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Sample records for active aromatic polyamides

  1. Novel Organic Phototransistor-Based Nonvolatile Memory Integrated with UV-Sensing/Green-Emissive Aggregation Enhanced Emission (AEE)-Active Aromatic Polyamide Electret Layer.

    Science.gov (United States)

    Cheng, Shun-Wen; Han, Ting; Huang, Teng-Yung; Chang Chien, Yu-Hsin; Liu, Cheng-Liang; Tang, Ben Zhong; Liou, Guey-Sheng

    2018-05-30

    A novel aggregation enhanced emission (AEE)-active polyamide TPA-CN-TPE with a high photoluminesence characteristic was successfully synthesized by the direct polymerization of 4-cyanotriphenyl diamine (TPA-CN) and tetraphenylethene (TPE)-containing dicarboxylic acid. The obtained luminescent polyamide plays a significant role as the polymer electret layer in organic field-effect transistors (OFETs)-type memory. The strong green emission of TPA-CN-TPE under ultraviolet (UV) irradiation can be directly absorbed by the pentacene channel, displaying a light-induced programming and voltage-driven erasing organic phototransistor-based nonvolatile memory. Memory window can be effectively manipulated between the programming and erasing states by applying UV light illumination and electrical field, respectively. The photoinduced memory behavior can be maintained for over 10 4 s between these two states with an on/off ratio of 10 4 , and the memory switching can be steadily operated for many cycles. With high photoresponsivity ( R) and photosensitivity ( S), this organic phototransistor integrated with AEE-active polyamide electret layer could serve as an excellent candidate for UV photodetectors in optical applications. For comparison, an AEE-inactive aromatic polyimide TPA-PIS electret with much weaker solid-state emission was also applied in the same OFETs device architecture, but this device did not show any UV-sensitive and UV-induced memory characteristics, which further confirmed the significance of the light-emitting capability of the electret layer.

  2. Living Polycondensation: Synthesis of Well-Defined Aromatic Polyamide-Based Polymeric Materials

    KAUST Repository

    Alyami, Mram Z.

    2016-01-01

    Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low

  3. Aromatic-aliphatic polyamide/montmorillonite clay nanocomposite materials: Synthesis, nanostructure and properties

    International Nuclear Information System (INIS)

    Zulfiqar, Sonia; Ahmad, Zahoor; Ishaq, Muhammad; Sarwar, Muhammad Ilyas

    2009-01-01

    New type of aromatic-aliphatic polyamide/montmorillonite nanocomposites were produced using solution intercalation technique in dimethylacetamide. The modification of clay was carried out with ammonium salt of long chain alkyl amine. The nanocomposites were probed for organoclay dispersion, mechanical, thermal and water absorption measurements. Formation of delaminated and intercalated nanostructures was confirmed by X-ray diffraction and TEM studies. Improvement in tensile strength and modulus was observed for nanocomposites with optimum organoclay content (8-wt.%). Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. Differential scanning calorimetric results revealed increase in glass transition temperatures (T g ) with augmenting organoclay in the nanocomposites. Water uptake of the nanocomposites reduced than the neat polyamide rendering decreased permeability.

  4. Aromatic-aliphatic polyamide/montmorillonite clay nanocomposite materials: Synthesis, nanostructure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Zulfiqar, Sonia [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ahmad, Zahoor [Department of Chemistry, Faculty of Science, Kuwait University, P. O. Box: 5969, Safat 13060 (Kuwait); Ishaq, Muhammad [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Sarwar, Muhammad Ilyas, E-mail: ilyassarwar@hotmail.com [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716 (United States)

    2009-11-15

    New type of aromatic-aliphatic polyamide/montmorillonite nanocomposites were produced using solution intercalation technique in dimethylacetamide. The modification of clay was carried out with ammonium salt of long chain alkyl amine. The nanocomposites were probed for organoclay dispersion, mechanical, thermal and water absorption measurements. Formation of delaminated and intercalated nanostructures was confirmed by X-ray diffraction and TEM studies. Improvement in tensile strength and modulus was observed for nanocomposites with optimum organoclay content (8-wt.%). Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. Differential scanning calorimetric results revealed increase in glass transition temperatures (T{sub g}) with augmenting organoclay in the nanocomposites. Water uptake of the nanocomposites reduced than the neat polyamide rendering decreased permeability.

  5. Living Polycondensation: Synthesis of Well-Defined Aromatic Polyamide-Based Polymeric Materials

    KAUST Repository

    Alyami, Mram Z.

    2016-11-01

    Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low polydispersity and controlled molecular weights, and on the other hand, on studying their thermal properties. In the first project, well-defined poly (N-octyl-p-aminobenzoate) and poly (N-butyl-p-aminobenzoate) were synthesized, and for the first time, their thermal properties were studied. In the second project, ethyl4-aminobenzoate, ethyl 4-octyl aminobenzoate and 4-(hydroxymethyl) benzoic acid were used as novel efficient initiators of ε-caprolactone with t-BuP2 as a catalyst. Macroinitiator and Macromonomer of poly (ε-caprolactone) were synthesized with ethyl 4-octyl aminobenzoate and ethyl 4-aminobenzoate as initiators to afford polyamide-block-poly (ε-caprolactone) and polyamide-graft-poly (ε-caprolactone) by chain growth condensation polymerization (CGCP). In the third project, a new study has been done on chain growth condensation polymerization to discover the probability to synthesize new polymers and studied their thermal properties. For this purpose, poly (N-cyclohexyl-p-aminobenzoate) and poly (N-hexyl-p-aminobenzoate) were synthesized with low polydispersity and controlled molecular weights.

  6. Irradiation effects on properties of reverse osmosis membrane based on cross-linked aromatic polyamide

    International Nuclear Information System (INIS)

    Nakase, Yoshiaki; Yanagi, Tadashi; Uemura, Tadahiro.

    1994-01-01

    In order to develop a membrane suitable for reverse osmotic condensation of radioactive liquid wastes, a new cross-linked aromatic polyamide composite reverse osmosis membrane (ROM) was irradiated in water or in wet system, and its mechanical and some thermal properties, and the separation performance for inorganic salt were investigated. A membrane was degraded by irradiation more severely in wet system than in dry system, probably due to the reaction with OH-radicals. In the separation performance for NaCl, the salt rejection of the membrane was kept over 88% until irradiation reached 2MGy, maintaining about 90% of its original water flux. (author)

  7. SYNTHESIS AND CHARACTERIZATION OF NEW THERMALLY STABLE POLYAMIDES BASED ON 2,5-PYRIDINE DICARBOXYLIC ACID AND AROMATIC DIAMINES

    OpenAIRE

    FAGHIHI, KHALIL

    2009-01-01

    Six new thermally stable polyamides 3a-f were synthesized through the polycondensation reaction of 2,5-pyridine dicarboxylic acid 1 with six different derivatives of aromatic diamines 2a-f in amedium consisting of N-methyl-2-pyrrolidone, triphenyl phosphite, calcium chloride and pyridine. The polycondensation reaction produced a series of novel polyamides containing pyridyl moieties in the main chain in high yield with inherent viscosities between 0.50-0.82 dL/g. The resulting polymers were f...

  8. Thermal stability and degradation behavior of novel wholly aromatic azo polyamide-hydrazides

    International Nuclear Information System (INIS)

    Al-Ghamdia, R.F.; Fahmib, M.M.; Mohamed, N.A.

    2005-01-01

    Thermal stability and degradation behavior of a series of novel wholly aromatic azo polyamide-hydrazides have been investigated in nitrogen and in air atmospheres using differential scanning ealorimetry, thermogravimetry, infrared spectroscopy and elemental analysis. The influences of controlled structural variations and molecular weight on the thermal stability and degradation behavior of this series of polymers have also been studied. The structural differences were achieved by varying the content of para- and meta substituted phenylene rings incorporated within this series. The polymers were prepared by a low temperature solution polycondensation reaction of p aminosalicylic acid hydrazide and an equimolar amount of 4,4-azo dibenzoyl chloride [4,4 ADBC] or 3,3-azo dibenzoyl chloride [3,3ADBC] or mixtures of various molar ratios of 4,4ADBC and 3,3ADBC in anhydrous N,N- dimethyl acetamide [DMAc] containing lithium chloride as a solvent at -10 degree C. The results clearly reveal that these polymers are characterized by high thermal stability. Their weight loss occurred in three distinctive steps. The first was small and assigned to the evaporation of absorbed moisture. The second was appreciable and was attributed to the cyclo dehydration reaction of the hydrazide groups into 1,3,4-oxadiazole rings by losing water, combined with elimination of azo groups by losing molecular nitrogen. This is not a true degradation but rather a thermo-chemical transformation reaction of the azo polyamide-hydrasdes into the corresponding polyamide-l,3,4-oxadiazoles. The third was relatively severe and sharp, particularly in air, and corresponded to the decomposition of the resulting polyamide-l, 3,4-oxadiazoles. In both degradation atmospheres, the improved resistance to high temperatures was always associated with increased content of para- phenylene moieties of the investigated polymer. Further, with exception of 160-200 degree C temperature range, where the lower molecular weight

  9. Simulating the growth process of aromatic polyamide layer by monomer concentration controlling method

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Yan [Vontron Technology Co., Ltd., Guiyang 550018, Guizhou (China); Liang, Songmiao, E-mail: liangsongmiao@vontron.com.cn [Vontron Technology Co., Ltd., Guiyang 550018, Guizhou (China); Wu, Zongce; Cai, Zhiqi [Vontron Technology Co., Ltd., Guiyang 550018, Guizhou (China); Zhao, Ning [National Laboratory of Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190 (China)

    2014-09-30

    Highlights: • A concentration controlling method to simulate the growth process of polyamide layer was developed. • The surface structure features and properties of polyamide layer at its different growth stages were systematically investigated. • Structure transition from spherical aggregator to leaf-like to typical ridge-and-valley was observed. • The performance of RO membrane is closely related to the structure of polyamide. - Abstract: With the wide distribution and gradual increase of TMC concentration (C{sub TMC}) from 1 × 10{sup −4} wt% to 2.5 × 10{sup −1} wt%, the main purpose of this work is to simulate the surface structure and properties of polyamide layer of reverse osmosis membranes at its different growth stage. The surface structure and properties of the resulted membranes were then characterized by atomic force microscopy (AFM), scanning electron microscope (SEM), attenuated total reflectance infrared (ATR-IR) spectroscopy, drop shape analysis system and electrokinetic analyzer. The structure growth of polyamide layer underwent in turn three different stages including spherical aggregator, leaf-like and typical ridge-valley structure. Spherical aggregator is the intrinsic structure in the inner layer of polyamide while leaf-like structure is transitional on the outmost polyamide layer. Furthermore, to clarify the effect of the structure change on the properties of polyamide layer, contact angle and zeta potential in the surface of polyamide layer were studied. Hydrophilic surface of polyamide layer is accessible at higher TMC concentration because of the presence of negative charged groups. Performances of the membranes were further measured with an emphasis on studying its structure–performance relationship during the growth process of polyamide layer.

  10. Thin Film Polyamide Membranes with Photoresponsive Antibacterial Activity

    KAUST Repository

    Duong, Phuoc H. H.

    2017-08-09

    Membranes containing a photosensitizer molecule as part of the selective layer are proposed with demonstrated anti-biofouling activity. For the membrane preparation, mixtures of an amine-functionalized photosensitizer molecule, (5,10,15,20-(tetra-4-aminophenyl)porphyrin) and m-phenylene diamine (MPD) reacted with trimesoyl chloride (TMC) by interfacial polymerization to form thin polyamide films on top of an asymmetric porous support. A highly permeable membrane (35.4 Lm−2h−1bar−1) with 99 % rejection of Brilliant Blue R (826 g/mol) was obtained using 0.25 wt% porphyrin and 0.75 wt% MPD as amine monomers. Under visible light exposure, singlet oxygen (1O2) is generated in the porphyrin containing-polyamide film, reaching the bacteria in the feed by diffusion and enhancing the biofouling resistance and anti-microbial activity. Anti-biofouling and anti-microbial photoactivity in solution are demonstrated on Staphylococcus aureus at different porphyrin concentrations and light exposure time.

  11. Thin Film Polyamide Membranes with Photoresponsive Antibacterial Activity

    KAUST Repository

    Duong, Phuoc H. H.; Hong, Pei-Ying; Musteata, Valentina-Elena; Peinemann, Klaus-Viktor; Nunes, Suzana Pereira

    2017-01-01

    Membranes containing a photosensitizer molecule as part of the selective layer are proposed with demonstrated anti-biofouling activity. For the membrane preparation, mixtures of an amine-functionalized photosensitizer molecule, (5,10,15,20-(tetra-4-aminophenyl)porphyrin) and m-phenylene diamine (MPD) reacted with trimesoyl chloride (TMC) by interfacial polymerization to form thin polyamide films on top of an asymmetric porous support. A highly permeable membrane (35.4 Lm−2h−1bar−1) with 99 % rejection of Brilliant Blue R (826 g/mol) was obtained using 0.25 wt% porphyrin and 0.75 wt% MPD as amine monomers. Under visible light exposure, singlet oxygen (1O2) is generated in the porphyrin containing-polyamide film, reaching the bacteria in the feed by diffusion and enhancing the biofouling resistance and anti-microbial activity. Anti-biofouling and anti-microbial photoactivity in solution are demonstrated on Staphylococcus aureus at different porphyrin concentrations and light exposure time.

