rotata (L. rotata, Duyiwei) is an orally available Tibetan analgesic herb widely prescribed in China. Shanzhiside methylester (SM) is a principle effective iridoid glycoside of L. rotata and serves as a small molecule glucagon-like peptide-1 (GLP-1) receptor agonist. This study aims to evaluate the signal mechanisms underlying SM anti-allodynia, determine the ability of SM to induce anti-allodynic tolerance, and illustrate the interactions between SM and morphine, or SM and β-endorphin, in anti-allodynia and anti-allodynic tolerance. Intrathecal SM exerted dose-dependent and long-lasting (>4 h) anti-allodynic effects in spinal nerve injury-induced neuropathic rats, with a maximal inhibition of 49% and a projected ED50 of 40.4 μg. SM and the peptidic GLP-1 receptor agonist exenatide treatments over 7 days did not induce self-tolerance to anti-allodynia or cross-tolerance to morphine or β-endorphin. In contrast, morphine and β-endorphin induced self-tolerance and cross-tolerance to SM and exenatide. In the spinal dorsal horn and primary microglia, SM significantly evoked β-endorphin expression, which was completely prevented by the microglial inhibitor minocycline and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. SM anti-allodynia was totally inhibited by the GLP-1 receptor antagonist exendin(9-39), minocycline, β-endorphin antiserum, μ-opioid receptor antagonist CTAP, and SB203580. SM and exenatide specifically activated spinal p38 MAPK phosphorylation. These results indicate that SM reduces neuropathic pain by activating spinal GLP-1 receptors and subsequently stimulating microglial β-endorphin expression via the p38 MAPK signaling. Stimulation of the endogenous β-endorphin expression may be a novel and effective strategy for the discovery and development of analgesics for the long-term treatment of chronic pain. PMID:26363192

  11. Dynamic dielectric properties of some carboxylic acid esters in benzene solution

    NASA Astrophysics Data System (ADS)

    Ghoneim, Ahmed M.; Stockhause, Martina; Becker, U.; Biedenkap, R.; Elsebrock, R.

    1997-06-01

    The dielectric absorption spectrum between some MHz and 36 GHz has been measured at 20 degrees C for S(-)-lactic acid methylester, succinic acid dimethylester, L(-)- malic acid dimethylester and L(+)-tartaric acid diethylester, over the whole concentration range of benzene solutions of these substances. The loss function can be described by up to four Debye type spectral components. The relaxation parameters are reported and discussed in particular with respect to association effects.

  12. POSS-enhanced phase separation in air-processed P3HT:PCBM bulk heterojunction photovoltaic systems.

    PubMed

    Wu, Qi; Bhattacharya, Mithun; Morgan, Sarah E

    2013-07-10

    Nanoparticles have been shown in some cases to improve phase separation and morphology in bulk heterojunction organic photovoltaic cells. In this study, the effect of incorporation of polyhedral oligomeric silsesquioxane (POSS) molecules of different structures in air processed poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) films and photovoltaic cells was evaluated. Morphology and composition of the nanoscalephase-separated domains were determined via conductive atomic force microscopy in conjunction with nanomechanical mapping and Raman imaging. UV-vis and fluorescence spectroscopy analysis of the films was performed at different stages of the process and with different levels of solvent vapor and thermal annealing. It was found that POSS molecules of selected structures provided enhancement in morphology control in films, translating to improvements in fill factor and power conversion efficiency of laboratory-scale OPV cells. The findings indicate the potential for further improvements in solar cell performance with specifically tailored POSS/polymer phase-separated systems.

  13. Thermal annealing study on P3HT: PCBM based bulk heterojunction organic solar cells using impedance spectroscopy

    SciTech Connect

    Gollu, Sankara Rao; Sharma, Ramakant G, Srinivas Gupta, Dipti

    2014-10-15

    Recently, Thermal annealing is an important process for bulk heterojunction organic solar cells (BHJ OSCs) to improve the device efficiency and performance of the organic solar cells. Here in, we have examined the changes in the efficiency and morphology of P3HT: PCBM film according to the thermal annealing temperature to find the changes during the annealing process by measuring the optical absorption, atomic force microscope and X-ray diffraction. We also investigated the effect of different annealing process conditions (without, pre- and post-annealing) on the device performance of the inverted bulk heterojunction organic solar cells consist the structure of ITO/ ZnO / P3HT: PCBM / MoO{sub 3}/ Al by measuring AC impedance characteristics. Particularly, the power conversion efficiency (PCE), crystalline nature of the polymer, light absorption and the surface smoothness of P3HT: PCBM films are significantly improved after the annealing process. These results indicated the improvement in terms of PCE, interface smoothness between the P3HT: PCBM and MoO{sub 3} layers of the post annealed device originated from the decrease of series resistance between P3HT: PCBM layer and Al electrodes, which could be due to decrease in the effective life time of charge carriers.

  14. The Role of Fullerene Mixing Behavior in the Performance of Organic Rhotovoltaics: PCBM in Low-Bandgap Polymers.

    SciTech Connect

    Chen, Huipeng; Peet, Jeff; Hu, Sheng; Azoulay, Jason; Bazan, Guillermo; Dadmun, Mark D

    2014-01-01

    This manuscript reports the mixing behavior, interdiffusion, and depth profile of 1-[3-(methoxycarbonyl)propyl]-1-phenyl-[6,6]C 61 (PCBM):low-bandgap (LBG) polymer thin fi lms that are formed by thermally annealing initial bilayers. The extent of mixing of PCBM is higher in polymers that include the 2,1,3-benzothiadiazole (BT) unit than in polymers that incorporate the 2,1,3-benzooxadiazole (BO) unit. This difference is ascribed to the enhanced mixing behavior of PCBM with the benzothiadiazole functionality than with benzooxadiazole functionality, which is attributed to preferred intermolecular interactions. The increased polymer/fullerene mixing is found to be crucial for optimal device performance. A decrease of polymer/fullerene mixing reduces the donor/acceptor interface, which lowers the probability of exciton dissociation and charge generation. Moreover, low PCBM mixing provides limited pathways for electron transport out of a miscible region, due to long distances between adjacent PCBM in such a miscible phase. This inhibits electron transport and increases the recombination of free charge carriers, resulting in a decrease in short circuit current and device performance. These results further exemplify the importance of the thermodynamic mixing behavior of the polymer:fullerene pair in designing next-generation conjugated polymers for organic photovoltaic (OPV) applications, as this controls the fi nal morphology of the OPV active layer.

  15. A new model for the morphology of P3HT/PCBM organic photovoltaics from small-angle neutron scattering: rivers and streams.

    PubMed

    Yin, Wen; Dadmun, Mark

    2011-06-28

    Organic photovoltaics (OPVs) have attracted increasing interest as a lightweight, low-cost, and easy to process replacement for inorganic solar cells. Moreover, the morphology of the OPV active layer is crucial to its performance, where a bicontinuous, interconnected, phase-separated morphology of pure electron donor and acceptor phases is currently believed to be optimal. In this work, we use neutron scattering to investigate the morphology of a model OPV conjugated polymer bulk heterojunction, poly[3-hexylthiophene] (P3HT), and surface-functionalized fullerene 1-(3-methyloxycarbonyl) propyl(1-phenyl [6,6]) C(61) (PCBM). These results show that P3HT and PCBM form a homogeneous structure containing crystalline P3HT and an amorphous P3HT/PCBM matrix, up to ca. 20 vol % PCBM. At 50 vol % PCBM, the samples exhibit a complex structure containing at least P3HT crystals, PCBM crystals, and a homogeneous mixture of the two. The 20 vol % PCBM samples exhibit behavior consistent with the onset of phase separation after 6 h of thermal annealing at 150 °C, but appear to be miscible at shorter annealing times. This suggests that the miscibility limit of PCBM in P3HT is near 20%. Moreover, for the 50 vol % PCBM sample, the interface roughens under thermal annealing possibly owing to the growth of PCBM crystals. These observations suggest a different morphology than is commonly presented in the literature for optimal bulk heterojunctions. We propose a novel "rivers and streams" morphology to describe this system, which is consistent with these scattering results and previously reported photovoltaic functionality of P3HT/PCBM bulk heterojunctions.

  16. The influence of a novel pentadecapeptide, BPC 157, on N(G)-nitro-L-arginine methylester and L-arginine effects on stomach mucosa integrity and blood pressure.

    PubMed

    Sikirić, P; Seiwerth, S; Grabarević, Z; Rucman, R; Petek, M; Jagić, V; Turković, B; Rotkvić, I; Mise, S; Zoricić, I; Konjevoda, P; Perović, D; Jurina, L; Separović, J; Hanzevacki, M; Artuković, B; Bratulić, M; Tisljar, M; Gjurasin, M; Miklić, P; Stancić-Rokotov, D; Slobodnjak, Z; Jelovac, N; Marović, A

    1997-07-30

    The known effects of a novel stomach pentadecapeptide BPC157 (10 microg or 10 ng/kg), namely its salutary activity against ethanol (96%, i.g.)-induced gastric lesions (simultaneously applied i.p.) and in blood pressure maintenance (given i.v.), were investigated in rats challenged with a combination of N(G)-nitro-L-arginine methylester (L-NAME) (5 mg/kg i.v.), a competitive inhibitor of endothelium nitric oxide (NO)-generation and NO precursor, L-arginine (200 mg/kg i.v.) (D-arginine was ineffective). In the gastric lesions assay, NO agents were given 5 min before ethanol injury and BPC 157 medication. Given alone, BPC157 had an antiulcer effect, as did L-arginine, but L-NAME had no effect. L-NAME completely abolished the effect of L-arginine, whereas it only attenuated the effect of BPC 157. After application of the combination of L-NAME + L-arginine, the BPC157 effect was additionally impaired. In blood pressure studies, compared with L-arginine, pentadecapeptide BPC 157 (without effect on basal normal values) had both a mimicking effect (impaired L-NAME-blood pressure increase, when applied prophylactically and decreased already raised L-NAME values, given at the time of the maximal L-NAME-blood pressure increase (i.e., 10 min after L-NAME)) and preventive activity (L-arginine-induced moderate blood pressure decrease was prevented by BPC 157 pretreatment). When BPC 157 was given 10 min after L-NAME + L-arginine combination, which still led to a blood pressure increase, its previously clear effect (noted in L-NAME treated rats) disappeared. In vitro, in gastric mucosa from rat stomach tissue homogenates, BPC 157, given in the same dose (100 microM) as L-arginine, induced a comparable generation of NO. But, BPC 157 effect could not be inhibited by L-NAME, even when L-NAME was given in a tenfold (100 versus 1000 microM) higher dose than that needed for inhibition of the L-arginine effect. NO synthesis was blunted when the pentadecapeptide BPC 157 and L

  17. Modeling of the polymer solar cell with a P3HT:PCBM active layer

    NASA Astrophysics Data System (ADS)

    Jelić, Ž.; Petrović, J.; Matavulj, P.; Melancon, J.; Sharma, A.; Zellhofer, C.; Živanović, S.

    2014-09-01

    In this paper we present a theoretical model for simulating the behavior of a polymer solar cell with a poly(3-hexylthiophene):1-(3-methoxycarbonyl) propyl-1-phenyl-[6, 6]-methanofullerene (P3HT:PCBM) active layer. Two different types of boundary conditions were considered, Dirichlet’s and mixed. For Dirichlet’s boundary conditions we have achieved an excellent agreement with the experiment. The influence of boundary conditions on the appearance of the s-shaped current-voltage characteristic (sometimes observed in experiments) has been investigated. When mixed boundary conditions are applied, calculated current-voltage characteristics are inevitably s-shaped. By altering the boundary carrier concentration, an s-shaped deformation in current-voltage characteristics is numerically simulated by using Dirichlet’s boundary conditions.

  18. Tuning the energy level offset between donor and acceptor with ferroelectric dipole layers for increased efficiency in bilayer organic photovoltaic cells.

    PubMed

    Yang, Bin; Yuan, Yongbo; Sharma, Pankaj; Poddar, Shashi; Korlacki, Rafal; Ducharme, Stephen; Gruverman, Alexei; Saraf, Ravi; Huang, Jinsong

    2012-03-15

    Ultrathin ferroelectric polyvinylidene fluoride (70%)-tetrafluoroethylene (30%) copolymer film is inserted between the poly3(hexylthiophene) (P3HT) donor and [6,6]-phenyl-C61-butyric acid methylester (PCBM) acceptor layers as the dipole layer to tune the relative energy levels, which can potentially maximize the open circuit voltage of bilayer organic solar cells. In this work, the power conversion efficiency of P3HT/PCBM bilayer solar cells is demonstrated to be doubled with the inserted dipoles. PMID:22328442

  19. Molecular modeling study of agglomeration of [6,6]-phenyl-C61-butyric acid methyl ester in solvents.

    PubMed

    Mortuza, S M; Banerjee, Soumik

    2012-12-28

    The molecular interactions between solvent and nanoparticles during photoactive layer formation in organic photovoltaic (OPV) cells influence the morphology of the photoactive layer and hence determine the power conversion efficiency. Prediction of optimal synthesis parameters in OPVs, such as choice of solvent, processing temperature, and nanoparticle concentration, requires fundamental understanding of the mechanisms that govern the agglomeration of nanoparticles in solvents. In this study, we used molecular dynamics simulations to simulate a commonly used organic nanoparticle, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), in various solvents to correlate solvent-nanoparticle interactions with the size of the agglomerate structure of PCBM. We analyzed the effects of concentration of PCBM and operating temperature on the molecular rearrangement and agglomeration of PCBM in three solvents: (i) toluene, (ii) indane, and (iii) toluene-indane mixture. We evaluated the agglomeration behavior of PCBM by determining sizes of the largest clusters of PCBM and the corresponding size distributions. To obtain further insight into the agglomerate structure of PCBMs, we evaluated radial distribution functions (RDFs) and coordination numbers of the various moieties of PCBMs with respect to solvent atoms as well as with respect to that of other PCBMs. Our simulations demonstrate that PCBMs form larger clusters in toluene while they are relatively dispersed in indane, which indicates the greater solubility of PCBM in indane than in toluene. In toluene-indane mixture, PCBMs are clustered to a greater extent than in indane and less than that in toluene. To correlate agglomerate size to nanoparticle-solvent interactions, we also evaluated the potential of mean force (PMF) of the fullerene moiety of PCBM in toluene and indane. Our results also show that the cluster size of PCBM molecules increases with the increase of concentration of PCBM and the processing temperature. To

  20. Organic-Inorganic Hybrid Ternary Bulk Heterojunction of Nanostructured Perovskite-Low Bandgap Polymer-PCBM for Improved Efficiency of Organic Solar Cells.

    PubMed

    Jeong, Hanbin; Lee, Jae Kwan

    2015-12-30

    A new organic-inorganic ternary bulk heterojunction (TBHJ) hybrid configuration comprised of nanostructured (CH3)3NHPbI3 (MAPbI3) perovskite-low bandgap PCPDTBT-PCBM was investigated. Well-organized TBHJ films were readily prepared by sequential spin-casting of sparsely covered MAPbI3 nano dots and PCPDTBT-PCBM bulk heterojunction (BHJ) composites on ITO/PEDOT:PSS substrates. The TBHJ hybrid device configuration comprising diiooctane (DIO) treated MAPbI3 perovskite nano dots and a PCPDTBT-PCBM BHJ composite processed with DIO additive exhibited excellent performances. The DIO additive played a key role in developing perovskite structures of MAPbI3 nano dots and induced the (110) directional crystallinity growth of longitudinal constructive morphologies such as nano rods. The improved photocurrent and fill factor compared to those of conventional BHJ devices led to an increase in efficiency of ∼28%. This improved photovoltaic performance originated from the higher quantum efficiencies contributed by the charge transfer from nanostructured MAPbI3 perovskite to PCBM. These TBHJs composed of nanostructured MAPbI3 perovskite, PCPDTBT, and PCBM also facilitated the exciton dissociation in the multi-BHJ system between MAPbI3 perovskite, PCPDTBT, and PCBM.

  1. Addition of P3HT-grafted Silica nanoparticles improves bulk-heterojunction morphology in P3HT-PCBM blends

    PubMed Central

    Garg, Mohit; Padmanabhan, Venkat

    2016-01-01

    We present molecular dynamics simulations of a ternary blend of P3HT, PCBM and P3HT-grafted silica nanoparticles (SiNP) for applications in polymer-based solar cells. Using coarse-grained models, we study the effect of SiNP on the spatial arrangement of PCBM in P3HT. Our results suggest that addition of SiNP not only alters the morphology of PCBM clusters but also improves the crystallinity of P3HT. We exploit the property of grafted SiNP to self-assemble into a variety of anisotropic structures and the tendency of PCBM to preferentially adhere to SiNP surface, due to favorable interactions, to achieve morphologies with desirable characteristics for the active layer, including domain size, crystallinity of P3HT, and elimination of isolated islands of PCBM. As the concentration of SiNP increases, the number of isolated PCBM molecules decreases, which in turn improves the crystallinity of P3HT domains. We also observe that by tuning the grafting parameters of SiNP, it is possible to achieve structures ranging from cylindrical to sheets to highly interconnected network of strings. The changes brought about by addition of SiNP shows a promising potential to improve the performance of these materials when used as active layers in organic photovoltaics. PMID:27628895

  2. Addition of P3HT-grafted Silica nanoparticles improves bulk-heterojunction morphology in P3HT-PCBM blends

    NASA Astrophysics Data System (ADS)

    Garg, Mohit; Padmanabhan, Venkat

    2016-09-01

    We present molecular dynamics simulations of a ternary blend of P3HT, PCBM and P3HT-grafted silica nanoparticles (SiNP) for applications in polymer-based solar cells. Using coarse-grained models, we study the effect of SiNP on the spatial arrangement of PCBM in P3HT. Our results suggest that addition of SiNP not only alters the morphology of PCBM clusters but also improves the crystallinity of P3HT. We exploit the property of grafted SiNP to self-assemble into a variety of anisotropic structures and the tendency of PCBM to preferentially adhere to SiNP surface, due to favorable interactions, to achieve morphologies with desirable characteristics for the active layer, including domain size, crystallinity of P3HT, and elimination of isolated islands of PCBM. As the concentration of SiNP increases, the number of isolated PCBM molecules decreases, which in turn improves the crystallinity of P3HT domains. We also observe that by tuning the grafting parameters of SiNP, it is possible to achieve structures ranging from cylindrical to sheets to highly interconnected network of strings. The changes brought about by addition of SiNP shows a promising potential to improve the performance of these materials when used as active layers in organic photovoltaics.

  3. Organic-Inorganic Hybrid Ternary Bulk Heterojunction of Nanostructured Perovskite-Low Bandgap Polymer-PCBM for Improved Efficiency of Organic Solar Cells.

    PubMed

    Jeong, Hanbin; Lee, Jae Kwan

    2015-12-30

    A new organic-inorganic ternary bulk heterojunction (TBHJ) hybrid configuration comprised of nanostructured (CH3)3NHPbI3 (MAPbI3) perovskite-low bandgap PCPDTBT-PCBM was investigated. Well-organized TBHJ films were readily prepared by sequential spin-casting of sparsely covered MAPbI3 nano dots and PCPDTBT-PCBM bulk heterojunction (BHJ) composites on ITO/PEDOT:PSS substrates. The TBHJ hybrid device configuration comprising diiooctane (DIO) treated MAPbI3 perovskite nano dots and a PCPDTBT-PCBM BHJ composite processed with DIO additive exhibited excellent performances. The DIO additive played a key role in developing perovskite structures of MAPbI3 nano dots and induced the (110) directional crystallinity growth of longitudinal constructive morphologies such as nano rods. The improved photocurrent and fill factor compared to those of conventional BHJ devices led to an increase in efficiency of ∼28%. This improved photovoltaic performance originated from the higher quantum efficiencies contributed by the charge transfer from nanostructured MAPbI3 perovskite to PCBM. These TBHJs composed of nanostructured MAPbI3 perovskite, PCPDTBT, and PCBM also facilitated the exciton dissociation in the multi-BHJ system between MAPbI3 perovskite, PCPDTBT, and PCBM. PMID:26636343

  4. Addition of P3HT-grafted Silica nanoparticles improves bulk-heterojunction morphology in P3HT-PCBM blends.

    PubMed

    Garg, Mohit; Padmanabhan, Venkat

    2016-01-01

    We present molecular dynamics simulations of a ternary blend of P3HT, PCBM and P3HT-grafted silica nanoparticles (SiNP) for applications in polymer-based solar cells. Using coarse-grained models, we study the effect of SiNP on the spatial arrangement of PCBM in P3HT. Our results suggest that addition of SiNP not only alters the morphology of PCBM clusters but also improves the crystallinity of P3HT. We exploit the property of grafted SiNP to self-assemble into a variety of anisotropic structures and the tendency of PCBM to preferentially adhere to SiNP surface, due to favorable interactions, to achieve morphologies with desirable characteristics for the active layer, including domain size, crystallinity of P3HT, and elimination of isolated islands of PCBM. As the concentration of SiNP increases, the number of isolated PCBM molecules decreases, which in turn improves the crystallinity of P3HT domains. We also observe that by tuning the grafting parameters of SiNP, it is possible to achieve structures ranging from cylindrical to sheets to highly interconnected network of strings. The changes brought about by addition of SiNP shows a promising potential to improve the performance of these materials when used as active layers in organic photovoltaics. PMID:27628895

  5. Evolution of lateral structures during the functional stack build-up of P3HT:PCBM-based bulk heterojunction solar cells.

    PubMed

    Guo, Shuai; Ruderer, Matthias A; Rawolle, Monika; Körstgens, Volker; Birkenstock, Christopher; Perlich, Jan; Müller-Buschbaum, Peter

    2013-09-11

    Bulk heterojunction (BHJ) solar cells from 1,2-dichlorobenzene solution processed regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) are prepared and investigated at different steps of the multilayer stack build-up of the device. The inner structure is probed from the molecular to the mesoscale with grazing incidence small/wide-angle X-ray scattering (GISAXS/GIWAXS) and X-ray reflectivity (XRR). The surface morphology is detected with atomic force microscopy (AFM). Therefore, an in-depth knowledge of the three-dimensional morphology of the bulk heterojunction solar cell, starting from the cleaned ITO substrate up to the final post-treated solar cell, is generated. The active layer structure is influenced by the annealing as well as by the top contact deposition. Structures coarsen during the evaporation of the metal contacts. The P3HT crystal structure strongly depends on the device processing as well. These morphological changes together with the diffusion of aluminum atoms to the active layer are of importance for the device efficiency. PMID:23942383

  6. Graphene composite for improvement in the conversion efficiency of flexible poly 3-hexyl-thiophene:[6,6]-phenyl C71 butyric acid methyl ester polymer solar cells

    NASA Astrophysics Data System (ADS)

    Chauhan, A. K.; Gusain, Abhay; Jha, P.; Koiry, S. P.; Saxena, Vibha; Veerender, P.; Aswal, D. K.; Gupta, S. K.

    2014-03-01

    The solution of thin graphene-sheets obtained from a simple ultrasonic exfoliation process was found to chemically interact with [6,6]-phenyl C71 butyric acid methyl ester (PCBM) molecules. The thinner graphene-sheets have significantly altered the positions of highest occupied molecular orbital and lowest unoccupied molecular orbital of PCBM, which is beneficial for the enhancement of the open circuit voltage of the solar cells. Flexible bulk heterojunction solar cells fabricated using poly 3-hexylthiophene (P3HT):PCBM-graphene exhibited a power conversion efficiency of 2.51%, which is a ˜2-fold increase as compared to those fabricated using P3HT:PCBM. Inclusion of graphene-sheets not only improved the open-circuit voltage but also enhanced the short-circuit current density owing to an improved electron transport.

  7. Efficient bulk heterojunction solar cells with poly[2,7-(9,9-dihexylfluorene)-alt-bithiophene] and 6,6-phenyl C61 butyric acid methyl ester blends and their application in tandem cells.

    PubMed

    Zhao, Dewei; Tang, Weihua; Ke, Lin; Tan, Swee Tiam; Sun, Xiao Wei

    2010-03-01

    We present herein efficient bulk heterojunction (BHJ) solar cells via mixing poly[2,7-(9,9-dihexylfluorene)-alt-bithiophene] (F6T2) and 6,6-phenyl C61 butyric acid methyl ester (PCBM) with variable weight ratios. The photo-physics and morphology of F6T2:PCBM blend films and the electrical characteristics of their corresponding single cells were studied in details by changing PCBM concentration. The complete photoluminescence quenching of F6T2 emission occurs with only a small fraction of PCBM blended, demonstrating effective photoinduced charge transfer between F6T2 and PCBM. Morphology images from atomic force microscopy and scanning electron microscopy (SEM) reveal that the phase separation in F6T2:PCBM blend films becomes pronounced with the increase of PCBM concentration, resulting in the increased fill factor from 25.2% (1:1) to 56.9% (1:6). A SEM image also shows the phase separation is within the range of 10 - 20 nm. With the optimized F6T2:PCBM weight ratio (1:2), the single cell exhibits a highest power conversion efficiency of 2.46% due to the balance of light absorption and charge transport. Finally, the polymer-small molecule tandem cells are constructed using F6T2:PCBM BHJ as the bottom cell and copper phthalocyanine (CuPc):fullerene (C(60)) as the top cell. The open-circuit voltage (V(oc)) of tandem cell (1.27 V) is equal to the summation of the V(oc) values of the bottom cell (0.86 V) and the top cell (0.43 V). PMID:20356288

  8. Ultrafast exciton dissociation followed by nongeminate charge recombination in PCDTBT:PCBM photovoltaic blends.

    PubMed

    Etzold, Fabian; Howard, Ian A; Mauer, Ralf; Meister, Michael; Kim, Tae-Dong; Lee, Kwang-Sup; Baek, Nam Seob; Laquai, Frédéric

    2011-06-22

    The precise mechanism and dynamics of charge generation and recombination in bulk heterojunction polymer:fullerene blend films typically used in organic photovoltaic devices have been intensively studied by many research groups, but nonetheless remain debated. In particular the role of interfacial charge-transfer (CT) states in the generation of free charge carriers, an important step for the understanding of device function, is still under active discussion. In this article we present direct optical probes of the exciton dynamics in pristine films of a prototypic polycarbazole-based photovoltaic donor polymer, namely poly[N-11''-henicosanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), as well as the charge generation and recombination dynamics in as-cast and annealed photovoltaic blend films using methanofullerene (PC(61)BM) as electron acceptor. In contrast to earlier studies we use broadband (500-1100 nm) transient absorption spectroscopy including the previously unobserved but very important time range between 2 ns and 1 ms, which allows us not only to observe the entire charge carrier recombination dynamics but also to quantify the existing decay channels. We determine that ultrafast exciton dissociation occurs in blends and leads to two separate pools of products, namely Coulombically bound charge-transfer (CT) states and unbound (free) charge carriers. The recombination dynamics are analyzed within the framework of a previously reported model for poly(3-hexylthiophene):PCBM (Howard, I. A. J. Am. Chem. Soc. 2010, 132, 14866) based on concomitant geminate recombination of CT states and nongeminate recombination of free charge carriers. The results reveal that only ~11% of the initial photoexcitations generate interfacial CT states that recombine exclusively by fast nanosecond geminate recombination and thus do not contribute to the photocurrent, whereas ~89% of excitons create free charge carriers on an ultrafast time scale

  9. Multiscale Molecular Simulation of Solution Processing of SMDPPEH: PCBM Small-Molecule Organic Solar Cells.

    PubMed

    Lee, Cheng-Kuang; Pao, Chun-Wei

    2016-08-17

    Solution-processed small-molecule organic solar cells are a promising renewable energy source because of their low production cost, mechanical flexibility, and light weight relative to their pure inorganic counterparts. In this work, we developed a coarse-grained (CG) Gay-Berne ellipsoid molecular simulation model based on atomistic trajectories from all-atom molecular dynamics simulations of smaller system sizes to systematically study the nanomorphology of the SMDPPEH/PCBM/solvent ternary blend during solution processing, including the blade-coating process by applying external shear to the solution. With the significantly reduced overall system degrees of freedom and computational acceleration from GPU, we were able to go well beyond the limitation of conventional all-atom molecular simulations with a system size on the order of hundreds of nanometers with mesoscale molecular detail. Our simulations indicate that, similar to polymer solar cells, the optimal blending ratio in small-molecule organic solar cells must provide the highest specific interfacial area for efficient exciton dissociation, while retaining balanced hole/electron transport pathway percolation. We also reveal that blade-coating processes have a significant impact on nanomorphology. For given donor/acceptor blending ratios, applying an external shear force can effectively promote donor/acceptor phase segregation and stacking in the SMDPPEH domains. The present study demonstrated the capability of an ellipsoid-based coarse-grained model for studying the nanomorphology evolution of small-molecule organic solar cells during solution processing/blade-coating and provided links between fabrication protocols and device nanomorphologies.

  10. Multiscale Molecular Simulation of Solution Processing of SMDPPEH: PCBM Small-Molecule Organic Solar Cells.

    PubMed

    Lee, Cheng-Kuang; Pao, Chun-Wei

    2016-08-17

    Solution-processed small-molecule organic solar cells are a promising renewable energy source because of their low production cost, mechanical flexibility, and light weight relative to their pure inorganic counterparts. In this work, we developed a coarse-grained (CG) Gay-Berne ellipsoid molecular simulation model based on atomistic trajectories from all-atom molecular dynamics simulations of smaller system sizes to systematically study the nanomorphology of the SMDPPEH/PCBM/solvent ternary blend during solution processing, including the blade-coating process by applying external shear to the solution. With the significantly reduced overall system degrees of freedom and computational acceleration from GPU, we were able to go well beyond the limitation of conventional all-atom molecular simulations with a system size on the order of hundreds of nanometers with mesoscale molecular detail. Our simulations indicate that, similar to polymer solar cells, the optimal blending ratio in small-molecule organic solar cells must provide the highest specific interfacial area for efficient exciton dissociation, while retaining balanced hole/electron transport pathway percolation. We also reveal that blade-coating processes have a significant impact on nanomorphology. For given donor/acceptor blending ratios, applying an external shear force can effectively promote donor/acceptor phase segregation and stacking in the SMDPPEH domains. The present study demonstrated the capability of an ellipsoid-based coarse-grained model for studying the nanomorphology evolution of small-molecule organic solar cells during solution processing/blade-coating and provided links between fabrication protocols and device nanomorphologies. PMID:27435212

  11. Multiscale analysis of the effect of micro-phase separation on the charge transfer at the PEDOT:PSS and P3HT:PCBM layer interface

    NASA Astrophysics Data System (ADS)

    Huang, Min

    2015-09-01

    The influence of micro phase behavior on the charge transfer at the interface between PEDOT:PSS and P3HT:PCBM layers was studied using multiscale analysis. Calculated Flory- Huggins parameters indicated that the PEDOT attracts P3HT and repulses PCBM that agrees well with the experimental observation of the development of P3HT rich interface during the BHJ layer formation. Based on the calculated Flory-Huggins parameters, mesoscale DPD simulations were conducted for PEDOT:PSS and P3HT:PCBM layers. Results were mapped to the CG (coarse grained) and then atomistic scales where atomistic details of the interface were studied. The density of nonbonding close contacts including that from reorientation between PEDOT and P3HT was quantified, vibronic coupling and carrier transfer efficiency were discussed.

  12. Graphene composite for improvement in the conversion efficiency of flexible poly 3-hexyl-thiophene:[6,6]-phenyl C{sub 71} butyric acid methyl ester polymer solar cells

    SciTech Connect

    Chauhan, A. K. E-mail: akc.barc@gmail.com; Gusain, Abhay; Jha, P.; Koiry, S. P.; Saxena, Vibha; Veerender, P.; Aswal, D. K.; Gupta, S. K.

    2014-03-31

    The solution of thin graphene-sheets obtained from a simple ultrasonic exfoliation process was found to chemically interact with [6,6]-phenyl C{sub 71} butyric acid methyl ester (PCBM) molecules. The thinner graphene-sheets have significantly altered the positions of highest occupied molecular orbital and lowest unoccupied molecular orbital of PCBM, which is beneficial for the enhancement of the open circuit voltage of the solar cells. Flexible bulk heterojunction solar cells fabricated using poly 3-hexylthiophene (P3HT):PCBM-graphene exhibited a power conversion efficiency of 2.51%, which is a ∼2-fold increase as compared to those fabricated using P3HT:PCBM. Inclusion of graphene-sheets not only improved the open-circuit voltage but also enhanced the short-circuit current density owing to an improved electron transport.

  13. Improvement of quantum efficiency of P3HT:PCBM-based organic photovoltaic cells using DMDCNQI as an N-type dopant and buffer layer.

    PubMed

    Lee, Joo Hyung; Yang, Eui Yeol; Oh, Se Young

    2013-03-01

    In previous work, we have reported that a P3HT:PCBM-based organic photovoltaic cell using a thermally evaporated DMDCNQI buffer layer shows a high power conversion efficiency. In the present work, we have fabricated organic photovoltaic cells consisting of ITO/PEDOT:PSS/P3HT:PCBM:DMDCNQI/DMDCNQI/Al using an all-solution process. A thin, uniform DMDCNQI film was obtained in a methanol solution with high solubility and low viscosity. The prepared device shows a high power conversion efficiency of 2.9%. In particular, a maximum external quantum efficiency of 81% was obtained.