  12. Radiolytic crosslinking and chain scission in aliphatic and alkyl-aromatic polyamides: Pt. 2

    International Nuclear Information System (INIS)

    Lyons, B.J.; Glover, L.C. Jr.

    1991-01-01

    Regression analysis of the radiation parameters of nine aliphatic polyamides exposed to ionizing radiation leads to the conclusion that the decline in the ratio of chain scission to crosslinking in higher aliphatic polyamides is best related to the linear increase in the methylene content of, or the number of methylene groups in, the polyamide repeat unit. G(crosslink)[G(X)] and G(chain scission) [G(CS)] values, however, do not correlate well with either of these parameters. Rather it is found that the major determinant of yields [about 80-85% of the variation for G(X), 70% for G(CS)] is the number of hydrogen atoms or methylene groups in the amine residue. Although, logically, the yields of crosslinks and chain scissions in polyamides would be expected to tend to that of polyethylene as the number of methylene groups in the repeat unit increases, use of two models assuming an exponential trend to the G(X) value characteristic of polyethylene in the analysis did not provide better fits to the data than the simple linear model referred to above. Indeed, the assumption of a significant exponential trend factor led to a marked drop in the goodness of fit. (author)

  13. Modification of PSf/SPSf Blended Porous Support for Improving the Reverse Osmosis Performance of Aromatic Polyamide Thin Film Composite Membranes

    Directory of Open Access Journals (Sweden)

    Li-Fen Liu

    2018-06-01

    Full Text Available In this study, modification of polysulfone (PSf/sulfonated polysulfone (SPSf blended porous ultrafiltration (UF support membranes was proposed to improve the reverse osmosis (RO performance of aromatic polyamide thin film composite (TFC membranes. The synergistic effects of solvent, polymer concentration, and SPSf doping content in the casting solution were investigated systematically on the properties of both porous supports and RO membranes. SEM and AFM were combined to characterize the physical properties of the membranes, including surface pore natures (porosity, mean pore radius, surface morphology, and section structure. A contact angle meter was used to analyze the membrane surface hydrophilicity. Permeate experiments were carried out to evaluate the separation performances of the membranes. The results showed that the PSf/SPSf blended porous support modified with 6 wt % SPSf in the presence of DMF and 14 wt % PSf had higher porosity, bigger pore diameter, and a rougher and more hydrophilic surface, which was more beneficial for fabrication of a polyamide TFC membrane with favorable reverse osmosis performance. This modified PSf/SPSf support endowed the RO membrane with a more hydrophilic surface, higher water flux (about 1.2 times, as well as a slight increase in salt rejection than the nascent PSf support. In a word, this work provides a new facile method to improve the separation performance of polyamide TFC RO membranes via the modification of conventional PSf porous support with SPSf.

  14. Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2014-01-01

    We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

  15. Amide Link Scission in the Polyamide Active Layers of Thin-Film Composite Membranes upon Exposure to Free Chlorine: Kinetics and Mechanisms.

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2015-10-20

    The volume-averaged amide link scission in the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine was quantified at a variety of free chlorine exposure times, concentrations, and pH and rinsing conditions. The results showed that (i) hydroxyl ions are needed for scission to occur, (ii) hydroxide-induced amide link scission is a strong function of exposure to hypochlorous acid, (iii) the ratio between amide links broken and chlorine atoms taken up increased with the chlorination pH and reached a maximum of ∼25%, (iv) polyamide disintegration occurs when high free chlorine concentrations, alkaline conditions, and high exposure times are combined, (v) amide link scission promotes further chlorine uptake, and (vi) scission at the membrane surface is unrepresentative of volume-averaged scission in the active layer. Our observations are consistent with previously proposed mechanisms describing amide link scission as a result of the hydrolysis of the N-chlorinated amidic N-C bond due to nucleophilic attack by hydroxyl ions. This study increases the understanding of the physicochemical changes that could occur for membranes in treatment plants using chlorine as an upstream disinfectant and the extent and rate at which those changes would occur.

  16. Synthesis and characterization of new optically active poly(amide ...

    African Journals Online (AJOL)

    Synthesis and characterization of new optically active poly(amide-imide)s based on N -trimellitimido- ... Bulletin of the Chemical Society of Ethiopia ... (DMAc), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP) at room temperature.

  17. Synthesis and characterization of new optically active poly(amide

    African Journals Online (AJOL)

    Preferred Customer

    Six new optically active poly(amide-imide)s (8a-f) were synthesized through the direct ... polyimides are widely used in the semiconductor and electronic packaging ... chiral polymers is of particular interest from the viewpoint of material science ...

  18. Adsorption of pharmaceuticals onto isolated polyamide active layer of NF/RO membranes.

    Science.gov (United States)

    Liu, Yan-Ling; Wang, Xiao-Mao; Yang, Hong-Wei; Xie, Yuefeng F

    2018-06-01

    Adsorption of trace organic compounds (TrOCs) onto the membrane materials has a great impact on their rejection by nanofiltration (NF) and reverse osmosis (RO) membranes. This study aimed to investigate the difference in adsorption of various pharmaceuticals (PhACs) onto different NF/RO membranes and to demonstrate the necessity of isolating the polyamide (PA) active layer from the polysulfone (PS) support layer for adsorption characterization and quantification. Both the isolated PA layers and the PA+PS layers of NF90 and ESPA1 membranes were used to conduct static adsorption tests. Results showed that apparent differences existed between the PA layer and the PA+PS layer in the adsorption capacity of PhACs as well as the time necessary to reach the adsorption equilibrium. PhACs with different physicochemical properties could be adsorbed to different extents by the isolated PA layer, which was mainly attributed to electrostatic attraction/repulsion and hydrophobic interactions. The PA layer of ESPA1 exhibited apparently higher adsorption capacities for the positively charged PhACs and similar adsorption capacities for the neutral PhACs although it had significantly less total interfacial area (per unit membrane surface area) for adsorption compared to the PA layer of NF90. The higher affinity of the PA layer of ESPA1 for the PhACs could be due to its higher capacity of forming hydrogen bonds with PhACs resulted from the modified chemistry with more -OH groups. This study provides a novel approach to determining the TrOC adsorption onto the active layer of membranes for the ease of investigating adsorption mechanisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    International Nuclear Information System (INIS)

    Rajagopal, Appavu; Deepa, Mohan; Govindaraju, Munisamy

    2016-01-01

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”

  20. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, Appavu; Deepa, Mohan [Molecular Biophysics Unit, Indian Institute of Sciences-Bangalore, Karnataka (India); Govindaraju, Munisamy [Bio-Spatial Technology Research Unit, Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu (India)

    2016-02-26

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  1. Activity relationships for aromatic crown ethers

    International Nuclear Information System (INIS)

    Wilson, Mark James

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities from molecular modelling and this rational has been applied to the study of proton ionisable and lariating crown ethers. The incorporation of crown ethers into polyamic acid and polyimide frameworks has also been investigated, where the resulting materials have been found to exhibit unusual cation binding and uptake properties. These results imply that the combination of the crown ethers' macrocycle and adjacent carboxylic acid residues, from the polyamic acids, are conducive to effective cationic binding. NMR measurements, in conjunction with molecular modelling, have been used to explore the geometry changes encountered as the crown ether goes from it's uncomplexed to its complexed state. The energy requirement for these geometry changes has subsequently been used to examine the cation selectivity of these materials. The electronic charge changes associated with the complexation have also been investigated and correlated with the theoretical results. (author)

  2. 3D morphological characterization of the polyamide active layer of RO and NF membranes using TEM and soft X-ray scattering

    Science.gov (United States)

    Culp, Tyler; Paul, Mou; Roy, Abhishek; Rosenberg, Steve; Behr, Michael; Kumar, Manish; Gomez, Enrique; Penn State Team; Dow Team

    Polyamide-based thin-film composite (TFC) membranes used for reverse osmosis (RO) and nanofiltration (NF) separation processes are at the forefront of water desalination and purification technologies due to their high salt rejection, high energy efficiency, and ease of operation. Nevertheless, in spite of the benefits of RO and NF membranes, many open questions about the internal nanostructure of the membrane active layer remain, such as the dispersion and distribution of acid functional groups. We demonstrate that resonant soft X-ray scattering (RSOXS), where the X-ray energy is tuned to absorption edges of the constituent materials, is a powerful tool to examine the microstructure of the polyamide layer. In conjunction with complementary techniques such as transmission electron microscopy (TEM), where tomography is used to obtain a 3D reconstruction of the polyamide active layer, the effect of cross-linking can be quantified in 3D for a systematic series of membranes. This relationship can then be applied to a series of commercially available RO and NF membranes where the effect of polyamide cross-linking on their respective structure and water transport properties can be evaluated. The combination of RSOXS with traditional characterization tools provides a strategy for linking the chemical structure to the morphology and water transport properties of RO and NF membranes.

  3. New polyvinyl chloride (PVC) nanocomposite consisting of aromatic polyamide and chitosan modified ZnO nanoparticles with enhanced thermal stability, low heat release rate and improved mechanical properties

    Science.gov (United States)

    Hajibeygi, Mohsen; Maleki, Mahdiye; Shabanian, Meisam; Ducos, Franck; Vahabi, Henri

    2018-05-01

    New ternary nanocomposite systems containing polylvinyl chloride (PVC), chitosan modified ZnO (CMZN) nanoparticles and new synthesized polyamide (PA) were designed and prepared by solution casting method. As a potential reinforcement, CMZN was used in PVC system combined with and without PA. Morphology, mechanical, thermal and combustion properties of the all PVC systems were studied. In the presence of the CMZN, PA showed a synergistic effect on improvement of the all investigated properties of PVC. The 5 mass% loss temperature (T5) was increased from 195 °C to 243 °C in PVC/CMZN-PA nanocomposite containing 1 mass% of each PA and CMZN (PZP 2). The peak of heat release rate was decreased from 131 W/g for PVC to 104 W/g for PVC/CMZN-PA nanocomposite containing 3 mass% of each PA and CMZN (PZP 6). According to the tensile tests, compared to the neat PVC, the tensile strength was increased from 35.4 to 53.4 MPa for PZP 6.

  4. Synthesis and characterization of new soluble polyamides from Acenaphtohydrazinomercaptotriazole diamine

    Directory of Open Access Journals (Sweden)

    Hossein Mighani

    2015-08-01

    Full Text Available AbstractA diamine Acenaphtohydrazinomercaptotriazole (AHTD was synthesized in one step from acenaphthoqinone and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole. The diamin was characterized by FTIR, 1HNMR, 13CNMR and melting point. Diamin was used to prepare novel polyamides. The low temperature solution polycondensation of diamin with tow aromatic and tow aliphatic diacid chlorides afforded diamin-containing polyamides with inherent viscosities of 0.38–0.47 dl/g in DMF at 25 °C. The polyamides were generally soluble in a wide range of solvents such as dimethylformamide(DMF, N-Methylpyrolidone(NMP, tetrachloroethane (TCE, dimethylsulfoxide(DMSO and H2SO4. Thermal analysis showed that these polyamides were practically crustily and with Tg under 100 °C.

  5. Effects of Green Tea Extract on Physicochemical and Antioxidant Properties of Polyamide Packaging Film

    OpenAIRE

    Ali Asghar Barzegaran; Maryam Jokar; Majid Javanmard Dakheli

    2014-01-01

    Polyamide 6 has been widely used in food packaging applications and also green tea contains amounts of antioxidant compounds. The aim of this study was investigation of green tea effects on properties of polyamide packaging polymer. Polyamide 6 was dissolved in methanol which was saturated with calcium chloride. The active packaging film was produced by incorporation of methanol green tea extracts at levels of 2.5, 5, 10 and 20% in polyamide solution by solution casting method. Mechanical and...

  6. Size and Aging Effects on Antimicrobial Efficiency of Silver Nanoparticles Coated on Polyamide Fabrics Activated by Atmospheric DBD Plasma.

    Science.gov (United States)

    Zille, Andrea; Fernandes, Margarida M; Francesko, Antonio; Tzanov, Tzanko; Fernandes, Marta; Oliveira, Fernando R; Almeida, Luís; Amorim, Teresa; Carneiro, Noémia; Esteves, Maria F; Souto, António P

    2015-07-01

    This work studies the surface characteristics, antimicrobial activity, and aging effect of plasma-pretreated polyamide 6,6 (PA66) fabrics coated with silver nanoparticles (AgNPs), aiming to identify the optimum size of nanosilver exhibiting antibacterial properties suitable for the manufacture of hospital textiles. The release of bactericidal Ag(+) ions from a 10, 20, 40, 60, and 100 nm AgNPs-coated PA66 surface was a function of the particles' size, number, and aging. Plasma pretreatment promoted both ionic and covalent interactions between AgNPs and the formed oxygen species on the fibers, favoring the deposition of smaller-diameter AgNPs that consequently showed better immediate and durable antimicrobial effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. Surprisingly, after 30 days of aging, a comparable bacterial growth inhibition was achieved for all of the fibers treated with AgNPs silver. Overall, the results suggest that instead of reducing the size of the AgNPs, which is associated with higher toxicity, similar long-term effects can be achieved with larger NPs (40-60 nm), even in lower concentrations. Because the antimicrobial efficiency of AgNPs larger than 30 nm is mainly ruled by the release of Ag(+) over time and not by the size and number of the AgNPs, this parameter is crucial for the development of efficient antimicrobial coatings on plasma-treated surfaces and contributes to the safety and durability of clothing used in clinical settings.

  7. A comparison of the performance of aromatic polyamide and cellulose acetate reverse osmosis membrane on the regeneration of secondary effluents; Comparacion del funcionamiento de membranas de osmosis inversa de poliamida aromatica y acetato de celulosa en la regeneracion de efluentes secundarios

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Ramirez, J. A.; Carrasco Vega, M.; Sales Marquez, D.; Quiroga Alonso, J. M.

    2002-07-01

    The application of reverse osmosis in regenerating waste waters has aroused a great deal of interest, although relatively few experiments using this technique have so far been carried out in Spain. In 1994, an experimental pilot plant was built at the La Barrosa waste water treatment plant in Chiclana de la Frontera in the province of Cadiz. This pilot plant with a capacity of 100 m''3/day, was equipped with various advanced treatments, most notably reverse osmosis, for treating urban waste waters for re-use. Since this pilot plant was built, various experiments have been carried out employing cellulose acetate (Hydranautics) and different types of Spanish-made aromatic polyamide membranes (Pridesa). Each type of membrane proposed different operating characteristics and feed-water requirements making each one suitable for a particular purpose. In this study, the secondary effluents was subjected to different kinds of treatment-called intense treatment, moderate treatment and minimum treatment-before reaching the reverse osmosis unit, which influenced the conditions in which the membranes operated. Following each type of treatment, the waters entering and leaving the installation were analysed to evaluate the quality of the final effluent and the effectiveness of the treatment carried out. The quality was extremely good in all the permeate samples analysed, almost irrespective of the type of treatment applied. It was also found that the cellulose acetate membranes tended to become less dirty than the aromatic polyamide membranes,due to their surface morphology. Nevertheless, the polyamide membranes have various advantages allowing them to be used in a wide range of applications at a lower energy cost. (Author) 8 refs.

  8. Effects of hydrophilic solvent and oxidation resistance post surface treatment on molecular structure and forward osmosis performance of polyamide thin-film composite (TFC) membranes

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Qibo; Xu, Yangyu [School of Environment, Tsinghua University, Beijing 100084 (China); Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Haijun, E-mail: yanghj@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhou, Lu, E-mail: zhoulu@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-11-30

    Graphical abstract: - Highlights: • NMP promotes swelling of polyamide, which enhances the TFC FO membrane water flux. • Electron-withdrawing carboxyl groups reduce the activity of polyamide molecules. • TMC and oxalic acid can improve the oxidation resistance properties of the FO membrane. • Oxalic acid and EDC improve the FO membrane separation performance significantly. - Abstract: In this article, novel hydrophilic solvents and antioxidants were used to post-treat aromatic polyamide thin-film composite (TFC) hollow fiber forward osmosis (FO) membranes. The effects of trimesoyl chloride (TMC) and oxalic acid on the structure of polyamide skin layer were investigated using ATR-FTIR and XPS analyses. Pure water flux and rejection of salts were detected using 2 M NaCl solution as draw solutions in FO processes. The results demonstrated that hydrophilic solvent N-methyl pyrrolidone (NMP) enhanced the water flux and kept a high salt retention of the TFC FO membrane. TMC and oxalic acid were both found to improve the oxidation resistance properties of the skin layer of TFC membrane because the electron-withdrawing carboxyl groups reduced the activity of polyamide molecular. The effects of the oxalic acid and carbodiimide on the molecular structures and the FO water flux of the polyamide TFC membranes were more marked than those of TMC. The novel TFC FO membrane treated by oxalic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) exhibited a high level of water flux (20.33 L m{sup −2} h{sup −1}), and the rates of salt rejection and salt reverse rejection were higher by 50% and 83%, respectively.

  9. Ethynyl-Containing Aromatic Polyamide Resin.

    Science.gov (United States)

    1988-06-21

    added over two hours at 130"-150" C. and the final 17 polymer, e.g., an alcohol such as methanol, thereby ml was added over two hours at 150*-160* C...2,5A.(phayIbyly) 4,4’. Oxyd n flne 0.30 (b) 2W0 295 (c) etahaloyl chinde IV 2.S-bi(pmykihynyl) 4.,V-pbmyieue- 0.51 19 222 250 (c) tewephd loyl chloride

  10. Antifungal activity of polycyclic aromatic hydrocarbons against Ligninolytic fungi

    Directory of Open Access Journals (Sweden)

    Memić Mustafa

    2011-01-01

    Full Text Available Environmental contamination by polycyclic aromatic hydrocarbons (PAHs has caused increasing concern because of their known, or suspected, carcinogenic and mutagenic effects. Polycyclic aromatic hydrocarbons occurring in the environment are usually the result of the incomplete combustion of carbon containing materials. The main sources of severe PAHs contamination in soil come from fossil fuels, i.e. production or use of fossil fuels or their products, such as coal tar and creosote. Creosote is used as a wood preservation for railway ties, bridge timbers, pilling and large-sized lumber. It consists mainly of PAHs, phenol and cresol compounds that cause harmful health effects. Research on biodegradation has shown that a special group of microorganisms, the white-rot fungi and brown-rot fungi, has a remarkable potential to degrade PAHs. This paper presents a study of the antifungal activity of 12 selected PAHs against two ligninolytic fungi Hypoxylon fragiforme (white rot and Coniophora puteana (brown rot. The antifungal activity of PAHs was determined by the disc-diffusion method by measuring the diameter of the zone of inhibition. The results showed that the antifungal activity of the tested PAHs (concentration of 2.5 mmol/L depends on the their properties such as molar mass, solubility in water, values of log Kow, ionization potential and Henry’s Law constant as well as number of aromatic rings, molecule topology or pattern of ring linkage. Among the 12 investigated PAHs, benzo(k fluoranthene with five rings, and pyrene with four cyclic condensed benzene rings showed the highest antifungal activity.

  11. Effects of Green Tea Extract on Physicochemical and Antioxidant Properties of Polyamide Packaging Film

    Directory of Open Access Journals (Sweden)

    Ali Asghar Barzegaran

    2014-08-01

    Full Text Available Polyamide 6 has been widely used in food packaging applications and also green tea contains amounts of antioxidant compounds. The aim of this study was investigation of green tea effects on properties of polyamide packaging polymer. Polyamide 6 was dissolved in methanol which was saturated with calcium chloride. The active packaging film was produced by incorporation of methanol green tea extracts at levels of 2.5, 5, 10 and 20% in polyamide solution by solution casting method. Mechanical and barrier properties of polyamide films were investigated using ASTM standards and antioxidant activity of polyamide films was evaluated using DPPH method. Results indicated that green tea extract increased antioxidant properties and tensile and young modulus of polyamide films. Oxygen and water vapor permeability of films were decreased by incorporation of green tea extract into polyamide matrix. Green tea extract improved barrier and tensile properties of polyamide films, however elongation at break reduced as increasing of green tea extract in polyamide-based films significantly (P<0.05.

  12. Characterization and Solubilization of Pyrrole–Imidazole Polyamide Aggregates

    OpenAIRE

    Hargrove, Amanda E.; Raskatov, Jevgenij A.; Meier, Jordan L.; Montgomery, David C.; Dervan, Peter B.

    2012-01-01

    To optimize the biological activity of pyrrole–imidazole polyamide DNA-binding molecules, we characterized the aggregation propensity of these compounds through dynamic light scattering and fractional solubility analysis. Nearly all studied polyamides were found to form measurable particles 50–500 nm in size under biologically relevant conditions, while HPLC-based analyses revealed solubility trends in both core sequences and peripheral substituents that did not correlate with overall ionic c...

  13. Stabilization of modified polyamide matrix

    International Nuclear Information System (INIS)

    Marchini, Leonardo G.; Parra, Duclerc F.; Lugao, Ademar B.

    2011-01-01

    Films of PA 6 (polyamide) doped with europium luminescent complexes have been develop and studied for applications in advanced technologies. Development of optical marker for process monitoring is the focus of the present study. Based in doped luminescent polyamide samples were prepared for polymer processing use. Films were prepared by dissolution of PA 6 in acid moiety with addition of europium complex. Stability evaluation was done in samples submitted to irradiation with 10 and 100 kGy of ionizing source. The luminescent polymer matrices were characterized using the techniques of infrared, thermogravimetry, differential scanning calorimetry and photoluminescent properties by electron emission spectroscopy. (author)

  14. Stabilization of modified polyamide matrix

    Energy Technology Data Exchange (ETDEWEB)

    Marchini, Leonardo G.; Parra, Duclerc F.; Lugao, Ademar B., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Films of PA 6 (polyamide) doped with europium luminescent complexes have been develop and studied for applications in advanced technologies. Development of optical marker for process monitoring is the focus of the present study. Based in doped luminescent polyamide samples were prepared for polymer processing use. Films were prepared by dissolution of PA 6 in acid moiety with addition of europium complex. Stability evaluation was done in samples submitted to irradiation with 10 and 100 kGy of ionizing source. The luminescent polymer matrices were characterized using the techniques of infrared, thermogravimetry, differential scanning calorimetry and photoluminescent properties by electron emission spectroscopy. (author)

  15. 3D visualization of the internal nanostructure of polyamide thin films in RO membranes

    KAUST Repository

    Pacheco Oreamuno, Federico

    2015-11-02

    The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.

  16. 3D visualization of the internal nanostructure of polyamide thin films in RO membranes

    KAUST Repository

    Pacheco Oreamuno, Federico; Sougrat, Rachid; Reinhard, Martin; Leckie, James O.; Pinnau, Ingo

    2015-01-01

    The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.

  17. Screening of radical scavenging activity of some medicinal and aromatic plant extracts

    NARCIS (Netherlands)

    Miliauskas, G.; Venskutonis, R.P.; Beek, van T.A.

    2004-01-01

    Extracts of 12 medicinal and aromatic plants were investigated for their radical scavenging activity using DPPH and ABTS assays: Salvia sclarea, Salvia glutinosa, Salvia pratensis, Lavandula angustifolia, Calendula officinalis, Matricaria recutita, Echinacea purpurea, Rhaponticum carthamoides,

  18. Synthesis of Heteroaromatic Compounds by Oxidative Aromatization Using an Activated Carbon/Molecular Oxygen System

    Directory of Open Access Journals (Sweden)

    Masahiko Hayashi

    2009-08-01

    Full Text Available A variety of heteroaromatic compounds, such as substituted pyridines, pyrazoles, indoles, 2-substituted imidazoles, 2-substituted imidazoles, 2-arylbenzazoles and pyrimidin-2(1H-ones are synthesized by oxidative aromatization using the activated carbon and molecular oxygen system. Mechanistic study focused on the role of activated carbon in the synthesis of 2-arylbenzazoles is also discussed. In the final section, we will disclose the efficient synthesis of substituted 9,10-anthracenes via oxidative aromatization.

  19. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    2000-01-01

    Nine structurally different polycyclic aromatic hydrocarbons (PAHs) were tested for their ability to either agonize or antagonize the human androgen receptor (hAR) in a sensitive reporter gene assay based on CHO cells transiently cotransfected with a hAR vector and an MMTV-LUC vector. Benz...

  20. A Polyamide Inhibits Replication of Vesicular Stomatitis Virus by Targeting RNA in the Nucleocapsid

    Energy Technology Data Exchange (ETDEWEB)

    Gumpper, Ryan H.; Li, Weike; Castañeda, Carlos H.; Scuderi, M. José; Bashkin, James K.; Luo, Ming; Dutch, Rebecca Ellis

    2018-02-07

    Polyamides have been shown to bind double-stranded DNA by complementing the curvature of the minor groove and forming various hydrogen bonds with DNA. Several polyamide molecules have been found to have potent antiviral activities against papillomavirus, a double-stranded DNA virus. By analogy, we reason that polyamides may also interact with the structured RNA bound in the nucleocapsid of a negative-strand RNA virus. Vesicular stomatitis virus (VSV) was selected as a prototype virus to test this possibility since its genomic RNA encapsidated in the nucleocapsid forms a structure resembling one strand of an A-form RNA duplex. One polyamide molecule, UMSL1011, was found to inhibit infection of VSV. To confirm that the polyamide targeted the nucleocapsid, a nucleocapsid-like particle (NLP) was incubated with UMSL1011. The encapsidated RNA in the polyamide-treated NLP was protected from thermo-release and digestion by RNase A. UMSL1011 also inhibits viral RNA synthesis in the intracellular activity assay for the viral RNA-dependent RNA polymerase. The crystal structure revealed that UMSL1011 binds the structured RNA in the nucleocapsid. The conclusion of our studies is that the RNA in the nucleocapsid is a viable antiviral target of polyamides. Since the RNA structure in the nucleocapsid is similar in all negative-strand RNA viruses, polyamides may be optimized to target the specific RNA genome of a negative-strand RNA virus, such as respiratory syncytial virus and Ebola virus.