  14. Optical and Magnetic Resonance Studies of Regio-Regular and Regio-Random Poly (3-hexylthiophene)/PCBM Blends

    NASA Astrophysics Data System (ADS)

    Hukic-Markosian, Golda; Zhang, Ye; Singh, Sanjeev; Vardeny, Valy

    2010-03-01

    Regio-regular (RR) P3HT has been successfully used as donor polymer in organic bulk heterojunction photovoltaic cells based on blends with fullerene acceptors; with power conversion efficiencies of over 6%. However, when regio-random (RR-a) P3HT is used as donor polymer in the blend, the power conversion efficiency drops to less than 0.5%. We have used various optical and magnetic resonance techniques to elucidate the charge photogeneration in the two polymer/fullerene blends. Using tunneling electron microscopy we conclude that phase separation takes place in blends based on RR P3HT but not in blends based on RR-a P3HT. Photoluminescence spectrum shows a prominent band in RR-a P3HT blend at 1.32 eV, indicating the dominance of charge transfer exciton recombination. Photoinduced absorption shows higher localization of polarons in RRa-P3HT blend, with a distinct PA band due to negative polaron on PCBM molecules. Photoinduced absorption detected magnetic resonance resolves the contributions of RR-a P3HT and PCBM as two resonances indicating positive polarons on the polymer and negative polaron on the fullerene. A model based on our experimental results will be discussed.

  15. Improved performance of P3HT:PCBM solar cells by both anode modification and short-wavelength energy utilization using Tb(aca)3phen

    NASA Astrophysics Data System (ADS)

    Zhuo, Zu-Liang; Wang, Yong-Sheng; He, Da-Wei; Fu, Ming

    2014-09-01

    The performance of P3HT:PCBM solar cells was improved by anode modification using spin-coated Tb(aca)3phen ultrathin films. The modification of the Tb(aca)3phen ultrathin film between the indium tin oxide (ITO) anode and the PE-DOT:PSS layer resulted in a maximum power conversion efficiency (PCE) of 2.99% compared to 2.66% for the reference device, which was due to the increase in the short-circuit current density (Jsc). The PCE improvement could be attributed to the short-wavelength energy utilization and the optimized morphology of the active layers. Tb(aca)3phen with its strong down-conversion luminescence properties is suitable for the P3HT:PCBM blend active layer, and the absorption region of the ternary blend films is extended into the near ultraviolet region. Furthermore, the crystallization and the surface morphology of P3HT:PCBM films were improved with the Tb(aca)3phen ultrathin film. The ultraviolent—visible absorption spectra, atomic force microscope (AFM), and X-ray diffraction (XRD) of the films were investigated. Both anode modification and short-wavelength energy utilization using Tb(aca)3phen in P3HT:PCBM solar cells led to about a 12% PCE increase.

  16. Shockley-Read-Hall recombination in P3HT:PCBM solar cells as observed under ultralow light intensities

    SciTech Connect

    Tzabari, Lior; Tessler, Nir

    2011-03-15

    We present light intensity dependent measurements of the quantum efficiency of P3HT:PCBM photovoltaic devices. Unlike previous studies we focus on ultralow light intensities down to 10{sup -3} mW/cm{sup 2}. We find that although when the devices are excited at intensities close to 1 Sun they exhibit very little bias or light intensity dependence, this is clearly not the case for light intensities below 1 mW/cm{sup 2}, where the cell's efficiency becomes highly dependent on the bias and light intensity. Using a simple model for the device efficiency we can fit the experimental data across a wide range of parameters and thus separate the effects of generation efficiency (geminate recombination) and charge recombination. Our finding suggests that recombination through trap (charge transfer) states is an important loss mechanism and we are able to quantify the density and depth of these states.

  17. Structures, optical absorption and electrical properties of pulsed-laser-deposited CuIn0.8Ga0.2Se2 thin films and their use in CIGS/PCBM photovoltaic structures

    NASA Astrophysics Data System (ADS)

    Zhao, Yu; Wu, JiaDa; Xu, Ning

    2016-10-01

    Polycrystalline CuIn0.8Ga0.2Se2 (CIGS) thin films are deposited on ITO-glass substrates at different substrate temperatures by pulsed laser deposition using a Nd:YAG laser. The crystallinity of the as-deposited CIGS films significantly improved as the substrate temperature increased. The experimental results indicate that the ordered defect compound model is also applicable to the CIGS films deposited in these experiments. All the as-deposited CIGS thin films show absorption coefficients of 105 cm‑1 magnitude in a wavelength range of 400–900 nm. The CIGS thin films deposited at substrate temperatures lower than 400 °C exhibit n-type conductivity while those deposited at a substrate temperature of 500 °C display p-type conductivity. The CIGS/phenyl-C61-butyric acid methyl ester (PCBM) photovoltaic structure, with a CIGS layer as the only absorber, demonstrates an apparent photovoltaic response with a short circuit current density of 0.389 mA cm‑2 and an open circuit voltage of 0.327 V.

  18. Correlation between blend morphology and recombination dynamics in additive-added P3HT:PCBM solar cells.

    PubMed

    Solanki, Ankur; Wu, Bo; Salim, Teddy; Lam, Yeng Ming; Sum, Tze Chien

    2015-10-21

    The addition of a small amount of high boiling point solvent in organic donor/acceptor blends to control their morphology is a viable approach to enhance the power conversion efficiency of bulk heterojunction (BHJ) organic solar cells. Herein, through transient absorption spectroscopy (TAS) correlated with physical characterizations and device studies, we investigate the effects of a family of thiol-based additives (i.e., 1,5-pentanedithiol (PDT), 1,6-hexanedithiol (HDT) and 1,8-octanedithiol (ODT)) in P3HT:PCBM blend films in a bid to establish a morphology-function-charge dynamics relationship with their photovoltaic performances. The performance of solar cell devices (ηHDT = 2.8%, ηODT = 2.8%, ηPDT = 1.7%) is related to the additive-induced phase separation and the degree of ordering of P3HT. TAS uncovers a more efficient initial exciton and polaron generation in the additive-treated blend samples compared to the non-additive treated control sample. HDT and ODT-added blends exhibit decay dynamics and performances similar to those of the thermally annealed samples. However, the PDT-added blend exhibits a strong trap-assisted recombination in the subsequent nanosecond-microsecond timescales. We attribute this to the loss of charge carriers in the larger isolated P3HT domains due to the lack of percolation paths to the electrode. Our findings illustrate that understanding the complex interplay of the crystalline order, intermixed phases and percolation pathways is key to optimizing the performance of thermal-annealing free, additive-treated organic solar cells. PMID:26377255

  19. Monte Carlo modeling of the spatially dispersive carrier transport in P3HT and P3HT:PCBM blends

    NASA Astrophysics Data System (ADS)

    Jiang, Xin

    2009-10-01

    The presence of traps, arising from morpohological or chemical defects, can be critical to the performance of organic semiconductor devices. Traps can reduce the charge carrier mobility, disturb the internal electrical field, drive recombination, and reduce the overall device efficiency as well as operational stability. In this work, we investigate the role of traps in determining charge transport properties of organic semiconductors and blends such as P3HT and P3HT:PCBM through Monte-Carlo (MC) simulations in conjunction with time-of-flight (TOF) mobility measurements. We employ a Marcus theory description of individual hopping events based on the molecular reorganization energy (lambda) for the MC simulations. Trap states are modeled as diffuse bands that reside at some energy away from the main transport band. This model is used to simulate TOF transients, and the results are compared to experimental data. As is expected from the Marcus theory equation, the mobility is seen to be maximum for an optimal value of lambda. This optimal value is strongly field dependent, but is found to be independent of the trap density. In comparing MC simulations with TOF data, it is found that inclusion of traps results in a much better fit to the data and provides for a mechanism to simulate dispersive transport with a long tail resulting from trapping and detrapping of carriers before they exit the device. We present results for a range of trap densities and statistical distributions and discuss the implications on the operation of bulk heterojunction organic photovoltaic devices.

  20. Light-induced electron paramagnetic resonance evidence of charge transfer in electrospun fibers containing conjugated polymer/fullerene and conjugated polymer/fullerene/carbon nanotube blends

    SciTech Connect

    Shames, Alexander I.; Bounioux, Celine; Katz, Eugene A.; Yerushalmi-Rozen, Rachel; Zussman, Eyal

    2012-03-12

    Electrospun sub-micron fibers containing conjugated polymer (poly(3-hexylthiophene), P3HT) with a fullerene derivative, phenyl-C61-butyric acid methylester (PCBM) or a mixture of PCBM and single-walled carbon nanotubes (SWCNTs) were studied by light-induced electron paramagnetic resonance spectroscopy. The results provide experimental evidence of electron transfer between PCBM and P3HT components in both fiber systems and suggest that the presence of a dispersing block-copolymer, which acts via physical adsorption onto the PCBM and SWCNT moieties, does not prevent electron transfer at the P3HT-PCBM interface. These findings suggest a research perspective towards utilization of fibers of functional nanocomposites in fiber-based organic optoelectronic and photovoltaic devices. The latter can be developed in the textile-type large area photovoltaics or individual fiber-based solar cells that will broaden energy applications from macro-power tools to micro-nanoscale power conversion devices and smart textiles.

  1. Light-induced electron paramagnetic resonance evidence of charge transfer in electrospun fibers containing conjugated polymer/fullerene and conjugated polymer/fullerene/carbon nanotube blends

    NASA Astrophysics Data System (ADS)

    Shames, Alexander I.; Bounioux, Céline; Katz, Eugene A.; Yerushalmi-Rozen, Rachel; Zussman, Eyal

    2012-03-01

    Electrospun sub-micron fibers containing conjugated polymer (poly(3-hexylthiophene), P3HT) with a fullerene derivative, phenyl-C61-butyric acid methylester (PCBM) or a mixture of PCBM and single-walled carbon nanotubes (SWCNTs) were studied by light-induced electron paramagnetic resonance spectroscopy. The results provide experimental evidence of electron transfer between PCBM and P3HT components in both fiber systems and suggest that the presence of a dispersing block-copolymer, which acts via physical adsorption onto the PCBM and SWCNT moieties, does not prevent electron transfer at the P3HT-PCBM interface. These findings suggest a research perspective towards utilization of fibers of functional nanocomposites in fiber-based organic optoelectronic and photovoltaic devices. The latter can be developed in the textile-type large area photovoltaics or individual fiber-based solar cells that will broaden energy applications from macro-power tools to micro-nanoscale power conversion devices and smart textiles.

  2. Bulk heterojunction photovoltaic cells based on tetra-methyl substituted copper(II) phthalocyanine:P3HT:PCBM composite.

    PubMed

    Xu, Zong-Xiang; Roy, V A L; Low, Kam-Hung; Che, Chi-Ming

    2011-09-14

    Insoluble CuMePc nanocrystals were incorporated into P3HT:PCBM bulk heterojunction photovoltaic cells to increase the carrier mobility and photon harvesting. The P1C1-based (weight ratio of P3HT: CuMePc = 1:1) OPV cell exhibited the best photovoltaic performance with a J(SC) of 16.3 mA cm(-2), V(OC) of 0.58 V, FF of 0.56 and PCE of 5.3%.

  3. On the improvement of photovoltaic action of ZnO/P3HT:PCBM by controlling roughness of window layer

    SciTech Connect

    Geethu, R. Menon, M. R. Rajesh Kartha, C. Sudha Vijayakumar, K. P.

    2014-04-24

    Polymer solar cells with configuration ITO/ZnO/P3HT:PCBM/Ag were fabricated using cost effective chemical spray pyrolysis and spin coating techniques. When surface of ZnO layer was modified with a second layer so as to increase the roughness, considerable improvement in cell parameters were observed. Optimum conditions for the required roughness were identified and changes in cell parameters with variation in surface roughness were studied. Major enhancements were observed in the open circuit voltage and in the cell efficiency.

  4. Toward Improved Lifetimes of Organic Solar Cells under Thermal Stress: Substrate-Dependent Morphological Stability of PCDTBT:PCBM Films and Devices

    PubMed Central

    Li, Zhe; Ho Chiu, Kar; Shahid Ashraf, Raja; Fearn, Sarah; Dattani, Rajeev; Cheng Wong, Him; Tan, Ching-Hong; Wu, Jiaying; Cabral, João T.; Durrant, James R.

    2015-01-01

    Morphological stability is a key requirement for outdoor operation of organic solar cells. We demonstrate that morphological stability and lifetime of polymer/fullerene based solar cells under thermal stress depend strongly on the substrate interface on which the active layer is deposited. In particular, we find that the stability of benchmark PCDTBT/PCBM solar cells under modest thermal stress is substantially increased in inverted solar cells employing a ZnO substrate compared to conventional devices employing a PEDOT:PSS substrate. This improved stability is observed to correlate with PCBM nucleation at the 50 nm scale, which is shown to be strongly influenced by different substrate interfaces. Employing this approach, we demonstrate remarkable thermal stability for inverted PCDTBT:PC70BM devices on ZnO substrates, with negligible (<2%) loss of power conversion efficiency over 160 h under 85 °C thermal stress and minimal thermally induced “burn-in” effect. We thus conclude that inverted organic solar cells, in addition to showing improved environmental stability against ambient humidity exposure as widely reported previously, can also demonstrate enhanced morphological stability. As such we show that the choice of suitable substrate interfaces may be a key factor in achieving prolonged lifetimes for organic solar cells under thermal stress conditions. PMID:26468676

  5. Elucidation of barrier homogeneity in ZnO/P3HT:PCBM junctions through temperature dependent I-V characteristics

    NASA Astrophysics Data System (ADS)

    Khare, Neeraj; Zubair Ansari, Mohd; Hoye, Robert L. Z.; Iza, Diana C.; MacManus-Driscoll, Judith L.

    2016-07-01

    The current-voltage (I-V) characteristics of ZnO/P3HT:PCBM junctions using as-deposited ZnO and 300 °C-annealed ZnO (prior to device fabrication) were probed as a function of temperature. The ZnO films were synthesized using two scalable, low temperature methods: Atmospheric pressure spatial atomic layer deposition (AP-SALD) and electrodeposition (ED). In both cases the zero bias Schottky barrier height ({Φ\\text{B}} ) decreases and ideality factor (n) increases with a reduction in the operating temperature of the junctions. This was attributed to the presence of barrier inhomogeneities at the interface from surface states/defects in the ZnO causing a localized variation of work function. For the as-deposited ZnO junctions, two mean barrier heights, arising from a large density of surface states was observed. For the annealed ZnO junction one mean barrier height was observed, indicating reduction in the inhomogeneities of barrier height at the interface for the annealed ZnO. The photoresponce of ZnO/P3HT:PCBM junction was higher for the annealed ZnO which is due to the higher mean barrier height and lower value of ideality factor. This demonstrates that moderate annealing of chemically grown ZnO is crucial for reducing surface defects and barrier inhomogeneities.

  6. Toward Improved Lifetimes of Organic Solar Cells under Thermal Stress: Substrate-Dependent Morphological Stability of PCDTBT:PCBM Films and Devices

    NASA Astrophysics Data System (ADS)

    Li, Zhe; Ho Chiu, Kar; Shahid Ashraf, Raja; Fearn, Sarah; Dattani, Rajeev; Cheng Wong, Him; Tan, Ching-Hong; Wu, Jiaying; Cabral, João T.; Durrant, James R.

    2015-10-01

    Morphological stability is a key requirement for outdoor operation of organic solar cells. We demonstrate that morphological stability and lifetime of polymer/fullerene based solar cells under thermal stress depend strongly on the substrate interface on which the active layer is deposited. In particular, we find that the stability of benchmark PCDTBT/PCBM solar cells under modest thermal stress is substantially increased in inverted solar cells employing a ZnO substrate compared to conventional devices employing a PEDOT:PSS substrate. This improved stability is observed to correlate with PCBM nucleation at the 50 nm scale, which is shown to be strongly influenced by different substrate interfaces. Employing this approach, we demonstrate remarkable thermal stability for inverted PCDTBT:PC70BM devices on ZnO substrates, with negligible (<2%) loss of power conversion efficiency over 160 h under 85 °C thermal stress and minimal thermally induced “burn-in” effect. We thus conclude that inverted organic solar cells, in addition to showing improved environmental stability against ambient humidity exposure as widely reported previously, can also demonstrate enhanced morphological stability. As such we show that the choice of suitable substrate interfaces may be a key factor in achieving prolonged lifetimes for organic solar cells under thermal stress conditions.

  7. Improving charge transport of P3HT:PCBM organic solar cell using MoO3 nanoparticles as an interfacial buffer layer

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hyoung; Park, Eung-Kyu; Kim, Ji-Hwan; Cho, Hyeong Jun; Lee, Dong-Hoon; Kim, Yong-Sang

    2016-05-01

    In this work, P3HT:PCBM based organic solar cells (OSCs) were fabricated. We investigated the protection of PEDOT:PSS from active layer using the solution processed molybdenum oxide nanoparticles layer (MoO3 NPs, ≤100 nm). The device structure was ITO/ZnO/P3HT: PCBM/MoO3/PEDOT:PSS/Ag. A thin film MoO3 NPs was spin-coated and it acts as a hole transporting layer between the active layer and PEDOT:PSS. The MoO3 NPs based device showed an improved short circuit current compared without MoO3 NP layer. The pristine OSCs showed short circuit current density ( J sc ) of 11.56 mA/cm2 and PCE of 3.70% under AM 1.5G (100 mW/cm2). MoO3 NPs based device showed an increased PCE of 4.11% with J sc of 12.74 mA/cm2. MoO3 NPs also decreased the charge recombination and resistance of the OSCs. [Figure not available: see fulltext.

  8. The effects of organic solvents and their co-solvents on the optical, structural, morphological of P3HT:PCBM organic solar cells

    NASA Astrophysics Data System (ADS)

    Kadem, Burak Y.; Hassan, Aseel K.; Cranton, Wayne

    2016-07-01

    The effect of different solvents on the optical, structural, morphology and solar cell performance of P3HT:PCBM based devices were carried out using UV-visible absorption spectroscopy, XRD, AFM, SEM, electrical conductivity as well as current density-voltage (J-V) measurements in dark and under illumination. Chloroform (CF), chlorobenzene (CB), di-chlorobenzene (DCB), and their mixtures (DCB:CB, DCB:CF and CF:CB) in the ratio 1:1 were used as solvents to produce active layers of P3HT:PCBM heterojunctions. UV-visible absorption spectra have demonstrated different absorption intensities subject to the used solvents as well as a decrease in the optical bandgap from around 1.9eV to 1.8eV. AFM and SEM images gave an indication on the films' morphological properties, which have exhibited different topographies due to the used solvent. The electrical conductivity as well as the dark J-V characteristics were analysed using Richardson-Schottky model as well as space charge limited conduction theory to evaluate the diode properties of the produced solar cells. The electrical conductivity were found to vary from 9.7-77.7 mS.cm-1 and the higher values were associated with using CB:CF co-solvents based devices while the series resistance decreased from 33.3KΩ to 0.54KΩ using the same co-solvents. This was associated with an increase in the charge carriers' mobility that reached 6.69x10-6 cm2V-1s-1 in CB:CF based device. OSC devices produced using CB:CF co-solvents has exhibited the highest performance with PCE=2.73%, FF=53% and Jsc=8.3mA.cm-2 while Voc remained unchanged.

  9. Negative polarity of phenyl-C{sub 61} butyric acid methyl ester adjacent to donor macromolecule domains

    SciTech Connect

    Alley, Olivia J.; Dawidczyk, Thomas J.; Hardigree, Josué F. Martínez; Katz, Howard E.; Wu, Meng-Yin; Johns, Gary L.; Markovic, Nina; Arnold, Michael S.

    2015-01-19

    Interfacial fields within organic photovoltaics influence the movement of free charge carriers, including exciton dissociation and recombination. Open circuit voltage (V{sub oc}) can also be dependent on the interfacial fields, in the event that they modulate the energy gap between donor HOMO and acceptor LUMO. A rise in the vacuum level of the acceptor will increase the gap and the V{sub oc}, which can be beneficial for device efficiency. Here, we measure the interfacial potential differences at donor-acceptor junctions using Scanning Kelvin Probe Microscopy, and quantify how much of the potential difference originates from physical contact between the donor and acceptor. We see a statistically significant and pervasive negative polarity on the phenyl-C{sub 61} butyric acid methyl ester (PCBM) side of PCBM/donor junctions, which should also be present at the complex interfaces in bulk heterojunctions. This potential difference may originate from molecular dipoles, interfacial interactions with donor materials, and/or equilibrium charge transfer due to the higher work function and electron affinity of PCBM. We show that the contact between PCBM and poly(3-hexylthiophene) doubles the interfacial potential difference, a statistically significant difference. Control experiments determined that this potential difference was not due to charges trapped in the underlying substrate. The direction of the observed potential difference would lead to increased V{sub oc}, but would also pose a barrier to electrons being injected into the PCBM and make recombination more favorable. Our method may allow unique information to be obtained in new donor-acceptor junctions.

  10. A high omega 3 fatty acid diet alters fatty acid composition of heart, liver, kidney, adipose tissue and skeletal muscle in swine.

    PubMed

    Otten, W; Wirth, C; Iaizzo, P A; Eichinger, H M

    1993-01-01

    The fatty acid profiles and total lipid contents of two skeletal muscles, adipose tissue, heart, liver and kidney of swine fed a diet rich in omega 3 (n-3) fatty acids (i.e., 5% fish oil) was investigated. These values were compared to those determined for animals which were fed an equal caloric diet low in n-3 fatty acids (i.e., 5% coconut oil). All supplementations were given over a 13-week period. The lipids were extracted with chloroform-methanol, trans-esterified and the relative fatty acid methyl-esters concentrations were determined using capillary gas chromatography. The fish oil diet significantly enhanced the relative amounts of n-3 fatty acids (i.e., eicosapentaenoic acid and docosahexaenoic acid) in all tissues examined. In the heart, liver and kidney, the increases in n-3 fatty acids were compensated by decreases primarily in arachidonic acid, but in the other tissues the contents of lauric and myristic acids were also reduced. In general, the n-3 fatty acid contents were 40-165% higher in the animals fed the fish oil. Supplementation of n-3 fatty acids in swine induced a significant incorporation of these fatty acids throughout the body, however the extent of this incorporation differed between tissues perhaps due to tissue-specific metabolic pathways. PMID:8373137

  11. Micron-sized [6,6]-phenyl C61 butyric acid methyl ester crystals grown by dip coating in solvent vapour atmosphere: interfaces for organic photovoltaics.

    PubMed

    Dabirian, R; Feng, X; Ortolani, L; Liscio, A; Morandi, V; Müllen, K; Samorì, P; Palermo, V

    2010-05-01

    We have devised a novel dip coating procedure to form highly crystalline and macroscopic pi-conjugated architectures on solid surfaces. We have employed this approach to a technologically relevant system, i.e. the electron-acceptor [6,6]-phenyl C61 butyric acid methyl ester molecule (PCBM), which is the most commonly used electron-acceptor in organic photovoltaics. Highly ordered, hexagonal shaped crystals of PCBM, ranging between 1 to 80 mum in diameter and from 20 to 500 nm in thickness, have been grown by dip coating the substrates into a solution containing the fullerene derivative. These crystals have been found to possess a monocrystalline character, to exhibit a hexagonal symmetry and to display micron sized molecularly flat terraces. The crystals have been prepared on a wide variety of surfaces such as SiO(x), silanized SiO(x), Au, graphite, amorphous carbon-copper grids and ITO. Their multiscale characterization has been performed by atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), X-ray diffraction (XRD), optical microscopy, scanning and transmission electron microscopy (SEM, TEM).To test the stability of these electron accepting PCBM crystals, they have been coated with a complementary, electron donor hexa-peri-hexabenzocoronene (HBC) derivative by solution processing from acetone and chloroform-methanol blends. The HBC self assembles in a well-defined network of nanofibers on the PCBM substrate, and the two materials can be clearly resolved by AFM and KPFM.Due to its structural precision on the macroscopic scale, the PCBM crystals appear as ideal interface to perform fundamental photophysical studies in electron-acceptor and -donor blends, as well as workbench for unravelling the architecture vs. function relationship in organic solar cells prototypes.

  12. Photovoltaic cells based on ternary P3HT:PCBM:polymethine dye active layer transparent in the visible range of light

    NASA Astrophysics Data System (ADS)

    Bliznyuk, Valery N.; Gasiorowski, Jacek; Ishchenko, Alexander A.; Bulavko, Gennadiy V.; Rahaman, Mahfujur; Hingerl, Kurt; Zahn, Dietrich R. T.; Sariciftci, Niyazi S.

    2016-12-01

    Optical and photovoltaic properties were studied for ternary photovoltaic cells containing a traditional donor-acceptor bulk-heterojunction (BHJ) active layer modified with polymethine dye molecules in a broad range of compositions and wavelengths. An effect of composition induced optical transparency, due to the strong modification of the density of states, was observed for symmetrical compositions with approximately equal amount of components. Based on our spectroscopic ellipsometry and atomic force microscopy (AFM) studies we can suggest that the variation of the refractive index, which is significantly reduced in the visible range for ternary systems, is involved in the physical mechanism of the phenomenon. Despite of an addition of the IR absorbing component (which allows broadening of the absorption band to up to 800 nm) no improvement in the power conversion efficiency (PCE) is observed in comparison to the binary BHJ system (P3HT:PCBM). Nevertheless, we believe that further advance of the efficiency will be possible if the energy levels will be chemically designed to avoid formation of charge traps at the BHJ interface during light excitation. Such fine adjustment of the system should become possible with a proper choice of polymer:dye composition due to a high versatility of the polymethine dyes demonstrated in previous studies.

  13. Consequences of anode interfacial layer deletion. HCl-treated ITO in P3HT:PCBM-based bulk-heterojunction organic photovoltaic devices.

    PubMed

    Irwin, Michael D; Liu, Jun; Leever, Benjamin J; Servaites, Jonathan D; Hersam, Mark C; Durstock, Michael F; Marks, Tobin J

    2010-02-16

    In studies to simplify the fabrication of bulk-heterojunction organic photovoltaic (OPV) devices, it was found that when glass/tin-doped indium oxide (ITO) substrates are treated with dilute aqueous HCl solutions, followed by UV ozone (UVO), and then used to fabricate devices of the structure glass/ITO/P3HT:PCBM/LiF/Al, device performance is greatly enhanced. Light-to-power conversion efficiency (Eff) increases from 2.4% for control devices in which the ITO surface is treated only with UVO to 3.8% with the HCl + UVO treatment--effectively matching the performance of an identical device having a PEDOT:PSS anode interfacial layer. The enhancement originates from increases in V(OC) from 463 to 554 mV and FF from 49% to 66%. The modified-ITO device also exhibits a 4x enhancement in thermal stability versus an identical device containing a PEDOT:PSS anode interfacial layer. To understand the origins of these effects, the ITO surface is analyzed as a function of treatment by ultraviolet photoelectron spectroscopy work function measurements, X-ray photoelectron spectroscopic composition analysis, and atomic force microscopic topography and conductivity imaging. Additionally, a diode-based device model is employed to further understand the effects of ITO surface treatment on device performance.

  14. Fabrication and characterization of P3HT:PCBM-based thin film organic solar cells with zinc phthalocyanine

    SciTech Connect

    Maruhashi, Haruto Oku, Takeo Suzuki, Atsushi Akiyama, Tsuyoshi; Yamasaki, Yasuhiro

    2015-02-27

    [6,6]–phenyl C{sub 61}–butyric acid methyl ester and poly(3–hexylthiophene) bulk heterojunction solar cells added with zinc–tetra–tertiary–butyl–phthalocyanine (ZnPc) were fabricated and characterized. The photovoltaic properties of the solar cells with an inverted structure were improved by the ZnPc addition, which were investigated on the bases of current density–voltage characteristics, incident photon to current conversion efficiency.

  15. Effect of Dual Cathode Buffer Layer on the Charge Carrier Dynamics of rrP3HT:PCBM Based Bulk Heterojunction Solar Cell.

    PubMed

    Singh, Ashish; Dey, Anamika; Das, Dipjyoti; Iyer, Parameswar Krishnan

    2016-05-01

    In bulk heterojunction (BHJ) solar cells, the buffer layer plays a vital role in enhancing the power conversion efficiency (PCE) by improving the charge carrier dynamics. A comprehensive understanding of the contacts is especially essential in order to optimize the performance of organic solar cells (OSCs). Although there are several fundamental reports on this subject, a proper correlation of the physical processes with experimental evidence at the photoactive layer and contact materials is essential. In this work, we incorporated three different additional buffer layers, namely, tris(8-hydroxyquinolinato) aluminum (Alq3), bathophenanthroline (BPhen) or bathocuproine (BCP) with LiF/Al as conventional cathode contact in both rrP3HT:PC61BM and rrP3HT:PC71BM blend BHJ solar cells and their corresponding photovoltaic performances were systematically correlated with their energy level diagram. The device with dual cathode buffer layer having ITO/PEDOT:PSS/blend polymer/BCP/LiF/Al configuration showed the best device performance with PCE, η = 4.96%, Jsc = 13.53 mA/cm(2), Voc = 0.60 V and FF= 61% for rrP3HT:PC71BM and PCE, η = 4.5% with Jsc = 13.3 mA/cm(2), Voc = 0.59 V and FF = 59% for rrP3HT:PC61BM. This drastic improvement in PCE in both the device configurations are due to the combined effects of better hole-blocking capacity of BCP and low work function provided by LiF/Al with the blend polymer. These results successfully explain the role of dual cathode buffer layers and their contribution to the PCE improvement and overall device performance with rrP3HT:PCBM based BHJ solar cell. PMID:27075007

  16. Effect of Dual Cathode Buffer Layer on the Charge Carrier Dynamics of rrP3HT:PCBM Based Bulk Heterojunction Solar Cell.

    PubMed

    Singh, Ashish; Dey, Anamika; Das, Dipjyoti; Iyer, Parameswar Krishnan

    2016-05-01

    In bulk heterojunction (BHJ) solar cells, the buffer layer plays a vital role in enhancing the power conversion efficiency (PCE) by improving the charge carrier dynamics. A comprehensive understanding of the contacts is especially essential in order to optimize the performance of organic solar cells (OSCs). Although there are several fundamental reports on this subject, a proper correlation of the physical processes with experimental evidence at the photoactive layer and contact materials is essential. In this work, we incorporated three different additional buffer layers, namely, tris(8-hydroxyquinolinato) aluminum (Alq3), bathophenanthroline (BPhen) or bathocuproine (BCP) with LiF/Al as conventional cathode contact in both rrP3HT:PC61BM and rrP3HT:PC71BM blend BHJ solar cells and their corresponding photovoltaic performances were systematically correlated with their energy level diagram. The device with dual cathode buffer layer having ITO/PEDOT:PSS/blend polymer/BCP/LiF/Al configuration showed the best device performance with PCE, η = 4.96%, Jsc = 13.53 mA/cm(2), Voc = 0.60 V and FF= 61% for rrP3HT:PC71BM and PCE, η = 4.5% with Jsc = 13.3 mA/cm(2), Voc = 0.59 V and FF = 59% for rrP3HT:PC61BM. This drastic improvement in PCE in both the device configurations are due to the combined effects of better hole-blocking capacity of BCP and low work function provided by LiF/Al with the blend polymer. These results successfully explain the role of dual cathode buffer layers and their contribution to the PCE improvement and overall device performance with rrP3HT:PCBM based BHJ solar cell.

  17. Poly-(3-hexylthiophene)/[6,6]-phenyl-C61-butyric-acid-methyl-ester bilayer deposition by matrix-assisted pulsed laser evaporation for organic photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Caricato, A. P.; Cesaria, M.; Gigli, G.; Loiudice, A.; Luches, A.; Martino, M.; Resta, V.; Rizzo, A.; Taurino, A.

    2012-02-01

    A poly-(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) bilayer structure has been realized by single step matrix-assisted pulsed laser evaporation (ss-MAPLE) technique using the same solvent for both the polymers under vacuum conditions. Our ss-MAPLE procedure allows the fabrication of polymeric multilayer device stacks, which are very difficult to realize with the conventional solvent assisted deposition methods. A proof of concept bilayer P3HT/PCBM solar cell based on ss-MAPLE deposition has been realized and characterized. This demonstration qualifies ss-MAPLE as a general and alternative technique for the implementation of polymeric materials in hetero-structure device technology.

  18. Study of a ternary blend system for bulk heterojunction thin film solar cells

    NASA Astrophysics Data System (ADS)

    Ahmad, Zubair; Touati, Farid; Shakoor, R. A.; Al-Thani, N. J.

    2016-08-01

    In this research, we report a bulk heterojunction (BHJ) solar cell consisting of a ternary blend system. Poly(3-hexylthiophene) P3HT is used as a donor and [6,6]-phenyl C61-butyric acid methylester (PCBM) plays the role of acceptor whereas vanadyl 2,9,16,23-tetraphenoxy-29H, 31H-phthalocyanine (VOPcPhO) is selected as an ambipolar transport material. The materials are selected and assembled in such a fashion that the generated charge carriers could efficiently be transported rightwards within the blend. The organic BHJ solar cells consist of ITO/PEDOT:PSS/ternary BHJ blend/Al structure. The power conversion efficiencies of the ITO/ PEDOT:PSS/P3HT:PCBM/Al and ITO/PEDOT:PSS/ P3HT:PCBM:VOPcPhO/Al solar cells are found to be 2.3% and 3.4%, respectively. This publication was made possible by PDRA (Grant No. PDRA1-0117-14109) from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors.