    IMPORTANCENegative-strand RNA viruses (NSVs) include several life-threatening pathogens, such as rabies virus, respiratory syncytial virus, and Ebola virus. There are no effective antiviral drugs against these viruses. Polyamides offer an exceptional opportunity because they may be optimized to target each NSV. Our studies on vesicular stomatitis virus, an NSV, demonstrated that a polyamide molecule could specifically target the viral RNA in the nucleocapsid and inhibit

  1. Structure-activity relationship studies of the aromatic positions in cyclopentapeptide CXCR4 antagonists

    DEFF Research Database (Denmark)

    Mungalpara, Jignesh; Zachariassen, Zack G; Thiele, Stefanie

    2013-01-01

    , and autoimmune diseases. While the structure-activity relationships for Arg(1), Arg(2), and Gly(4) are well established, less is understood about the roles of the aromatic residues 2-Nal(3) and D-Tyr(5). Here we report further structure-activity relationship studies of these two positions, which showed that (i......) the distal aromatic ring of the 2-Nal(3) side chain is required in order to maintain high potency and (ii) replacement of D-Tyr(5) with conformationally constrained analogues results in significantly reduced activity. However, a simplified analogue that contained Gly instead of D-Tyr(5) was only 13-fold less...

  2. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    KAUST Repository

    Louie, Jennifer Sarah; Pinnau, Ingo; Reinhard, Martin

    2011-01-01

    are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux

  3. The Raman and vibronic activity of intermolecular vibrations in aromatic-containing complexes and clusters

    International Nuclear Information System (INIS)

    Maxton, P.M.; Schaeffer, M.W.; Ohline, S.M.; Kim, W.; Venturo, V.A.; Felker, P.M.

    1994-01-01

    Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic-containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic--rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic-rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic-localized transition. It is found that intermolecular vibrational excitations can accompany aromatic-localized vibronic excitations by the usual Franck--Condon mechanism or by a mechanism dependent on the librational amplitude of the aromatic moiety during the course of the pertinent intermolecular vibration. The latter mechanism can impart appreciable intensity to bands that are forbidden by rigid-molecule symmetry selection rules. The applicability of such rules is therefore called into question. Finally, experimental spectra of intermolecular transitions, obtained by mass-selective, ionization-detected stimulated Raman spectroscopies, are reported for benzene--X (X=Ar, --Ar 2 , N 2 , HCl, CO 2 , and --fluorene), fluorobenzene--Ar and --Kr, aniline--Ar, and fluorene--Ar and --Ar 2 . The results support the conclusions of the theoretical analyses and provide further evidence for the value of Raman methods in characterizing intermolecular vibrational level structures

  4. Vibration electrospinning of Polyamide-66/Multiwall Carbon Nanotube Nanocomposite: introducing electrically conductive, ultraviolet blocking and antibacterial properties

    Directory of Open Access Journals (Sweden)

    Zohoori Salar

    2017-09-01

    Full Text Available Fabrication of electro-conductive fiber is a novel process. Nanocomposites of multiwall carbon nanotube/polyamide66 were produced by electrospinning with different amounts of multiwall carbon nanotube. Field emission scanning electron microscope and Fourier transform infrared spectroscopy of samples proved the existence of multiwall carbon nanotube distribution in polyamide 66 nanofibers. Results showed that electro conductivity of electrospun multiwall carbon nanotube/polyamide 66 nano fiber has increased in comparison with electrospun polyamide 66. Moreover, UV blocking of samples was investigated which has shown that using multiwall carbon nanotube in polyamide 66 increases UV blocking of fibers. Furthermore, anti-bacterial activity of nanocomposite showed that these nanocomposites have antibacterial property against both Staphylococcus Aureus and Escherichia Coli bacteria according to AATCC test method.

  5. Extraction of sediment-associated polycyclic aromatic hydrocarbons with granular activated carbon

    NARCIS (Netherlands)

    Rakowska, M.I.; Kupryianchyk, D.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.; Koelmans, A.A.

    2013-01-01

    Addition of activated carbon (AC) to sediments has been proposed as a method to reduce ecotoxicological risks of sediment-bound contaminants. The present study explores the effectiveness of granular AC (GAC) in extracting polycyclic aromatic hydrocarbon (PAH) from highly contaminated sediments. Four

  6. Sequence-specific DNA alkylation by tandem Py-Im polyamide conjugates.

    Science.gov (United States)

    Taylor, Rhys Dylan; Kawamoto, Yusuke; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

    2014-09-01

    Tandem N-methylpyrrole-N-methylimidazole (Py-Im) polyamides with good sequence-specific DNA-alkylating activities have been designed and synthesized. Three alkylating tandem Py-Im polyamides with different linkers, which each contained the same moiety for the recognition of a 10 bp DNA sequence, were evaluated for their reactivity and selectivity by DNA alkylation, using high-resolution denaturing gel electrophoresis. All three conjugates displayed high reactivities for the target sequence. In particular, polyamide 1, which contained a β-alanine linker, displayed the most-selective sequence-specific alkylation towards the target 10 bp DNA sequence. The tandem Py-Im polyamide conjugates displayed greater sequence-specific DNA alkylation than conventional hairpin Py-Im polyamide conjugates (4 and 5). For further research, the design of tandem Py-Im polyamide conjugates could play an important role in targeting specific gene sequences. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks.

    Directory of Open Access Journals (Sweden)

    Patrick Tarnow

    Full Text Available The majority of printing inks are based on mineral oils (MOs which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans.

  8. Structure-Activity Relationships for Rates of Aromatic Amine Oxidation by Manganese Dioxide.

    Science.gov (United States)

    Salter-Blanc, Alexandra J; Bylaska, Eric J; Lyon, Molly A; Ness, Stuart C; Tratnyek, Paul G

    2016-05-17

    New energetic compounds are designed to minimize their potential environmental impacts, which includes their transformation and the fate and effects of their transformation products. The nitro groups of energetic compounds are readily reduced to amines, and the resulting aromatic amines are subject to oxidation and coupling reactions. Manganese dioxide (MnO2) is a common environmental oxidant and model system for kinetic studies of aromatic amine oxidation. In this study, a training set of new and previously reported kinetic data for the oxidation of model and energetic-derived aromatic amines was assembled and subjected to correlation analysis against descriptor variables that ranged from general purpose [Hammett σ constants (σ(-)), pKas of the amines, and energies of the highest occupied molecular orbital (EHOMO)] to specific for the likely rate-limiting step [one-electron oxidation potentials (Eox)]. The selection of calculated descriptors (pKa, EHOMO, and Eox) was based on validation with experimental data. All of the correlations gave satisfactory quantitative structure-activity relationships (QSARs), but they improved with the specificity of the descriptor. The scope of correlation analysis was extended beyond MnO2 to include literature data on aromatic amine oxidation by other environmentally relevant oxidants (ozone, chlorine dioxide, and phosphate and carbonate radicals) by correlating relative rate constants (normalized to 4-chloroaniline) to EHOMO (calculated with a modest level of theory).

  9. Structure-Activity Relationships for Rates of Aromatic Amine Oxidation by Manganese Dioxide

    International Nuclear Information System (INIS)

    Salter-Blanc, Alexandra J.; Lyon, Molly A.; Science University, Portland, OR; Ness, Stuart C.; Science University, Portland, OR; Tratnyek, Paul G.; Science University, Portland, OR

    2016-01-01

    New energetic compounds are designed to minimize their potential environmental impacts, which includes their transformation and the fate and effects of their transformation products. The nitro groups of energetic compounds are readily reduced to amines, and the resulting aromatic amines are subject to oxidation and coupling reactions. Manganese dioxide (MnO 2 ) is a common environmental oxidant and model system for kinetic studies of aromatic amine oxidation. Here in this study, a training set of new and previously reported kinetic data for the oxidation of model and energetic-derived aromatic amines was assembled and subjected to correlation analysis against descriptor variables that ranged from general purpose [Hammett σ constants (σ − ), pK a s of the amines, and energies of the highest occupied molecular orbital (E HOMO )] to specific for the likely rate-limiting step [one-electron oxidation potentials (E ox )]. The selection of calculated descriptors (pK a ), E HOMO , and E ox ) was based on validation with experimental data. All of the correlations gave satisfactory quantitative structure-activity relationships (QSARs), but they improved with the specificity of the descriptor. The scope of correlation analysis was extended beyond MnO 2 to include literature data on aromatic amine oxidation by other environmentally relevant oxidants (ozone, chlorine dioxide, and phosphate and carbonate radicals) by correlating relative rate constants (normalized to 4-chloroaniline) to E HOMO (calculated with a modest level of theory).

  10. Synthesis and Properties of Cross-Linked Polyamide Aerogels

    Science.gov (United States)

    Williams, Jarrod C.; Meador, Mary Ann; McCorkle, Linda

    2015-01-01

    We report the first synthesis of cross-linked polyamide aerogels through step growth polymerization using a combination of diamines, diacid chloride and triacid chloride. Polyamide oligomers endcapped with amines are prepared as stable solutions in N-methylpyrrolidinone from several different diamine precursors and 1,3-benzenedicarbonyl dichloride. Addition of 1,3,5-benzenetricarbonyl trichloride yields gels which form in under five minutes according to the scheme shown. Solvent exchange of the gels into ethanol, followed by drying using supercritical CO2 extraction gives colorless aerogels with densities around 0.1 to 0.2 gcm3. Thicker monolithes of the polyamide aerogels are stiff and strong, while thin films of certain formulations are highly flexible, durable, and even translucent. These materials may have use as insulation for deployable space structures, rovers, habitats or extravehicular activity suits as well as in many terrestrial applications. Strucure property relationships of the aerogels, including surface area, mechanical properties, and thermal conductivity will be discussed.

  11. Prediction of activation energies for aromatic oxidation by cytochrome P450

    DEFF Research Database (Denmark)

    Rydberg, Patrik; Ryde, Ulf; Olsen, Lars

    2008-01-01

    We have estimated the activation energy for aromatic oxidation by compound I in cytochrome P450 for a diverse set of 17 substrates using state-of-the-art density functional theory (B3LYP) with large basis sets. The activation energies vary from 60 to 87 kJ/mol. We then test if these results can...... be reproduced by computationally less demanding methods. The best methods (a B3LYP calculation of the activation energy of a methoxy-radical model or a partial least-squares model of the semiempirical AM1 bond dissociation energies and spin densities of the tetrahedral intermediate for both a hydroxyl...

  12. Aromatic Medicinal Plants of the Lamiaceae Family from Uzbekistan: Ethnopharmacology, Essential Oils Composition, and Biological Activities

    Directory of Open Access Journals (Sweden)

    Nilufar Z. Mamadalieva

    2017-02-01

    Full Text Available Plants of the Lamiaceae family are important ornamental, medicinal, and aromatic plants, many of which produce essential oils that are used in traditional and modern medicine, and in the food, cosmetics, and pharmaceutical industry. Various species of the genera Hyssopus, Leonurus, Mentha, Nepeta, Origanum, Perovskia, Phlomis, Salvia, Scutellaria, and Ziziphora are widespread throughout the world, are the most popular plants in Uzbek traditional remedies, and are often used for the treatment of wounds, gastritis, infections, dermatitis, bronchitis, and inflammation. Extensive studies of the chemical components of these plants have led to the identification of many compounds, as well as essentials oils, with medicinal and other commercial values. The purpose of this review is to provide a critical overview of the literature surrounding the traditional uses, ethnopharmacology, biological activities, and essential oils composition of aromatic plants of the family Lamiaceae, from the Uzbek flora.

  13. Detection of chlorinated aromatic compounds

    Science.gov (United States)

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  14. Synthesis and Thermal and Photo Behaviors of New Polyamide/Organocaly Nanocomposites Containing Para Phenylenediacrylic Moiety

    Science.gov (United States)

    Faghihi, Khalil; Soleimani, Masoumeh; Shabanian, Meisam; Abootalebi, Ashraf Sadat

    2011-06-01

    New type of aromatic polyamide/montmorillonite nanocomposites were produced using solution process in N-methyl-2-pyrolidone. Amide chains were synthesized from 4,4'-diaminodiphenyl sulfone and p-phenylenediacrylic acid in N-methyl-2-pyrolidone. The resulting nanocomposite films containing 5-15 mass % of organoclay were characterized for FT-IR, scanning electronmicroscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), optical transparency and water absorption measurements. The distribution of organoclay and nanostructure of the composites were investigated by (XRD) and SEM analyses. Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. The percentage optical transparency and water absorption of these hybrids was found to be much reduced upon the addition of modified layered silicate indicating decreased permeability.

  15. Polyamide copolymers having 2,5-furan dicarboxamide units

    Science.gov (United States)

    Chisholm, Bret Ja; Samanta, Satyabrata

    2017-09-19

    Polyamide copolymers, and methods of making and using polyamide copolymers, having 2,5-furan dicarboxamide units are disclosed herein. Such polymers can be useful for engineering thermoplastics having advantageous physical and/or chemical properties.

  16. Adsorption behaviour of aromatic in different activated carbon: (Frendlich and Langmuir models)

    International Nuclear Information System (INIS)

    Nouri, S.; Haghseresht, F.; Lu, Max

    2001-01-01

    Adsorption behavior of p-Cresol, Benzoic acid and nitrobenzene on the two different activated carbons was carried out at 301 K and at controlled ph conditions. In acidic conditions, well below the pK a of all solutes, it was observed that the adsorbate solubility and the electron density of its aromatic ring were the influencing factors on the extent of the adsorption by affecting the extent of London dispersion forces. In higher solution ph conditions, on the other hand, it was found that the electrostatic forces played a significant role on the extent on adsorption. The Effect of ph must be considered from its combined effects on the carbon surface and on the solute molecules. It was found that the uptake of the molecular form of the aromatic solute was dependent on the substituents of the aromatic ring. Adsorption of the solutes in higher ph values was found to be dependent on the concentration of anionic form of the solutes. All isotherms on the F 100 and S E I were fitted into Langmuir and Freundlich isotherm Equations, respectively to find the relative factors

  17. Synthesis and antifungal activity of halogenated aromatic bis-γ-lactones analogous to avenaciolide

    Directory of Open Access Journals (Sweden)

    Pedro A. Castelo-Branco

    2012-01-01

    Full Text Available Here we describe the total syntheses and characterization by elemental analyses, infrared and NMR spectroscopy of three new compounds analogous to avenaciolide, a bis-γ-lactone isolated from Aspergillus avenaceus that possesses antifungal activity, where the octyl group of the natural product was replaced by aromatic groups containing chlorine and fluorine atoms. The effects of the avenaciolide, the novel compounds and their synthetic precursors on mycelia development and conidia germination of Colletotrichum gloeosporioides and Fusarium solani were evaluated in vitro. The title compounds were almost as active as avenaciolide. The absolute structures of the chlorinated analogs were determined by X-ray diffraction analysis.

  18. Influence of activated carbon surface acidity on adsorption of heavy metal ions and aromatics from aqueous solution

    International Nuclear Information System (INIS)

    Sato, Sanae; Yoshihara, Kazuya; Moriyama, Koji; Machida, Motoi; Tatsumoto, Hideki

    2007-01-01

    Adsorption of toxic heavy metal ions and aromatic compounds onto activated carbons of various amount of surface C-O complexes were examined to study the optimum surface conditions for adsorption in aqueous phase. Cadmium(II) and zinc(II) were used as heavy metal ions, and phenol and nitrobenzene as aromatic compounds, respectively. Activated carbon was de-ashed followed by oxidation with nitric acid, and then it was stepwise out-gassed in helium flow up to 1273 K to gradually remove C-O complexes introduced by the oxidation. The oxidized activated carbon exhibited superior adsorption for heavy metal ions but poor performance for aromatic compounds. Both heavy metal ions and aromatics can be removed to much extent by the out-gassed activated carbon at 1273 K. Removing C-O complexes, the adsorption mechanisms would be switched from ion exchange to Cπ-cation interaction for the heavy metals adsorption, and from some kind of oxygen-aromatics interaction to π-π dispersion for the aromatics

  19. Processing for maximizing the level of crystallinity in linear aromatic polyimides

    Science.gov (United States)

    St.clair, Terry L. (Inventor)

    1991-01-01

    The process of the present invention includes first treating a polyamide acid (such as LARC-TPI polyamide acid) in an amide-containing solvent (such as N-methyl pyrrolidone) with an aprotic organic base (such as triethylamine), followed by dehydrating with an organic dehydrating agent (such as acetic anhydride). The level of crystallinity in the linear aromatic polyimide so produced is maximized without any degradation in the molecular weight thereof.

  20. Trends in biological activity research of wild-growing aromatic plants from Central Balkans

    Directory of Open Access Journals (Sweden)

    Džamić, A.M.

    2016-12-01

    Full Text Available Flowering plants consists of more than 300.000 species around the world, out of which a small percentage has been sufficiently investigated from phytochemical and biological activity aspects. Plant diversity of the Balkans is very rich, but still poorly investigated. The aim of this paper is survey of current status and trends in research of wild-growing aromatic plants from Central Balkans. Many aromatic plants are investigated from morphological, physiological, ecological, systematic and phytochemical aspects. However, traditionally used medicinal and aromatic plants can also be considered from applicative aspects, concerning their health effects, and from wide range of usage in cosmetics, and as food, agrochemical and pharmaceutical products. In order to achieve all planned objectives, following methodology has been applied: field research, taxonomic authentication and, comparative biologically assayed phytochemical investigations. The total herbal extracts, postdistillation waste (deodorized extracts, essential oils and individual compounds of some autochthonous plants have been considered as potential source of antibacterial, antifungal, anti-biofilm, antioxidant and cytotoxic agents. In this manuscript, composition of essential oils and extracts were evaluated in a number of species, from the Apiaceae, Lamiaceae, Rosaceae and Asteraceae families. Extracts which were rich in phenols mostly of flavonoids, often showed high antioxidant potential. Also, phenolic compounds identified in essential oils and extracts were mostly responsible for expected antimicrobial activity. Current worldwide demand is to reduce or, if possible, eliminate chemically synthesized food additives. Plant-produced compounds are becoming of interest as a source of more effective and safe substances than synthetically produced antimicrobial agents (as inhibitors, growth reducers or even inactivators that control growth of microorganisms. Many different pathogens have

  1. Antimicrobial activity of essential oils from Mediterranean aromatic plants against several foodborne and spoilage bacteria.

    Science.gov (United States)

    Silva, Nuno; Alves, Sofia; Gonçalves, Alexandre; Amaral, Joana S; Poeta, Patrícia

    2013-12-01

    The antimicrobial activity of essential oils extracted from a variety of aromatic plants, often used in the Portuguese gastronomy was studied in vitro by the agar diffusion method. The essential oils of thyme, oregano, rosemary, verbena, basil, peppermint, pennyroyal and mint were tested against Gram-positive (Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, and Staphylococcus epidermidis) and Gram-negative strains (Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa). For most essential oils examined, S. aureus, was the most susceptible bacteria, while P. aeruginosa showed, in general, least susceptibility. Among the eight essential oils evaluated, thyme, oregano and pennyroyal oils showed the greatest antimicrobial activity, followed by rosemary, peppermint and verbena, while basil and mint showed the weakest antimicrobial activity. Most of the essential oils considered in this study exhibited a significant inhibitory effect. Thyme oil showed a promising inhibitory activity even at low concentration, thus revealing its potential as a natural preservative in food products against several causal agents of foodborne diseases and food spoilage. In general, the results demonstrate that, besides flavoring the food, the use of aromatic herbs in gastronomy can also contribute to a bacteriostatic effect against pathogens.

  2. Metabolic activation of polycyclic and heterocyclic aromatic hydrocarbons and DNA damage: A review

    International Nuclear Information System (INIS)

    Xue Weiling; Warshawsky, David

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic compounds (HACs) constitute a major class of chemical carcinogens present in the environment. These compounds require activation to electrophilic metabolites to exert their mutagenic or carcinogenic effects. There are three principal pathways currently proposed for metabolic activation of PAH and HAC: the pathway via bay region dihydrodiol epoxide by cytochrome P450 enzymes (CYPs), the pathway via radical cation by one-electron oxidation, and the ortho-quinone pathway by dihydrodiol dehydrogenase (DD). In addition to these major pathways, a brief description of a minor metabolic activation pathway, sulfonation, for PAHs that contain a primary benzylic alcoholic group or secondary hydroxyl group(s) is included in this review. The DNA damages caused through the reactive metabolites of PAH/HAC are described involving the DNA covalent binding to form stable or depurinating adducts, the formation of apurinic sites, and the oxidative damage. The review emphasizes the chemical/biochemical reactions involved in the metabolic processes and the chemical structures of metabolites and DNA adducts

  3. Adsorption of aromatic compounds from the biodegradation of azo dyes on activated carbon

    Science.gov (United States)

    Faria, P. C. C.; Órfão, J. J. M.; Figueiredo, J. L.; Pereira, M. F. R.

    2008-03-01

    The adsorption of three selected aromatic compounds (aniline, sulfanilic acid and benzenesulfonic acid) on activated carbons with different surface chemical properties was investigated at different solution pH. A fairly basic commercial activated carbon was modified by means of chemical treatment with HNO 3, yielding an acid activated carbon. The textural properties of this sample were not significantly changed after the oxidation treatment. Equilibrium isotherms of the selected compounds on the mentioned samples were obtained and the results were discussed in relation to their surface chemistry. The influence of electrostatic and dispersive interactions involved in the uptake of the compounds studied was evaluated. The Freundlich model was used to fit the experimental data. Higher uptakes are attained when the compounds are present in their molecular form. In general, adsorption was disfavoured by the introduction of oxygen-containing groups on the surface of the activated carbon.

  4. Promoter scanning of the human COX-2 gene with 8-ring polyamides: unexpected weakening of polyamide-DNA binding and selectivity by replacing an internal N-Me-pyrrole with β-alanine.

    Science.gov (United States)

    Bashkin, James K; Aston, Karl; Ramos, Joseph P; Koeller, Kevin J; Nanjunda, Rupesh; He, Gaofei; Dupureur, Cynthia M; David Wilson, W

    2013-02-01

    Rules for polyamide-DNA recognition have proved invaluable for the design of sequence-selective DNA binding agents in cell-free systems. However, these rules are not fully transferrable to predicting activity in cells, tissues or animals, and additional refinements to our understanding of DNA recognition would help biomedical studies. Similar complexities are encountered when using internal β-alanines as polyamide building blocks in place of N-methylpyrrole; β-alanines were introduced in polyamide designs to maintain good hydrogen bonding registry with the target DNA, especially for long polyamides or those with several GC bp (P.B. Dervan, A.R. Urbach, Essays Contemp. Chem. (2001) 327-339). Thus, to clarify important subtleties of molecular recognition, we studied the effects of replacing a single pyrrole with β-alanine in 8-ring polyamides designed against the Ets-1 transcription factor. Replacement of a single internal N-methylpyrrole with β-alanine to generate a β/Im pairing in two 8-ring polyamides causes a decrease in DNA binding affinity by two orders of magnitude and decreases DNA binding selectivity, contrary to expectations based on the literature. Measurements were made by fluorescence spectroscopy, quantitative DNA footprinting and surface plasmon resonance, with these vastly different techniques showing excellent agreement. Furthermore, results were validated for a range of DNA substrates from small hairpins to long dsDNA sequences. Docking studies helped show that β-alanine does not make efficient hydrophobic contacts with the rest of the polyamide or nearby DNA, in contrast to pyrrole. These results help refine design principles and expectations for polyamide-DNA recognition. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. Lignans and aromatic glycosides from Piper wallichii and their antithrombotic activities.

    Science.gov (United States)

    Shi, Yan-Ni; Shi, Yi-Ming; Yang, Lian; Li, Xing-Cong; Zhao, Jin-Hua; Qu, Yan; Zhu, Hong-Tao; Wang, Dong; Cheng, Rong-Rong; Yang, Chong-Ren; Xu, Min; Zhang, Ying-Jun

    2015-03-13

    Piper wallichii (Miq.) Hand.-Mazz. is a medicinal plant used widely for the treatment of rheumatoid arthritis, inflammatory diseases, cerebral infarction and angina in China. Previous study showed that lignans and neolignans from Piper spp. had potential inhibitory activities on platelet aggregation. In the present study, we investigated the chemical constituents of Piper wallichii and their antithrombotic activities, to support its traditional uses. The methanolic extract of the air-dried stems of Piper wallichii was separated and purified using various chromatographic methods, including semi-preparative HPLC. The chemical structures of the isolates were determined by detailed spectroscopic analysis, and acidic hydrolysis in case of the new glycoside 2. Determination of absolute configurations of the new compound 1 was facilitated by calculated electronic circular dichroism using time-dependent density-functional theory. All compounds were tested for their inhibitory effects on platelet aggregation induced by platelet activating factor (PAF) in rabbits׳ blood model, from which the active ones were further evaluated the in vivo antithrombotic activity in zebrafish model. A new neolignan, piperwalliol A (1), and four new aromatic glycosides, piperwalliosides A-D (2-5) were isolated from the stems of Piper wallichii, along with 25 known compounds, including 13 lignans, six aromatic glycosides, two phenylpropyl aldehydes, and four biphenyls. Five known compounds (6-10) showed in vitro antiplatelet aggregation activities. Among them, (-)-syringaresinol (6) was the most active compound with an IC50 value of 0.52 mM. It is noted that in zebrafish model, the known lignan 6 showed good in vivo antithrombotic effect with a value of 37% at a concentration of 30 μM, compared with the positive control aspirin with the inhibitory value of 74% at a concentration of 125μM. This study demonstrated that lignans, phenylpropanoid and biphenyl found in Piper wallichii may be

  6. Antisickling activity evaluation of 4 aromatic aldehydes using proton magnetic relaxation

    International Nuclear Information System (INIS)

    Falcon Dieguez, J.E.; Grisel del Toro Garcia; Yamirka Alonso Geli; Lores Guevara, M.A.

    2006-12-01

    The formation of a Shiff base aduct hemoglobin-aromatic aldehyde, has been reported as inhibitor of the hemoglobin S polymerization. Using the Proton Magnetic Resonance methodology, the polymerization kinetics can be studied and the delay time can be determined. Our studies in vitro show the inhibitor effect of the isovanillin, o-vanillin, m-hydroxybenzaldehyde and the p-hydroxybenzaldehyde, using molar ratio (hemoglobin S/compound) 1:1, 1:4 and 1:8. The td increment (expressed in percents) obtained for each one of the molar ratio was the following: isovanillin: 34±6% (1:1), 68±16% (1:4), ovanillin: 26±10% (1:1), 63±20% (1:4), m-hydroxybelzaldehyde: 16±4% (1:1), 44±12% (1:4) and the phydroxybenzaldehyde: 10±3% (1:1), 32±8% (1:4). In the case of 1:8, the characteristic kinetics curve was not obtained. At the used concentrations, hemolytic activity was not found on the red blood cell. These results confirm the antisickling activity of these aromatic aldehydes, for a technique different to that reported in literature that also allows the quantification of concentration effect. The same ones will facilitate the study of the therapeutic usefulness of these compounds in the sickle cell anemia treatment. (author)

  7. Methylated polycyclic aromatic hydrocarbons and/or their metabolites are important contributors to the overall estrogenic activity of polycyclic aromatic hydrocarbon-contaminated soils.