  19. Field-effect transistor-based solution-processed colloidal quantum dot photodetector with broad bandwidth into near-infrared region.

    PubMed

    Yang, Shengyi; Zhao, Na; Zhang, Li; Zhong, Haizheng; Liu, Ruibin; Zou, Bingsuo

    2012-06-29

    We demonstrate a solution-processed colloidal quantum dot (CQDs) photodetector with the configuration of a field-effect transistor (FET), in which the drain and source electrodes are fabricated by a shadow mask. By blending PbS CQDs into the hybrid blend, poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C(61)-butyric acid methylester (PCBM), the photosensitive spectrum of the nanocomposite blend is extended into the near-infrared region. A FET-based photodetector ITO/PMMA (180 nm)/P3HT:PCBM:PbS (110 nm)/Al, in which PMMA (polymethylmethacrylate) acts as the dielectric layer and P3HT:PCBM:PbS (in weight ratio of 1:1:1) as the active layer, shows a broad spectral bandwidth, a responsivity of 0.391 mA W(-1) and a specific detectivity of 1.31 × 10(11) Jones are obtained at V(GS) = 1 V under 600 nm illumination with an intensity of 30 μW cm(-2). Therefore, it provides an easy way to fabricate such a FET-based photodetector with a channel length of some hundreds of micrometers by a shadow mask.

  20. Fatty Acids Composition of Vegetable Oils and Its Contribution to Dietary Energy Intake and Dependence of Cardiovascular Mortality on Dietary Intake of Fatty Acids

    PubMed Central

    Orsavova, Jana; Misurcova, Ladislava; Vavra Ambrozova, Jarmila; Vicha, Robert; Mlcek, Jiri

    2015-01-01

    Characterizations of fatty acids composition in % of total methylester of fatty acids (FAMEs) of fourteen vegetable oils—safflower, grape, silybum marianum, hemp, sunflower, wheat germ, pumpkin seed, sesame, rice bran, almond, rapeseed, peanut, olive, and coconut oil—were obtained by using gas chromatography (GC). Saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), palmitic acid (C16:0; 4.6%–20.0%), oleic acid (C18:1; 6.2%–71.1%) and linoleic acid (C18:2; 1.6%–79%), respectively, were found predominant. The nutritional aspect of analyzed oils was evaluated by determination of the energy contribution of SFAs (19.4%–695.7% ERDI), PUFAs (10.6%–786.8% ERDI), n-3 FAs (4.4%–117.1% ERDI) and n-6 FAs (1.8%–959.2% ERDI), expressed in % ERDI of 1 g oil to energy recommended dietary intakes (ERDI) for total fat (ERDI—37.7 kJ/g). The significant relationship between the reported data of total fat, SFAs, MUFAs and PUFAs intakes (% ERDI) for adults and mortality caused by coronary heart diseases (CHD) and cardiovascular diseases (CVD) in twelve countries has not been confirmed by Spearman’s correlations. PMID:26057750

  1. Fatty Acids Composition of Vegetable Oils and Its Contribution to Dietary Energy Intake and Dependence of Cardiovascular Mortality on Dietary Intake of Fatty Acids.

    PubMed

    Orsavova, Jana; Misurcova, Ladislava; Ambrozova, Jarmila Vavra; Vicha, Robert; Mlcek, Jiri

    2015-06-05

    Characterizations of fatty acids composition in % of total methylester of fatty acids (FAMEs) of fourteen vegetable oils--safflower, grape, silybum marianum, hemp, sunflower, wheat germ, pumpkin seed, sesame, rice bran, almond, rapeseed, peanut, olive, and coconut oil--were obtained by using gas chromatography (GC). Saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), palmitic acid (C16:0; 4.6%-20.0%), oleic acid (C18:1; 6.2%-71.1%) and linoleic acid (C18:2; 1.6%-79%), respectively, were found predominant. The nutritional aspect of analyzed oils was evaluated by determination of the energy contribution of SFAs (19.4%-695.7% E(RDI)), PUFAs (10.6%-786.8% E(RDI)), n-3 FAs (4.4%-117.1% E(RDI)) and n-6 FAs (1.8%-959.2% E(RDI)), expressed in % E(RDI) of 1 g oil to energy recommended dietary intakes (E(RDI)) for total fat (E(RDI)--37.7 kJ/g). The significant relationship between the reported data of total fat, SFAs, MUFAs and PUFAs intakes (% E(RDI)) for adults and mortality caused by coronary heart diseases (CHD) and cardiovascular diseases (CVD) in twelve countries has not been confirmed by Spearman's correlations.

  2. Fatty Acids Composition of Vegetable Oils and Its Contribution to Dietary Energy Intake and Dependence of Cardiovascular Mortality on Dietary Intake of Fatty Acids.

    PubMed

    Orsavova, Jana; Misurcova, Ladislava; Ambrozova, Jarmila Vavra; Vicha, Robert; Mlcek, Jiri

    2015-01-01

    Characterizations of fatty acids composition in % of total methylester of fatty acids (FAMEs) of fourteen vegetable oils--safflower, grape, silybum marianum, hemp, sunflower, wheat germ, pumpkin seed, sesame, rice bran, almond, rapeseed, peanut, olive, and coconut oil--were obtained by using gas chromatography (GC). Saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), palmitic acid (C16:0; 4.6%-20.0%), oleic acid (C18:1; 6.2%-71.1%) and linoleic acid (C18:2; 1.6%-79%), respectively, were found predominant. The nutritional aspect of analyzed oils was evaluated by determination of the energy contribution of SFAs (19.4%-695.7% E(RDI)), PUFAs (10.6%-786.8% E(RDI)), n-3 FAs (4.4%-117.1% E(RDI)) and n-6 FAs (1.8%-959.2% E(RDI)), expressed in % E(RDI) of 1 g oil to energy recommended dietary intakes (E(RDI)) for total fat (E(RDI)--37.7 kJ/g). The significant relationship between the reported data of total fat, SFAs, MUFAs and PUFAs intakes (% E(RDI)) for adults and mortality caused by coronary heart diseases (CHD) and cardiovascular diseases (CVD) in twelve countries has not been confirmed by Spearman's correlations. PMID:26057750

  3. Absence of Structural Impact of Noble Nanoparticles on P3HT:PCBM Blends for Plasmon-Enhanced Bulk-Heterojunction Organic Solar Cells Probed by Synchrotron GI-XRD

    PubMed Central

    Lilliu, Samuele; Alsari, Mejd; Bikondoa, Oier; Emyr Macdonald, J.; Dahlem, Marcus S.

    2015-01-01

    The incorporation of noble metal nanoparticles, displaying localized surface plasmon resonance, in the active area of donor-acceptor bulk-heterojunction organic photovoltaic devices is an industrially compatible light trapping strategy, able to guarantee better absorption of the incident photons and give an efficiency improvement between 12% and 38%. In the present work, we investigate the effect of Au and Ag nanoparticles blended with P3HT: PCBM on the P3HT crystallization dynamics by synchrotron grazing incidence X-ray diffraction. We conclude that the presence of (1) 80 nm Au, (2) mix of 5 nm, 50 nm, 80 nm Au, (3) 40 nm Ag, and (4) 10 nm, 40 nm, 60 nm Ag colloidal nanoparticles, at different concentrations below 0.3 wt% for Au and below 0.1% for Ag in P3HT: PCBM blends, does not affect the behaviour of the blends themselves. PMID:26030351

  4. Sterically controlled azomethine ylide cycloaddition polymerization of phenyl-C61-butyric acid methyl ester.

    PubMed

    Stephen, Meera; Ramanitra, Hasina H; Santos Silva, Hugo; Dowland, Simon; Bégué, Didier; Genevičius, Kristijonas; Arlauskas, Kęstutis; Juška, Gytis; Morse, Graham E; Distler, Andreas; Hiorns, Roger C

    2016-05-01

    Phenyl-C61-butyric acid methyl ester (PCBM) is polymerized simply using a one-pot reaction to yield soluble, high molecular weight polymers. The sterically controlled azomethine ylide cycloaddition polymerization (SACAP) is demonstrated to be highly adaptable and yields polymers with probable Mn≈ 24 600 g mol(-1) and Mw≈ 73 800 g mol(-1). Products are metal-free and of possible benefit to organic and hybrid photovoltaics and electronics as they form thin films from solution and have raised LUMOs. The promising electronic properties of this new polymer are discussed. PMID:27066898

  5. Acute effects of aspartame on large neutral amino acids and monoamines in rat brain.

    PubMed

    Fernstrom, J D; Fernstrom, M H; Gillis, M A

    1983-04-01

    The dipeptide aspartame (APM; aspartylphenylalanine methylester), an artificial sweetener, was studied in vivo for its ability to influence brain levels of the large neutral amino acids and the rates of hydroxylation of the aromatic amino acids. The administration by gavage of APM (200 mg/kg) caused large increments in blood and brain levels of phenylalanine and tyrosine by 60 minutes. Brain tryptophan level was occasionally reduced significantly, but the brain levels of the branched-chain amino acids were always unaffected. Smaller doses (50, 100 mg/kg) also raised blood and brain tyrosine and phenylalanine, but did not reduce brain tryptophan levels. At the highest dose (200 mg/kg), APM gavage caused an insignificant increase in dopa accumulation (after NSD-1015), and a modest reduction in 5-hydroxytryptophan accumulation. No changes in the brain levels of serotonin, 5-hydroxyindoleacetic acid, dopamine, dihydroxyphenylacetic acid, homovanillic acid, or norepinephrine were produced by APM administration (200 mg/kg). These results thus indicate that APM, even when administered in amounts that cause large increments in brain tyrosine and phenylalanine, produce minimal effects on the rates of formation of monoamine transmitters.

  6. Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C61-butyric acid methyl ester

    NASA Astrophysics Data System (ADS)

    Lazzerini, Giovanni Mattia; Paternò, Giuseppe Maria; Tregnago, Giulia; Treat, Neil; Stingelin, Natalie; Yacoot, Andrew; Cacialli, Franco

    2016-02-01

    We report high-resolution, traceable atomic force microscopy measurements of high-quality, solvent-free single crystals of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). These were grown by drop-casting PCBM solutions onto the spectrosil substrates and by removing the residual solvent in a vacuum. A home-built atomic force microscope featuring a plane mirror differential optical interferometer, fiber-fed from a frequency-stabilized laser (emitting at 632.8 nm), was used to measure the crystals' height. The optical interferometer together with the stabilized laser provides traceability (via the laser wavelength) of the vertical measurements made with the atomic force microscope. We find that the crystals can conform to the surface topography, thanks to their height being significantly smaller compared to their lateral dimensions (namely, heights between about 50 nm and 140 nm, for the crystals analysed, vs. several tens of microns lateral dimensions). The vast majority of the crystals are flat, but an isolated, non-flat crystal provides insights into the growth mechanism and allows identification of "molecular terraces" whose height corresponds to one of the lattice constants of the single PCBM crystal (1.4 nm) as measured with X-ray diffraction.

  7. Enhanced performance of planar perovskite solar cells via incorporation of Bphen/Cs2CO3-MoO3 double interlayers

    NASA Astrophysics Data System (ADS)

    Jiang, Yurong; Liu, Hairui; Gong, Xiu; Li, Chen; Qin, Ruiping; Ma, Heng

    2016-11-01

    This work proposes a new perovskite solar cell structure by inserting the double modified interlayers consisting of the 4,7-diphenyl-1,10-phenanthroline (Bphen) and cesium carbonate (Cs2CO3)-MoO3 layer between perovskite (CH3NH3PbI3-xClx)/PCBM (phenyl-C61-butyric acid methylester) and an Ag electrode. The double interlayers improve the photovoltaic efficiency to 15.59%, which is higher than that of reference devices with Bphen (13.41%) or alone, the champion PCE of 16.01% is obtained. The enhanced opening circuit voltage (Voc) is ascribed as the main factor to improve the efficiency. Further studies show, the reduced work function of cathode by means of the Cs2CO3-MoO3 could effectively extract the electrons and reduce the carrier recombination and thus result in a higher Voc.

  8. Dependence of Device Characteristics of Bulk-Heterojunction Organic Thin-Film Solar Cells on Concentration of Glycerol and Sorbitol Addition in Pedot:. PSS Solutions for Fabricating Buffer Layers

    NASA Astrophysics Data System (ADS)

    Yamaki, Yusuke; Marumoto, Kazuhiro; Fujimori, Takuya; Mori, Tatsuo

    We have investigated the dependence of device characteristics of bulk-heterojunction organic thin-film solar cells on the concentration of glycerol and sorbitol addition in poly(3,4-ethylenedioxy thiophene):poly(4-styrene sulfonate) (PEDOT:PSS) solutions for fabricating buffer layers. The device structure is ITO/buffer/regioregular poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61-butyric acid methylester (PCBM)/Al. Glycerol addition is effective for increasing power conversion efficiency (PCE) from 1.25 to 1.41% because of the increase in short-circuit current density (Jsc) without decreasing open-circuit voltage (Voc). On the other hand, sorbitol addition decreases PCE from 1.25 to 1.04%, owing to the decrease in Voc. This difference in Voc behavior is ascribed to different work function of PEDOT:PSS with glycerol and sorbitol treatment.

  9. Enhancement of the Power Conversion Efficiency in the Inverted Organic Solar Cells Fabricated Utilizing a CeO2 Interlayer Between the Poly(3-hexylthiophene) (P3HT):[6,6]-Phenyl C6 Butyric Acid Methyl Ester and the Cathode.

    PubMed

    Arul, N Sabari; Lee, Yong Hun; Lee, Dea Uk; Kim, Tae Whan

    2015-01-01

    CeO2 nanoparticles were synthesized by using a precipitation method. High-resolution transmission electron microscopy images, X-ray diffraction patterns, energy dispersive X-ray spectroscopy spectra, and UV-Visible absorption spectroscopy spectra showed that the formed samples were CeO2 polycrystalline nanoparticles. Inverted organic solar cells with a structure of indium-tin-oxide/CeO2/poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61 butyric acid methyl ester (PCBM)/MoO3/Ag were fabricated. Current density-voltage results showed that the power conversion efficiency of the device of the fabricated inverted OPV cells with a CeO2 interlayer between the P3HT:PCBM and the cathode was 0.39% larger than that without a CeO2 interlayer.

  10. A Combined Supplementation of Omega-3 Fatty Acids and Micronutrients (Folic Acid, Vitamin B12) Reduces Oxidative Stress Markers in a Rat Model of Pregnancy Induced Hypertension

    PubMed Central

    Kemse, Nisha G.; Kale, Anvita A.; Joshi, Sadhana R.

    2014-01-01

    Objectives Our earlier studies have highlighted that an altered one carbon metabolism (vitamin B12, folic acid, and docosahexaenoic acid) is associated with preeclampsia. Preeclampsia is also known to be associated with oxidative stress and inflammation. The current study examines whether maternal folic acid, vitamin B12 and omega-3 fatty acid supplementation given either individually or in combination can ameliorate the oxidative stress markers in a rat model of pregnancy induced hypertension (PIH). Materials and Methods Pregnant Wistar rats were assigned to control and five treatment groups: PIH; PIH + vitamin B12; PIH + folic acid; PIH + Omega-3 fatty acids and PIH + combined micronutrient supplementation (vitamin B12 + folic acid + omega-3 fatty acids). L-Nitroarginine methylester (L-NAME; 50 mg/kg body weight/day) was used to induce hypertension during pregnancy. Blood Pressure (BP) was recorded during pregnancy and dams were dissected at d20 of gestation. Results Animals from the PIH group demonstrated higher (p<0.01 for both) systolic and diastolic BP; lower (p<0.01) pup weight; higher dam plasma homocysteine (p<0.05) and dam and offspring malondialdehyde (MDA) (p<0.01), lower (p<0.05) placental and offspring liver DHA and higher (p<0.01) tumor necrosis factor–alpha (TNF–ά) levels as compared to control. Individual micronutrient supplementation did not offer much benefit. In contrast, combined supplementation lowered systolic BP, homocysteine, MDA and placental TNF-ά levels in dams and liver MDA and protein carbonyl in the offspring as compared to PIH group. Conclusion Key constituents of one carbon cycle (folic acid, vitamin B12 and DHA) may play a role in reducing oxidative stress and inflammation in preeclampsia. PMID:25405347

  11. Group 11 complexes with amino acid derivatives: Synthesis and antitumoral studies.

    PubMed

    Ortego, Lourdes; Meireles, Margarida; Kasper, Cornelia; Laguna, Antonio; Villacampa, M Dolores; Gimeno, M Concepción

    2016-03-01

    Gold(I), gold(III), silver(I) and copper(I) complexes with modified amino acid esters and phosphine ligands have been prepared in order to test their cytotoxic activity. Two different phosphine fragments, PPh3 and PPh2py (py=pyridine), have been used. The amino acid esters have been modified by introducing an aromatic amine as pyridine that coordinates metal fragments through the nitrogen atom, giving complexes of the type [M(L)(PR3)](+) or [AuCl3(L)] (L=l-valine-N-(4-pyridylcarbonyl) methyl ester (L1), l-alanine-N-(4-pyridylcarbonyl) methyl ester (L2), l-phenylalanine-N-(4-pyridylcarbonyl) methyl-ester) (L3); M=Au(I), Ag(I), Cu(I), PR3=PPh3, PPh2py). The in vitro cytotoxic activity of metal complexes was tested against four tumor human cell lines and one tumor mouse cell line. A metabolic activity test (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT) was used and IC50 values were compared with those obtained for cisplatin. Several complexes displayed significant cytotoxic activities. In order to determine whether antiproliferation and cell death are associated with apoptosis, NIH-3T3 cells were exposed to five selected complexes (Annexin V+ FITC, PI) and analyzed by flow cytometry. These experiments showed that the mechanism by which the complexes inhibit cell proliferation inducing cell death in NIH-3T3 cells is mainly apoptotic.

  12. Bacterial production of free fatty acids from freshwater macroalgal cellulose

    PubMed Central

    Hoovers, Spencer W.; Marner, Wesley D.; Brownson, Amy K.; Lennen, Rebecca M.; Wittkopp, Tyler M.; Yoshitani, Jun; Zulkifly, Shahrizim; Graham, Linda E.; Chaston, Sheena D.; McMahon, Katherine D.

    2013-01-01

    The predominant strategy for using algae to produce biofuels relies on the overproduction of lipids in microalgae with subsequent conversion to biodiesel (methyl-esters) or green diesel (alkanes). Conditions that both optimize algal growth and lipid accumulation rarely overlap, and differences in growth rates can lead to wild species outcompeting the desired lipid-rich strains. Here, we demonstrate an alternative strategy in which cellulose contained in the cell walls of multicellular algae is used as a feedstock for cultivating biofuel-producing micro-organisms. Cellulose was extracted from an environmental sample of Cladophora glomerata-dominated periphyton that was collected from Lake Mendota, WI, USA. The resulting cellulose cake was hydrolyzed by commercial enzymes to release fermentable glucose. The hydrolysis mixture was used to formulate an undefined medium that was able to support the growth, without supplementation, of a free fatty acid (FFA)-overproducing strain of Escherichia coli (Lennen et. al 2010). To maximize free fatty acid production from glucose, an isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible vector was constructed to express the Umbellularia californica acyl–acyl carrier protein (ACP) thioesterase. Thioesterase expression was optimized by inducing cultures with 50 μM IPTG. Cell density and FFA titers from cultures grown on algae-based media reached 50% of those (~90 μg/mL FFA) cultures grown on rich Luria–Bertani broth supplemented with 0.2% glucose. In comparison, cultures grown in two media based on AFEX-pretreated corn stover generated tenfold less FFA than cultures grown in algae-based media. This study demonstrates that macroalgal cellulose is a potential carbon source for the production of biofuels or other microbially synthesized compounds. PMID:21643704

  13. Inhibitory actions of hydroxocobalamin, cyanocobalamin, and folic acid on the ultraviolet light-induced relaxation of the frog upper oesophageal strip.

    PubMed

    Uçar, P; Göçmen, C; Seçilmiş, A; Karataş, Y; Singirik, E; Onder, S; Dikmen, A; Baysal, F

    2000-08-01

    The applications of ultraviolet (UV) light (336 nm) on the upper oesophageal strips of frog elicited relaxant responses in the presence of NaNO2 (50 microM). The tissues were mounted under the tension 0.5 g in an organ bath containing Ringer solution, maintained at 25 degrees C and gassed with 100% O2. The responses were recorded on a kymograph via an isotonic lever. Antimegaloblastic agents, including hydroxocobalamin (1, 10, and 100 microM), cyanocobalamin (1, 10, 25, and 100 microM), and folic acid (1, 10, 50, 100, and 200 microM), significantly attenuated the relaxation response to UV light. Folinic acid (1, 10, 25, and 100 microM), however, enhanced the relaxation. Pyrogallol (50 microM), hydroquinone (50 microM), and diethyldithiocarbamic acid (8 mM) were found ineffective for attenuation, though FeSO4 (200, 400, and 500 microM) and hemoglobin (50 microM), respectively, exerted significant inhibition. L-arginine methylester (500 microM) did not impair UV-induced relaxation. Based on these results, we concluded that a mechanism involving undefined action(s) of antimegaloblastic drugs may cause alterations in the UV light-induced relaxation of the tissue used. PMID:10985174

  14. UV/Vis Study of the Alkali Salts of Poly(thiophen-3-ylacetic acid) in Water.

    PubMed

    Hostnik, Gregor; Vlachy, Vojko; Bondarev, Dmitrij; Vohlídal, Jiří; Cerar, Janez

    2012-09-01

    UV/Vis spectroscopic investigation of aqueous solutions of regio-irregular poly(thiophen-3-ylacetic acid) (PTAA) with and without methyl-ester groups in the presence of sodium and lithium ions as counterions is presented. The samples were carefully purified and characterized with respect to molar mass and the amount of -COOH groups present. We examined how the UV/Vis spectra of solution change with aging of PTAA solution, polymer concentration, addition of low molecular weight salt, temperature, and some other parameters. We show that results crucially depend on whether the spectra are taken for freshly prepared or mature solutions. We demonstrate the validity of the Beer-Lambert law for PTANa, PTAA/Na, and PTAA/Li (aged solution), and violation of this law for PTANa/Me (fresh) solutions in water; the latter system is instead found to exhibit an isosbetic point at 402 nm. We prove that UV/Vis spectra of polythiophene derivatives in water depend on the "age" (time after dissolution) of the solution. The inconsistencies among the spectroscopic data found in literature, as also the discrepancies with our own measurements on PTAA-based systems are discussed. PMID:24061313

  15. Synthesis, spectroscopic characterization and crystal structure of 5-bromo-1-(2-cyano-pyridin-4-yl)-1 H-indazole-3-carboxylic acid diethylamide

    NASA Astrophysics Data System (ADS)

    Anuradha, G.; Vasuki, G.; Surendrareddy, G.; Veerareddy, A.; Dubey, P. K.

    2014-07-01

    The title compound 5-bromo-1-(2-cyano-pyridin-4-yl)-1 H-indazole-3-carboxylic acid diethylamide, C18H16BrN5O, is prepared from 5-bromoindazole-3-carboxylic acid methylester. N 1-arylation is carried out with 4-chloro-2-cyanopyridine and the resulting product is converted to diethylamide by reacting with thionyl chloride and diethylamine. The structure is identified from its FT-IR, 1H NMR, 13C NMR spectroscopy, elemental analysis data and unambiguously confirmed by single crystal X-ray diffraction studies. There are two symmetry independent molecules in the asymmetric unit with no significant differences in bond lengths and angles. The title compound crystallizes in the triclinic system, space group , with a = 11.2330(2); b = 11.6130(2); c = 15.4710(3) Å, α = 92.515(1)°; β = 109.956(1)°; γ = 107.199(1)°; V = 1788.45(6)Å3 and z = 4. An intramolecular C-H…N hydrogen bond forms an S(6) ring motif in one of the unique molecules. In the crystal, two molecules are linked about a center of inversion by C-H…O hydrogen bonded dimers generating an R {2/2}(16) ring motif. The crystal packing is stabilized by C-H…N, C-H…O hydrogen bonds and π…π stacking interactions.

  16. Potential vasorelaxant effects of oleanolic acid and erythrodiol, two triterpenoids contained in 'orujo' olive oil, on rat aorta.

    PubMed

    Rodríguez-Rodríguez, Rosalía; Herrera, María Dolores; Perona, Javier S; Ruiz-Gutiérrez, Valentina

    2004-10-01

    'Orujo' olive oil is obtained by chemical processes from the waste resulting from the mechanical extraction of virgin olive oil. The aim of the present study was to evaluate a new pharmacological property of two natural triterpenoids contained in olive oil, as vasodilatory agents, and to determine their mechanism of action. The two compounds studied were oleanolic acid and erythrodiol. The vasorelaxant effect induced by these pentacyclic triterpenoids was studied in isolated thoracic rat aorta. Oleanolic acid and erythrodiol, accumulatively added, showed vasorelaxant activities in aortic rings with endothelium pre-contracted by 10(-6) m-phenylephrine (maximum percentage of relaxation 86.38 (sem 2.89) and 73.53 (sem 6.01), respectively). They had almost no relaxant effect on depolarised or endothelium-denuded aortic segments. The relaxation was significantly attenuated by pre-treatment with the NO synthase inhibitor N(omega)-nitro-L-arginine-methylester (L-NAME; 3x10(-4) m). To characterise the involvement of endothelial factors, in addition to NO, arteries with endothelium were exposed to 10(-5) m-indomethacin (INDO), a cyclo-oxygenase inhibitor, or INDO plus L-NAME. INDO did not have any significant effect on the relaxant response of both compounds. The combination of L-NAME plus INDO only abolished the oleanolic acid-induced relaxation. The present results suggest that the mechanism of relaxation seems to be mainly mediated by the endothelial production of NO; however, other mechanisms cannot be excluded. It can be concluded that oleanolic acid and erythrodiol may have interesting therapeutic potential as new vasodilator drugs, thus protecting the cardiovascular system. Therefore, the intake of 'orujo' olive oil, as a source of these compounds, might be beneficial in this regard.

  17. Disruption of heme-peptide covalent cross-linking in mammalian peroxidases by hypochlorous acid

    PubMed Central

    Abu-Soud, Husam M.; Maitra, Dhiman; Shaeib, Faten; Khan, Sana; Byun, Jaeman; Abdulhamid, Ibrahim; Yang, Zhe; Saed, Ghassan M.; Diamond, Michael P.; Andreana, Peter R.; Pennathur, Subramaniam

    2015-01-01

    Myeloperoxidase (MPO), lactoperoxidase (LPO) and eosinophil peroxidase (EPO) play a central role in oxidative damage in inflammatory disorders by utilizing hydrogen peroxide and halides/pseudo halides to generate the corresponding hypohalous acid. The catalytic sites of these enzymes contain a covalently modified heme group, which is tethered to the polypeptide chain at two ester linkages via the methyl group (MPO, EPO and LPO) and one sulfonium bond via the vinyl group (MPO only). Covalent cross-linking of the catalytic site heme to the polypeptide chain in peroxidases is thought to play a protective role, since it renders the heme moiety less susceptible to the oxidants generated by these enzymes. Mass-spectrometric analysis revealed the following possible pathways by which hypochlorous acid (HOCl) disrupts the heme-protein cross-linking: (1) the methyl-ester bond is cleaved to form an alcohol; (2) the alcohol group undergoes an oxygen elimination reaction via the formation of an aldehyde intermediate or undergoes a demethylation reaction to lose the terminal CH2 group; and (3) the oxidative cleavage of the vinyl-sulfonium linkage. Once the heme moiety is released it undergoes cleavage at the carbon-methyne bridge either along the δ-β or a α-γ axis to form different pyrrole derivatives. These results indicate that covalent cross-linking is not enough to protect the enzymes from HOCl mediated heme destruction and free iron release. Thus, the interactions of mammalian peroxidases with HOCl modulates their activity and sets a stage for initiation of the Fenton reaction, further perpetuating oxidative damage at sites of inflammation. PMID:25193127

  18. Determination of 2-[N-[(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S,3S,5S)-2- azabicyclo[3.3.0]octane-3-carboxylic acid (Hoe 498) and its hydrolysis product in serum and urine.

    PubMed

    Hajdú, P; Schmidt, D; Bomm, M; Hack, L; Keller, A

    1984-01-01

    A highly sensitive and specific enzymatic assay for the quantitative determination of 2-[N-[(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S,3S, 5S)-2-azabicyclo[3.3.0]octane-3-carboxylic acid (Hoe 498) and its hydrolysis product Hoe 498-diacid in serum and a GLC method for the simultaneous determination of both compounds in urine are described. Both methods involve extraction from the respective biological fluid using disposable C 18 columns. In serum, the enzyme-inhibiting properties of Hoe 498-diacid (Hoe 498 can readily be converted to its hydrolysis product) are utilized for the determination of both compounds concurrently. The serum extract is dissolved in buffer solution and incubated with human serum as angiotensin converting enzyme (peptidyl-dipeptide-hydrolase, EC 3.4.15.1) source and hip-his-leu substrate. The hippuric acid liberated is quantitated by HPLC. The urine extract is treated with diazomethane followed by trifluoroacetic anhydride to convert Hoe 498 and Hoe 498-diacid to their methylester, trifluoroacetyl derivatives, which are then determined simultaneously by GLC using a nitrogen specific detector.

  19. Broadband gain in poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester photodetectors enabled by a semicontinuous gold interlayer

    SciTech Connect

    Melancon, Justin M.; Živanović, Sandra R.

    2014-10-20

    Substantial broadband photoconductive gain has been realized for organic, thin-film photodetectors with a poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester (P3HT:PCBM) active layer at low bias voltages. External quantum efficiencies upwards of 1500% were achieved when a semicontinuous gold layer was introduced at the anode interface. Significant gain was also observed in the sub-band gap, near infrared region where the external quantum efficiency approached 100% despite the lack of a sensitizer. The gain response was highly dependent on the thickness of the active layer of the photodetector with the best results achieved with the thinnest devices. The gain is the result of the injection of secondary electrons due to hole charge trapping at the semicontinuous gold layer.

  20. Folic Acid

    MedlinePlus

    Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

  1. Folic Acid

    MedlinePlus

    Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

  2. Amino acids

    MedlinePlus

    ... amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan , and valine. Nonessential amino acids "Nonessential" means that our bodies produce an amino ...

  3. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

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

  4. Acid rain

    SciTech Connect

    Not Available

    1985-01-01

    This report has four parts: they discuss acid rain in relation to acid soils, agriculture, forests, and aquatic ecosystems. Among findings: modern sources of acid deposition from the atmosphere for all the acid soils in the world, nor even chiefly responsible for those of northern U.S. Agriculture has its problems, but acid precipitation is probably not one of them. More research is needed to determine to what extent acid precipitation is responsible for forest declines and for smaller detrimental effects on forest growth where no damage to the foliage is evident. Many lakes and streams are extremely sensitive to added acids.

  5. Transparent Conductive ITO/Ag/ITO Electrode Deposited at Room Temperature for Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ho; Kang, Tae-Woon; Kwon, Sung-Nam; Na, Seok-In; Yoo, Young-Zo; Im, Hyeong-Seop; Seong, Tae-Yeon

    2016-09-01

    We investigated the optical and electrical properties of room-temperature-deposited indium-tin-oxide (ITO)/Ag (19 nm)/ITO multilayer films as a function of ITO layer thickness. The optical and electrical properties of the ITO/Ag/ITO films were compared with those of high-temperature-deposited ITO-only films for use as an anode in organic solar cells (OSCs). The ITO/Ag/ITO multilayer films had sheet resistances in the range 5.40-5.78 Ω/sq, while the ITO-only film showed 14.18 Ω/sq. The carrier concentration of the ITO/Ag/ITO films gradually decreased from 2.01 × 1022 to 7.20 × 1021 cm-3 as the ITO thickness increased from 17 nm to 83 nm. At 530 nm, the transmittance of the ITO/Ag/ITO (50 nm/19 nm/50 nm) films was ~90%, while that of the ITO-only film gave 96.5%. The multilayer film had a smooth surface with a root mean square (RMS) roughness of 0.49 nm. Poly (3-hexylthiophene) (P3HT):[6,6]-phenyl-C61 butyric acid methylester (PCBM) bulk heterojunction (BHJ)-based OSCs fabricated with the ITO/Ag/ITO (50 nm/19 nm/50 nm) film showed a power conversion efficiency (PCE) (2.84%) comparable to that of OSCs with a conventional ITO-only anode (3.48%).

  6. Aminocaproic Acid

    MedlinePlus

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

  7. Ethacrynic Acid

    MedlinePlus

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

  8. Aristolochic Acids

    MedlinePlus

    ... Sciences NIH-HHS www.niehs.nih.gov Aristolochic Acids Key Points Report on Carcinogens Status Known to be human carcinogens Aristolochia Clematitis Aristolochic Acids n Known human carcinogens n Found in certain ...