    Science.gov (United States)

    Lam, Monika M; Engwall, Magnus; Denison, Michael S; Larsson, Maria

    2018-02-01

    In the present study 42 polycyclic aromatic compounds (PACs) were investigated for their estrogenic potential using the VM7Luc4E2 transactivation assay. Relative potencies were determined for mass-balance analysis. In addition, compounds were tested in combination with the estrogen receptor (ER) antagonist ICI182,780 (ICI) and the aryl hydrocarbon receptor antagonist/CYP1A1 inhibitor α-naphthoflavone. Luciferase induction and CYP1A1-dependent ethoxyresorufin-O-deethylase (EROD) activity were measured to assess whether the estrogenic activity was elicited by the compound itself and/or by its metabolites. Relative potencies ranged between 10 -7 and 10 -4 . The ability of ICI to decrease luciferase activity stimulated by all compounds indicated that the induction responses were ER-dependent. The aryl hydrocarbon receptor antagonist/CYP1A1 inhibitor α-naphthoflavone decreased luciferase induction and EROD activity by several compounds, including the methylated chrysenes, suggesting that metabolites of these chemicals contributed to ER activation. Several PACs, such as acridine and its derivatives, appear to directly activate the ER. Furthermore, extracts of soils from industrial areas were examined using this bioassay, and estrogenic activity was detected in all soil samples. Mass-balance analysis using a combination of relative potencies and chemical analysis of the samples suggested that polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs, such as 1- and 3-methylchrysene, are important contributors to the overall estrogenic activity. However, these results revealed that a considerable proportion of the estrogenic activity in the soil remained unexplained, indicating the presence of other significant estrogenic compounds. Environ Toxicol Chem 2018;37:385-397. © 2017 SETAC. © 2017 SETAC.

  8. Reaction of active uranium and thorium with aromatic carbonyls and pinacols in hydrocarbon solvents

    International Nuclear Information System (INIS)

    Kahn, B.E.; Rieke, R.D.

    1988-01-01

    Highly reactive uranium and thorium metal powders have been prepared by reduction of the anhydrous metal(IV) chlorides in hydrocarbon solvents. The reduction employs the crystalline hydrocarbon-soluble reducing agent [(TMEDA)Li] 2 [Nap] (TMEDA = N,N,N',N'-tetramethylethylenediamine, Nap = naphthalene). The resulting active metal powders have been shown to be extremely reactive with oxygen-containing compounds and have been used in the reductive coupling of aromatic ketones giving tetra-arylethylenes. Reactions with pinacols have given some mechanistic insight into the ketone coupling reaction. These finely divided metal powders activate very weakly acidic C-H bonds forming metal hydrides, which can be transferred to organic substrates

  9. Aromatic plants play an important role in promoting soil biological activity related to nitrogen cycling in an orchard ecosystem.

    Science.gov (United States)

    Chen, Xinxin; Song, Beizhou; Yao, Yuncong; Wu, Hongying; Hu, Jinghui; Zhao, Lingling

    2014-02-15

    Aromatic plants can substantially improve the diversity and structure of arthropod communities, as well as reduce the number of herbivore pests and regulate the abundance of predators and parasitoids. However, it is not clear whether aromatic plants are also effective in improving soil quality by enhancing nutrient cycling. Here, field experiments are described involving intercropping with aromatic plants to investigate their effect on soil nitrogen (N) cycling in an orchard ecosystem. The results indicate that the soil organic nitrogen and available nitrogen contents increased significantly in soils intercropped with aromatic plants. Similarly, the activities of soil protease and urease increased, together with total microbial biomass involved in N cycling, including nitrifying bacteria, denitrifying bacteria and azotobacters, as well as the total numbers of bacteria and fungi. This suggests that aromatic plants improve soil N cycling and nutrient levels by enriching the soil in organic matter through the regulation of both the abundance and community structure of microorganisms, together with associated soil enzyme activity, in orchard ecosystems. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Antioxidant activity of a new aromatic geranyl derivative of the resinous exudates from Heliotropium glutinosum Phil.

    Science.gov (United States)

    Modak, Brenda; Rojas, Macarena; Torres, René; Rodilla, Jesús; Luebert, Federico

    2007-05-21

    Heliotropium glutinosum Phil. (Heliotropiceae) is a resinous bush that grows at a height of 2000 m in Chañaral, Chile. From the resinous exudates of Heliotropium glutinosum Phil. a new aromatic geranyl derivative: 4-methoxy-3-[(2)-7'-methyl-3'-hydroxymethyl-2',6'-octadienyl] phenol (1) and three flavonoids: 5,3'-dihydroxy-7,4'-dimethoxyflavanone (2), 5,4'-dihydroxy-7-methoxyflavanone (3) and 4'-acetyl-5-hydroxy-7-methoxyflavanone (4) were isolated and their structures were determined. Their antioxidant activity were evaluated using the bleaching of ABTS and DPPH derived cation radical methods and expressed in terms of FRE (fast reacting equivalents) and TRE (total reacting equivalents), where FRE is a good measure of the quick protection of a given compound against oxidants and TRE measures the degree of long-term protection of the antioxidant, or how effective it is against a strong oxidative stress.

  11. Emission of Polycyclic Aromatic Hydrocarbons from the Exhalation Zones of Thermally Active Mine Waste Dumps

    Directory of Open Access Journals (Sweden)

    Patrycja Kuna-Gwoździewicz

    2013-01-01

    Full Text Available The article presents results of research carried out on the occurrence of polycyclic aromatic hydrocarbons (PAH in gases of exhalation zones, created on the surface of a thermally active coal mine waste dump. The oxidation and self-heating of mine waste are accompanied with the intensive emission of flue gases, including PAH group compounds. Taking into consideration the fact the hydrocarbons show strong genotoxic, mutagenic and carcinogenic properties, research was conducted to establish their content in the examined gases. The research object was a gangue dump located in Rybnik. The research was performed in 2012. In total, 24 samples of gas were collected with PUF (polyurethane foam sampling cartridges with a quartz fibre filter and an aspirator. The collected samples were analysed with the use of high performance liquid chromatography (HPLC and a fluorescence detector (FLD to evaluate the amount of PAH present.

  12. Synthesis and Antiradical Activity of Isoquercitrin Esters with Aromatic Acids and Their Homologues

    Directory of Open Access Journals (Sweden)

    Eva Heřmánková-Vavříková

    2017-05-01

    Full Text Available Isoquercitrin, (IQ, quercetin-3-O-β-d-glucopyranoside is known for strong chemoprotectant activities. Acylation of flavonoid glucosides with carboxylic acids containing an aromatic ring brings entirely new properties to these compounds. Here, we describe the chemical and enzymatic synthesis of a series of IQ derivatives at the C-6″. IQ benzoate, phenylacetate, phenylpropanoate and cinnamate were prepared from respective vinyl esters using Novozym 435 (Lipase B from Candida antarctica immobilized on acrylic resin. The enzymatic procedure gave no products with “hydroxyaromatic” acids, their vinyl esters nor with their benzyl-protected forms. A chemical protection/deprotection method using Steglich reaction yielded IQ 4-hydroxybenzoate, vanillate and gallate. In case of p-coumaric, caffeic, and ferulic acid, the deprotection lead to the saturation of the double bonds at the phenylpropanoic moiety and yielded 4-hydroxy-, 3,4-dihydroxy- and 3-methoxy-4-hydroxy-phenylpropanoates. Reducing capacity of the cinnamate, gallate and 4-hydroxyphenylpropanoate towards Folin-Ciocalteau reagent was significantly lower than that of IQ, while other derivatives displayed slightly better or comparable capacity. Compared to isoquercitrin, most derivatives were less active in 1,1-diphenyl-2-picrylhydrazyl (DPPH radical scavenging, but they showed significantly better 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid, ABTS scavenging activity and were substantially more active in the inhibition of tert-butylhydroperoxide induced lipid peroxidation of rat liver microsomes. The most active compounds were the hydroxyphenylpropanoates.

  13. Chemical composition and antimicrobial activity of the essential oil from the edible aromatic plant Aristolochia delavayi.

    Science.gov (United States)

    Li, Zhi-Jian; Njateng, Guy S S; He, Wen-Jia; Zhang, Hong-Xia; Gu, Jian-Long; Chen, Shan-Na; Du, Zhi-Zhi

    2013-11-01

    The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)-dec-2-enal (52.0%), (E)-dodec-2-enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 μg/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 μg/ml, while (E)-dec-2-enal presented a lower antifungal activity than the essential oil. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

  14. Synthesis of Cyclic Py-Im Polyamide Libraries

    OpenAIRE

    Li, Benjamin C.; Montgomery, David C.; Puckett, James W.; Dervan, Peter B.

    2013-01-01

    Cyclic Py-Im polyamides containing two GABA turn units exhibit enhanced DNA binding affinity, but extensive studies of their biological properties have been hindered due to synthetic inaccessibility. A facile modular approach toward cyclic polyamides has been developed via microwave-assisted solid-phase synthesis of hairpin amino acid oligomer intermediates followed by macrocyclization. A focused library of cyclic polyamides 1–7 targeted to the androgen response element (ARE) and the estrogen...

  15. Sorption kinetics of polycyclic aromatic hydrocarbons removal using granular activated carbon: Intraparticle diffusion coefficients

    International Nuclear Information System (INIS)

    Valderrama, C.; Gamisans, X.; Heras, X. de las; Farran, A.; Cortina, J.L.

    2008-01-01

    Granular activated carbon (GAC) was evaluated as a suitable sorbent for polycyclic aromatic hydrocarbons (PAHs) removal from aqueous solutions. For this purpose, kinetic measurements on the extraction of a family of six PAHs were taken. A morphology study was performed by means of a scanning electron microscopy (SEM) analysis of GAC samples. Analyses of the batch rate data for each PAH were carried out using two kinetic models: the homogenous particle diffusion model (HPDM) and the shell progressive model (SPM). The process was controlled by diffusion rate the solutes (PAHs) that penetrated the reacted layer at PAH concentrations in the range of 0.2-10 mg L -1 . The effective particle diffusion coefficients (D eff ) derived from the two models were determined from the batch rate data. The Weber and Morris intraparticle diffusion model made a double contribution to the surface and pore diffusivities in the sorption process. The D eff values derived from both the HPMD and SPM equations varied from 1.1 x 10 -13 to 6.0 x 10 -14 m 2 s -1 . The simplest model, the pore diffusion model, was applied first for data analysis. The model of the next level of complexity, the surface diffusion model, was applied in order to gain a deeper understanding of the diffusion process. This model is able to explain the data, and the apparent surface diffusivities are in the same order of magnitude as the values for the sorption of functionalized aromatic hydrocarbons (phenols and sulphonates) that are described in the literature

  16. Polycyclic aromatic hydrocarbons pollution effect on soil biological activity in the anthropogenic contaminated area

    Science.gov (United States)

    Batukaev, Abdulmalik; Sushkova, Svetlana; Minkina, Tatiana; Antonenko, Elena; Salamova, Anzhelika; Gimp, Alina; Deryabkina, Irina

    2017-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are one of the most significant environmental contaminants with mutagenic and carcinogenic properties to all living organisms. The changes in microbial community structure in technogenic polluted soil may be used as tools for predicting and monitoring natural degradation and for search the most effective and appropriate pathways of bioremediation. The present study is aimed to research the biological activity of the soil in the emission zone of Novocherkassk Power station (NPs) (Russia) polluted by PAHs in 2015. The NPs is one of the largest thermal power stations in the south of Russia burning low-quality coal appurtenant the enterprises of I hazardous class. Monitoring plots were located on virgin or no-till fallow areas and not subject to the sanitary-protection zone of the NPs. Soil samples were taken from a depth of 0- to 20-cm, because the major part of PAHs are accumulated in the surface soil layer. The soils of the plots mainly include Chernozems Calcic (plots 1, 4, 5, 7, 9 and 10), Phaeozems Haplic (plots 3, 6, 8 and 11) Fluvisols Umbric (plots 2 and 12). In the soil of 12 monitoring plots located around NPs there were determined the main enzymes, abundance of soil bacteria and 17 priority PAHs. PAHs extraction from soil was performed by new developed ecologically clean method of subcritical water extraction without organic solvents (Sushkova et al., 2015). The level of PAHs around NPs is high at the nearest to factory monitoring plots situated at distance 1,0-1,2 km and reaches from 1600,1±14,7 up to 373,6±7,1 mkg/kg in the 20-cm soil layer. Gradually decrease of PAHs contamination is observed while increasing the distance from the NPs. The level of highmolecular PAHs (4-6 aromatic rings) exceeds the level of lowmolecular (2-3 aromatic rings) PAHs in all monitoring plots situated though the prevailing wind direction from NPs. The close correlations were found between PAHs content and biological activity parameters

  17. Electron beam induced modification of grafted polyamides

    International Nuclear Information System (INIS)

    Timus, D.M.; Brasoveanu, M.M.; Bradley, D.A.; Popov, A.M.