  9. Obeticholic Acid

    MedlinePlus

    Obeticholic acid is used alone or in combination with ursodiol (Actigall, Urso) to treat primary biliary cholangitis (PBC; a ... were not treated successfully with ursodiol alone. Obeticholic acid is in a class of medications called farnesoid ...

  10. Acid mucopolysaccharides

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003368.htm Acid mucopolysaccharides To use the sharing features on this page, please enable JavaScript. Acid mucopolysaccharides is a test that measures the amount ...

  11. Fatty acids - trans fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The data supporting a negative effect of dietary trans fatty acids on cardiovascular disease risk is consistent. The primary dietary sources of trans fatty acids include partially hydrogenated fat and rudiment fat. The adverse effect of trans fatty acids on plasma lipoprotein profiles is consisten...

  12. Aspartic acid

    MedlinePlus

    ... Hormone production and release Normal nervous system function Plant sources of aspartic acid include: Legumes such as soybeans, garbanzo beans, and lentils Peanuts, almonds, walnuts, and flaxseeds Animal ...

  13. Usnic acid.

    PubMed

    Ingólfsdóttir, K

    2002-12-01

    Since its first isolation in 1844, usnic acid [2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzo-furandione] has become the most extensively studied lichen metabolite and one of the few that is commercially available. Usnic acid is uniquely found in lichens, and is especially abundant in genera such as Alectoria, Cladonia, Usnea, Lecanora, Ramalina and Evernia. Many lichens and extracts containing usnic acid have been utilized for medicinal, perfumery, cosmetic as well as ecological applications. Usnic acid as a pure substance has been formulated in creams, toothpaste, mouthwash, deodorants and sunscreen products, in some cases as an active principle, in others as a preservative. In addition to antimicrobial activity against human and plant pathogens, usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory and analgesic activity. Ecological effects, such as antigrowth, antiherbivore and anti-insect properties, have also been demonstrated. A difference in biological activity has in some cases been observed between the two enantiomeric forms of usnic acid. Recently health food supplements containing usnic acid have been promoted for use in weight reduction, with little scientific support. The emphasis of the current review is on the chemistry and biological activity of usnic acid and its derivatives in addition to rational and ecologically acceptable methods for provision of this natural compound on a large scale.

  14. Acid rain

    SciTech Connect

    Elsworth, S.

    1985-01-01

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

  15. Acid rain

    SciTech Connect

    White, J.C. )

    1988-01-01

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

  16. How Acidic Is Carbonic Acid?

    PubMed

    Pines, Dina; Ditkovich, Julia; Mukra, Tzach; Miller, Yifat; Kiefer, Philip M; Daschakraborty, Snehasis; Hynes, James T; Pines, Ehud

    2016-03-10

    Carbonic, lactic, and pyruvic acids have been generated in aqueous solution by the transient protonation of their corresponding conjugate bases by a tailor-made photoacid, the 6-hydroxy-1-sulfonate pyrene sodium salt molecule. A particular goal is to establish the pK(a) of carbonic acid H2CO3. The on-contact proton transfer (PT) reaction rate from the optically excited photoacid to the carboxylic bases was derived, with unprecedented precision, from time-correlated single-photon-counting measurements of the fluorescence lifetime of the photoacid in the presence of the proton acceptors. The time-dependent diffusion-assisted PT rate was analyzed using the Szabo-Collins-Kimball equation with a radiation boundary condition. The on-contact PT rates were found to follow the acidity order of the carboxylic acids: the stronger was the acid, the slower was the PT reaction to its conjugate base. The pK(a) of carbonic acid was found to be 3.49 ± 0.05 using both the Marcus and Kiefer-Hynes free energy correlations. This establishes H2CO3 as being 0.37 pK(a) units stronger and about 1 pK(a) unit weaker, respectively, than the physiologically important lactic and pyruvic acids. The considerable acid strength of intact carbonic acid indicates that it is an important protonation agent under physiological conditions. PMID:26862781

  17. Acid rain

    SciTech Connect

    Sweet, W.

    1980-06-20

    Acid precipitation includes not only rain but also acidified snow, hail and frost, as well as sulfur and nitrogen dust. The principal source of acid precipitation is pollution emitted by power plants and smelters. Sulfur and nitrogen compounds contained in the emissions combine with moisture to form droplets with a high acid content - sometimes as acidic as vinegar. When sufficiently concentrated, these acids can kill fish and damage material structures. Under certain circumstances they may reduce crop and forest yields and cause or aggravate respiratory diseases in humans. During the summer, especially, pollutants tend to collect over the Great Lakes in high pressure systems. Since winds typically are westerly and rotate clockwise around high pressure systems, the pollutants gradually are dispersed throughout the eastern part of the continent.

  18. Asparagusic acid.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H

    2014-01-01

    Asparagusic acid (1,2-dithiolane-4-carboxylic acid) is a simple sulphur-containing 5-membered heterocyclic compound that appears unique to asparagus, though other dithiolane derivatives have been identified in non-food species. This molecule, apparently innocuous toxicologically to man, is the most probable culprit responsible for the curious excretion of odorous urine following asparagus ingestion. The presence of the two adjacent sulphur atoms leads to an enhanced chemical reactivity, endowing it with biological properties including the ability to substitute potentially for α-lipoic acid in α-keto-acid oxidation systems. This brief review collects the scattered data available in the literature concerning asparagusic acid and highlights its properties, intermediary metabolism and exploratory applications.

  19. Acid rain

    SciTech Connect

    Bess, F.D.

    1980-01-01

    The acid rain problem in the northeastern U.S. has been growing in severity and geographical areas affected. Acid rain has damaged, or will result in damage to visibility, physical structures and materials, aquatic life, timber, crops, and soils. The principal causes of acid rain in the northeastern U.S. are sulfur oxide and nitrogen oxide emissions from large power plants and smelters in the Ohio River Valley. Immediate corrective action and appropriate research are needed to reduce acid precipitation. Short-term programs that will define the rate of environmental deterioration, remaining environmental capacity to resist sudden deterioration, mechanisms of acid rain formation, and costs of various control options must be developed. (3 maps, 13 references, 1 table)

  20. Asparagusic acid.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H

    2014-01-01

    Asparagusic acid (1,2-dithiolane-4-carboxylic acid) is a simple sulphur-containing 5-membered heterocyclic compound that appears unique to asparagus, though other dithiolane derivatives have been identified in non-food species. This molecule, apparently innocuous toxicologically to man, is the most probable culprit responsible for the curious excretion of odorous urine following asparagus ingestion. The presence of the two adjacent sulphur atoms leads to an enhanced chemical reactivity, endowing it with biological properties including the ability to substitute potentially for α-lipoic acid in α-keto-acid oxidation systems. This brief review collects the scattered data available in the literature concerning asparagusic acid and highlights its properties, intermediary metabolism and exploratory applications. PMID:24099657

  1. Acid fog

    SciTech Connect

    Hileman, B.

    1983-03-01

    Fog in areas of southern California previously thought to be pollution-free has been shown to have a pH as low as 1.69. It has been found to be most acidic after smoggy days, suggesting that it forms on the aerosol associated with the previously exiting smog. Studies on Whiteface Mountain in the Adirondacks show that fog water is often 10 times as acidic as rainwater. As a result of their studies, California plans to spend $4 million on acid deposition research in the coming year. (JMT)

  2. Tranexamic Acid

    MedlinePlus

    ... is used to treat heavy bleeding during the menstrual cycle (monthly periods) in women. Tranexamic acid is in ... tablets for more than 5 days in a menstrual cycle or take more than 6 tablets in a ...

  3. Mefenamic Acid

    MedlinePlus

    ... as mefenamic acid may cause ulcers, bleeding, or holes in the stomach or intestine. These problems may ... like coffee grounds, blood in the stool, or black and tarry stools.Keep all appointments with your ...

  4. Acid Precipitation

    ERIC Educational Resources Information Center

    Likens, Gene E.

    1976-01-01

    Discusses the fact that the acidity of rain and snow falling on parts of the U.S. and Europe has been rising. The reasons are still not entirely clear and the consequences have yet to be well evaluated. (MLH)

  5. Neurotransmitter transporter family including SLC6A6 and SLC6A13 contributes to the 5-aminolevulinic acid (ALA)-induced accumulation of protoporphyrin IX and photodamage, through uptake of ALA by cancerous cells.

    PubMed

    Tran, Tai Tien; Mu, Anfeng; Adachi, Yuka; Adachi, Yasushi; Taketani, Shigeru

    2014-01-01

    δ-Aminolevulinic acid (ALA)-induced protoporphyrin accumulation is widely used in the treatment of cancer, as photodynamic therapy (PDT). To clarify the mechanisms of ALA uptake by tumor cells, we have examined the ALA-induced accumulation of protoporphyrin by the treatment of colon cancer DLD-1 and epithelial cancer HeLa cells with γ-aminobutyric acid (GABA)-related compounds. When the cells were treated with GABA, taurine and β-alanine, the level of protoporphyrin was decreased, suggesting that plasma membrane transporters involved in the transport of neurotransmitters contribute to the uptake of ALA. By transfection with neurotransmitter transporters SLC6A6, SLC6A8 and SLC6A13 cDNA, the ALA- and ALA methylester-dependent accumulation of protoporphyrin markedly increased in HEK293T cells, dependent on an increase in the uptake of ALA. When ALA-treated cells were exposed to white light, the extent of photodamage increased in SLC6A6- and SLC6A13-expressing cells. Conversely, knockdown of SLC6A6 or SLC6A13 with siRNAs in DLD-1 and HeLa cells decreased the ALA-induced accumulation. The expression of SLC6A6 and SLC6A13 was found in some cancer cell lines. Immunohistochemical studies revealed that the presence of these transporters was elevated in colon cancerous cells. These results indicated that neurotransmitter transporters including SLC6A6 and SLC6A13 mediate the uptake of ALA and can play roles in the enhancement of ALA-induced accumulation of protoporphyrin in cancerous cells.

  6. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

    At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

  7. Dramatic enhancement of fullerene anion formation in polymer solar cells by thermal annealing: Direct observation by electron spin resonance

    SciTech Connect

    Liu, Dong; Nagamori, Tatsuya; Yabusaki, Masaki; Yasuda, Takeshi; Han, Liyuan; Marumoto, Kazuhiro

    2014-06-16

    Using electron spin resonance (ESR), we clarified the origin of the efficiency degradation of polymer solar cells containing a lithium-fluoride (LiF) buffer layer created by a thermal annealing process after the deposition of an Al electrode (post-annealing). The device structure was indium-tin-oxide/ poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/poly (3-hexylthiophene):phenyl-C{sub 61}-butyric acid methyl ester (P3HT:PCBM)/LiF/Al. Three samples consisting of quartz/P3HT:PCBM/LiF/Al, quartz/P3HT:PCBM/Al, and quartz/PCBM/LiF/Al were investigated and compared. A clear ESR signal from radical anions on the PCBM was observed after LiF/Al was deposited onto a P3HT:PCBM layer because of charge transfer at the interface between the PCBM and the LiF/Al, which indicated the formation of PCBM{sup −}Li{sup +} complexes. The number of radical anions on the PCBM was enhanced remarkably by the post-annealing process; this enhancement was caused by the surface segregation of PCBM and by the dissociation of LiF at the Al interface by the post-annealing process. The formation of a greater number of anions enhanced the electron scattering, decreased the electron-transport properties of the PCBM molecules, and caused an energy-level shift at the interface. These effects led to degradation in the device performance.

  8. Salicylic acids

    PubMed Central

    Hayat, Shamsul; Irfan, Mohd; Wani, Arif; Nasser, Alyemeni; Ahmad, Aqil

    2012-01-01

    Salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. The area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. The skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under the prevailing external conditions. The metabolic status that allows the host invasion either as pathogenesis or symbiosis with possible intermediary stages in close systems has been tried to underpin here. PMID:22301975

  9. Stearic Acid

    ERIC Educational Resources Information Center

    Young, Jay A.

    2004-01-01

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

  10. Trichloroacetic acid

    Integrated Risk Information System (IRIS)

    Trichloroacetic acid ( TCA ) ; CASRN 76 - 03 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonca

  11. Acrylic acid

    Integrated Risk Information System (IRIS)

    Acrylic acid ( CASRN 79 - 10 - 7 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  12. Selenious acid

    Integrated Risk Information System (IRIS)

    Selenious acid ; CASRN 7783 - 00 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  13. Dichloroacetic acid

    Integrated Risk Information System (IRIS)

    Dichloroacetic acid ; CASRN 79 - 43 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  14. Cacodylic acid

    Integrated Risk Information System (IRIS)

    Cacodylic acid ; CASRN 75 - 60 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  15. Phosphoric acid

    Integrated Risk Information System (IRIS)

    Phosphoric acid ; CASRN 7664 - 38 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  16. Benzoic acid

    Integrated Risk Information System (IRIS)

    Benzoic acid ; CASRN 65 - 85 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  17. Formic acid

    Integrated Risk Information System (IRIS)

    Formic acid ; CASRN 64 - 18 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  18. [Hyaluronic acid].

    PubMed

    Pomarede, N

    2008-01-01

    Hyaluronic Acid (HA) is now a leader product in esthetic procedures for the treatment of wrinkles and volumes. The structure of HA, its metabolism, its physiological function are foremost breaking down then its use in aesthetic dermatology: steps of injection, possible side effects, benefits and downsides of the use of HA in aesthetic dermatology.

  19. Hydroxycarboxylic acids and salts

    DOEpatents

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

    2015-02-24

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

  20. Improvement of Performance and Stability of Polymer Photovoltaic Cells by WO3/CUPC as Anode Buffer Layers

    NASA Astrophysics Data System (ADS)

    Varnamkhasti, M. G.; Shahriaria, E.

    2015-05-01

    In this work, bulk-hetrojunction polymer photovoltaic cells based on poly-(3-hexylthiophene) (P3HT): [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were fabricated with tungsten oxide (WO3) and copper phthalocyanine (CuPc) as anodic buffer layers. The WO3 plays an important role in reducing the interfacial resistance, efficiently extracting holes and good band structure matching between the work function of the anode and the highest occupied molecular orbital of the organic material. The insertion of CuPc improves the device In this work, bulk-hetrojunction polymer photovoltaic cells based on poly-(3-hexylthiophene) (P3HT): [6, 6]-phenyl C61 butyric acid methylester (PCBM) were fabricated with tungsten oxide (WO3) and copper phthalocyanine (CuPc) as anodic buffer layers. The WO3 plays animportant role in reducing the interfacial resistance, efficiently extracting holes and good band structure matching between the workfunction of the anode and the highest occupied molecular orbital of the organic material. The insertion of CuPc improves the device performance and expands the absorption spectra range of the photovoltaic devices. The effects of WO3 and CuPc thickness on the performance of the photovoltaic devices were investigated. The optimum thicknesses of WO3 and CuPc were 10 nm and 8 nm, respectively. The obtained power conversion efficiency of optimized cell was about 4.21%. Also, the device performance was analyzed based on thesurface roughness of bare ITO and ITO that was covered with poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) or WO3/CuPc. The device stability in an ambient atmosphere without encapsulation under continuous light irradiation was also investigated.For the cell with PEDOT:PSS, the power conversion efficiency reduced down to 50% of the maximum value (half-life) after light irradiation for 12 h, while the half-life of device for WO3/CuPc was about 120 h. Therefore, the lifetime of unpackaged devices was improved with

  1. Methylmalonic acid blood test

    MedlinePlus

    ... acid is a substance produced when proteins, called amino acids, in the body break down. The health care ... Cederbaum S, Berry GT. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Devaskar ...

  2. Folic Acid and Pregnancy

    MedlinePlus

    ... 5 Things to Know About Zika & Pregnancy Folic Acid and Pregnancy KidsHealth > For Parents > Folic Acid and ... before conception and during early pregnancy . About Folic Acid Folic acid, sometimes called folate, is a B ...

  3. Preparation of Oxaliplatin-Deoxycholic Acid Derivative Nanocomplexes and In Vivo Evaluation of Their Oral Absorption and Tumor Growth Suppression.

    PubMed

    Jeon, Ok-Cheol; Byun, Youngro; Park, Jin Woo

    2016-02-01

    To prepare orally available oxaliplatin (OXA), nanocomplexes were formed by ionic conjugation of OXA with the deoxycholic acid derivative, Nalpha-deoxycholy-L-lysyl-methylester (DCK), as an oral absorption enhancer. We characterized the DCK-conjugated OXA nanocomplexes by differential scanning calorimetry, particle size determination, and morphological analysis. To evaluate the effects of DCK on the intestinal permeability of OXA, we assessed the solubilities and partition coefficients of OXA and the OXA/DCK nanocomplex, and then conducted in vitro artificial intestinal membrane and Caco-2 cell permeability studies. Finally, bioavailability in rats and tumor growth inhibition in the squamous cell carcinoma (SCC7) model after oral administration of the OXA/DCK nanocomplex were investigated compared to pure OXA. Analysis of the ionic complex formation of OXA with DCK revealed that OXA existed in an amorphous form within the complex, resulting in for- mation of nanocomp;exes (35.05 +/- 4.48 nm in diameter). The solubility of OXA in water was approximately 7.07 mg/mL, whereas the water solubility of OXA/DCK was approximately 2.04 mg/mL and its partition coefficient was approximately 1.2-fold higher than that of OXA. The in vitro intestinal membrane permeability of OXA was significantly enhanced by complex formation with DCK. An in vivo pharmacokinetic study revealed that the Cm value of the OXA/DCK nanocomplex was 3.18-fold higher than that of OXA (32.22 +/- 10.24 ng/mL), and the resulting oral bioavailability of the OXA/DCK nanocomplex was 39.3-fold more than that of OXA. Furthermore, the oral administration of OXA/DCK significantly inhibited tumor growth in SCC7-bearing mice, and maximally inhibited tumor volume by 54% compared to the control. These findings demonstrate the therapeutic potential of the OXA/DCK nanocomplex as an oral anti-cancer therapy because it improves the oral absorption of OXA, which may improve patient compliance and expand the therapeutic

  4. Understanding Acid Rain

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

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

  5. Nitric oxide donors prevent while the nitric oxide synthase inhibitor L-NAME increases arachidonic acid plus CYP2E1-dependent toxicity

    SciTech Connect

    Wu Defeng; Cederbaum, Arthur . E-mail: arthur.cederbaum@mssm.edu

    2006-10-15

    Polyunsaturated fatty acids such as arachidonic acid (AA) play an important role in alcohol-induced liver injury. AA promotes toxicity in rat hepatocytes with high levels of cytochrome P4502E1 and in HepG2 E47 cells which express CYP2E1. Nitric oxide (NO) participates in the regulation of various cell activities as well as in cytotoxic events. NO may act as a protectant against cytotoxic stress or may enhance cytotoxicity when produced at elevated concentrations. The goal of the current study was to evaluate the effect of endogenously or exogenously produced NO on AA toxicity in liver cells with high expression of CYP2E1 and assess possible mechanisms for its actions. Pyrazole-induced rat hepatocytes or HepG2 cells expressing CYP2E1 were treated with AA in the presence or absence of an inhibitor of nitric oxide synthase L-N {sup G}-Nitroarginine Methylester (L-NAME) or the NO donors S-nitroso-N-acetylpenicillamine (SNAP), and (Z)-1-[-(2-aminoethyl)-N-(2-aminoethyl)]diazen-1-ium-1,2-diolate (DETA-NONO). AA decreased cell viability from 100% to 48 {+-} 6% after treatment for 48 h. In the presence of L-NAME, viability was further lowered to 23 {+-} 5%, while, SNAP or DETA-NONO increased viability to 66 {+-} 8 or 71 {+-} 6%. The L-NAME potentiated toxicity was primarily necrotic in nature. L-NAME did not affect CYP2E1 activity or CYP2E1 content. SNAP significantly lowered CYP2E1 activity but not protein. AA treatment increased lipid peroxidation and lowered GSH levels. L-NAME potentiated while SNAP prevented these changes. Thus, L-NAME increased, while NO donors decreased AA-induced oxidative stress. Antioxidants prevented the L-NAME potentiation of AA toxicity. Damage to mitochondria by AA was shown by a decline in the mitochondrial membrane potential (MMP). L-NAME potentiated this decline in MMP in association with its increase in AA-induced oxidative stress and toxicity. NO donors decreased this decline in MMP in association with their decrease in AA

  6. Criteria for validating polaron pair dissociation in polymer-fullerene bulk heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Inche Ibrahim, M. L.

    2016-04-01

    The dissociation of polaron pairs into free charge carriers in organic bulk heterojunction solar cells is a fundamental step in generating photocurrent and is still in debate. In this study, we propose two simple criteria that can be used to test the validity of any polaron pair dissociation model for polymer-fullerene bulk heterojunction solar cells. The first criterion states that the ratio of the bimolecular recombination current density to the maximum photocurrent density should increase as a function of applied voltage. The second criterion states that the ratio of the bimolecular recombination current density to the maximum photocurrent density at short circuit should not be larger than 1. We apply these criteria to test the validity of the widely used Onsager-Braun model by using the experimental current-voltage data of poly[2-methoxy-5-(3'-7'-dimethyloctyloxy)-p-phenylene vinylene] (OC1C10-PPV) and [6,6]-phenyl C61-butyric acid methylester (PCBM) based solar cells. We find that our numerical analysis is not suitable to employ these criteria. Our analytical analysis, on the other hand, clearly demonstrates that the Onsager-Braun model simply cannot fulfill the first criteria. The reason is because the polaron pair dissociation given by the Onsager-Braun model is too strongly influenced by the electric field (i.e., decreases too rapidly as the electric field decreases). The analysis provides a further evidence against the widely used Onsager-Braun model. The proposed criteria can help us to determine the correct model for polaron pair dissociation by serving as a guideline on how strongly the electric field is allowed to influence the polaron pair dissociation.

  7. Electrogenerated Chemiluminescence and Fluorescence Lifetime Spatial Heterogeneity of Poly (2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene) in Presence of [6,6]-phenyl-C61-butyric Acid Methyl Ester

    SciTech Connect

    Geng, Hongwei; Pan, Shanlin; Hu, Dehong

    2013-04-01

    In this paper, we studied the luminescence property and fluorescence lifetime mapping of MEH-PPV/PCBM system by using electrogenerated chemiluminescence (ECL) and time-correlated single photo counting (TC-SPC) technologies. The ECL results showed that the oxidation peak of MEH-PPV near 0.7 V (vs. SCE) and ECL response of films shifted positively towards 1.2 V when in the presence of PCBM. At the same time, the oxidation peak current density of MEH-PPV increases while the ECL response decreased with the loading of PCBM in the composite films. The fluorescence lifetime images clearly show that the lifetime fluctuation is effected by different substrates and MEH-PPV/PCBM ratios. Meanwhile, the lifetime of MEH-PPV decreases with the increasing of film thickness. The lifetimes of MEH-PPV films on TiO2 substrate are lower than them of films on cover slips.

  8. Precipitation: its acidic nature.

    PubMed

    Frohliger, J O; Kane, R

    1975-08-01

    A comparison of the free hydrogen ion concentration and the total hydrogen ion concentration of rain samples shows that rain is a weak acid. The weak acid nature of rain casts doubt on the concepts that the acidity of rain is increasing and that these increases are due to strong acids such as sulfuric acid.

  9. Amino Acid Metabolism Disorders

    MedlinePlus

    ... defects & other health conditions > Amino acid metabolism disorders Amino acid metabolism disorders E-mail to a friend Please ... baby’s newborn screening may include testing for certain amino acid metabolism disorders. These are rare health conditions that ...

  10. Carbolic acid poisoning

    MedlinePlus

    Phenol poisoning; Phenylic acid poisoning; Hydroxybenzene poisoning; Phenic acid poisoning; Benzenol poisoning ... Below are symptoms of carbolic acid poisoning in different parts of the ... urine Decreased urine output No urine output EYES, EARS, ...

  11. Azelaic Acid Topical

    MedlinePlus

    Azelaic acid gel is used to clear the bumps, lesions, and swelling caused by rosacea (a skin disease that ... redness, flushing, and pimples on the face). Azelaic acid cream is used to treat acne. Azelaic acid ...

  12. Uric acid test (image)

    MedlinePlus

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

  13. Facts about Folic Acid

    MedlinePlus

    ... Information For... Media Policy Makers Facts About Folic Acid Language: English Español (Spanish) Recommend on Facebook Tweet ... of the baby's brain and spine. About folic acid Folic acid is a B vitamin. Our bodies ...

  14. Acid Lipase Disease

    MedlinePlus

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

  15. Acid distribution in phosphoric acid fuel cells

    SciTech Connect

    Okae, I.; Seya, A.; Umemoto, M.

    1996-12-31

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

  16. Netupitant, a Potent and Highly Selective NK1 Receptor Antagonist, Alleviates Acetic Acid-Induced Bladder Overactivity in Anesthetized Guinea-Pigs.

    PubMed

    Palea, Stefano; Guilloteau, Véronique; Rekik, Moéz; Lovati, Emanuela; Guerard, Marc; Guardia, Maria-Alba; Lluel, Philippe; Pietra, Claudio; Yoshiyama, Mitsuharu

    2016-01-01

    Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1-3 mg/kg, i.v.) or L-733,060 (3-10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex circuit

  17. Netupitant, a Potent and Highly Selective NK1 Receptor Antagonist, Alleviates Acetic Acid-Induced Bladder Overactivity in Anesthetized Guinea-Pigs

    PubMed Central

    Palea, Stefano; Guilloteau, Véronique; Rekik, Moéz; Lovati, Emanuela; Guerard, Marc; Guardia, Maria-Alba; Lluel, Philippe; Pietra, Claudio; Yoshiyama, Mitsuharu

    2016-01-01

    Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1–3 mg/kg, i.v.) or L-733,060 (3–10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex

  18. Acid tolerance in amphibians

    SciTech Connect

    Pierce, B.A.

    1985-04-01

    Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities. Amphibians as a group appear to be relatively acid tolerant, with many species suffering increased mortality only below pH 4. However, amphibians exhibit much intraspecific variation in acid tolerance, and some species are sensitive to even low levels of acidity. Furthermore, nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.

  19. Bioconversions of ferulic acid, an hydroxycinnamic acid.

    PubMed

    Mathew, Sindhu; Abraham, T Emilia

    2006-01-01

    Ferulic acid is the most abundant hydroxycinnamic acid in the plant world and is ester linked to arabinose, in various plant polysaccharides such as arabinoxylans and pectins. It is a precursor to vanillin, one of the most important aromatic flavor compound used in foods, beverages, pharmaceuticals, and perfumes. This article presents an overview of the various biocatalytic routes, focusing on the relevant biotransformations of ferulic acid using plant sources, microorganisms, and enzymes.

  20. 21 CFR 201.21 - Declaration of presence of phenylalanine as a component of aspartame in over-the-counter and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Declaration of presence of phenylalanine as a...: GENERAL LABELING General Labeling Provisions § 201.21 Declaration of presence of phenylalanine as a... methylester of a dipeptide composed of two amino acids, phenylalanine and aspartic acid. When these two...

  1. 21 CFR 201.21 - Declaration of presence of phenylalanine as a component of aspartame in over-the-counter and...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Declaration of presence of phenylalanine as a...: GENERAL LABELING General Labeling Provisions § 201.21 Declaration of presence of phenylalanine as a... methylester of a dipeptide composed of two amino acids, phenylalanine and aspartic acid. When these two...

  2. 21 CFR 201.21 - Declaration of presence of phenylalanine as a component of aspartame in over-the-counter and...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Declaration of presence of phenylalanine as a...: GENERAL LABELING General Labeling Provisions § 201.21 Declaration of presence of phenylalanine as a... methylester of a dipeptide composed of two amino acids, phenylalanine and aspartic acid. When these two...

  3. 21 CFR 201.21 - Declaration of presence of phenylalanine as a component of aspartame in over-the-counter and...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Declaration of presence of phenylalanine as a...: GENERAL LABELING General Labeling Provisions § 201.21 Declaration of presence of phenylalanine as a... methylester of a dipeptide composed of two amino acids, phenylalanine and aspartic acid. When these two...

  4. 21 CFR 201.21 - Declaration of presence of phenylalanine as a component of aspartame in over-the-counter and...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Declaration of presence of phenylalanine as a...: GENERAL LABELING General Labeling Provisions § 201.21 Declaration of presence of phenylalanine as a... methylester of a dipeptide composed of two amino acids, phenylalanine and aspartic acid. When these two...

  5. Acid Thunder: Acid Rain and Ancient Mesoamerica

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  6. Quantity of acid in acid fog

    SciTech Connect

    Deal, W.J.

    1983-07-01

    This communication notes the actual magnitude of the acidity in acidic fog particles and suggests a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air.

  7. Lactic acid test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003507.htm Lactic acid test To use the sharing features on this page, please enable JavaScript. Lactic acid is mainly produced in muscle cells and red ...

  8. Omega-6 Fatty Acids

    MedlinePlus

    ... types of fats. Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean ... from studying specific omega-6 fatty acids or plant oils containing omega-6 fatty acids. See the separate ...

  9. Fatty acid analogs

    DOEpatents

    Elmaleh, David R.; Livni, Eli

    1985-01-01

    In one aspect, a radioactively labeled analog of a fatty acid which is capable of being taken up by mammalian tissue and which exhibits an in vivo beta-oxidation rate below that with a corresponding radioactively labeled fatty acid.

  10. Deoxycholic Acid Injection

    MedlinePlus

    Deoxycholic acid injection is used to improve the appearance and profile of moderate to severe submental fat ('double chin'; fatty tissue located under the chin). Deoxycholic acid injection is in a class of medications called ...

  11. Aminocaproic Acid Injection

    MedlinePlus

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

  12. Zoledronic Acid Injection

    MedlinePlus

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

  13. Uric Acid Test

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Uric Acid Share this page: Was this page helpful? Also known as: Serum Urate; UA Formal name: Uric Acid Related tests: Synovial Fluid Analysis , Kidney Stone Analysis , ...

  14. Methylmalonic Acid Test

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Methylmalonic Acid Share this page: Was this page helpful? Also known as: MMA Formal name: Methylmalonic Acid Related tests: Vitamin B12 and Folate , Homocysteine , Intrinsic ...

  15. Hydrochloric acid poisoning

    MedlinePlus

    Hydrochloric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe ... discusses poisoning due to swallowing or breathing in hydrochloric acid. This article is for information only. Do ...

  16. Mixed Acid Oxidation

    SciTech Connect

    Pierce, R.A.

    1999-10-26

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

  17. Plant fatty acid hydroxylases

    DOEpatents

    Somerville, Chris; Broun, Pierre; van de Loo, Frank

    2001-01-01

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

  18. PRODUCTION OF TRIFLUOROACETIC ACID

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-07-19

    A method is given for the production of improved yields of trifluoroacetic acid. The compound is prepared by oxidizing m-aminobenzotrifluoride with an alkali metal or alkaline earth metal permanganate at a temperature in the range of 80 deg C to 100 deg C while dissolved ln a mixture of water with glacial acetic acid and/or trifluoroacetic acid. Preferably a mixture of water and trifluoroacetic acid ls used as the solvent.

  19. Quantity of acid in acid fog

    SciTech Connect

    Deal, W.J.

    1983-07-01

    The chemical composition of fog particles has become of considerable interest, because of both the possibility of interpreting atmospheric- chemistry processes in fog particles in terms of the principles of aqueous chemistry and the potential health effects of species present in fog particles. The acidity of fog particles has received wide attention. This communication noted the actual magnitude of the excess acidity in acidic fog particles and suggested a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air. (DP)

  20. Acid Rain Study Guide.

    ERIC Educational Resources Information Center

    Hunger, Carolyn; And Others

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

  1. The Acid Rain Reader.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.; And Others

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

  2. What Is Acid Rain?

    ERIC Educational Resources Information Center

    Likens, Gene E.

    2004-01-01

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

  3. [alpha]-Oxocarboxylic Acids

    ERIC Educational Resources Information Center

    Kerber, Robert C.; Fernando, Marian S.

    2010-01-01

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

  4. Nucleic acid detection compositions

    DOEpatents

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

    2008-08-05

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

  5. Cleavage of nucleic acids

    DOEpatents

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

    2000-01-01

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

  6. Nucleic acid detection assays

    DOEpatents

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

    2005-04-05

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

  7. Cleavage of nucleic acids

    DOEpatents

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

    2007-12-11

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

  8. Cleavage of nucleic acids

    SciTech Connect

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

    2010-11-09

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

  9. Editorial: Acid precipitation

    SciTech Connect

    1995-09-01

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

  10. [Safety of folic acid].

    PubMed

    Ströhle, Alexander; Wolters, Maike; Hahn, Andreas

    2015-08-01

    Improving dietary folate intake is a central public health goal. However, critical voices have become louder warning of too high intake of folic acid. Safety concerns of a high folic acid exposure are usually limited to synthetic folic acid contained in drugs and food supplements. Against this background, the present article focuses on two matters: (a) How do the absorption and metabolism of synthetic folic acid differ from that of other folates? (b) How has the longterm safety of folic acid to be judged, especially regarding the risk of colorectal cancer, autism, asthma, impaired immune defence, masking vitamin B12 deficiency and interactions with the methotrexate metabolism?

  11. Amino acid analysis

    NASA Technical Reports Server (NTRS)

    Winitz, M.; Graff, J. (Inventor)

    1974-01-01

    The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

  12. Features in optical absorption and photocurrent spectra of organic solar cells due to organic/organic interface

    NASA Astrophysics Data System (ADS)

    Ismail, Yasser A. M.; Soga, Tetsuo; Jimbo, Takashi

    2011-05-01

    We surprisingly found that, organic/organic interface had a direct and pronounced impact on optical absorption and photocurrent spectra of organic solar cell at a favorable wavelength region of the visible solar spectrum. The organic/organic interface was formed as a result of connection between coumarin 6 (C6): [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) blend films and indium-tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) electrode. Optical absorption measurement was carried out for ITO/PEDOT:PSS/C6:PCBM films, while external quantum efficiency measurement was carried out for ITO/PEDOT:PSS/C6:PCBM/Al solar cells, with varying C6:PCBM blend concentration. We found that, the C6:PCBM blend in the ITO/PEDOT:PSS/C6:PCBM films had an additional feature in the absorption spectra at the wavelength range of 520-800 nm, at which the C6 dye, PCBM, PEDOT:PSS, and ITO were transparent. An additional feature, also, appeared in photocurrent spectra of the C6:PCBM films in the ITO/PEDOT:PSS/C6:PCBM/Al solar cells at the same wavelength range. The new features in the optical absorption and photocurrent spectra of the investigated solar cells originated, in all probability, due to optically induced sup-band transitions in the C6:PCBM blend films at the interface with ITO/PEDOT:PSS electrode. Thus, the C6:PCBM blend films produced a charge carrier generation interface due to connection with ITO/PEDOT:PSS electrode. As a result of this charge carrier generation interface, the power conversion efficiency of the corresponding solar cell is improved. Taking into consideration these new findings, the high-band-gap organic materials will take more importance as sensitizers in organic optoelectronic applications.

  13. Acidic Ionic Liquids.

    PubMed

    Amarasekara, Ananda S

    2016-05-25

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

  14. Nucleic acid detection kits

    DOEpatents

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

    2005-03-29

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

  15. Acidic Ionic Liquids.

    PubMed

    Amarasekara, Ananda S

    2016-05-25

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

  16. Boric acid and boronic acids inhibition of pigeonpea urease.

    PubMed

    Reddy, K Ravi Charan; Kayastha, Arvind M

    2006-08-01

    Urease from the seeds of pigeonpea was competitively inhibited by boric acid, butylboronic acid, phenylboronic acid, and 4-bromophenylboronic acid; 4-bromophenylboronic acid being the strongest inhibitor, followed by boric acid > butylboronic acid > phenylboronic acid, respectively. Urease inhibition by boric acid is maximal at acidic pH (5.0) and minimal at alkaline pH (10.0), i.e., the trigonal planar B(OH)3 form is a more effective inhibitor than the tetrahedral B(OH)4 -anionic form. Similarly, the anionic form of phenylboronic acid was least inhibiting in nature.

  17. Biotransformation of cinnamic acid, p-coumaric acid, caffeic acid, and ferulic acid by plant cell cultures of Eucalyptus perriniana.

    PubMed

    Katsuragi, Hisashi; Shimoda, Kei; Kubota, Naoji; Nakajima, Nobuyoshi; Hamada, Hatsuyuki; Hamada, Hiroki

    2010-01-01

    Biotransformations of phenylpropanoids such as cinnamic acid, p-coumaric acid, caffeic acid, and ferulic acid were investigated with plant-cultured cells of Eucalyptus perriniana. The plant-cultured cells of E. perriniana converted cinnamic acid into cinnamic acid β-D-glucopyranosyl ester, p-coumaric acid, and 4-O-β-D-glucopyranosylcoumaric acid. p-Coumaric acid was converted into 4-O-β-D-glucopyranosylcoumaric acid, p-coumaric acid β-D-glucopyranosyl ester, 4-O-β-D-glucopyranosylcoumaric acid β-D-glucopyranosyl ester, a new compound, caffeic acid, and 3-O-β-D-glucopyranosylcaffeic acid. On the other hand, incubation of caffeic acid with cultured E. perriniana cells gave 3-O-β-D-glucopyranosylcaffeic acid, 3-O-(6-O-β-D-glucopyranosyl)-β-D-glucopyranosylcaffeic acid, a new compound, 3-O-β-D-glucopyranosylcaffeic acid β-D-glucopyranosyl ester, 4-O-β-D-glucopyranosylcaffeic acid, 4-O-β-D-glucopyranosylcaffeic acid β-D-glucopyranosyl ester, ferulic acid, and 4-O-β-D-glucopyranosylferulic acid. 4-O-β-D-Glucopyranosylferulic acid, ferulic acid β-D-glucopyranosyl ester, and 4-O-β-D-glucopyranosylferulic acid β-D-glucopyranosyl ester were isolated from E. perriniana cells treated with ferulic acid.

  18. Process for the preparation of lactic acid and glyceric acid

    DOEpatents

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

    2008-12-02

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

  19. Well acidizing compositions and methods

    SciTech Connect

    Swanson, B. L.

    1980-12-23

    Gelled acidic compositions suitable for matrix acidizing or fracture acidizing of subterranean formations are provided comprising water, a water-dispersible polymeric viscosifier such as a polymer of acrylamide, an acid, and a polyphenolic material such as lignite.

  20. Bile acids but not acidic acids induce Barrett's esophagus.

    PubMed

    Sun, Dongfeng; Wang, Xiao; Gai, Zhibo; Song, Xiaoming; Jia, Xinyong; Tian, Hui

    2015-01-01

    Barrett's esophagus (BE) is associated with the development of esophageal adenocarcinoma (EAC). Bile acids (BAs) refluxing into the esophagus contribute to esophageal injury, which results in BE and subsequent EAC. We developed two animal models to test the role of BAs in the pathogenesis of BE. We surgically generated BA reflux, with or without gastric acid, in rats. In a second experiment, we fed animals separately with BAs and gastric acid. Pathologic changes were examined and the expression of Muc2 and Cdx2 in BE tissue was tested by immunostaining. Inflammatory factors in the plasma, as well as differentiation genes in BE were examined through highly sensitive ELISA and semi-quantitative RT-PCR techniques. We found that BAs are sufficient for the induction of esophagitis and Barrett's-like metaplasia in the esophagus. Overexpression of inflammatory cells, IL-6, and TNF-α was observed both in animals fed with BAs and surgically generated BA reflux. Furthermore, elevated levels of Cdx2, Muc2, Bmp4, Kit19, and Tff2 (differentiation genes in BE) were found in BA-treated rats. In conclusion, BAs, but not gastric acid, are a major causative factor for BE. We confirmed that BAs contribute to the development of BE by inducing the inflammatory response in the esophagus. Inhibiting BAs may be a promising therapy for BE.

  1. Microorganisms for producing organic acids

    DOEpatents

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

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

  2. Acid-Base Homeostasis.

    PubMed

    Hamm, L Lee; Nakhoul, Nazih; Hering-Smith, Kathleen S

    2015-12-01

    Acid-base homeostasis and pH regulation are critical for both normal physiology and cell metabolism and function. The importance of this regulation is evidenced by a variety of physiologic derangements that occur when plasma pH is either high or low. The kidneys have the predominant role in regulating the systemic bicarbonate concentration and hence, the metabolic component of acid-base balance. This function of the kidneys has two components: reabsorption of virtually all of the filtered HCO3(-) and production of new bicarbonate to replace that consumed by normal or pathologic acids. This production or generation of new HCO3(-) is done by net acid excretion. Under normal conditions, approximately one-third to one-half of net acid excretion by the kidneys is in the form of titratable acid. The other one-half to two-thirds is the excretion of ammonium. The capacity to excrete ammonium under conditions of acid loads is quantitatively much greater than the capacity to increase titratable acid. Multiple, often redundant pathways and processes exist to regulate these renal functions. Derangements in acid-base homeostasis, however, are common in clinical medicine and can often be related to the systems involved in acid-base transport in the kidneys.

  3. Citric Acid Alternative to Nitric Acid Passivation

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie L. (Compiler)

    2013-01-01

    The Ground Systems Development and Operations GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described as the launch support and infrastructure modernization program in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the purpose of this project is to demonstratevalidate citric acid as a passivation agent for stainless steel. Successful completion of this project will result in citric acid being qualified for use as an environmentally preferable alternative to nitric acid for passivation of stainless steel alloys in NASA and DoD applications.

  4. Enzymatic gallic acid esterification.

    PubMed

    Weetal, H H

    1985-02-01

    Gallic acid esters of n-propyl and amyl alcohols have been produced by enzymatic synthesis in organic solvents using immobilized tannase. Studies indicate that maximum esterification of gallic acid occurs with amyl alcohol. The enzyme shows broad alcohol specificity. However, the enzyme exhibits absolute specificity for the acid portion of the ester. Studies were carried out on K(m), V(max), pH, and temperature optima.

  5. Nanoparticle distribution in polymer solar cells

    NASA Astrophysics Data System (ADS)

    Kirby, B. J.; Kiel, J. W.; Maranville, B. B.; Majkrzak, C. F.; Mackay, M. E.

    2010-03-01

    Polymer based solar cells (PSC) hold the promise of cheap, versatile devices for harnessing solar energy. A widely studied PSC is poly-3-hexylthiophene (P3HT) blended with [6,6] - phenyl-C61 - butyric acid methyl ester (PCBM) nanoparticles. The acceptor PCBM is needed to inhibit exciton recombination, thus, proper PCBM distribution is critical for photovoltaic performance. However, determining this distribution is challenging, as PCBM is extremely difficult to distinguish from P3HT via standard techniques like microscopy or x-ray diffraction. Neutron scattering presents a solution, as the scattering potential for PCBM is ˜5 x that of P3HT. Thus, we have studied PCBM:P3HT thin film samples using neutron reflectometry, which is sensitive to the compositional depth profile.[1] Measurements were conducted both with a weak scatterer (air) and then with a strong scatterer (D2O) backing the sample, such that the depth profile could be calculated from the reflectometry data with no fitting parameters, and/or model fitted with virtually no ambiguity. We find that PCBM aggregates near the substrate and surface interfaces of the P3HT film, implying that the PCBM is not optimally distributed for best photovoltaic performance. In general, this work demonstrates the extreme utility of neutron reflectometry for studying this class of materials. [1] Kiel, et al. Soft Matter, DOI:10.1039/B920979D (2009).

  6. Amino acids and proteins.

    PubMed

    van Goudoever, Johannes B; Vlaardingerbroek, Hester; van den Akker, Chris H; de Groof, Femke; van der Schoor, Sophie R D

    2014-01-01

    Amino acids and protein are key factors for growth. The neonatal period requires the highest intake in life to meet the demands. Those demands include amino acids for growth, but proteins and amino acids also function as signalling molecules and function as neurotransmitters. Often the nutritional requirements are not met, resulting in a postnatal growth restriction. However, current knowledge on adequate levels of both amino acid as well as protein intake can avoid under nutrition in the direct postnatal phase, avoid the need for subsequent catch-up growth and improve later outcome.

  7. USGS Tracks Acid Rain

    USGS Publications Warehouse

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

    1995-01-01

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

  8. Recovery of organic acids

    DOEpatents

    Verser, Dan W.; Eggeman, Timothy J.

    2011-11-01

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

  9. Recovery of organic acids

    DOEpatents

    Verser, Dan W.; Eggeman, Timothy J.

    2009-10-13

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

  10. Polycyclic aromatic hydrocarbons (PAHs) in exhaust emissions from diesel engines powered by rapeseed oil methylester and heated non-esterified rapeseed oil

    NASA Astrophysics Data System (ADS)

    Vojtisek-Lom, Michal; Czerwinski, Jan; Leníček, Jan; Sekyra, Milan; Topinka, Jan

    2012-12-01

    Polycyclic aromatic hydrocarbons (PAHs) of exhaust emissions were studied in four direct-injection turbocharged four-cylinder diesel engines, with power ratings of 90-136 kW. The engines were operated on biodiesel (B-100), a blend of 30% biodiesel in diesel fuel (B-30), and heated rapeseed oil (RO) in two independent laboratories. Diesel particle filters (DPF) and selective catalytic reduction (SCR) systems were used with B-30 and B-100. Concentrations of individual PAHs sampled in different substrates (quartz, borosilicate fiber and fluorocarbon membrane filters, polyurethane foam) were analyzed using different methods. Benzo[a]pyrene toxic equivalents (BaP TEQ) were calculated using different sets of toxic equivalency factors (TEF). Operation on B-100 without aftertreatment devices, compared to diesel fuel, yielded a mean reduction in PAHs of 73%, consistent across engines and among TEF used. A lower PAH reduction was obtained using B-30. The BaP TEQ reductions on DPF were 91-99% using B-100, for one non-catalyzed DPF, and over 99% in all other cases. The BaP TEQ for heated RO were higher than those for B-100 and one half lower to over twice as high as that of diesel fuel. B-100 and RO samples featured, compared to diesel fuel, a relatively high share of higher molecular weight PAH and a relatively low share of lighter PAHs. Using different sets of TEF or different detection methods did not consistently affect the observed effect of fuels on BaP TEQ. The compilation of multiple tests was helpful for discerning emerging patterns. The collection of milligrams of particulate matter per sample was generally needed for quantification of all individual PAHs.

  11. Mutant fatty acid desaturase

    DOEpatents

    Shanklin, John; Cahoon, Edgar B.

    2004-02-03

    The present invention relates to a method for producing mutants of a fatty acid desaturase having a substantially increased activity towards fatty acid substrates with chains containing fewer than 18 carbons relative to an unmutagenized precursor desaturase having an 18 carbon atom chain length substrate specificity. The method involves inducing one or more mutations in the nucleic acid sequence encoding the precursor desaturase, transforming the mutated sequence into an unsaturated fatty acid auxotroph cell such as MH13 E. coli, culturing the cells in the absence of supplemental unsaturated fatty acids, thereby selecting for recipient cells which have received and which express a mutant fatty acid desaturase with an elevated specificity for fatty acid substrates having chain lengths of less than 18 carbon atoms. A variety of mutants having 16 or fewer carbon atom chain length substrate specificities are produced by this method. Mutant desaturases produced by this method can be introduced via expression vectors into prokaryotic and eukaryotic cells and can also be used in the production of transgenic plants which may be used to produce specific fatty acid products.

  12. Amino Acid Crossword Puzzle

    ERIC Educational Resources Information Center

    Sims, Paul A.

    2011-01-01

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

  13. Toxicology of Perfluoroalkyl acids

    EPA Science Inventory

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

  14. Uric acid - blood

    MedlinePlus

    ... High levels of uric acid can sometimes cause gout or kidney disease. You may have this test if you have had or are about to have certain types of chemotherapy. Rapid weight loss, which may occur with such treatments, can increase the amount of uric acid in ...

  15. Bile acid transporters

    PubMed Central

    Dawson, Paul A.; Lan, Tian; Rao, Anuradha

    2009-01-01

    In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na+ taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OSTα-OSTβ. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers. PMID:19498215

  16. Analysis of Organic Acids.

    ERIC Educational Resources Information Center

    Griswold, John R.; Rauner, Richard A.

    1990-01-01

    Presented are the procedures and a discussion of the results for an experiment in which students select unknown carboxylic acids, determine their melting points, and investigate their solubility behavior in water and ethanol. A table of selected carboxylic acids is included. (CW)

  17. Omega-3 Fatty Acids

    MedlinePlus

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

  18. Toxicology of Perfluoroalkyl Acids*

    EPA Science Inventory

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

  19. Salicylic Acid Topical

    MedlinePlus

    ... skin blemishes in people who have acne. Topical salicylic acid is also used to treat skin conditions that involve scaling or overgrowth of skin ... water for 15 minutes.Do not apply topical salicylic acid to skin that is broken, red, swollen, irritated, or infected. ...

  20. Uric acid and hypertension.

    PubMed

    Feig, Daniel I

    2011-09-01

    A link between serum uric acid and the development of hypertension was first hypothesized in the 1870s. Although numerous epidemiologic studies in the 1980s and 1990s suggested an association, relatively little attention was paid to it until recently. Animal models have suggested a two-step pathogenesis by which uric acid initially activates the renin angiotensin system and suppresses nitric oxide, leading to uric acid-dependent increase in systemic vascular resistance, followed by a uric acid-mediated vasculopathy, involving renal afferent arterioles, resulting in a late sodium-sensitive hypertension. Initial clinical trials in young patients have supported these mechanisms in young patients but do not yet support pharmacologic reduction of serum uric acid as first-line therapy for hypertension.

  1. Biosynthesis of pulcherriminic acid

    PubMed Central

    MacDonald, J. C.

    1965-01-01

    1. Candida pulcherrima was grown on a complex medium to which various compounds had been added to determine their effect on the biosynthesis of pulcherriminic acid. Most of the pulcherriminic acid synthesized by C. pulcherrima PRL2019 was derived from the l-[1-14C]leucine added to the medium. 2. The cyclic dipeptide of l-leucine (cyclo-l-leucyl-l-leucyl) was shown, by trapping experiments involving cycloleucyl-leucyl isomers, to be synthesized by strain PRL2019. Cyclo-l-leucyl-l-leucyl was derived from l-leucine and was converted into pulcherriminic acid. Cyclo-l-leucyl-l-leucyl was a precursor of pulcherriminic acid in strain PRL2007 also. 3. The results supported the hypothesis that pulcherriminic acid is derived from l-leucine and that cyclo-l-leucyl-l-leucyl is an intermediate in the biosynthesis. PMID:5837792

  2. Total syntheses of cis-cyclopropane fatty acids: dihydromalvalic acid, dihydrosterculic acid, lactobacillic acid, and 9,10-methylenehexadecanoic acid.

    PubMed

    Shah, Sayali; White, Jonathan M; Williams, Spencer J

    2014-12-14

    cis-Cyclopropane fatty acids (cis-CFAs) are widespread constituents of the seed oils of subtropical plants, membrane components of bacteria and protozoa, and the fats and phospholipids of animals. We describe a systematic approach to the synthesis of enantiomeric pairs of four cis-CFAs: cis-9,10-methylenehexadecanoic acid, lactobacillic acid, dihydromalvalic acid, and dihydrosterculic acid. The approach commences with Rh2(OAc)4-catalyzed cyclopropenation of 1-octyne and 1-decyne, and hinges on the preparative scale chromatographic resolution of racemic 2-alkylcycloprop-2-ene-1-carboxylic acids using a homochiral Evan's auxiliary. Saturation of the individual diastereomeric N-cycloprop-2-ene-1-carbonylacyloxazolidines, followed by elaboration to alkylcyclopropylmethylsulfones, allowed Julia-Kocienski olefination with various ω-aldehyde-esters. Finally, saponification and diimide reduction afforded the individual cis-CFA enantiomers. PMID:25321346

  3. Gluconic acid production.

    PubMed

    Anastassiadis, Savas; Morgunov, Igor G

    2007-01-01

    Gluconic acid, the oxidation product of glucose, is a mild neither caustic nor corrosive, non toxic and readily biodegradable organic acid of great interest for many applications. As a multifunctional carbonic acid belonging to the bulk chemicals and due to its physiological and chemical characteristics, gluconic acid itself, its salts (e.g. alkali metal salts, in especially sodium gluconate) and the gluconolactone form have found extensively versatile uses in the chemical, pharmaceutical, food, construction and other industries. Present review article presents the comprehensive information of patent bibliography for the production of gluconic acid and compares the advantages and disadvantages of known processes. Numerous manufacturing processes are described in the international bibliography and patent literature of the last 100 years for the production of gluconic acid from glucose, including chemical and electrochemical catalysis, enzymatic biocatalysis by free or immobilized enzymes in specialized enzyme bioreactors as well as discontinuous and continuous fermentation processes using free growing or immobilized cells of various microorganisms, including bacteria, yeast-like fungi and fungi. Alternatively, new superior fermentation processes have been developed and extensively described for the continuous and discontinuous production of gluconic acid by isolated strains of yeast-like mold Aureobasidium pullulans, offering numerous advantages over the traditional discontinuous fungi processes.

  4. Trans Fatty Acids

    NASA Astrophysics Data System (ADS)

    Doyle, Ellin

    1997-09-01

    Fats and their various fatty acid components seem to be a perennial concern of nutritionists and persons concerned with healthful diets. Advice on the consumption of saturated, polyunsaturated, monounsaturated, and total fat bombards us from magazines and newspapers. One of the newer players in this field is the group of trans fatty acids found predominantly in partially hydrogenated fats such as margarines and cooking fats. The controversy concerning dietary trans fatty acids was recently addressed in an American Heart Association (AHA) science advisory (1) and in a position paper from the American Society of Clinical Nutrition/American Institute of Nutrition (ASCN/AIN) (2). Both reports emphasize that the best preventive strategy for reducing risk for cardiovascular disease and some types of cancer is a reduction in total and saturated fats in the diet, but a reduction in the intake of trans fatty acids was also recommended. Although the actual health effects of trans fatty acids remain uncertain, experimental evidence indicates that consumption of trans fatty acids adversely affects serum lipid levels. Since elevated levels of serum cholesterol and triacylglycerols are associated with increased risk of cardiovascular disease, it follows that intake of trans fatty acids should be minimized.

  5. Sulfuric Acid on Europa

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

    This image is based on data gathered by Galileo's near infrared mapping spectrometer.

    Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

    Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  6. Strongly Acidic Auxin Indole-3-Methanesulfonic Acid

    PubMed Central

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

    1985-01-01

    A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles. PMID:16664007

  7. Understanding acid rain

    SciTech Connect

    Budiansky, S.

    1981-06-01

    The complexities of the phenomenon of acid rain are described. Many factors, including meteorology, geology, chemistry, and biology, all play parts. Varying weather, varying soils, the presence of other pollutants and species differences all act to blur the connections between industrial emissions, acid rain, and environmental damage. Some experts believe that the greatest pH shock to lakes occurs during snow melt and runoff in the spring; others believe that much of the plant damage ascribed to acid rain is actually due to the effects of ozone. Much work needs to be done in the area of sampling. Historical data are lacking and sampling methods are not sufficiently accurate. (JMT)

  8. Understanding Acid Base Disorders.

    PubMed

    Gomez, Hernando; Kellum, John A

    2015-10-01

    The concentration of hydrogen ions is regulated in biologic solutions. There are currently 3 recognized approaches to assess changes in acid base status. First is the traditional Henderson-Hasselbalch approach, also called the physiologic approach, which uses the relationship between HCO3(-) and Pco2; the second is the standard base excess approach based on the Van Slyke equation. The third approach is the quantitative or Stewart approach, which uses the strong ion difference and the total weak acids. This article explores the origins of the current concepts framing the existing methods to analyze acid base balance.

  9. Acid rain and soil.

    PubMed

    vanLoon, G W

    1984-08-01

    A summary of important chemical properties of soil is given and the way in which acid rain may affect these properties is discussed. Acid rain may suppress microbiological decomposition and nitrification processes, thus influencing the nutrient status of soils. It has also been found that soil organic matter is less soluble in more acid solutions. Changed nutrient availability patterns are predicted in a low pH environment and enhanced leaching of essential elements from the soil exchange complex has been observed. Increased solubility of potentially toxic elements such as aluminium may also occur from soils which have been exposed to acidified rainfall.

  10. Disorders of Amino Acid Metabolism

    MedlinePlus

    ... Aspiration Syndrome Additional Content Medical News Disorders of Amino Acid Metabolism By Lee M. Sanders, MD, MPH NOTE: ... Metabolic Disorders Disorders of Carbohydrate Metabolism Disorders of Amino Acid Metabolism Disorders of Lipid Metabolism Amino acids are ...

  11. Pantothenic acid and biotin

    MedlinePlus

    ... well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board ... level that is thought to ensure enough nutrition. Dietary Reference Intakes for pantothenic acid: Age 0 to 6 months: ...

  12. Amino Acid Metabolism Disorders

    MedlinePlus

    Metabolism is the process your body uses to make energy from the food you eat. Food is ... One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup ...

  13. [Hydrofluoric acid burns].

    PubMed

    Holla, Robin; Gorter, Ramon R; Tenhagen, Mark; Vloemans, A F P M Jos; Breederveld, Roelf S

    2016-01-01

    Hydrofluoric acid is increasingly used as a rust remover and detergent. Dermal contact with hydrofluoric acid results in a chemical burn characterized by severe pain and deep tissue necrosis. It may cause electrolyte imbalances with lethal consequences. It is important to identify high-risk patients. 'High risk' is defined as a total affected body area > 3% or exposure to hydrofluoric acid in a concentration > 50%. We present the cases of three male patients (26, 31, and 39 years old) with hydrofluoric acid burns of varying severity and describe the subsequent treatments. The application of calcium gluconate 2.5% gel to the skin is the cornerstone of the treatment, reducing pain as well as improving wound healing. Nails should be thoroughly inspected and possibly removed if the nail is involved, to ensure proper healing. In high-risk patients, plasma calcium levels should be evaluated and cardiac monitoring is indicated.

  14. Folic acid - test

    MedlinePlus

    ... folic acid before and during pregnancy helps prevent neural tube defects, such as spina bifida. Women who ... take more if they have a history of neural tube defects in earlier pregnancies. Ask your provider ...

  15. Nitric acid poisoning

    MedlinePlus

    Symptoms from swallowing nitric acid may include: Abdominal pain - severe Burns to skin or mouth Drooling Fever Mouth pain - severe Rapid drop in blood pressure (shock) Throat swelling, which leads to breathing difficulty ...

  16. [Hydrofluoric acid burns].

    PubMed

    Holla, Robin; Gorter, Ramon R; Tenhagen, Mark; Vloemans, A F P M Jos; Breederveld, Roelf S

    2016-01-01

    Hydrofluoric acid is increasingly used as a rust remover and detergent. Dermal contact with hydrofluoric acid results in a chemical burn characterized by severe pain and deep tissue necrosis. It may cause electrolyte imbalances with lethal consequences. It is important to identify high-risk patients. 'High risk' is defined as a total affected body area > 3% or exposure to hydrofluoric acid in a concentration > 50%. We present the cases of three male patients (26, 31, and 39 years old) with hydrofluoric acid burns of varying severity and describe the subsequent treatments. The application of calcium gluconate 2.5% gel to the skin is the cornerstone of the treatment, reducing pain as well as improving wound healing. Nails should be thoroughly inspected and possibly removed if the nail is involved, to ensure proper healing. In high-risk patients, plasma calcium levels should be evaluated and cardiac monitoring is indicated. PMID:27189091

  17. Difficult Decisions: Acid Rain.

    ERIC Educational Resources Information Center

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

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

  18. Hyaluronic acid fillers.

    PubMed

    Monheit, Gary D; Coleman, Kyle M

    2006-01-01

    Although hyaluronic acids are a relatively new treatment for facial lines and wrinkles, they have provided numerous advances in the area of cosmetic surgery. This article discusses the inherent properties of hyaluronic acid fillers that make them ideal for treatment of facial lines. It encompasses a review of the current literature on U.S. Food and Drug Administration-approved hyaluronic acid fillers and the role that each of these fillers currently has in facial cosmetics. This article also discusses the potential pitfalls and adverse effects that can be associated with using hyaluronic acids for filling facial lines. Finally, it serves as an overview of current techniques for clinical assessment of patients as well as administration and treatment of facial lines and wrinkles.

  19. Boric acid poisoning

    MedlinePlus

    Borax poisoning ... The main symptoms of boric acid poisoning are blue-green vomit, diarrhea, and a bright red rash on the skin. Other symptoms may include: Blisters Collapse Coma Convulsions Drowsiness ...

  20. Stomach acid test

    MedlinePlus

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

  1. Aminolevulinic Acid Topical

    MedlinePlus

    ... under the skin that result from exposure to sunlight and can develop into skin cancer) of the ... acid will make your skin very sensitive to sunlight (likely to get sunburn). Avoid exposure of treated ...

  2. Amino Acids and Chirality

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.

    2012-01-01

    Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

  3. (Acid rain workshop)

    SciTech Connect

    Turner, R.S.

    1990-12-05

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

  4. Folic acid in diet

    MedlinePlus

    ... a regular supply of the vitamin in the foods you eat. ... vitamins have been added to the food. Many foods are now fortified with folic acid. Some of these are enriched breads, cereals, flours, ...

  5. Valproic Acid and Pregnancy

    MedlinePlus

    ... in the treatment of epilepsy, and to treat bipolar disorder and migraines. I have been taking valproic acid ... that women with seizure disorders and women with bipolar disorder might have menstrual problems and difficulty getting pregnant. ...

  6. Citric acid urine test

    MedlinePlus

    ... The test is used to diagnose renal tubular acidosis and evaluate kidney stone disease. Normal Results The ... level of citric acid may mean renal tubular acidosis and a tendency to form calcium kidney stones. ...

  7. Folic Acid Quiz

    MedlinePlus

    ... more easily than natural food folate. Close × Answer: D CORRECT: Folic acid reduces the risk for spina ... g., orange juice and green vegetables). Close × Answer: D CORRECT: Spina bifida and anencephaly are neural tube ...

  8. Hydrofluoric acid poisoning

    MedlinePlus

    ... your skin or eyes, you may have: Blisters Burns Pain Vision loss Hydrofluoric acid poisoning can have ... urine tests Camera down the throat to see burns in the esophagus and the stomach (endoscopy) Fluids ...

  9. Portable nucleic acid thermocyclers.

    PubMed

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

    2013-11-21

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

  10. Neutron Nucleic Acid Crystallography.

    PubMed

    Chatake, Toshiyuki

    2016-01-01

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

  11. Neutron Nucleic Acid Crystallography.

    PubMed

    Chatake, Toshiyuki

    2016-01-01

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

  12. Utilization of acid tars

    SciTech Connect

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

    1987-01-01

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

  13. Method for isolating nucleic acids

    SciTech Connect

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

    2015-09-29

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

  14. Acidification and Acid Rain

    NASA Astrophysics Data System (ADS)

    Norton, S. A.; Veselã½, J.

    2003-12-01

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

  15. Discovery of essential fatty acids

    PubMed Central

    Spector, Arthur A.; Kim, Hee-Yong

    2015-01-01

    Dietary fat was recognized as a good source of energy and fat-soluble vitamins by the first part of the 20th century, but fatty acids were not considered to be essential nutrients because they could be synthesized from dietary carbohydrate. This well-established view was challenged in 1929 by George and Mildred Burr who reported that dietary fatty acid was required to prevent a deficiency disease that occurred in rats fed a fat-free diet. They concluded that fatty acids were essential nutrients and showed that linoleic acid prevented the disease and is an essential fatty acid. The Burrs surmised that other unsaturated fatty acids were essential and subsequently demonstrated that linolenic acid, the omega-3 fatty acid analog of linoleic acid, is also an essential fatty acid. The discovery of essential fatty acids was a paradigm-changing finding, and it is now considered to be one of the landmark discoveries in lipid research. PMID:25339684

  16. Boric acid catalyzed chemoselective esterification of alpha-hydroxycarboxylic acids.

    PubMed

    Houston, Todd A; Wilkinson, Brendan L; Blanchfield, Joanne T

    2004-03-01

    Boric acid catalyzes the selective esterification of alpha-hydroxycarboxylic acids without causing significant esterification to occur with other carboxylic acids. The procedure is simple, high-yielding, and applicable to the esterification of alpha-hydroxy carboxylates in the presence of other carboxylic acids including beta-hydroxyacids within the same molecule. [reaction: see text

  17. 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)

  18. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  19. Analysis of Bile Acids

    NASA Astrophysics Data System (ADS)

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

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

  20. Optical high acidity sensor

    DOEpatents

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

    1997-07-22

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

  1. Optical high acidity sensor

    DOEpatents

    Jorgensen, Betty S.; Nekimken, Howard L.; Carey, W. Patrick; O'Rourke, Patrick E.

    1997-01-01

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

  2. Acid sludge utilization

    SciTech Connect

    Suarez, M.

    1980-09-01

    The Peak Oil Company of Tampa, Florida, in cooperation with the United States Department of Energy, has completed an initial study for the incorporation of acid-sludge derived from the rerefining of used lubricating oil into a useful and salable building material. Both bricks and paving materials have been produced using a formulation developed by Peak. Equipment has been designed and constructed for the specific purpose of preparing emulsions containing the acid-sludge, which is a vital ingredient in the final formulation. Testing of products obtained from these initial efforts shows that the acid in the sludge has been effectively neutralized and that heavy metals are not leached from the bricks or paving material in normal testing. While some properties of the building materials that incorporate the acid-sludge by-product are below standards for clay and shale brick, uses are defined for the product as is, and there is some promise of eventual production of building materials that meet all specifications for competitive materials. Initial cost estimations are encouraging, indicating that a profit can be derived by converting a hazardous and noxious by-product of rerefining to a construction material. Acid-sludge has presented a complex and costly disposal problem to the industry resulting in a serious depletion in the capacity for rerefining used lubricating oil.

  3. Domoic acid epileptic disease.

    PubMed

    Ramsdell, John S; Gulland, Frances M

    2014-03-01

    Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis. PMID:24663110

  4. Domoic Acid Epileptic Disease

    PubMed Central

    Ramsdell, John S.; Gulland, Frances M.