    1998-01-01

    It is well known that irradiation, when applied on its own or in combination with other physical and chemical treatments, can manifest in radiation damage to materials. Radiation processing technology focuses upon producing favourable modification of materials through use of relatively high dose and dose rates. Current interest is in modifying the thermal and electrical properties of textured polymers in an effort to improve safety and wear comfort of clothing. No less important is the production of textiles which are safe to use, both in homes and offices. Present investigations provide additional data in support of findings which show that polyamides, a particular class of textured polymer, are amenable to radiation processing. Accelerated electron beam irradiation of sheets of polyamide fibre results in induced grafting of acrylic and methacrylic acids. The degree of grafting is critically dependent upon irradiation dose and the extent of monomers dilution. Of particular importance is the high correlation which is found between degree of grafting and a decrease in the softening rate of the modified polyamide. A systematic modification of electrical conductivity is also observed. (author)

  18. Antioxidant and Anti-Osteoporotic Activities of Aromatic Compounds and Sterols from Hericium erinaceum.

    Science.gov (United States)

    Li, Wei; Lee, Sang Hyun; Jang, Hae Dong; Ma, Jin Yeul; Kim, Young Ho

    2017-01-11

    Hericium erinaceum , commonly called lion's mane mushroom, is a traditional edible mushroom widely used in culinary applications and herbal medicines in East Asian countries. In this study, a new sterol, cerevisterol 6-cinnamate ( 6 ), was isolated from the fruiting bodies of H. erinaceum together with five aromatic compounds 1 - 5 and five sterols 7 - 11 . The chemical structures of these compounds were elucidated using chemical and physical methods and comparison of HRESIMS, ¹D-NMR (¹H, 13 C, and DEPT) and 2D-NMR (COSY, HMQC, HMBC, and NOESY) spectra with previously reported data. The antioxidant and anti-osteoporotic activities of extracts and the isolated compounds 1 - 11 were investigated. All compounds exhibited peroxyl radical-scavenging capacity but only compounds 1 , 3 , and 4 showed potent reducing capacity. Moreover, compounds 1 , 2 , 4 , and 5 showed moderate effects on cellular antioxidant activity and inhibited the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastic differentiation. These results suggested that H. erinaceum could be utilized in the development of natural antioxidant and anti-osteoporotic nutraceuticals and functional foods.

  19. Antioxidant and Anti-Osteoporotic Activities of Aromatic Compounds and Sterols from Hericium erinaceum

    Directory of Open Access Journals (Sweden)

    Wei Li

    2017-01-01

    Full Text Available Hericium erinaceum, commonly called lion’s mane mushroom, is a traditional edible mushroom widely used in culinary applications and herbal medicines in East Asian countries. In this study, a new sterol, cerevisterol 6-cinnamate (6, was isolated from the fruiting bodies of H. erinaceum together with five aromatic compounds 1–5 and five sterols 7–11. The chemical structures of these compounds were elucidated using chemical and physical methods and comparison of HRESIMS, 1D-NMR (1H, 13C, and DEPT and 2D-NMR (COSY, HMQC, HMBC, and NOESY spectra with previously reported data. The antioxidant and anti-osteoporotic activities of extracts and the isolated compounds 1–11 were investigated. All compounds exhibited peroxyl radical-scavenging capacity but only compounds 1, 3, and 4 showed potent reducing capacity. Moreover, compounds 1, 2, 4, and 5 showed moderate effects on cellular antioxidant activity and inhibited the receptor activator of nuclear factor κB ligand (RANKL-induced osteoclastic differentiation. These results suggested that H. erinaceum could be utilized in the development of natural antioxidant and anti-osteoporotic nutraceuticals and functional foods.

  20. Using quantitative structure-activity relationships (QSAR) to predict toxic endpoints for polycyclic aromatic hydrocarbons (PAH).

    Science.gov (United States)

    Bruce, Erica D; Autenrieth, Robin L; Burghardt, Robert C; Donnelly, K C; McDonald, Thomas J

    2008-01-01

    Quantitative structure-activity relationships (QSAR) offer a reliable, cost-effective alternative to the time, money, and animal lives necessary to determine chemical toxicity by traditional methods. Additionally, humans are exposed to tens of thousands of chemicals in their lifetimes, necessitating the determination of chemical toxicity and screening for those posing the greatest risk to human health. This study developed models to predict toxic endpoints for three bioassays specific to several stages of carcinogenesis. The ethoxyresorufin O-deethylase assay (EROD), the Salmonella/microsome assay, and a gap junction intercellular communication (GJIC) assay were chosen for their ability to measure toxic endpoints specific to activation-, induction-, and promotion-related effects of polycyclic aromatic hydrocarbons (PAH). Shape-electronic, spatial, information content, and topological descriptors proved to be important descriptors in predicting the toxicity of PAH in these bioassays. Bioassay-based toxic equivalency factors (TEF(B)) were developed for several PAH using the quantitative structure-toxicity relationships (QSTR) developed. Predicting toxicity for a specific PAH compound, such as a bioassay-based potential potency (PP(B)) or a TEF(B), is possible by combining the predicted behavior from the QSTR models. These toxicity estimates may then be incorporated into a risk assessment for compounds that lack toxicity data. Accurate toxicity predictions are made by examining each type of endpoint important to the process of carcinogenicity, and a clearer understanding between composition and toxicity can be obtained.

  1. Comparison of the properties polyamide 6.6 surfaces treated by plasma and by ionizing radiation

    International Nuclear Information System (INIS)

    Irineu, Rosa Maria da Silva

    2010-01-01

    This study aims to compare the surface properties of polyamide 6.6 plasma treatment and ionizing radiation, as well as determine the best technique and condition of the surface activation, adhesion of the same order and polyacrylic rubber used in manufacturing of automotive retainers. Treatment of polyamide 6.6 plasma was performed using an equipment 'Electronic Diener - Plasma - Surface-Technology LFG40' with nitrogen gas at a pressure of 1.40 kg/cm 2 . Samples of polyamide 6.6 were also treated with ionizing radiation, atmospheric pressure and in vacuum, using an industrial electron accelerator, Dynamitron JOB 188 with radiation dose of 5, 10, 20, 40, 50, 100, 200, 300, 400 and 500kGy with a dose rate of 11.22 kGy/s for all doses and rate of 11.22 kGy/s and 22.38 kGy/s for a dose of 20kGy. After the processes of surface modification of polyamide 6.6, part of the untreated samples, treated by plasma and by ionizing radiation were incorporated into the polyacrylic rubber, and another part was designed to characterize the surface using the techniques of SEM / EDS, FT- IR, PIXE / RBS, AFM and contact angle. Untreated samples and the irradiated samples did not join the polyacrylic rubber. The samples treated by plasma joined the polyacrylic rubber efficiently and showed differences in roughness in SEM and AFM, and an increase in contact angle when compared with untreated samples. The irradiated samples showed no significant differences in the analysis of properties used in this study when compared with untreated samples. Ionizing radiation was not effective in surface modification of polyamide 6.6 for adherence with polyacrylic rubber. (author)

  2. Aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Roder, M.

    1985-01-01

    Papers dealing with radiolysis of aromatic hydrocarbons of different composition (from benzene to terphenyls and hydrocarbons with condensed rings) as well as their mixtures (with alkanes, alkenes, other aromatic hydrocarbons) are reviewed. High radiation stability of aromatic hydrocarbons in condensed phases associated with peculiarities of molecular structure of compounds is underlined. Mechanisms of radiolytic processes, vaues of product yields are considered

  3. Kinetics of the deformation induced memory effect in polyamide-6

    NARCIS (Netherlands)

    Drongelen, van M.; Stroeks, A.A.M.; Peters, G.W.M.

    2015-01-01

    Nascent polyamide-6 shows a peculiar and irreversible effect; the quiescent crystallization kinetics on cooling are accelerated upon deformation in the melt, even after full relaxation of the melt. This phenomenon, known as the orientation (or better, deformation) induced memory effect of polyamide

  4. 21 CFR 177.2450 - Polyamide-imide resins.

    Science.gov (United States)

    2010-04-01

    ... Components of Articles Intended for Repeated Use § 177.2450 Polyamide-imide resins. Polyamide-imide resins identified in paragraph (a) of this section may be safely used as components of articles intended for... Safety and Applied Nutrition (HFS-200), Food and Drug Administration, 5100 Paint Branch Pkwy., College...

  5. Polyamides : hydrogen bonding, the Brill transition, and superheated water

    NARCIS (Netherlands)

    Dijkstra - Vinken, E.

    2008-01-01

    Aliphatic polyamide, commonly known as nylon, was the world’s first synthetic fiber and has found its largest application range in tires, carpets, stockings, upholstery, and adhesives. All polyamides have a recurring amide group (–CONH–) present in the molecular structure with hydrogen bonds between

  6. Activated carbon as catalyst for microwave-assisted wet peroxide oxidation of aromatic hydrocarbons.

    Science.gov (United States)

    Garcia-Costa, Alicia L; Lopez-Perela, Lucia; Xu, Xiyan; Zazo, Juan A; Rodriguez, Juan J; Casas, Jose A

    2018-05-21

    This paper addresses the removal of four aromatic hydrocarbons typically found in petrochemical wastewater: benzene (B), toluene (T), o-xylene (X), and naphthalene (N), by microwave-assisted catalytic wet peroxide oxidation (MW-CWPO) using activated carbon (AC) as catalyst. Under the studied conditions, complete pollutant elimination (B, 1.28 mM; T, 1.09 mM; X, 0.94 mM; and N, 0.78 mM) was achieved, with more than 90% TOC removal after only 15-min reaction time, working at 120 °C, pH 0  = 3, AC at 1 g L -1 , and H 2 O 2 at the stoichiometric dose. Furthermore, in the case of toluene, naphthalene, and xylene, the hydroxylation and breakdown of the ring is very rapid and toxic intermediates were not detected. The process follows two steps: (i) pollutant adsorption onto AC followed by (ii) adsorbed compounds oxidation. Thus, MW-CWPO with AC as catalyst appears a promising way for a fast and effective process for B, T, X, and N removal in aqueous phase.

  7. Halogenating reaction activity of aromatic organic compounds during disinfection of drinking water

    International Nuclear Information System (INIS)

    Guo Gaimei; Chen Xiaodong

    2009-01-01

    The halogenating reactions of five aromatic organic compounds (AOCs) with aqueous chlorine (HOCl/OCl - ) and aqueous bromine (HOBr/OBr - ) were studied with an aim to compare the formation properties of haloacetic acids (HAAs) for the corresponding chlorination or bromination reactions of AOCs, respectively. The experiment results indicated that the HAAs substitution efficiency for the bromination reactions of AOCs was greater than that for the chlorination reactions, and the formation of HAAs had a strong dependence on the chemical structure of AOCs. The chlorination or bromination reaction activities for the AOCs with electron donating functional groups were higher than that for them with electron withdrawing functional groups. The kinetic experiments indicated that the reactions of aqueous bromine with phenol were faster than those of aqueous chlorine with phenol and the halogen consumption exhibited rapid initial and slower consumption stages for the reactions of phenol with aqueous chlorine and bromine, respectively. In addition, the HAAs production for the chlorination reaction of phenol decreased with the increase of pH. These conclusions could provide the valuable information for the effective control of the disinfection by-products during drinking water treatment operation

  8. Removing polycyclic aromatic hydrocarbons from water using granular activated carbon: kinetic and equilibrium adsorption studies.

    Science.gov (United States)

    Eeshwarasinghe, Dinushika; Loganathan, Paripurnanda; Kalaruban, Mahatheva; Sounthararajah, Danious Pratheep; Kandasamy, Jaya; Vigneswaran, Saravanamuthu

    2018-05-01

    Polycyclic aromatic hydrocarbons (PAHs) constitute a group of highly persistent, toxic and widespread environmental micropollutants that are increasingly found in water. A study was conducted in removing five PAHs, specifically naphthalene, acenaphthylene, acenaphthene, fluorene and phenanthrene, from water by adsorption onto granular activated carbon (GAC). The pseudo-first-order (PFO) model satisfactorily described the kinetics of adsorption of the PAHs. The Weber and Morris diffusion model's fit to the data showed that there were faster and slower rates of intra-particle diffusion probably into the mesopores and micropores of the GAC, respectively. These rates were negatively related to the molar volumes of the PAHs. Batch equilibrium adsorption data fitted well to the Langmuir, Freundlich and Dubinin-Radushkevich models, of which the Freundlich model exhibited the best fit. The adsorption affinities were related to the hydrophobicity of the PAHs as determined by the log K ow values. Free energies of adsorption calculated from the Dubinin-Radushkevich model and the satisfactory kinetic data fitting to the PFO model suggested physical adsorption of the PAHs. Adsorption of naphthalene, acenaphthylene and acenaphthene in fixed-bed columns containing a mixture of GAC (0.5 g) + sand (24.5 g) was satisfactorily simulated by the Thomas model.