    2014-01-01

    Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis. PMID:24663110

  5. A Demonstration of Acid Rain

    ERIC Educational Resources Information Center

    Fong, Man Wai

    2004-01-01

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

  6. DOCOSAHEXAENOIC ACID AND ARACHIDONIC ACID PREVENT ESSENTIAL FATTY ACID DEFICIENCY AND HEPATIC STEATOSIS

    PubMed Central

    Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Fallon, Erica M.; Gura, Kathleen M.; Nose, Vania; Bistrian, Bruce R.; Puder, Mark

    2012-01-01

    Objectives Essential fatty acids are important for growth, development, and physiologic function. Alpha-linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, we hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids. Methods Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, we provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis. Results Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks. Conclusion Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without alpha-linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model. PMID:22038210

  7. Biodegradation of cyanuric acid.

    PubMed

    Saldick, J

    1974-12-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO(2) and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand.

  8. Exposures to acidic aerosols.

    PubMed

    Spengler, J D; Keeler, G J; Koutrakis, P; Ryan, P B; Raizenne, M; Franklin, C A

    1989-02-01

    Ambient monitoring of acid aerosols in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. Measurements made in Kingston, TN, and Steubenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 times during summer months. Periods of elevated acidic aerosols occur less frequently in winter months. The H+ determined during episodic conditions in southern Ontario indicates that respiratory tract deposition can exceed the effects level reported in clinical studies. Observed 12-hr H+ concentrations exceeded 550 nmole/m3 (approximately 27 micrograms/m3 H2SO4). The maximum estimated 1-hr concentration exceeded 1500 nmole/m3 for H+ ions. At these concentrations, an active child might receive more than 2000 nmole of H+ ion in 12 hr and in excess of 900 nmole during the hour when H2SO4 exceeded 50 micrograms/m3.

  9. Biodegradation of Cyanuric Acid

    PubMed Central

    Saldick, Jerome

    1974-01-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO2 and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand. PMID:4451360

  10. Calorimetry of Nucleic Acids.

    PubMed

    Rozners, Eriks; Pilch, Daniel S; Egli, Martin

    2015-12-01

    This unit describes the application of calorimetry to characterize the thermodynamics of nucleic acids, specifically, the two major calorimetric methodologies that are currently employed: differential scanning (DSC) and isothermal titration calorimetry (ITC). DSC is used to study thermally induced order-disorder transitions in nucleic acids. A DSC instrument measures, as a function of temperature (T), the excess heat capacity (C(p)(ex)) of a nucleic acid solution relative to the same amount of buffer solution. From a single curve of C(p)(ex) versus T, one can derive the following information: the transition enthalpy (ΔH), entropy (ΔS), free energy (ΔG), and heat capacity (ΔCp); the state of the transition (two-state versus multistate); and the average size of the molecule that melts as a single thermodynamic entity (e.g., the duplex). ITC is used to study the hybridization of nucleic acid molecules at constant temperature. In an ITC experiment, small aliquots of a titrant nucleic acid solution (strand 1) are added to an analyte nucleic acid solution (strand 2), and the released heat is monitored. ITC yields the stoichiometry of the association reaction (n), the enthalpy of association (ΔH), the equilibrium association constant (K), and thus the free energy of association (ΔG). Once ΔH and ΔG are known, ΔS can also be derived. Repetition of the ITC experiment at a number of different temperatures yields the ΔCp for the association reaction from the temperature dependence of ΔH.

  11. Acid rain in Asia

    NASA Astrophysics Data System (ADS)

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

    1992-07-01

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

  12. Acid Precipitation; (USA)

    SciTech Connect

    Rushing, J.W.; Hicks, S.C.

    1991-01-01

    This publication, Acid Precipitation (APC) announces on a monthly basis the current worldwide information on acid precipitation and closely related subjects, including wet and dry deposition, long-range transport, environmental effects, modeling, and socioeconomic factors. Information on the following subjects is included within the scope of this publication, but all subjects may not appear in each issue: Pollution sources and pollution control technology; atmospheric transport and chemistry; terrestrial transport and chemistry; aquatic transport and chemistry; biological effects; corrosive effects; and socioeconomics, policy, and legislation.

  13. Whither acid rain?

    PubMed

    Brimblecombe, P

    2001-04-01

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

  14. NITRIC ACID PICKLING PROCESS

    DOEpatents

    Boller, E.R.; Eubank, L.D.

    1958-08-19

    An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

  15. Fatty acids of Thiobacillus thiooxidans.

    PubMed

    Levin, R A

    1971-12-01

    Fatty acid spectra were made on Thiobacillus thiooxidans cultures both in the presence and absence of organic compounds. Small additions of glucose or acetate had no significant effect either on growth or fatty acid content. The addition of biotin had no stimulatory effect but did result in slight quantitative changes in the fatty acid spectrum. The predominant fatty acid was a C(19) cyclopropane acid.

  16. Fatty Acids of Thiobacillus thiooxidans

    PubMed Central

    Levin, Richard A.

    1971-01-01

    Fatty acid spectra were made on Thiobacillus thiooxidans cultures both in the presence and absence of organic compounds. Small additions of glucose or acetate had no significant effect either on growth or fatty acid content. The addition of biotin had no stimulatory effect but did result in slight quantitative changes in the fatty acid spectrum. The predominant fatty acid was a C19 cyclopropane acid. PMID:4945206

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

  18. Lactic acid bacterial cell factories for gamma-aminobutyric acid.

    PubMed

    Li, Haixing; Cao, Yusheng

    2010-11-01

    Gamma-aminobutyric acid is a non-protein amino acid that is widely present in organisms. Several important physiological functions of gamma-aminobutyric acid have been characterized, such as neurotransmission, induction of hypotension, diuretic effects, and tranquilizer effects. Many microorganisms can produce gamma-aminobutyric acid including bacteria, fungi and yeasts. Among them, gamma-aminobutyric acid-producing lactic acid bacteria have been a focus of research in recent years, because lactic acid bacteria possess special physiological activities and are generally regarded as safe. They have been extensively used in food industry. The production of lactic acid bacterial gamma-aminobutyric acid is safe and eco-friendly, and this provides the possibility of production of new naturally fermented health-oriented products enriched in gamma-aminobutyric acid. The gamma-aminobutyric acid-producing species of lactic acid bacteria and their isolation sources, the methods for screening of the strains and increasing their production, the enzymatic properties of glutamate decarboxylases and the relative fundamental research are reviewed in this article. And the potential applications of gamma-aminobutyric acid-producing lactic acid bacteria were also referred to.

  19. Comparison of Buffer Effect of Different Acids During Sandstone Acidizing

    NASA Astrophysics Data System (ADS)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham; Hamid, Mohamed Ali

    2015-04-01

    The most important concern of sandstone matrix acidizing is to increase the formation permeability by removing the silica particles. To accomplish this, the mud acid (HF: HCl) has been utilized successfully for many years to stimulate the sandstone formations, but still it has many complexities. This paper presents the results of laboratory investigations of different acid combinations (HF: HCl, HF: H3PO4 and HF: HCOOH). Hydrofluoric acid and fluoboric acid are used to dissolve clays and feldspar. Phosphoric and formic acids are added as a buffer to maintain the pH of the solution; also it allows the maximum penetration of acid into the core sample. Different tests have been performed on the core samples before and after the acidizing to do the comparative study on the buffer effect of these acids. The analysis consists of permeability, porosity, color change and pH value tests. There is more increase in permeability and porosity while less change in pH when phosphoric and formic acids were used compared to mud acid. From these results it has been found that the buffer effect of phosphoric acid and formic acid is better than hydrochloric acid.

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

    PubMed

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

    2010-06-01

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

  1. Docosahexaenoic acid and lactation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Docosahexaenoic acid (DHA) is an important component of membrane phospholipids in the retina, and brain, and accumulates rapidly in these tissues during early infancy. DHA is present in human milk, but the amount varies considerably and is largely dependent on maternal diet. This article reviews dat...

  2. Orphenadrinium picrate picric acid

    PubMed Central

    Fun, Hoong-Kun; Hemamalini, Madhukar; Siddaraju, B. P.; Yathirajan, H. S.; Narayana, B.

    2010-01-01

    The asymmetric unit of the title compound N,N-dimethyl-2-[(2-methyl­phen­yl)phenyl­meth­oxy]ethanaminium picrate picric acid, C18H24NO+·C6H2N3O7 −·C6H3N3O7, contains one orphenadrinium cation, one picrate anion and one picric acid mol­ecule. In the orphenadrine cation, the two aromatic rings form a dihedral angle of 70.30 (7)°. There is an intra­molecular O—H⋯O hydrogen bond in the picric acid mol­ecule, which generates an S(6) ring motif. In the crystal structure, the orphenadrine cations, picrate anions and picric acid mol­ecules are connected by strong inter­molecular N—H⋯O hydrogen bonds, π⋯π inter­actions between the benzene rings of cations and anions [centroid–centroid distance = 3.5603 (9) Å] and weak C—H⋯O hydrogen bonds, forming a three-dimensional network. PMID:21580426

  3. Acid Rain Investigations.

    ERIC Educational Resources Information Center

    Hugo, John C.

    1992-01-01

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

  4. The Acid Rain Debate.

    ERIC Educational Resources Information Center

    Oates-Bockenstedt, Catherine

    1997-01-01

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

  5. Acid rain bibliography

    SciTech Connect

    Sayers, C.S.

    1983-09-01

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

  6. Acid Rain Classroom Projects.

    ERIC Educational Resources Information Center

    Demchik, Michael J.

    2000-01-01

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

  7. The Acid Rain Debate.

    ERIC Educational Resources Information Center

    Bybee, Rodger; And Others

    1984-01-01

    Describes an activity which provides opportunities for role-playing as industrialists, ecologists, and government officials. The activity involves forming an international commission on acid rain, taking testimony, and, based on the testimony, making recommendations to governments on specific ways to solve the problem. Includes suggestions for…

  8. The Acid Rain Game.

    ERIC Educational Resources Information Center

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

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

  9. Targeting tumor acidity

    NASA Astrophysics Data System (ADS)

    Reshetnyak, Yana K.; Engelman, Donald M.; Andreev, Oleg A.

    2012-02-01

    One of the main features of solid tumors is extracellular acidity, which correlates with tumor aggressiveness and metastatic potential. We introduced novel approach in targeting of acidic tumors, and translocation of cell-impermeable cargo molecules across cellular membrane. Our approach is based on main principle of insertion and folding of a polypeptide in lipid bilayer of membrane. We have identified family of pH Low Insertion Peptides (pHLIPs), which are capable spontaneous insertion and folding in membrane at mild acidic conditions. The affinity of peptides of pHLIP family to membrane at low pH is several times higher than at neutral pH. The process of peptides folding occurs within milliseconds. The energy released in a result of folding (about 2 kcal/mol) could be used to move polar cargo across a membrane, which is a novel concept in drug delivery. pHLIP peptides could be considered as a pH-sensitive single peptide molecular transporters and conjugated with imaging probes for fluorescence, MR, PET and SPECT imaging, they represent a novel in vivo marker of acidity. The work is supported by NIH grants CA133890 and GM073857 to OAA, DME, YRK.

  10. Spermatotoxicity of dichloroacetic acid

    EPA Science Inventory

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

  11. Plant fatty acid hydroxylase

    DOEpatents

    Somerville, Chris; van de Loo, Frank

    2000-01-01

    The present invention relates to the identification of nucleic acid sequences and constructs, and methods related thereto, and the use of these sequences and constructs to produce genetically modified plants for the purpose of altering the composition of plant oils, waxes and related compounds.

  12. Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

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

    SciTech Connect

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

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

  14. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by...

  15. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by...

  16. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as... sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by...

  17. Synthesis of acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters

    DOEpatents

    Moens, Luc

    2003-06-24

    A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a solvent selected from the group consisting of water, ethyl acetate, chloroform, acetone, ethanol, tetrahydrofuran and acetonitrile, to form a quaternary ammonium salt of the lower alkyl 5-bromolevulinate; and b) hydrolyzing the quaternary ammonium salt with an inorganic acid to form an acid addition salt of delta-aminolevulinic acid.

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

    PubMed

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

    2012-06-01

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

  19. Photo-degradation in air of the active layer components in a thiophene-quinoxaline copolymer:fullerene solar cell.

    PubMed

    Hansson, Rickard; Lindqvist, Camilla; Ericsson, Leif K E; Opitz, Andreas; Wang, Ergang; Moons, Ellen

    2016-04-28

    We have studied the photo-degradation in air of a blend of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1), and how the photo-degradation affects the solar cell performance. Using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, changes to the electronic structure of TQ1 and PCBM caused by illumination in ambient air are investigated and compared between the pristine materials and the blend. The NEXAFS spectra show that the unoccupied molecular orbitals of TQ1 are not significantly changed by the exposure of pristine TQ1 to light in air, whereas those of PCBM are severely affected as a result of photo-induced degradation of PCBM. Furthermore, the photo-degradation of PCBM is accelerated by blending it with TQ1. While the NEXAFS spectrum of TQ1 remains unchanged upon illumination in air, its valence band spectrum shows that the occupied molecular orbitals are weakly affected. Yet, UV-Vis absorption spectra demonstrate photo-bleaching of TQ1, which is attenuated in the presence of PCBM in blend films. Illumination of the active layer of TQ1:PCBM solar cells prior to cathode deposition causes severe losses in electrical performance. PMID:27051887

  20. Photo-degradation in air of the active layer components in a thiophene-quinoxaline copolymer:fullerene solar cell.

    PubMed

    Hansson, Rickard; Lindqvist, Camilla; Ericsson, Leif K E; Opitz, Andreas; Wang, Ergang; Moons, Ellen

    2016-04-28

    We have studied the photo-degradation in air of a blend of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1), and how the photo-degradation affects the solar cell performance. Using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, changes to the electronic structure of TQ1 and PCBM caused by illumination in ambient air are investigated and compared between the pristine materials and the blend. The NEXAFS spectra show that the unoccupied molecular orbitals of TQ1 are not significantly changed by the exposure of pristine TQ1 to light in air, whereas those of PCBM are severely affected as a result of photo-induced degradation of PCBM. Furthermore, the photo-degradation of PCBM is accelerated by blending it with TQ1. While the NEXAFS spectrum of TQ1 remains unchanged upon illumination in air, its valence band spectrum shows that the occupied molecular orbitals are weakly affected. Yet, UV-Vis absorption spectra demonstrate photo-bleaching of TQ1, which is attenuated in the presence of PCBM in blend films. Illumination of the active layer of TQ1:PCBM solar cells prior to cathode deposition causes severe losses in electrical performance.

  1. Gas expanded polymer process to anneal nanoparticle dispersion in thin films

    DOE PAGES

    Ambuken, Preejith V.; Stretz, Holly A.; Dadmun, Mark; Michael Kilbey, S.

    2015-04-21

    A spin-coating solution comprising poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles used to create organic photovoltaic (OPV) active layers have been shown to adopt a non-uniform concentration profile across the thin film dimension. This inhomogeneous distribution can reduce the efficiency of the device. For our new process, gas expanded polymer (GXP) annealing, is applied to P3HT/PCBM thin film blends, enabling the distribution of the PCBM nanoparticles to be manipulated by varying the GXP processing conditions. Films of 50 nm thickness (nominally) created by spin casting a blend of P3HT mixed with PCBM were annealed by oscillatory GXP andmore » GXP at constant pressure using high pressure CO2. An increase in P3HT crystallinity (detected by X-ray diffraction and UV-vis spectroscopy) along with a more uniform distribution of PCBM nanoparticles in the thickness dimension, as interpreted from neutron reflectivity measurements, were observed after oscillatory GXP annealing. In addition, static water contact angles suggest that the film/air interface is enriched in PCBM relative to the as-cast film. Finally, these results demonstrate that GXP annealing, which is commercially scalable, can be successfully used to create a uniform distribution of PCBM nanoparticles across the thickness dimension in a P3HT thin film.« less

  2. Gas expanded polymer process to anneal nanoparticle dispersion in thin films

    SciTech Connect

    Ambuken, Preejith V.; Stretz, Holly A.; Dadmun, Mark; Michael Kilbey, S.

    2015-04-21

    A spin-coating solution comprising poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles used to create organic photovoltaic (OPV) active layers have been shown to adopt a non-uniform concentration profile across the thin film dimension. This inhomogeneous distribution can reduce the efficiency of the device. For our new process, gas expanded polymer (GXP) annealing, is applied to P3HT/PCBM thin film blends, enabling the distribution of the PCBM nanoparticles to be manipulated by varying the GXP processing conditions. Films of 50 nm thickness (nominally) created by spin casting a blend of P3HT mixed with PCBM were annealed by oscillatory GXP and GXP at constant pressure using high pressure CO2. An increase in P3HT crystallinity (detected by X-ray diffraction and UV-vis spectroscopy) along with a more uniform distribution of PCBM nanoparticles in the thickness dimension, as interpreted from neutron reflectivity measurements, were observed after oscillatory GXP annealing. In addition, static water contact angles suggest that the film/air interface is enriched in PCBM relative to the as-cast film. Finally, these results demonstrate that GXP annealing, which is commercially scalable, can be successfully used to create a uniform distribution of PCBM nanoparticles across the thickness dimension in a P3HT thin film.

  3. Fatty acid-producing hosts

    DOEpatents

    Pfleger, Brian F; Lennen, Rebecca M

    2013-12-31

    Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

  4. Acid diffusion through polyaniline membranes

    SciTech Connect

    Su, T.M.; Huang, S.C.; Conklin, J.A.

    1995-12-01

    Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

  5. Treatment of Bile Acid Amidation Defects with Glycocholic Acid

    PubMed Central

    Heubi, James E.; Setchell, Kenneth D.R.; Jha, Pinky; Buckley, Donna; Zhang, Wujuan; Rosenthal, Philip; Potter, Carol; Horslen, Simon; Suskind, David

    2014-01-01

    Bile acid amidation defects were predicted to present with fat/fat soluble vitamin malabsorption with minimal cholestasis. We identified and treated 5 patients (1 male/4 females) from 4 families with defective bile acid amidation due to a genetically confirmed deficiency in bile acid CoA:amino acid N-acyl transferase (BAAT) with the conjugated bile acid, glycocholic acid (GCA). Fast atom bombardment-mass spectrometry analysis of urine and bile at baseline revealed predominantly unconjugated cholic acid and absence of the usual glycine and taurine conjugated primary bile acids. Treatment with 15 mg/kg GCA resulted in total duodenal bile acid concentrations of 23.3 ± 19.1 mmol/L (mean ± SD) and 63.5 ± 4.0% of the bile acids were secreted in bile in the conjugated form of which GCA represented 59.6 ± 9.3% of the total biliary bile acids. Unconjugated cholic acid continued to be present in high concentrations in bile because of partial intestinal deconjugation of orally administered GCA. Serum total bile acid concentrations did not significantly differ between pretreatment and post-treatment samples and serum contained predominantly unconjugated cholic acid. These findings confirmed efficient intestinal absorption, hepatic extraction and biliary secretion of the administered GCA. Oral tolerance tests for vitamin D2 (1000 IU vitamin D2/kg) and tocopherol (100 IU/kg tocopherol acetate) demonstrated improvement in fat-soluble vitamin absorption after GCA treatment. Growth improved in 3/3 growth-delayed prepubertal patients. Conclusions: Oral glycocholic acid therapy is safe and effective in improving growth and fat-soluble vitamin absorption in children and adolescents with inborn errors of bile acid metabolism due to amidation defects. PMID:25163551

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

    PubMed

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

    2016-03-01

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

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

    SciTech Connect

    Not Available

    1990-06-01

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

  8. Acid Earth--The Global Threat of Acid Pollution.

    ERIC Educational Resources Information Center

    McCormick, John

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

  9. Usnic acid controls the acidity tolerance of lichens.

    PubMed

    Hauck, Markus; Jürgens, Sascha-René

    2008-11-01

    The hypotheses were tested that, firstly, lichens producing the dibenzofuran usnic acid colonize substrates characterized by specific pH ranges, secondly, this preferred pH is in a range where soluble usnic acid and its corresponding anion occur in similar concentrations, and thirdly, usnic acid makes lichens vulnerable to acidity. Lichens with usnic acid prefer an ambient pH range between 3.5 and 5.5 with an optimum between 4.0 and 4.5. This optimum is close to the pK(a1) value of usnic acid of 4.4. Below this optimum pH, dissolved SO(2) reduces the chlorophyll fluorescence yield more in lichens with than without their natural content of usnic acid. This suggests that usnic acid influences the acidity tolerance of lichens. The putative mechanism of the limited acidity tolerance of usnic acid-containing lichens is the acidification of the cytosol by molecules of protonated usnic acid shuttling protons through the plasma membrane at an apoplastic pH

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

    ERIC Educational Resources Information Center

    McClary, LaKeisha; Talanquer, Vicente

    2011-01-01

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

  11. Acid hydrolysis of cellulose

    SciTech Connect

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  12. [Progress in glucaric acid].

    PubMed

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

    2015-04-01

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

  13. Eucomic acid methanol monosolvate

    PubMed Central

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

    2011-01-01

    In the crystal structure of the title compound [systematic name: 2-hy­droxy-2-(4-hy­droxy­benz­yl)butane­dioic acid methanol monosolvate], C11H12O6·CH3OH, the dihedral angles between the planes of the carboxyl groups and the benzene ring are 51.23 (9) and 87.97 (9)°. Inter­molecular O—H⋯O hydrogen-bonding inter­actions involving the hy­droxy and carb­oxy­lic acid groups and the methanol solvent mol­ecule give a three-dimensional structure. PMID:22091200

  14. Industrial ecotoxicology "acid rain".

    PubMed

    Astolfi, E; Gotelli, C; Higa, J

    1986-01-01

    The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent. PMID:3758667

  15. Industrial ecotoxicology "acid rain".

    PubMed

    Astolfi, E; Gotelli, C; Higa, J

    1986-01-01

    The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent.

  16. (Radioiodinated free fatty acids)

    SciTech Connect

    Knapp, Jr., F. F.

    1987-12-11

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

  17. Immunomodulatory spherical nucleic acids.

    PubMed

    Radovic-Moreno, Aleksandar F; Chernyak, Natalia; Mader, Christopher C; Nallagatla, Subbarao; Kang, Richard S; Hao, Liangliang; Walker, David A; Halo, Tiffany L; Merkel, Timothy J; Rische, Clayton H; Anantatmula, Sagar; Burkhart, Merideth; Mirkin, Chad A; Gryaznov, Sergei M

    2015-03-31

    Immunomodulatory nucleic acids have extraordinary promise for treating disease, yet clinical progress has been limited by a lack of tools to safely increase activity in patients. Immunomodulatory nucleic acids act by agonizing or antagonizing endosomal toll-like receptors (TLR3, TLR7/8, and TLR9), proteins involved in innate immune signaling. Immunomodulatory spherical nucleic acids (SNAs) that stimulate (immunostimulatory, IS-SNA) or regulate (immunoregulatory, IR-SNA) immunity by engaging TLRs have been designed, synthesized, and characterized. Compared with free oligonucleotides, IS-SNAs exhibit up to 80-fold increases in potency, 700-fold higher antibody titers, 400-fold higher cellular responses to a model antigen, and improved treatment of mice with lymphomas. IR-SNAs exhibit up to eightfold increases in potency and 30% greater reduction in fibrosis score in mice with nonalcoholic steatohepatitis (NASH). Given the clinical potential of SNAs due to their potency, defined chemical nature, and good tolerability, SNAs are attractive new modalities for developing immunotherapies.

  18. Acid rain in Asia

    SciTech Connect

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

    1991-01-01

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

  19. Immunomodulatory spherical nucleic acids

    PubMed Central

    Radovic-Moreno, Aleksandar F.; Chernyak, Natalia; Mader, Christopher C.; Nallagatla, Subbarao; Kang, Richard S.; Hao, Liangliang; Walker, David A.; Halo, Tiffany L.; Merkel, Timothy J.; Rische, Clayton H.; Anantatmula, Sagar; Burkhart, Merideth; Mirkin, Chad A.; Gryaznov, Sergei M.

    2015-01-01

    Immunomodulatory nucleic acids have extraordinary promise for treating disease, yet clinical progress has been limited by a lack of tools to safely increase activity in patients. Immunomodulatory nucleic acids act by agonizing or antagonizing endosomal toll-like receptors (TLR3, TLR7/8, and TLR9), proteins involved in innate immune signaling. Immunomodulatory spherical nucleic acids (SNAs) that stimulate (immunostimulatory, IS-SNA) or regulate (immunoregulatory, IR-SNA) immunity by engaging TLRs have been designed, synthesized, and characterized. Compared with free oligonucleotides, IS-SNAs exhibit up to 80-fold increases in potency, 700-fold higher antibody titers, 400-fold higher cellular responses to a model antigen, and improved treatment of mice with lymphomas. IR-SNAs exhibit up to eightfold increases in potency and 30% greater reduction in fibrosis score in mice with nonalcoholic steatohepatitis (NASH). Given the clinical potential of SNAs due to their potency, defined chemical nature, and good tolerability, SNAs are attractive new modalities for developing immunotherapies. PMID:25775582

  20. Perfluorooctanoic acid and environmental risks

    EPA Science Inventory

    Perfluorooctanoic acid (PFOA) is a member of the perfluoroalkyl acids (PFAA) family of chemicals, which consist of a carbon backbone typically four to fourteen carbons in length and a charged functional moiety.

  1. Folic Acid Questions and Answers

    MedlinePlus

    ... swallow large pills. How can I take a vitamin with folic acid? A : These days, multivitamins with folic acid come in chewable chocolate or fruit flavors, liquids, and large oval or smaller round ...

  2. Omega-3 fatty acids (image)

    MedlinePlus

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

  3. Acid rain: Reign of controversy

    SciTech Connect

    Kahan, A.M.

    1986-01-01

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

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

    SciTech Connect

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

    1987-09-01

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

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

    PubMed

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

    2002-12-01

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

  6. Nervonic acid and demyelinating disease.

    PubMed

    Sargent, J R; Coupland, K; Wilson, R

    1994-04-01

    Demyelination in adrenoleukodystrophy (ALD) is associated with an accumulation of very long chain saturated fatty acids such as 26:0 stemming from a genetic defect in the peroxisomal beta oxidation system responsible for the chain shortening of these fatty acids. Long chain monoenoic acids such as erucic acid, 22:1(n-9), can normalise elevated serum levels of 26:0 in ALD by depressing their biosynthesis from shorter chain saturated fatty acids. Sphingolipids from post mortem ALD brain have decreased levels of nervonic acid, 24:1(n-9), and increased levels of stearic acid, 18:0. Increased levels of 26:0 are accompanied by decreased nervonic acid biosynthesis in skin fibroblasts from ALD patients. Sphingolipids from post mortem MS brain have the same decreased 24:1(n-9) and increased 18:0 seen in post mortem ALD brain. The 24:1(n-9) content of sphingomyelin is depressed in erythrocytes from multiple sclerosis (MS) patients. Defects in the microsomal biosynthesis of very long chain fatty acids including 24:1(n-9) in 'jumpy' and 'quaking' mice are accompanied by impaired myelination. An impairment in the provision of nervonic acid in demyelinating diseases is indicated, suggesting that dietary therapy with oils rich in very long chain monenoic acid fatty acids may be beneficial in such conditions.

  7. Pantothenic acid biosynthesis in zymomonas

    SciTech Connect

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

    2014-07-01

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

  8. An Umbrella for Acid Rain.

    ERIC Educational Resources Information Center

    Randal, Judith

    1979-01-01

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

  9. Carboxylic acid sorption regeneration process

    DOEpatents

    King, C.J.; Poole, L.J.

    1995-05-02

    Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine. 10 figs.

  10. Carboxylic acid sorption regeneration process

    DOEpatents

    King, C. Judson; Poole, Loree J.

    1995-01-01

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

  11. Heterogeneous uptake of amines by citric acid and humic acid.

    PubMed

    Liu, Yongchun; Ma, Qingxin; He, Hong

    2012-10-16

    Heterogeneous uptake of methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) onto citric acid and humic acid was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer at 298 K. Acid-base reactions between amines and carboxylic acids were confirmed. The observed uptake coefficients of MA, DMA, and TMA on citric acid at 298 K were measured to be 7.31 ± 1.13 × 10(-3), 6.65 ± 0.49 × 10(-3), and 5.82 ± 0.68 × 10(-3), respectively, and showed independence of sample mass. The observed uptake coefficients of MA, DMA, and TMA on humic acid at 298 K increased linearly with sample mass, and the true uptake coefficients of MA, DMA, and TMA were measured to be 1.26 ± 0.07 × 10(-5), 7.33 ± 0.40 × 10(-6), and 4.75 ± 0.15 × 10(-6), respectively. Citric acid, having stronger acidity, showed a higher reactivity than humic acid for a given amine; while the steric effect of amines was found to govern the reactivity between amines and citric acid or humic acid.

  12. On some derivatives of phenylethers, 2

    NASA Technical Reports Server (NTRS)

    Haeussermann, C.; Bauer, E.

    1983-01-01

    Products and the synthesis of chloronitrobenzol with certain phenolates are discussed, as is the p-oxyphenylether occasionally produced. Yield, melting point, and physical description are given for each product. The products include 2,4'-dinitrophenylether; 2,2'-dinitrophenylether; p-nitrophenylether-p-oxybenzoic acid and its methylester; p-aminophenylether-p-oxybenzoic acid, its sulfate, and its barium salt; and p-oxypenylether.

  13. Composition for nucleic acid sequencing

    SciTech Connect

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

    2008-08-26

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

  14. Evolution of rosmarinic acid biosynthesis.

    PubMed

    Petersen, Maike; Abdullah, Yana; Benner, Johannes; Eberle, David; Gehlen, Katja; Hücherig, Stephanie; Janiak, Verena; Kim, Kyung Hee; Sander, Marion; Weitzel, Corinna; Wolters, Stefan

    2009-01-01

    Rosmarinic acid and chlorogenic acid are caffeic acid esters widely found in the plant kingdom and presumably accumulated as defense compounds. In a survey, more than 240 plant species have been screened for the presence of rosmarinic and chlorogenic acids. Several rosmarinic acid-containing species have been detected. The rosmarinic acid accumulation in species of the Marantaceae has not been known before. Rosmarinic acid is found in hornworts, in the fern family Blechnaceae and in species of several orders of mono- and dicotyledonous angiosperms. The biosyntheses of caffeoylshikimate, chlorogenic acid and rosmarinic acid use 4-coumaroyl-CoA from the general phenylpropanoid pathway as hydroxycinnamoyl donor. The hydroxycinnamoyl acceptor substrate comes from the shikimate pathway: shikimic acid, quinic acid and hydroxyphenyllactic acid derived from l-tyrosine. Similar steps are involved in the biosyntheses of rosmarinic, chlorogenic and caffeoylshikimic acids: the transfer of the 4-coumaroyl moiety to an acceptor molecule by a hydroxycinnamoyltransferase from the BAHD acyltransferase family and the meta-hydroxylation of the 4-coumaroyl moiety in the ester by a cytochrome P450 monooxygenase from the CYP98A family. The hydroxycinnamoyltransferases as well as the meta-hydroxylases show high sequence similarities and thus seem to be closely related. The hydroxycinnamoyltransferase and CYP98A14 from Coleus blumei (Lamiaceae) are nevertheless specific for substrates involved in RA biosynthesis showing an evolutionary diversification in phenolic ester metabolism. Our current view is that only a few enzymes had to be "invented" for rosmarinic acid biosynthesis probably on the basis of genes needed for the formation of chlorogenic and caffeoylshikimic acid while further biosynthetic steps might have been recruited from phenylpropanoid metabolism, tocopherol/plastoquinone biosynthesis and photorespiration. PMID:19560175

  15. Evolution of rosmarinic acid biosynthesis.

    PubMed

    Petersen, Maike; Abdullah, Yana; Benner, Johannes; Eberle, David; Gehlen, Katja; Hücherig, Stephanie; Janiak, Verena; Kim, Kyung Hee; Sander, Marion; Weitzel, Corinna; Wolters, Stefan

    2009-01-01

    Rosmarinic acid and chlorogenic acid are caffeic acid esters widely found in the plant kingdom and presumably accumulated as defense compounds. In a survey, more than 240 plant species have been screened for the presence of rosmarinic and chlorogenic acids. Several rosmarinic acid-containing species have been detected. The rosmarinic acid accumulation in species of the Marantaceae has not been known before. Rosmarinic acid is found in hornworts, in the fern family Blechnaceae and in species of several orders of mono- and dicotyledonous angiosperms. The biosyntheses of caffeoylshikimate, chlorogenic acid and rosmarinic acid use 4-coumaroyl-CoA from the general phenylpropanoid pathway as hydroxycinnamoyl donor. The hydroxycinnamoyl acceptor substrate comes from the shikimate pathway: shikimic acid, quinic acid and hydroxyphenyllactic acid derived from l-tyrosine. Similar steps are involved in the biosyntheses of rosmarinic, chlorogenic and caffeoylshikimic acids: the transfer of the 4-coumaroyl moiety to an acceptor molecule by a hydroxycinnamoyltransferase from the BAHD acyltransferase family and the meta-hydroxylation of the 4-coumaroyl moiety in the ester by a cytochrome P450 monooxygenase from the CYP98A family. The hydroxycinnamoyltransferases as well as the meta-hydroxylases show high sequence similarities and thus seem to be closely related. The hydroxycinnamoyltransferase and CYP98A14 from Coleus blumei (Lamiaceae) are nevertheless specific for substrates involved in RA biosynthesis showing an evolutionary diversification in phenolic ester metabolism. Our current view is that only a few enzymes had to be "invented" for rosmarinic acid biosynthesis probably on the basis of genes needed for the formation of chlorogenic and caffeoylshikimic acid while further biosynthetic steps might have been recruited from phenylpropanoid metabolism, tocopherol/plastoquinone biosynthesis and photorespiration.

  16. Microbial transformations of isocupressic acid.

    PubMed

    Lin, S J; Rosazza, J P

    1998-07-01

    Microbial transformations of the labdane-diterpene isocupressic acid (1) with different microorganisms yielded several oxygenated metabolites that were isolated and characterized by MS and NMR spectroscopic analyses. Nocardia aurantia (ATCC 12674) catalyzed the cleavage of the 13,14-double bond to yield a new nor-labdane metabolite, 2. Cunninghamella elegans (-) (NRRL 1393) gave 7beta-hydroxyisocupressic acid (3) and labda-7,13(E)-diene-6beta,15, 17-triol-19-oic acid (4), and Mucor mucedo (ATCC 20094) gave 2alpha-hydroxyisocupressic acid (5) and labda-8(17),14-diene-2alpha, 13-diol-19-oic acid (6).

  17. Invasive cleavage of nucleic acids

    DOEpatents

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

    2002-01-01

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

  18. Invasive cleavage of nucleic acids

    DOEpatents

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

    1999-01-01

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

  19. The politics of acid rain

    SciTech Connect

    Wilcher, M.E. )

    1989-01-01

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

  20. [A catalogue of fatty acids].

    PubMed

    Canalejo, E; Martín Peña, G; Gómez Molero, L; Ruiz Galiana, J

    1996-01-01

    Fatty acids structure and function is an area of renewed interest because of its effects on plasma lipids, biosynthesis of prostaglandins, leucotrienes and thromboxanes, and the obligatory demands of some fatty acids, especially for the newborn. Fatty acids are identified in three different ways: by the classical nomenclature, by its trivial name, and by the new methods also known as the omega system. These three different methods have created some confusion. The aim of this article is to revise fatty acids chemical structure and to compile a list of nutritional important fatty acids with the three different terminologies.

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

    ERIC Educational Resources Information Center

    Raw, C. J. G.; And Others

    1983-01-01

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

  2. Twinning of dodecanedicarboxylic acid

    NASA Technical Reports Server (NTRS)

    Sen, R.; Wilcox, W. R.

    1986-01-01

    Twinning of 1,10-dodecanedicarboxyl acid (DDA) was observed in 0.1 mm thick films with a polarizing microscope. Twins originated from polycrystalline regions which tended to nucleate on twin faces, and terminated by intersection gone another. Twinning increased dramatically with addition of organic compounds with a similar molecular size and shape. Increasing the freezing rate, increasing the temperature gradient, and addition of silica particles increased twinning. It is proposed that twins nucleate with polycrystals and sometimes anneal out before they become observable. The impurities may enhance twinning either by lowering the twin energy or by adsorbing on growing faces.

  3. Mycophenolic Acid in Silage

    PubMed Central

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

    2000-01-01

    We examined 233 silage samples and found that molds were present in 206 samples with counts between 1 × 103 and 8.9 × 107 (mean, 4.7 × 106) CFU/g. Mycophenolic acid, a metabolite of Penicillium roqueforti, was detected by liquid chromatography-mass spectrometry in 74 (32%) of these samples at levels ranging from 20 to 35,000 (mean, 1,400) μg/kg. This compound has well-known immunosuppressive properties, so feeding with contaminated silage may promote the development of infectious diseases in livestock. PMID:10919834

  4. Synthesis of amino acids

    DOEpatents

    Davis, J.W. Jr.

    1979-09-21

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

  5. Beyond acid rain

    SciTech Connect

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

    1987-06-01

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

  6. Interstellar isothiocyanic acid

    NASA Technical Reports Server (NTRS)

    Frerking, M. A.; Linke, R. A.; Thaddeus, P.

    1979-01-01

    Isothiocyanic acid (HNCS) has been identified in Sgr B2 from millimeter-wave spectral line observations. We have definitely detected three rotational lines, and have probably detected two others. The rotational temperature of HNCS in Sgr B2 is 14 plus or minus 5 K, its column density is 2.5 plus or minus 1.0 x 10 to the 13th per sq cm, and its abundance relative to HNCO is consistent with the cosmic S/O ratio, 1/42.

  7. 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids and blood pressure.

    PubMed

    McGiff, J C; Quilley, J

    2001-03-01

    The properties of 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids, vasoactivity and modulation of ion transport and mediation/modulation of the effects of vasoactive hormones, such as angiotensin II and endothelin, underscore their importance to renal vascular mechanisms and electrolyte excretion. 20-Hydroxyeicosatetraenoic acid is an integral component of renal autoregulation and tubuloglomerular feedback as well as cerebral autoregulation, eliciting vasoconstriction by the inhibition of potassium channels. Nitric oxide inhibits 20-hydroxyeicosatetraenoic acid formation, the removal of which contributes to the vasodilator effect of nitric oxide. In contrast, epoxyeicosatrienoic acids are generally vasodilatory by activating potassium channels and have been proposed as endothelium-derived hyperpolarizing factors. 20-Hydroxyeicosatetraenoic acid modulates ion transport in key nephron segments by influencing the activities of sodium--potassium-ATPase and the sodium--potassium--chloride co-transporter; however, the primacy of the various arachidonate oxygenases that generate products affecting these activities changes with age. The range and diversity of activity of 20-hydroxyeicosatetraenoic acid is influenced by its metabolism by cyclooxygenase to products affecting vasomotion and salt/water excretion. 20-Hydroxyeicosatetraenoic acid is the principal renal eicosanoid that interacts with several hormonal systems that are central to blood pressure regulation. This article reviews the most recent studies that address 20-hydroxyeicosatetraenoic acid and epoxyeicosatrienoic acids in vascular and renal tubular function and hypertension.

  8. Vibrational structure of the polyunsaturated fatty acids eicosapentaenoic acid and arachidonic acid studied by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Kiefer, Johannes; Noack, Kristina; Bartelmess, Juergen; Walter, Christian; Dörnenburg, Heike; Leipertz, Alfred

    2010-02-01

    The spectroscopic discrimination of the two structurally similar polyunsaturated C 20 fatty acids (PUFAs) 5,8,11,14,17-eicosapentaenoic acid and 5,8,11,14-eicosatetraenoic acid (arachidonic acid) is shown. For this purpose their vibrational structures are studied by means of attenuated total reflection (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The fingerprint regions of the recorded spectra are found to be almost identical, while the C-H stretching mode regions around 3000 cm -1 show such significant differences as results of electronic and molecular structure alterations based on the different degree of saturation that both fatty acids can be clearly distinguished from each other.

  9. Nucleic acid detection methods

    DOEpatents

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

    1998-05-19

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

  10. Nucleic Acid Detection Methods

    DOEpatents

    Smith, Cassandra L.; Yaar, Ron; Szafranski, Przemyslaw; Cantor, Charles R.

    1998-05-19

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

  11. Cryoprotection from lipoteichoic acid

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  12. Bicyclic glutamic acid derivatives.

    PubMed

    Meyer, Udo; Bisel, Philippe; Weckert, Edgar; Frahm, August Wilhelm

    2006-05-15

    For the second-generation asymmetric synthesis of the trans-tris(homoglutamic) acids via Strecker reaction of chiral ketimines, the cyanide addition as the key stereodifferentiating step produces mixtures of diastereomeric alpha-amino nitrile esters the composition of which is independent of the reaction temperature and the type of the solvent, respectively. The subsequent hydrolysis is exclusively achieved with concentrated H(2)SO(4) yielding diastereomeric mixtures of three secondary alpha-amino alpha-carbamoyl-gamma-esters and two diastereomeric cis-fused angular alpha-carbamoyl gamma-lactams as bicyclic glutamic acid derivatives, gained from in situ stereomer differentiating cyclisation of the secondary cis-alpha-amino alpha-carbamoyl-gamma-esters. Separation was achieved by CC. The pure secondary trans-alpha-amino alpha-carbamoyl-gamma-esters cyclise on heating and treatment with concentrated H(2)SO(4), respectively, to diastereomeric cis-fused angular secondary alpha-amino imides. Their hydrogenolysis led to the enantiomeric cis-fused angular primary alpha-amino imides. The configuration of all compounds was completely established by NMR methods, CD-spectra, and by X-ray analyses of the (alphaR,1R,5R)-1-carbamoyl-2-(1-phenylethyl)-2-azabicyclo[3.3.0]octan-3-one and of the trans-alphaS,1S,2R-2-ethoxycarbonylmethyl-1-(1-phenylethylamino)cyclopentanecarboxamide. PMID:16596563

  13. Ribonucleic acid purification.

    PubMed

    Martins, R; Queiroz, J A; Sousa, F

    2014-08-15

    Research on RNA has led to many important biological discoveries and improvement of therapeutic technologies. From basic to applied research, many procedures employ pure and intact RNA molecules; however their isolation and purification are critical steps because of the easy degradability of RNA, which can impair chemical stability and biological functionality. The current techniques to isolate and purify RNA molecules still have several limitations and the requirement for new methods able to improve RNA quality to meet regulatory demands is growing. In fact, as basic research improves the understanding of biological roles of RNAs, the biopharmaceutical industry starts to focus on them as a biotherapeutic tools. Chromatographic bioseparation is a high selective unit operation and is the major option in the purification of biological compounds, requiring high purity degree. In addition, its application in biopharmaceutical manufacturing is well established. This paper discusses the importance and the progress of RNA isolation and purification, considering RNA applicability both in research and clinical fields. In particular and in view of the high specificity, affinity chromatography has been recently applied to RNA purification processes. Accordingly, recent chromatographic investigations based on biorecognition phenomena occurring between RNA and amino acids are focused. Histidine and arginine have been used as amino acid ligands, and their ability to isolate different RNA species demonstrated a multipurpose applicability in molecular biology analysis and RNA therapeutics preparation, highlighting the potential contribution of these methods to overcome the challenges of RNA purification. PMID:24951289

  14. Titration of phosphonic acid derivatives in mixtures.

    PubMed

    Wittmann, Z

    1980-01-01

    An analytical procedure is described for the determination of the weak acids phosphonomethyliminodiacetic acid and phosphonomethyliminoacetic acid in their mixtures, and the dissociation constants of phosphonomethyliminoacetic acid are reported.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    SciTech Connect

    Dietz, E.A.; Cortellucci, N.J.; Singley, K.F. )

    1993-01-01

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

  17. Acid rain: Rhetoric and reality

    SciTech Connect

    Park, C.C.

    1987-01-01

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

  18. Therapeutic targeting of bile acids

    PubMed Central

    Gores, Gregory J.

    2015-01-01

    The first objectives of this article are to review the structure, chemistry, and physiology of bile acids and the types of bile acid malabsorption observed in clinical practice. The second major theme addresses the classical or known properties of bile acids, such as the role of bile acid sequestration in the treatment of hyperlipidemia; the use of ursodeoxycholic acid in therapeutics, from traditional oriental medicine to being, until recently, the drug of choice in cholestatic liver diseases; and the potential for normalizing diverse bowel dysfunctions in irritable bowel syndrome, either by sequestering intraluminal bile acids for diarrhea or by delivering more bile acids to the colon to relieve constipation. The final objective addresses novel concepts and therapeutic opportunities such as the interaction of bile acids and the microbiome to control colonic infections, as in Clostridium difficile-associated colitis, and bile acid targeting of the farnesoid X receptor and G protein-coupled bile acid receptor 1 with consequent effects on energy expenditure, fat metabolism, and glycemic control. PMID:26138466

  19. Bile Acid Metabolism and Signaling

    PubMed Central

    Chiang, John Y. L.

    2015-01-01

    Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans. PMID:23897684

  20. Bile acid interactions with cholangiocytes.

    PubMed

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

    2006-06-14

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

  1. Citric acid production patent review.

    PubMed

    Anastassiadis, Savas; Morgunov, Igor G; Kamzolova, Svetlana V; Finogenova, Tatiana V

    2008-01-01

    Current Review article summarizes the developments in citric acid production technologies in East and West last 100 years. Citric acid is commercially produced by large scale fermentation mostly using selected fungal or yeast strains in aerobe bioreactors and still remains one of the runners in industrial production of biotechnological bulk metabolites obtained by microbial fermentation since about 100 years, reflecting the historical development of modern biotechnology and fermentation process technology in East and West. Citric acid fermentation was first found as a fungal product in cultures of Penicillium glaucum on sugar medium by Wehmer in 1893. Citric acid is an important multifunctional organic acid with a broad range of versatile uses in household and industrial applications that has been produced industrially since the beginning of 20(th) century. There is a great worldwide demand for citric acid consumption due to its low toxicity, mainly being used as acidulant in pharmaceutical and food industries. Global citric acid production has reached 1.4 million tones, increasing annually at 3.5-4.0% in demand and consumption. Citric acid production by fungal submerged fermentation is still dominating, however new perspectives like solid-state processes or continuous yeast processes can be attractive for producers to stand in today's strong competition in industry. Further perspectives aiming in the improvement of citric acid production are the improvement of citric acid producing strains by classical and modern mutagenesis and selection as well as downstream processes. Many inexpensive by-products and residues of the agro-industry (e.g. molasses, glycerin etc.) can be economically utilized as substrates in the production of citric acid, especially in solid-state fermentation, enormously reducing production costs and minimizing environmental problems. Alternatively, continuous processes utilizing yeasts which reach 200-250 g/l citric acid can stand in today

  2. Bile acid interactions with cholangiocytes

    PubMed Central

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

    2006-01-01

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

  3. Interactions of amino acids, carboxylic acids, and mineral acids with different quinoline derivatives

    NASA Astrophysics Data System (ADS)

    Kalita, Dipjyoti; Deka, Himangshu; Samanta, Shyam Sundar; Guchait, Subrata; Baruah, Jubaraj B.

    2011-03-01

    A series of quinoline containing receptors having amide and ester bonds are synthesized and characterised. The relative binding abilities of these receptors with various amino acids, carboxylic acids and mineral acids are determined by monitoring the changes in fluorescence intensity. Among the receptors bis(2-(quinolin-8-yloxy)ethyl) isophthalate shows fluorescence enhancement on addition of amino acids whereas the other receptors shows fluorescence quenching on addition of amino acids. The receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy) propanamide has higher binding affinity for amino acids. However, the receptor N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide having similar structure do not bind to amino acids. This is attributed to the concave structure of the former which is favoured due to the presence of methyl substituent. The receptor bis(2-(quinolin-8-yloxy)ethyl) isophthalate do not bind to hydroxy carboxylic acids, but is a good receptor for dicarboxylic acids. The crystal structure of bromide and perchlorate salts of receptor 2-bromo-N-(quinolin-8-yl)-propanamide are determined. In both the cases the amide groups are not in the plane of quinoline ring. The structure of N-(quinolin-8-yl)-2-(quinolin-8-yloxy)acetamide, N-(2-methoxyphenethyl)-2-(quinolin-8-yloxy)acetamide and their salts with maleic acid as well as fumaric acid are determined. It is observed that the solid state structures are governed by the double bond geometry of these two acid. Maleic acid forms salt in both the cases, whereas fumaric acid forms either salt or co-crystals.

  4. Extraction and Analysis of C60, C70 and PCBM in Aqueous Suspensions

    EPA Science Inventory

    The goal of this work is to develop sampling and analytical methodologies for extracting and quantifying fullerenes in aqueous colloidal suspensions. Sampling and analysis of colloidal suspensions pose some unique challenges not encountered when working with true solutions. For...

  5. Effect of modular diffraction gratings on absorption in P3HT:PCBM layers.

    PubMed

    Cocilovo, Byron; Amooali, Akram; Lopez-Santiago, Alejandra; Favela, Jacob; Islam, Safatul; Duong, Binh; Gangopadhyay, Palash; Fallahi, Mahmoud; Pemberton, Jeanne E; Thomas, Jayan; Norwood, Robert A

    2013-02-10

    Various gratings with 700 nm feature spacings are patterned on the reverse side of organic solar cell active layers to increase the path length and constrain light to the cell through total internal reflection. The absorption enhancement is studied for 15, 40, and 120 nm active layers. We were able to confine 9% of the incident light over the wavelength range of 400-650 nm, with thinner gratings having a greater enhancement potential. The measurement setup utilizing an integrating sphere to fully characterize scattered or diffracted light is also fully described.

  6. Acidity of Strong Acids in Water and Dimethyl Sulfoxide.

    PubMed

    Trummal, Aleksander; Lipping, Lauri; Kaljurand, Ivari; Koppel, Ilmar A; Leito, Ivo

    2016-05-26

    Careful analysis and comparison of the available acidity data of HCl, HBr, HI, HClO4, and CF3SO3H in water, dimethyl sulfoxide (DMSO), and gas-phase has been carried out. The data include experimental and computational pKa and gas-phase acidity data from the literature, as well as high-level computations using different approaches (including the W1 theory) carried out in this work. As a result of the analysis, for every acid in every medium, a recommended acidity value is presented. In some cases, the currently accepted pKa values were revised by more than 10 orders of magnitude. PMID:27115918

  7. Esterification by the Plasma Acidic Water: Novel Application of Plasma Acid

    NASA Astrophysics Data System (ADS)

    Gu, Ling

    2014-03-01

    This work explores the possibility of plasma acid as acid catalyst in organic reactions. Plasma acidic water was prepared by dielectric barrier discharge and used to catalyze esterification of n-heptanioc acid with ethanol. It is found that the plasma acidic water has a stable and better performance than sulfuric acid, meaning that it is an excellent acid catalyst. The plasma acidic water would be a promising alternative for classic mineral acid as a more environment friendly acid.

  8. 49 CFR 173.158 - Nitric acid.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Nitric acid. 173.158 Section 173.158... Nitric acid. (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material. (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid...

  9. Acid rain degradation of nylon

    SciTech Connect

    Kyllo, K.E.

    1984-01-01

    Acid rain, precipitation with a pH less than 5.6, is known to damage lakes, vegetation and buildings. Degradation of outdoor textiles by acid rain is strongly suspected but not well documented. This study reports the effects of sunlight, aqueous acid, heat and humidity (acid rain conditions) on spun delustered nylon 6,6 fabric. Untreated nylon and nylon treated with sulfuric acid of pH 2.0, 3.0, and 4.4 were exposed to light in an Atlas Xenon-arc fadeometer at 63/sup 0/C and 65% R.H. for up to 640 AATCC Fading Units. The untreated and acid treated nylon fabrics were also exposed to similar temperature and humidity condition without light. Nylon degradation was determined by changes in breaking strength, elongation, molecular weight, color, amino end group concentration (NH/sub 2/) and /sup 13/C NMR spectra. Physical damage was assessed using SEM.

  10. A Simpler Nucleic Acid

    NASA Technical Reports Server (NTRS)

    Orgel, Leslie

    2000-01-01

    It has been supposed that for a nucleic acid analog to pair with RNA it must, like RNA, have a backbone with at least a sixatom repeat; a shorter backbone presumably would not stretch far enough to bind RNA properly. The Eschenmoser group has shown, however, that this first impression is incorrect.As they report in their new paper, Eschenmoser and co-workers ( I ) have now synthesized a substantial number of these polymers, which are called (L)-a-threofuranosyl oligonucleotides or TNAs. They are composed of bases linked to a threose sugar-phosphate backbone, with phosphodiester bonds connecting the nucleotides. The investigators discovered that pairs of complementary TNAs do indeed form stable Watson-Crick double helices and, perhaps more importantly, that TNAs form stable double helices with complementary RNAs and DNAs.

  11. [Hydrofluoric acid poisoning: case report].

    PubMed

    Cortina, Tatiana Judith; Ferrero, Hilario Andrés

    2013-01-01

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

  12. Preparation and characterization Al3+-bentonite Turen Malang for esterification fatty acid (palmitic acid, oleic acid and linoleic acid)

    NASA Astrophysics Data System (ADS)

    Abdulloh, Abdulloh; Aminah, Nanik Siti; Triyono, Mudasir, Trisunaryanti, Wega

    2016-03-01

    Catalyst preparation and characterization of Al3+-bentonite for esterification of palmitic acid, oleic acid and linoleic acid has been done. Al3+-bentonite catalyst was prepared from natural bentonite of Turen Malang through cation exchange reaction using AlCl3 solution. The catalysts obtained were characterized by XRD, XRF, pyridine-FTIR and surface area analyser using the BET method. Catalyst activity test of Al3+-bentonite for esterification reaction was done at 65°C using molar ratio of metanol-fatty acid of 30:1 and 0.25 g of Al3+-bentonite catalyst for the period of ½, 1, 2, 3, 4 and 5 hours. Based on the characterization results, the Al3+-bentonite Turen Malang catalyst has a d-spacing of 15.63 Ǻ, acid sites of Brönsted and Lewis respectively of 230.79 µmol/g and 99.39 µmol/g, surface area of 507.3 m2/g and the average of radius pore of 20.09 Å. GC-MS analysis results of the oil phase after esterification reaction showed the formation of biodiesel (FAME: Fatty acid methyl ester), namely methyl palmitate, methyl oleate and methyl linoleate. The number of conversions resulted in esterification reaction using Al3+-bentonite Turen Malang catalyst was 74.61%, 37.75%, and 20, 93% for the esterification of palmitic acid, oleic acid and linoleic acid respectively.

  13. Acidic gas capture by diamines

    SciTech Connect

    Rochelle, Gary; Hilliard, Marcus

    2011-05-10

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

  14. Molecular structural studies of lichen substances II: atranorin, gyrophoric acid, fumarprotocetraric acid, rhizocarpic acid, calycin, pulvinic dilactone and usnic acid

    NASA Astrophysics Data System (ADS)

    Edwards, Howell G. M.; Newton, Emma M.; Wynn-Williams, David D.

    2003-06-01

    The FT-Raman and infrared vibrational spectra of some important lichen compounds from two metabolic pathways are characterised. Key biomolecular marker bands have been suggested for the spectroscopic identification of atranorin, gyrophoric acid, fumarprotocetraric acid rhizocarpic acid, calycin, pulvinic dilactone and usnic acid. A spectroscopic protocol has been defined for the detection of these molecules in organisms subjected to environmental stresses such as UV-radiation exposure, desiccation and low temperatures. Use of the protocol will be made for the assessment of survival strategies used by stress-tolerant lichens in Antarctic cold deserts.

  15. Cryoprotection from bacterial teichoic acid

    NASA Astrophysics Data System (ADS)

    Rice, Charles V.; Harrison, William; Kirkpatrick, Karl; Brown, Eric D.

    2009-08-01

    Recent studies from our lab demonstrated that teichoic acid is surrounded by liquid water at -40 °C. The size and shape of the liquid water pockets has been visualized with fluorescence microscopy images of aqueous Rhodamine- B solutions. The long, thin channels surround ice crystals with a size of 5-20 microns. Subsequent studies show that B. subtilis Gram-positive bacteria are sequestered into large pockets without added teichoic acid. Here, the ice crystals are orders of manitude larger. When bacteria are mixed with teichoic acid solutions, the distribution of bacteria changes dramatically. The smaller ice crystals allow the bacteria to align in the thin channels of liquid water seen with teichoic acid only. The role of teichoic acid in the freeze tolerance was examined with live/dead fluorescence assays of bacteria mixed with teichoic acid. These quantitative assays were used to determine if teichoic acid acts in a synergetic fashion to enhance the survivability of E. coli, a gram-negative species which lacks teichoic acid. Additionally, we have obtained B. subtilis mutants lacking wall-associated teichoic acids to evaluate cryoprotection compared to the wild-type strain.

  16. Sulfuric acid as autocatalyst in the formation of sulfuric acid.

    PubMed

    Torrent-Sucarrat, Miquel; Francisco, Joseph S; Anglada, Josep M

    2012-12-26

    Sulfuric acid can act as a catalyst of its own formation. We have carried out a computational investigation on the gas-phase formation of H(2)SO(4) by hydrolysis of SO(3) involving one and two water molecules, and also in the presence of sulfuric acid and its complexes with one and two water molecules. The hydrolysis of SO(3) requires the concurrence of two water molecules, one of them acting as a catalyzer, and our results predict an important catalytic effect, ranging between 3 and 11 kcal·mol(-1) when the catalytic water molecule is substituted by a sulfuric acid molecule or one of its hydrates. In these cases, the reaction products are either bare sulfuric acid dimer or sulfuric acid dimer complexed with a water molecule. There are broad implications from these new findings. The results of the present investigation show that the catalytic effect of sulfuric acid in the SO(3) hydrolysis can be important in the Earth's stratosphere, in the heterogeneous formation of sulfuric acid and in the formation of aerosols, in H(2)SO(4) formation by aircraft engines, and also in understanding the formation of sulfuric acid in the atmosphere of Venus.

  17. Hydrazides of carboxylic acids as inhibitors of steel acidic corrosion

    SciTech Connect

    Aitov, R.G.; Shein, A.B.; Lesnov, A.E.

    1994-09-01

    Hydrazides of carboxylic acids (HCA) inhibit the corrosion of ferrous materials in acids and netral solutions such as stratum and waste waters of oil deposits. In this work, the authors try to explain the above-mentioned difference and to consider HCA as inhibitors of steel hydrogenation.

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

    PubMed Central

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

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism. PMID:26742061

  19. A comparison of chromic acid and sulfuric acid anodizing

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1992-01-01

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

  20. Acid rain on Acid soil: a new perspective.

    PubMed

    Krug, E C; Frink, C R

    1983-08-01

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

  1. Carbonic Acid Retreatment of Biomass

    SciTech Connect

    Baylor university

    2003-06-01

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

  2. Carbonic Acid Pretreatment of Biomass

    SciTech Connect

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

    2003-05-31

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

  3. Anacardic Acid, Salicylic Acid, and Oleic Acid Differentially Alter Cellular Bioenergetic Function in Breast Cancer Cells.

    PubMed

    Radde, Brandie N; Alizadeh-Rad, Negin; Price, Stephanie M; Schultz, David J; Klinge, Carolyn M

    2016-11-01

    Anacardic acid is a dietary and medicinal phytochemical that inhibits breast cancer cell proliferation and uncouples oxidative phosphorylation (OXPHOS) in isolated rat liver mitochondria. Since mitochondrial-targeted anticancer therapy (mitocans) may be useful in breast cancer, we examined the effect of anacardic acid on cellular bioenergetics and OXPHOS pathway proteins in breast cancer cells modeling progression to endocrine-independence: MCF-7 estrogen receptor α (ERα)+ endocrine-sensitive; LCC9 and LY2 ERα+, endocrine-resistant, and MDA-MB-231 triple negative breast cancer (TNBC) cells. At concentrations similar to cell proliferation IC50 s, anacardic acid reduced ATP-linked oxygen consumption rate (OCR), mitochondrial reserve capacity, and coupling efficiency while increasing proton leak, reflecting mitochondrial toxicity which was greater in MCF-7 compared to endocrine-resistant and TNBC cells. These results suggest tolerance in endocrine-resistant and TNBC cells to mitochondrial stress induced by anacardic acid. Since anacardic acid is an alkylated 2-hydroxybenzoic acid, the effects of salicylic acid (SA, 2-hydroxybenzoic acid moiety) and oleic acid (OA, monounsaturated alkyl moiety) were tested. SA inhibited whereas OA stimulated cell viability. In contrast to stimulation of basal OCR by anacardic acid (uncoupling effect), neither SA nor OA altered basal OCR- except OA inhibited basal and ATP-linked OCR, and increased ECAR, in MDA-MB-231 cells. Changes in OXPHOS proteins correlated with changes in OCR. Overall, neither the 2-hydroxybenzoic acid moiety nor the monounsaturated alky moiety of anacardic acid is solely responsible for the observed mitochondria-targeted anticancer activity in breast cancer cells and hence both moieties are required in the same molecule for the observed effects. J. Cell. Biochem. 117: 2521-2532, 2016. © 2016 Wiley Periodicals, Inc. PMID:26990649

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

    PubMed Central

    Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

    1988-01-01

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

  5. Acid rain: a background report

    SciTech Connect

    Glustrom, L.; Stolzenberg, J.

    1982-07-08

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

  6. Acid Rain: An Educational Opportunity?

    ERIC Educational Resources Information Center

    Marion, James I.

    1984-01-01

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

  7. Acid rain & electric utilities II

    SciTech Connect

    1997-12-31

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

  8. Acid Rain: The Scientific Challenge.

    ERIC Educational Resources Information Center

    Godfrey, Paul J.

    1991-01-01

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

  9. Acid Precipitation: Causes and Consequences.

    ERIC Educational Resources Information Center

    Babich, Harvey; And Others

    1980-01-01

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

  10. Acid Rain: What's the Forecast?

    ERIC Educational Resources Information Center

    Bybee, Rodger

    1984-01-01

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

  11. Synthesis of pyromellitic acid esters

    NASA Technical Reports Server (NTRS)

    Fedorova, V. A.; Donchak, V. A.; Martynyuk-Lototskaya, A. N.

    1985-01-01

    The ester acids necessary for studyng the thermochemical properties of pyromellitic acid (PMK)-based peroxides were investigated. Obtaining a tetramethyl ester of a PMK was described. The mechanism of an esterification reaction is discussed, as is the complete esterification of PMK with primary alcohol.

  12. Getting Back to Basics (& Acidics)

    ERIC Educational Resources Information Center

    Rhodes, Sam

    2006-01-01

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

  13. Acid Tests and Basic Fun.

    ERIC Educational Resources Information Center

    McBride, John W.

    1995-01-01

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

  14. Acid rain and environmental policy

    SciTech Connect

    Jacobson, J.S.

    1981-10-01

    Various seemingly paradoxical scientific questions are posed which relate to the problem of acid rain and its effect on the environment and environmental policy. The first paradox discussed concerns the supposed increase in fossil fuel usage over the last several decades, with the resultant increases in emissions of pollutants from the combustion of fuels which cause acid rain. Despite these increases, experts do not agree on whether acidity of rain has increased in eastern North America. The second paradox concerns the effect of acid rain on vegetation. If the rain is supposedly harmful, why have some reports shown increases and others, decreases in the growth of crops and trees with the application of simulated acid rain. The third paradox concerns the effect of acid rains on fish life in lakes. If acid rain falls throughout eastern North America, why have some lakes become acid and lost fish populations while others have not. Since unequivocal answers to these scientific questions are not available, a systematic approach is needed for developing policy which can be useful for solving the problem. It appears that traditional cost-benefit analysis can not be the sole basis for decision-making, but that it will be helpful. Research needs must be identified, and the upper and lower limits for alternative strategies must be determined. 14 references, 1 table.

  15. Impacts of acid rain legislation

    SciTech Connect

    Addison, E.L.

    1983-01-01

    The author warns against hasty acid rain legislation that would involve billions of dollars and affect thousands of jobs. He recommends further study into the causes of high acidity in lakes and streams. He states that there are too many uncertainties of whether the problem would be solved by reducing sulfur dioxide emissions from coal-fired power plants. (DMC)

  16. Acid rain: effects on fish and wildlife

    SciTech Connect

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

    1984-01-01

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

  17. Lead-acid battery

    SciTech Connect

    Rowlette, J.J.

    1983-09-20

    A light weight lead-acid battery is disclosed having a positive terminal and a negative terminal and including one or more cells or grid stacks having a plurality of vertically stacked conductive monoplates with positive active material and negative active material deposited on alternating plates in the cell or grid stack. Electrolyte layers positioned between each monoplate are included to provide a battery cell having four sides which is capable of being electrically charged and discharged. Two vertical positive bus bars are provided on opposite sides of the battery cell for connecting the monoplates with positive active material together in parallel current conducting relation. In addition, two negative bus bars on opposite sides of the battery cell each being adjacent the positive bus bars are provided for connecting the monoplates with negative active material together in parallel current conducting relation. The positive and negative bus bars not only provide a low resistance method for connecting the plurality of conductive monoplates of their respective battery terminals but also provides support and structural strength to the battery cell structure. In addition, horizontal orientation of monoplates is provided in a vertical stacking arrangement to reduce electrolyte stratification and short circuiting due to flaking of positive and negative active materials from the monoplates.

  18. Lead-acid battery

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1983-01-01

    A light weight lead-acid battery (30) having a positive terminal (36) and a negative terminal (34) and including one or more cells or grid stacks having a plurality of vertically stacked conductive monoplates (10, 20) with positive active material and negative active material deposited on alternating plates in the cell or grid stack. Electrolyte layers (26, 28) positioned between each monoplate are included to provide a battery cell having four sides which is capable of being electrically charged and discharged. Two vertical positive bus bars (42, 43) are provided on opposite sides of the battery cell for connecting the monoplates (10) with positive active material together in parallel current conducting relation. In addition, two negative bus bars (38, 39) on opposite sides of the battery cell each being adjacent the positive bus bars are provided for connecting the monoplates (20) with negative active material together in parallel current conducting relation. The positive (42, 43) and negative (38, 39) bus bars not only provide a low resistance method for connecting the plurality of conductive monoplates of their respective battery terminals (36, 34) but also provides support and structural strength to the battery cell structure. In addition, horizontal orientation of monoplates (10, 20) is provided in a vertical stacking arrangement to reduce electrolyte stratification and short circuiting due to flaking of positive and negative active materials from the monoplates.

  19. Synthesis of higher monocarboxylic acids

    SciTech Connect

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

    1981-01-01

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

  20. Atmospheric dust and acid rain

    SciTech Connect

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

    1996-12-01

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

  1. Amino acid management in cancer

    PubMed Central

    Tsun, Zhi-Yang; Possemato, Richard

    2016-01-01

    Amino acids have a dual role in cellular metabolism, as they are both the building blocks for protein synthesis and intermediate metabolites which fuel other biosynthetic reactions. Recent work has demonstrated that deregulation of both arms of amino acid management are common alterations seen in cancer. Among the most highly consumed nutrients by cancer cells are the amino acids glutamine and serine, and the biosynthetic pathways that metabolize them are required in various cancer subtypes and the object of current efforts to target cancer metabolism. Also altered in cancer are components of the machinery which sense amino acid sufficiency, nucleated by the mechanistic target of rapamycin (mTOR), a key regulator of cell growth via modulation of key processes including protein synthesis and autophagy. The precise ways in which altered amino acid management supports cellular transformation remain mostly elusive, and a fuller mechanistic understanding of these processes will be important for efforts to exploit such alterations for cancer therapy. PMID:26277542

  2. Fumaric acid production by fermentation

    PubMed Central

    Roa Engel, Carol A.; Zijlmans, Tiemen W.; van Gulik, Walter M.; van der Wielen, Luuk A. M.

    2008-01-01

    The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

  3. Formation of acrylic acid from lactic acid in supercritical water

    SciTech Connect

    Mok, W.S.L.; Antal, M.J. Jr. ); Jones, M. Jr. )

    1989-09-15

    Supercritical (SC) water is an unusual medium in which fast and specific heterolytic reactions can be conducted at temperatures as high as 400{degree}C. In supercritical water, lactic acid decomposes into gaseous and liquid products via three primary reaction pathways. Products of the acid-catalyzed heterolytic decarbonylation pathway are carbon monoxide, water, and acetaldehyde. Products of the homolytic, decarboxylation pathway are carbon dioxide, hydrogen, and acetaldehyde. Products of the heterolytic, dehydration pathway are acrylic acid and water. The intramolecular nucleophilic displacement of the {alpha}-hydroxyl by the carbonyl group of lactic acid, producing {alpha}-propiolactone as an unstable intermediate which subsequently rearranges to become the unsaturated acid, is a likely mechanism for acrylic acid formation, although an intramolecular E2 elimination initiated by attack of the carbonyl oxygen on a methyl hydrogen cannot be ruled out. Support for the former mechanism comes in part from the observed 100% relative yield of acrylic acid from {beta}-propiolactone in SC water.

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

    PubMed Central

    Saito, Kazumi; Kasai, Zenzaburo

    1984-01-01

    5-Keto-l-idionic acid (≡5-keto-d-gluconic acid, d-xylo-5-hexulosonic acid) was found as a metabolic product of l-ascorbic acid in slices of immature grapes, Vitis labrusca L. cv `Delaware'. Specifically labeled compounds, recognized as metabolic products of l-ascorbic acid in grapes, were fed to young grape tissues to investigate the metabolic pathway from l-ascorbic acid to l-(+)-tartaric acid. Label from dehydro-l-[1-14C]ascorbic acid, 2-keto-l-[1-14C]idonic acid (l-xylo-2-hexulosonic acid), l-[1-14C]idonic acid, or 5-keto-l-[1-14C] idonic acid was incorporated into l-(+)-tartaric acid in high yields as it was in the l-[1-14C]ascorbic acid experiment. In a double label experiment involving a mixture of l-[1-14C]idonic acid and l-[2-3H]idonic acid, the 3H/14C ratios of 5-keto-l-idonic acid and l-(+)-tartaric acid synthesized in young grape leaves were almost the same as the value of the l-idonic acid fed. Label from 5-keto-l-[6-14C]idonic acid was incorporated into sugars and insoluble residue in the same way as l-[6-14C]ascorbic acid was metabolized in grapes. These results provide strong evidence that in grapes l-(+)-tartaric acid is synthesized from the C4 fragment that corresponds to the C1 to C4 group of the 5-keto-l-idonic acid derived from l-ascorbic acid via 2-keto-l-idonic acid and l-idonic acid. PMID:16663792

  5. Molten fatty acid based microemulsions.

    PubMed

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

    2016-06-21

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

  6. Pentadecanoic and Heptadecanoic Acids: Multifaceted Odd-Chain Fatty Acids.

    PubMed

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

    The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid. PMID:27422507

  7. Pentadecanoic and Heptadecanoic Acids: Multifaceted Odd-Chain Fatty Acids.

    PubMed

    Pfeuffer, Maria; Jaudszus, Anke

    2016-07-01

    The odd-chain fatty acids (OCFAs) pentadecanoic acid (15:0) and heptadecanoic acid (17:0), which account for only a small proportion of total saturated fatty acids in milk fat and ruminant meat, are accepted biomarkers of dairy fat intake. However, they can also be synthesized endogenously, for example, from gut-derived propionic acid (3:0). A number of studies have shown an inverse association between OCFA concentrations in human plasma phospholipids or RBCs and risk of type 2 diabetes and cardiovascular disease. We propose a possible involvement in metabolic regulation from the assumption that there is a link between 15:0 and 17:0 and the metabolism of other short-chain, medium-chain, and longer-chain OCFAs. The OCFAs 15:0 and 17:0 can be elongated to very-long-chain FAs (VLCFAs) such as tricosanoic acid (23:0) and pentacosanoic acid (25:0) in glycosphingolipids, particularly found in brain tissue, or can be derived from these VLCFAs. Their chains can be shortened, yielding propionyl-coenzyme A (CoA). Propionyl-CoA, by succinyl-CoA, can replenish the citric acid cycle (CAC) with anaplerotic intermediates and, thus, improve mitochondrial energy metabolism. Mitochondrial function is compromised in a number of disorders and may be impaired with increasing age. Optimizing anaplerotic intermediate availability for the CAC may help to cope with demands in times of increased metabolic stress and with aging. OCFAs may serve as substrates for synthesis of both odd-numbered VLCFAs and propionyl-CoA or store away excess propionic acid.

  8. Acid soil and acid rain, 2nd edition

    SciTech Connect

    Kennedy, I.R.

    1992-01-01

    This book examines the basic chemical processes involved in acidification in order to better assess their long-term effects on the status of soils, the health of plants and other living species that depend on them. It also discusses acidity, pH and protons their significance in bioenergetics and the consequent role of autotrophic organisms in acidifying ecosystems. This edition incorporates and integrates recent findings that render more explanations of the causes of the environmental impacts of acidity, especially in forests and lakes. Also explores current research into acid rain and soil in order to devise appropriate measures for their amelioration.

  9. Functional nucleic acid probes and uses thereof

    DOEpatents

    Nilsen-Hamilton, Marit

    2006-10-03

    The present invention provides functional nucleic acid probes, and methods of using functional nucleic acid probes, for binding a target to carry out a desired function. The probes have at least one functional nucleic acid, at least one regulating nucleic acid, and at least one attenuator. The functional nucleic acid is maintained in an inactive state by the attenuator and activated by the regulating nucleic acid only in the presence of a regulating nucleic acid target. In its activated state the functional nucleic acid can bind to its target to carry out a desired function, such as generating a signal, cleaving a nucleic acid, or catalyzing a reaction.

  10. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and... Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid...

  11. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and... Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid...

  12. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and... Substances Affirmed as GRAS § 184.1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid...

  13. 21 CFR 184.1021 - Benzoic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Benzoic acid. 184.1021 Section 184.1021 Food and....1021 Benzoic acid. (a) Benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid occurs naturally are...

  14. 21 CFR 189.155 - Monochloroacetic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Monochloroacetic acid. 189.155 Section 189.155... Human Food § 189.155 Monochloroacetic acid. (a) Monochloroacetic acid is the chemical chloroacetic acid... in alcoholic and nonalcoholic beverages. Monochloroacetic acid is permitted in food package...

  15. Diabetes and Alpha Lipoic Acid

    PubMed Central

    Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy. PMID:22125537

  16. Cycloadditions for Studying Nucleic Acids.

    PubMed

    Kath-Schorr, Stephanie

    2016-02-01

    Cycloaddition reactions for site-specific or global modification of nucleic acids have enabled the preparation of a plethora of previously inaccessible DNA and RNA constructs for structural and functional studies on naturally occurring nucleic acids, the assembly of nucleic acid nanostructures, therapeutic applications, and recently, the development of novel aptamers. In this chapter, recent progress in nucleic acid functionalization via a range of different cycloaddition (click) chemistries is presented. At first, cycloaddition/click chemistries already used for modifying nucleic acids are summarized, ranging from the well-established copper(I)-catalyzed alkyne-azide cycloaddition reaction to copper free methods, such as the strain-promoted azide-alkyne cycloaddition, tetrazole-based photoclick chemistry and the inverse electron demand Diels-Alder cycloaddition reaction between strained alkenes and tetrazine derivatives. The subsequent sections contain selected applications of nucleic acid functionalization via click chemistry; in particular, site-specific enzymatic labeling in vitro, either via DNA and RNA recognizing enzymes or by introducing unnatural base pairs modified for click reactions. Further sections report recent progress in metabolic labeling and fluorescent detection of DNA and RNA synthesis in vivo, click nucleic acid ligation, click chemistry in nanostructure assembly and click-SELEX as a novel method for the selection of aptamers. PMID:27572987

  17. Phytic acid in green leaves.

    PubMed

    Hadi Alkarawi, H; Zotz, G

    2014-07-01

    Phytic acid or phytate, the free-acid form of myo-inositolhexakiphosphate, is abundant in many seeds and fruits, where it represents the major storage form of phosphorus. Although also known from other plant tissues, available reports on the occurrence of phytic acid, e.g. in leaves, have never been compiled, nor have they been critically reviewed. We found 45 published studies with information on phytic acid content in leaves. Phytic acid was almost always detected when studies specifically tried to detect it, and accounted for up to 98% of total P. However, we argue that such extreme values, which rival findings from storage organs, are dubious and probably result from measurement errors. Excluding these high values from further quantitative analysis, foliar phytic acid-P averaged 2.3 mg·g(-1) , and represented, on average, 7.6% of total P. Remarkably, the ratio of phytic acid-P to total P did not increase with total P, we even detected a negative correlation of the two variables within one species, Manihot esculenta. This enigmatic finding warrants further attention.

  18. Cycloadditions for Studying Nucleic Acids.

    PubMed

    Kath-Schorr, Stephanie

    2016-02-01

    Cycloaddition reactions for site-specific or global modification of nucleic acids have enabled the preparation of a plethora of previously inaccessible DNA and RNA constructs for structural and functional studies on naturally occurring nucleic acids, the assembly of nucleic acid nanostructures, therapeutic applications, and recently, the development of novel aptamers. In this chapter, recent progress in nucleic acid functionalization via a range of different cycloaddition (click) chemistries is presented. At first, cycloaddition/click chemistries already used for modifying nucleic acids are summarized, ranging from the well-established copper(I)-catalyzed alkyne-azide cycloaddition reaction to copper free methods, such as the strain-promoted azide-alkyne cycloaddition, tetrazole-based photoclick chemistry and the inverse electron demand Diels-Alder cycloaddition reaction between strained alkenes and tetrazine derivatives. The subsequent sections contain selected applications of nucleic acid functionalization via click chemistry; in particular, site-specific enzymatic labeling in vitro, either via DNA and RNA recognizing enzymes or by introducing unnatural base pairs modified for click reactions. Further sections report recent progress in metabolic labeling and fluorescent detection of DNA and RNA synthesis in vivo, click nucleic acid ligation, click chemistry in nanostructure assembly and click-SELEX as a novel method for the selection of aptamers.

  19. Terahertz spectrum of gallic acid

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

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

  20. Polyazomethine as a component of solar cells-theoretical and optical study

    NASA Astrophysics Data System (ADS)

    Korona, K. P.; Korona, T.; Rutkowska-Zbik, D.; Grankowska-Ciechanowicz, S.; Iwan, A.; Kamińska, M.

    2015-11-01

    A recently synthesized 25Th-cardo polyazomethine (PAZ) and its photocurrent generating junction with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) have been examined as possible materials for construction of new-generation solar cells. Properties of a 25Th-cardo/PCBM system, where PAZ and PCBM act as donor and acceptor materials, respectively, have been studied theoretically by time-dependent density-functional theory (TD-DFT) and experimentally by means of optical absorption, photocurrent spectroscopy (PCS), and time-resolved luminescence (TRPL). Theoretical calculations show that highest occupied molecular orbital (HOMO) energy levels of PAZ and PCBM are almost equal (values of -6.01 and -5.98 eV were obtained with the B3LYP functional and the def2-TZVP orbital basis for PAZ and PCBM, respectively), what suggests a possibility of charge transfer in both directions for this system. The shape of the calculated absorption spectrum is in a qualitative agreement with the experiment. The PCS measurements of the new material show that the external quantum efficiency is the highest (about 0.3%) in the near UV range. The TRPL studies reveal a fast decay of a Langevin type (in picosecond range) of the PAZ-related photoluminescence, which accelerates in presence of PCBM, probably due to the charge transfer to PCBM. In addition, our measurements document a usually neglected process of the hole transfer from a donor to an acceptor. A leakage of holes from PAZ to PCBM is supported by a small energy difference of the HOMO energies, as predicted by theory.

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

    PubMed

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

    2012-11-01

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

  2. Tropospheric cycle of nitrous acid

    NASA Astrophysics Data System (ADS)

    Harrison, Roy M.; Peak, John D.; Collins, Gareth M.

    1996-06-01

    Measurements of the land surface exchange of nitrous acid over grass and sugar beet surfaces reveal both upward and downward fluxes with flux reversal occurring at an ambient concentration of nitrogen dioxide of about 10 ppb. This confirms earlier preliminary findings and strengthens the hypothesis that substantial production of nitrous acid can occur on land surfaces from reaction of nitrogen dioxide and water vapor. Detailed measurements of nitrous acid have been made in central urban, suburban, and rural environments. These measurements, in conjunction with a simple box model, indicate that the atmospheric concentrations of nitrous acid are explicable in terms of a small number of basic processes in which the most important are the surface production of nitrous acid from nitrogen dioxide, atmospheric production from the NO-OH reaction and loss of nitrous acid by photolysis and dry deposition. In the suburban atmosphere, concentrations of nitrous acid are strongly correlated with nitrogen dioxide. In the rural atmosphere a different behavior is seen, with much higher nitrous acid to nitrogen dioxide ratios occurring in more polluted air with nitrogen dioxide concentrations in excess of 10 ppb. At lower nitrogen dioxide concentrations, net deposition of nitrous acid at the ground leads to very low concentrations in advected air. The model study indicates that during daytime in the suburban atmosphere, production of HONO from the NO-OH reaction can compete with photolysis giving a HONO concentration of a few tenths of a part per billion. At the highest observed daytime concentrations of HONO, production of OH radical from its photolysis can proceed at a rate more than 10 times faster than from photolysis of ozone.

  3. Engineering Molecular Order for Enhanced Stability of Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Guilbert, Anne; Nelson, Jenny; Cabral, Joao

    2014-03-01

    The microstructure of organic photovoltaics (OPV) is often unstable and very sensitive to processing parameters. It is known that fullerene crystallisation has a huge impact on device behaviour. However, the observation of different size and shape of fullerene crystals in different polymer matrices is not yet understood. We select as a model system amorphous regiorandom poly(3-hexylthiophene-2,5-diyl) (RRa-P3HT) and crystalline phenyl-C61-butyric acid methyl ester (PCBM). We study the nucleation and growth of PCBM crystals into RRa-P3HT matrix as a function of fullerene loading, solution concentration, film thickness, supercooling and surface energy (tuned by UV ozonolysis) using optical and atomic force microscopy, and DSC. We show that the shape of PCBM crystallites can be tuned from needles to spheroidal crystals by increasing undercooling. We argue that the different behaviour of polymer:PCBM blends can be rationalised in term of undercooling, viscosity and fragility of the composite. We finally evaluate the role of additives on the crystallisation of PCBM. By mapping the impact of the processing parameters in this model system, we establish a simple strategy towards controlling PCBM crystallisation at relevant lengthscales for OPV performance.

  4. Gamma linolenic acid: an antiinflammatory omega-6 fatty acid.

    PubMed

    Kapoor, Rakesh; Huang, Yung-Sheng

    2006-12-01

    Inflammation plays an important role in health and disease. Most of the chronic diseases of modern society, including cancer, diabetes, heart disease, arthritis, Alzheimer's disease, etc. have inflammatory component. At the same time, the link between diet and disease is also being recognized. Amongst dietary constituents, fat has gained most recognition in affecting health. Saturated and trans fatty acids have been implicated in obesity, heart disease, diabetes and cancer while polyunsaturated fatty acids (PUFAs) generally have a positive effect on health. The PUFAs of omega-3 and omega-6 series play a significant role in health and disease by generating potent modulatory molecules for inflammatory responses, including eicosanoids (prostaglandins, and leukotrienes), and cytokines (interleukins) and affecting the gene expression of various bioactive molecules. Gamma linolenic acid (GLA, all cis 6, 9, 12-Octadecatrienoic acid, C18:3, n-6), is produced in the body from linoleic acid (all cis 6,9-octadecadienoic acid), an essential fatty acid of omega-6 series by the enzyme delta-6-desaturase. Preformed GLA is present in trace amounts in green leafy vegetables and in nuts. The most significant source of GLA for infants is breast milk. GLA is further metabolized to dihomogamma linlenic acid (DGLA) which undergoes oxidative metabolism by cyclooxygenases and lipoxygenases to produce anti-inflammatory eicosanoids (prostaglandins of series 1 and leukotrienes of series 3). GLA and its metabolites also affect expression of various genes where by regulating the levels of gene products including matrix proteins. These gene products play a significant role in immune functions and also in cell death (apoptosis). The present review will emphasize the role of GLA in modulating inflammatory response, and hence its potential applications as an anti-inflammatory nutrient or adjuvant.

  5. Solid acids for green chemistry.

    PubMed

    Clark, James H

    2002-09-01

    Solid acids and especially those based on micelle-templated silicas and other mesoporous high surface area support materials are beginning to play a significant role in the greening of fine and specialty chemicals manufacturing processes. A wide range of important organic reactions can be efficiently catalyzed by these materials, which can be designed to provide different types of acidity as well as high degrees of reaction selectivity. The solid acids generally have high turnover numbers and can be easily separated from the organic components. The combination of this chemistry with innovative reaction engineering offers exciting opportunities for innovative green chemical manufacturing in the future. PMID:12234209

  6. Arsanilic acid toxicity in rabbits.

    PubMed

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

    1980-04-01

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

  7. Chemiluminescent measurement of atmospheric acid

    NASA Technical Reports Server (NTRS)

    Stedman, D. H.; Kok, G. L.

    1974-01-01

    The design and construction of a gas phase acid sensitive analyzer are reported. These studies showed that the chemical system was a practical analytical method. A complete instrument was developed and prepared for field testing. A Titan 3-C rocket was scheduled for launching on February 11, 1974. Through preparations made by NASA Langley the instrument was set up to monitor the acid concentration in the rocket exhaust. Due to adverse wind conditions no acid was detected. This entire trip is described in detail.

  8. Be an acid rain detective

    SciTech Connect

    Atwill, L.

    1982-07-01

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

  9. Decarboxylative functionalization of cinnamic acids.

    PubMed

    Borah, Arun Jyoti; Yan, Guobing

    2015-08-14

    Decarboxylative functionalization of α,β-unsaturated carboxylic acids is an emerging area that has been developed significantly in recent years. This critical review focuses on the different decarboxylative functionalization reactions of cinnamic acids leading to the formation of various C-C and C-heteroatom bonds. Apart from metal carboxylates, decarboxylation in cinnamic acids has been achieved efficiently under metal-free conditions, particularly via the use of hypervalent iodine reagents. We believe this review will encourage organic chemists to develop vinylic decarboxylation in a more appealing way with an understanding of new mechanistic insight.

  10. PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-08-30

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

  11. Acid rain: chemistry and transport.

    PubMed

    Irwin, J G; Williams, M L

    1988-01-01

    This review describes the more important features of the emission, chemistry, transport and deposition of pollutants involved in acid deposition. Global emissions, both natural and man-made, of sulphur and nitrogen oxides are discussed and examples of spatial distributions and trends over the last century presented. The more significant chemical and physical processes involved in the transformation of the primary emissions into their acidic end products are described, including a summary of the approximate timescales of the processes involved. Measurements and modelled calculations of spatial and temporal patterns in the deposition of acidic pollutants by both wet and dry pathways are presented.

  12. Free acidity measurement - a review.

    PubMed

    Srinivasan, T G; Vasudeva Rao, P R

    2014-01-01

    Free acidity is an important parameter especially in the presence of hydrolysable ions. Several methods have been developed for the determination of free acidity, attributing due importance to the accuracy and the precision of the measurement with the aim of the easiness of the methodology as well as post-measurement recovery in mind. This review covers important methods for the determination of free acidity with emphasis on actinide containing solutions, reported in the literature over the past several decades classifying them into different categories.

  13. Amino Acids from a Comet

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elisla

    2009-01-01

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

  14. Can crops tolerate acid rain

    SciTech Connect

    Kaplan, J.K.

    1989-11-01

    This brief article describes work by scientists at the ARS Air Quality-Plant Growth and Development Laboratory in Raleigh, North Carolina, that indicates little damage to crops as a result of acid rain. In studies with simulated acid rain and 216 exposed varieties of 18 crops, there were no significant injuries nor was there reduced growth in most species. Results of chronic and acute exposures were correlated in sensitive tomato and soybean plants and in tolerant winter wheat and lettuce plants. These results suggest that 1-hour exposures could be used in the future to screen varieties for sensitivity to acid rain.

  15. 40 CFR 721.10679 - Carboxylic acid, substituted alkylstannylene ester, reaction products with inorganic acid tetra...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alkylstannylene ester, reaction products with inorganic acid tetra alkyl ester (generic). 721.10679 Section 721... Carboxylic acid, substituted alkylstannylene ester, reaction products with inorganic acid tetra alkyl ester... identified generically as carboxylic acid, substituted alkylstannylene ester, reaction products...

  16. Treatment of Amino Acid Metabolism Disorders

    MedlinePlus

    ... Treatment of amino acid metabolism disorders Treatment of amino acid metabolism disorders E-mail to a friend Please ... this page It's been added to your dashboard . Amino acid metabolism disorders are rare health conditions that affect ...

  17. Acid preservation systems for food products

    SciTech Connect

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

    1984-10-16

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

  18. Genetics Home Reference: sialic acid storage disease

    MedlinePlus

    ... Home Health Conditions sialic acid storage disease sialic acid storage disease Enable Javascript to view the expand/ ... Download PDF Open All Close All Description Sialic acid storage disease is an inherited disorder that primarily ...

  19. Treatment of Fatty Acid Oxidation Disorders

    MedlinePlus

    ... of fatty acid oxidation disorders Treatment of fatty acid oxidation disorders E-mail to a friend Please ... page It's been added to your dashboard . Fatty acid oxidation disorders are rare health conditions that affect ...

  20. Molar extinction coefficients of some fatty acids

    NASA Astrophysics Data System (ADS)

    Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

    2002-10-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

  1. Biotechnological production of citric acid

    PubMed Central

    Max, Belén; Salgado, José Manuel; Rodríguez, Noelia; Cortés, Sandra; Converti, Attilio; Domínguez, José Manuel

    2010-01-01

    This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid. PMID:24031566

  2. Simulated acid rain on crops

    SciTech Connect

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

    1985-10-01

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

  3. Low acid producing solid propellants

    NASA Technical Reports Server (NTRS)

    Bennett, Robert R.

    1995-01-01

    The potential environmental effects of the exhaust products of conventional rocket propellants have been assessed by various groups. Areas of concern have included stratospheric ozone, acid rain, toxicity, air quality and global warming. Some of the studies which have been performed on this subject have concluded that while the impacts of rocket use are extremely small, there are propellant development options which have the potential to reduce those impacts even further. This paper discusses the various solid propellant options which have been proposed as being more environmentally benign than current systems by reducing HCI emissions. These options include acid neutralized, acid scavenged, and nonchlorine propellants. An assessment of the acid reducing potential and the viability of each of these options is made, based on current information. Such an assessment is needed in order to judge whether the potential improvements justify the expenditures of developing the new propellant systems.

  4. Abiotic synthesis of fatty acids

    NASA Technical Reports Server (NTRS)

    Leach, W. W.; Nooner, D. W.; Oro, J.

    1978-01-01

    The formation of fatty acids by Fischer-Tropsch-type synthesis was investigated with ferric oxide, ammonium carbonate, potassium carbonate, powdered Pueblito de Allende carbonaceous chondrite, and filings from the Canyon Diablo meteorite used as catalysts. Products were separated and identified by gas chromatography and mass spectrometry. Iron oxide, Pueblito de Allende chondrite, and Canyon Diablo filings in an oxidized catalyst form yielded no fatty acids. Canyon Diablo filings heated overnight at 500 C while undergoing slow purging by deuterium produced fatty acids only when potassium carbonate was admixed; potassium carbonate alone also produced these compounds. The active catalytic combinations gave relatively high yields of aliphatic and aromatic hydrocarbons; substantial amounts of n-alkenes were almost invariably observed when fatty acids were produced; the latter were in the range C6 to C18, with maximum yield in C9 or 10.

  5. Biopreservation by lactic acid bacteria.

    PubMed

    Stiles, M E

    1996-10-01

    Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Lactic acid bacteria have a major potential for use in biopreservation because they are safe to consume and during storage they naturally dominate the microflora of many foods. In milk, brined vegetables, many cereal products and meats with added carbohydrate, the growth of lactic acid bacteria produces a new food product. In raw meats and fish that are chill stored under vacuum or in an environment with elevated carbon dioxide concentration, the lactic acid bacteria become the dominant population and preserve the meat with a "hidden' fermentation. The same applies to processed meats provided that the lactic acid bacteria survive the heat treatment or they are inoculated onto the product after heat treatment. This paper reviews the current status and potential for controlled biopreservation of foods. PMID:8879414

  6. Phosphonic acid based exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1995-09-12

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

  7. Lead/acid battery myths

    NASA Astrophysics Data System (ADS)

    Moseley, P. T.

    The lead/acid battery deserves a more positive image than has been traditional heretofore—particularly with respect to a number of aspects that relate to its utility as a power source for electric vehicles. Recent results from a large internationally coordinated research programme indicate that: (i) with proper attention to construction, valve-regulated lead/acid batteries can be deep-discharged many times without capacity loss; (ii) lead/acid batteries can be recharged extremely rapidly so that long journeys of electric vehicles become a realistic possibility; (iii) ranges of over 150 km between charges are achievable, and (iv) the introduction of significant numbers of lead/acid-powered electric vehicles does offer a beneficial environmental impact.

  8. Making cents of acid recovery

    SciTech Connect

    Ondrey, G.; Shanley, A.

    1993-04-01

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

  9. Glucaric acids from Leonurus japonicus.

    PubMed

    Jiang, Jianshuang; Li, Yixiu; Feng, Ziming; Yang, Yanan; Zhang, Peicheng

    2015-12-01

    Three new glucaric acids, namely 2-feruloyl-4-syringoyl or 5-feruloyl-3-syringoyl glucaric acid (1), 2-syringoyl-4-feruloyl or 5-syringoyl-3-feruloyl glucaric acid (2), and 3-feruloyl-4-syringoyl or 4-feruloyl-3-syringoyl glucaric acid (3), were isolated from Leonurus japonicus Houtt. Their structures were elucidated by detailed spectroscopic means including UV, IR, HR-ESI-MS, 1D and 2D NMR data spectra. The bioactive assays of compounds 1-3 against hepatoprotection activity were determined. The result suggested that compound 2 exhibited a moderate hepatoprotection activity and the cell survival rate was 74% (10(-5)mol/L), using bicyclol (survival rate: 66%, 10(-5)mol/L) as a positive control. Furthermore, compounds 1-3 were evaluated cytotoxic activities in vitro using HCT-8, Bel-7402, BGC-823, A-549, and A2780 model and the results exhibited no obvious cytotoxicity activity.

  10. Biopreservation by lactic acid bacteria.

    PubMed

    Stiles, M E

    1996-10-01

    Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Lactic acid bacteria have a major potential for use in biopreservation because they are safe to consume and during storage they naturally dominate the microflora of many foods. In milk, brined vegetables, many cereal products and meats with added carbohydrate, the growth of lactic acid bacteria produces a new food product. In raw meats and fish that are chill stored under vacuum or in an environment with elevated carbon dioxide concentration, the lactic acid bacteria become the dominant population and preserve the meat with a "hidden' fermentation. The same applies to processed meats provided that the lactic acid bacteria survive the heat treatment or they are inoculated onto the product after heat treatment. This paper reviews the current status and potential for controlled biopreservation of foods.

  11. Microbial production of lactic acid.

    PubMed

    Eiteman, Mark A; Ramalingam, Subramanian

    2015-05-01

    Lactic acid is an important commodity chemical having a wide range of applications. Microbial production effectively competes with chemical synthesis methods because biochemical synthesis permits the generation of either one of the two enantiomers with high optical purity at high yield and titer, a result which is particularly beneficial for the production of poly(lactic acid) polymers having specific properties. The commercial viability of microbial lactic acid production relies on utilization of inexpensive carbon substrates derived from agricultural or waste resources. Therefore, optimal lactic acid formation requires an understanding and engineering of both the competing pathways involved in carbohydrate metabolism, as well as pathways leading to potential by-products which both affect product yield. Recent research leverages those biochemical pathways, while researchers also continue to seek strains with improved tolerance and ability to perform under desirable industrial conditions, for example, of pH and temperature.

  12. Phosphonic acid based exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1995-01-01

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

  13. 21 CFR 184.1009 - Adipic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Adipic acid. 184.1009 Section 184.1009 Food and... Substances Affirmed as GRAS § 184.1009 Adipic acid. (a) Adipic acid (C6H10O4, CAS Reg. No. 00124-04-9) is also known as 1,4-butanedicarboxylic acid or hexane-dioic acid. It is prepared by nitric acid...

  14. 21 CFR 184.1009 - Adipic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Adipic acid. 184.1009 Section 184.1009 Food and... Substances Affirmed as GRAS § 184.1009 Adipic acid. (a) Adipic acid (C6H10O4, CAS Reg. No. 00124-04-9) is also known as 1,4-butanedicarboxylic acid or hexane-dioic acid. It is prepared by nitric acid...

  15. 21 CFR 184.1091 - Succinic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Succinic acid. 184.1091 Section 184.1091 Food and... Substances Affirmed as GRAS § 184.1091 Succinic acid. (a) Succinic acid (C4H6O4, CAS Reg. No. 110-15-6), also referred to as amber acid and ethylenesuccinic acid, is the chemical 1,4-butanedioic acid. It...

  16. 21 CFR 184.1091 - Succinic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Succinic acid. 184.1091 Section 184.1091 Food and....1091 Succinic acid. (a) Succinic acid (C4H6O4, CAS Reg. No. 110-15-6), also referred to as amber acid and ethylenesuccinic acid, is the chemical 1,4-butanedioic acid. It is commercially prepared...

  17. 21 CFR 184.1009 - Adipic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Adipic acid. 184.1009 Section 184.1009 Food and... Substances Affirmed as GRAS § 184.1009 Adipic acid. (a) Adipic acid (C6H10O4, CAS Reg. No. 00124-04-9) is also known as 1,4-butanedicarboxylic acid or hexane-dioic acid. It is prepared by nitric acid...

  18. 21 CFR 184.1091 - Succinic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Succinic acid. 184.1091 Section 184.1091 Food and... Substances Affirmed as GRAS § 184.1091 Succinic acid. (a) Succinic acid (C4H6O4, CAS Reg. No. 110-15-6), also referred to as amber acid and ethylenesuccinic acid, is the chemical 1,4-butanedioic acid. It...

  19. 21 CFR 184.1009 - Adipic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Adipic acid. 184.1009 Section 184.1009 Food and... Substances Affirmed as GRAS § 184.1009 Adipic acid. (a) Adipic acid (C6H10O4, CAS Reg. No. 00124-04-9) is also known as 1,4-butanedicarboxylic acid or hexane-dioic acid. It is prepared by nitric acid...

  20. 21 CFR 184.1091 - Succinic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Succinic acid. 184.1091 Section 184.1091 Food and... Substances Affirmed as GRAS § 184.1091 Succinic acid. (a) Succinic acid (C4H6O4, CAS Reg. No. 110-15-6), also referred to as amber acid and ethylenesuccinic acid, is the chemical 1,4-butanedioic acid. It...