  9. Antioxidant Activity of a New Aromatic Geranyl Derivative of the Resinous Exudates from Heliotropium glutinosum Phil.

    Directory of Open Access Journals (Sweden)

    Federico Luebert

    2007-05-01

    Full Text Available Heliotropium glutinosum Phil. (Heliotropiceae is a resinous bush that grows at a height of 2000 m in Chañaral, Chile. From the resinous exudates of Heliotropium glutinosum Phil. a new aromatic geranyl derivative: 4-methoxy-3-[(2-7’-methyl-3’-hydroxymethyl-2’,6’-octadienyl] phenol (1 and three flavonoids: 5,3'-dihydroxy-7,4'-dimethoxyflavanone (2, 5,4'-dihydroxy-7-methoxyflavanone (3 and 4'-acetyl-5-hydroxy-7-methoxyflavanone (4 were isolated and their structures were determined. Their antioxidant activity were evaluated using the bleaching of ABTS and DPPH derived cation radical methods and expressed in terms of FRE (fast reacting equivalents and TRE (total reacting equivalents, where FRE is a good measure of the quick protection of a given compound against oxidants and TRE measures the degree of long-term protection of the antioxidant, or how effective it is against a strong oxidative stress.

  10. Reduction in uptake by rice and soybean of aromatic arsenicals from diphenylarsinic acid contaminated soil amended with activated charcoal

    International Nuclear Information System (INIS)

    Arao, Tomohito; Maejima, Yuji; Baba, Koji

    2011-01-01

    Activated charcoal (AC) amendment has been suggested as a promising method to immobilize organic contaminants in soil. We performed pot experiments with rice and soybean grown in agricultural soil polluted by aromatic arsenicals (AAs). The most abundant AA in rice grains and soybean seeds was methylphenylarsinic acid (MPAA). MPAA concentration in rice grains was significantly reduced to 2% and 3% in 0.2% AC treated soil compared to untreated soil in the first year of rice cultivation. In the second year, MPAA concentration in rice grains was significantly reduced to 15% in 0.2% AC treated soil compared to untreated soil. MPAA concentration in soybean seeds was significantly reduced to 44% in 0.2% AC treated soil compared to untreated soil. AC amendment was effective in reducing AAs in rice and soybean. - Highlights: → Pot experiments using agricultural soil contaminated with aromatic arsenicals (AAs). → Methylphenylarsinic acid (MPAA) was the most abundant AA in rice and soybean. → MPAA concentration in rice grains was dramatically reduced via 0.2% AC amendment. → MPAA concentration in soybean seeds was also reduced via 0.2% AC amendment. → AC amendment effectively reduced AAs in rice and soybean. - Activated charcoal amendment to soil contaminated with diphenylarsinic acid reduced aromatic arsenicals in rice and soybean.

  11. Reduction in uptake by rice and soybean of aromatic arsenicals from diphenylarsinic acid contaminated soil amended with activated charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Arao, Tomohito, E-mail: arao@affrc.go.jp [National Institute for Agro-Environmental Sciences, Soil Environmental Division, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 (Japan); Maejima, Yuji; Baba, Koji [National Institute for Agro-Environmental Sciences, Soil Environmental Division, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 (Japan)

    2011-10-15

    Activated charcoal (AC) amendment has been suggested as a promising method to immobilize organic contaminants in soil. We performed pot experiments with rice and soybean grown in agricultural soil polluted by aromatic arsenicals (AAs). The most abundant AA in rice grains and soybean seeds was methylphenylarsinic acid (MPAA). MPAA concentration in rice grains was significantly reduced to 2% and 3% in 0.2% AC treated soil compared to untreated soil in the first year of rice cultivation. In the second year, MPAA concentration in rice grains was significantly reduced to 15% in 0.2% AC treated soil compared to untreated soil. MPAA concentration in soybean seeds was significantly reduced to 44% in 0.2% AC treated soil compared to untreated soil. AC amendment was effective in reducing AAs in rice and soybean. - Highlights: > Pot experiments using agricultural soil contaminated with aromatic arsenicals (AAs). > Methylphenylarsinic acid (MPAA) was the most abundant AA in rice and soybean. > MPAA concentration in rice grains was dramatically reduced via 0.2% AC amendment. > MPAA concentration in soybean seeds was also reduced via 0.2% AC amendment. > AC amendment effectively reduced AAs in rice and soybean. - Activated charcoal amendment to soil contaminated with diphenylarsinic acid reduced aromatic arsenicals in rice and soybean.

  12. POLYCYCLIC AROMATIC HYDROCARBON AND EMISSION LINE RATIOS IN ACTIVE GALACTIC NUCLEI AND STARBURST GALAXIES

    International Nuclear Information System (INIS)

    Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R.

    2010-01-01

    We study the polycyclic aromatic hydrocarbon (PAH) bands, ionic emission lines, and mid-infrared continuum properties in a sample of 171 emission line galaxies taken from the literature plus 15 new active galactic nucleus (AGN) Spitzer spectra. We normalize the spectra at λ = 23 μm and grouped them according to the type of nuclear activity. The continuum shape steeply rises for longer wavelengths and can be fitted with a warm blackbody distribution of T ∼ 150-300 K. The brightest PAH spectral bands (6.2, 7.7, 8.6, 11.3, and 12.7 μm) and the forbidden emission lines of [Si II] 34.8 μm, [Ar II] 6.9 μm, [S III] 18.7 and 33.4 μm were detected in all the starbursts and in ∼80% of the Seyfert 2. Taking under consideration only the PAH bands at 7.7 μm, 11.3 μm, and 12.7 μm, we find that they are present in ∼80% of the Seyfert 1, while only half of this type of activity show the 6.2 μm and 8.6 μm PAH bands. The observed intensity ratios for neutral and ionized PAHs (6.2 μm/7.7 μm x 11.3 μm/7.7 μm) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH molecules (≥180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7 μm) and the neutral PAH bands (8.6 μm and 11.3 μm) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7 μm and 11.3 μm bands is nearly constant with the increase of [Ne III]15.5 μm/[Ne II] 12.8 μm, indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence (strongly decreasing) with [Ne III]/[Ne II], suggesting that the PAH molecules, emitting either ionized (7.7 μm) or neutral (11.3 μm) bands, may be destroyed with the increase of the hardness of the radiation field.

  13. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    Science.gov (United States)

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  14. Estrogenic activity of environmental polycyclic aromatic hydrocarbons in uterus of immature Wistar rats

    Czech Academy of Sciences Publication Activity Database

    Kummer, V.; Mašková, J.; Zralý, Z.; Neča, J.; Šimečková, P.; Vondráček, Jan; Machala, M.

    2008-01-01

    Roč. 180, č. 3 (2008), s. 212-221 ISSN 0378-4274 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : polycyclic aromatic hydrocarbons * rat immature uterothrophic assay * estrogen receptor Subject RIV: BO - Biophysics Impact factor: 3.249, year: 2008

  15. Antifungal and repellent activities of the essential oils from three aromatic herbs from western Himalaya

    Science.gov (United States)

    In this investigation we examined the essential oils of three aromatic plants; Zanthoxylum armatum, Juniperus communis, and, Dysphania ambrosioides, which are used by the local population of the western Himalayan region for medicinal purposes. These plants were studied for their antifungal, larvicid...

  16. Ene-ene-yne Reactions: Activation Strain Analysis and Role of Aromaticity

    NARCIS (Netherlands)

    Fernandez, I.; Bickelhaupt, F.M.; Cossío, F.P.

    2014-01-01

    The trend in reactivity of the thermal cycloisomerization reactions of 1,3-hexadien-5-ynes, A=B-C=D-E≡F, were explored and analyzed by using density functional theory at the M06-2X/def2-TZVPP level. These reactions proceed through formally aromatic transition states to form a bent-allene

  17. Experimental Determination of Activation Energy of Nucleophilic Aromatic Substitution on Porphyrins

    Science.gov (United States)

    Rizvi, Waqar; Khwaja, Emaad; Siddiqui, Saim; Bhupathiraju, N. V. S. Dinesh K.; Drain, Charles Michael

    2018-01-01

    A physical organic chemistry experiment is described for second-year college students. Students performed nucleophilic aromatic substitution (NAS) reactions on 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrin (TPPF[subscript 20]) using three different nucleophiles. Substitution occurs preferentially at the 4-position ("para")…

  18. Effects of solution P H on the adsorption of aromatic compounds from aqueous solutions by activated carbon

    International Nuclear Information System (INIS)

    Nouri, S.; Haghseresht, F.; Lu, M.

    2002-01-01

    Absorption of p-Cresol, Benzoic acid and Nitro Benzene by activated carbon from dilute aqueous solutions was carried out under controlled ph conditions at 310 k. In acidic conditions, well below the pK a of all solutes, it was observed that the adsorbate solubility and the electron density of its aromatic ring were the influencing factors on the extent of the adsorption by affecting the extent of London dispersion forces. In higher solution ph conditions, on the other hand, it was found that the electrostatic forces played a significant role on the extent of adsorption. The Effect of ph must be considered from its combined effects on the carbon surface and on the solute molecules. It was found that the uptake of the molecular forms of the aromatic solutes was dependent on the substituents of the aromatic ring. Adsorption of the solutes in higher P H values was found to be dependent on the concentration of anionic form of the solutes. All isotherms were fitted into Freundlich Isotherm Equations

  19. Identifying carcinogenic activity of methylated and non-methylated polycyclic aromatic hydrocarbons (PAHs) through electronic and topological indices

    CERN Document Server

    Braga, R S; Barone, P M V B

    2000-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a class of planar molecules, abundant in urban environment, which can induce chemical carcinogenesis. Their carcinogenic power varies in a large range, from very strong carcinogens to inactive ones. In a previous study, we proposed a methodology to identify the PAHs carcinogenic activity exploring electronic and topological indices. In the present work, we show that it is possible to simplify that methodology and expand its applicability to include methylated PAHs compounds. Using very simple rules, we can predict their carcinogenic activity with high accuracy (approx 89%).

  20. Stereochemical Basis for a Unified Structure Activity Theory of Aromatic and Heterocyclic Rings in Selected Opioids and Opioid Peptides

    Directory of Open Access Journals (Sweden)

    Joel S. Goldberg

    2010-02-01

    Full Text Available This paper presents a novel unified theory of the structure activity relationship of opioids and opioid peptides. It is hypothesized that a virtual or known heterocyclic ring exists in all opioids which have activity in humans, and this ring occupies relative to the aromatic ring of the drug, approximately the same plane in space as the piperidine ring of morphine. Since the rings of morphine are rigid, and the aromatic and piperidine rings are critical structural components for morphine’s analgesic properties, the rigid morphine molecule allows for approximations of the aromatic and heterocyclic relationships in subsequent drug models where bond rotations are common. This hypothesis and five propositions are supported by stereochemistry and experimental observations. Proposition #1 The structure of morphine provides a template. Proposition #2 Steric hindrance of some centric portion of the piperidine ring explains antagonist properties of naloxone, naltrexone and alvimopam. Proposition #3 Methadone has an active conformation which contains a virtual heterocyclic ring which explains its analgesic activity and racemic properties. Proposition #4 The piperidine ring of fentanyl can assume the morphine position under conditions of nitrogen inversion. Proposition #5 The first 3 amino acid sequences of beta endorphin (l-try-gly-gly and the active opioid dipeptide, l-tyr-pro, (as a result of a peptide turn and zwitterion bonding form a virtual piperazine-like ring which is similar in size, shape and location to the heterocyclic rings of morphine, meperidine, and methadone. Potential flaws in this theory are discussed. This theory could be important for future analgesic drug design.

  1. Synthesis and Antiradical Activity of Isoquercitrin Esters with Aromatic Acids and Their Homologues

    Czech Academy of Sciences Publication Activity Database

    Heřmánková-Vavříková, Eva; Křenková, Alena; Petrásková, Lucie; Chambers, Christopher S.; Zápal, Jakub; Kuzma, Marek; Valentová, Kateřina; Křen, Vladimír

    2017-01-01

    Roč. 18, č. 5 (2017), s. 1-14, č. článku 1074. E-ISSN 1422-0067 R&D Projects: GA ČR(CZ) GP14-14373P; GA MŠk(CZ) LD15082 Institutional support: RVO:61388971 Keywords : isoquercitrin * aromatic acid * gallic acid Subject RIV: CE - Biochemistry OBOR OECD: Microbiology Impact factor: 3.226, year: 2016

  2. Effect of acidic aqueous solution on chemical and physical properties of polyamide NF membranes

    Science.gov (United States)

    Jun, Byung-Moon; Kim, Su Hwan; Kwak, Sang Kyu; Kwon, Young-Nam

    2018-06-01

    This work was systematically investigated the effects of acidic aqueous solution (15 wt% sulfuric acid as model wastewater from smelting process) on the physical and chemical properties of commercially available nanofiltration (NF) polyamide membranes, using piperazine (PIP)-based NE40/70 membranes and m-phenylene diamine (MPD)-based NE90 membrane. Surface properties of the membranes were studied before and after exposure to strong acid using various analytical tools: Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), contact angle analyzer, and electrophoretic light scattering spectrophotometer. The characterization and permeation results showed piperazine-based NE40/70 membranes have relatively lower acid-resistance than MPD-based NE90 membrane. Furthermore, density functional theory (DFT) calculation was also conducted to reveal the different acid-tolerances between the piperazine-based and MPD-based polyamide membranes. The easiest protonation was found to be the protonation of oxygen in piperazine-based monomer, and the N-protonation of the monomer had the lowest energy barrier in the rate determining step (RDS). The calculations were well compatible with the surface characterization results. In addition, the energy barrier in RDS is highly correlated with the twist angle (τD), which determines the delocalization of electrons between the carbonyl πCO bond and nitrogen lone pair, and the tendency of the twist angle was also maintained in longer molecules (dimer and trimer). This study clearly explained why the semi-aromatic membrane (NE40/70) is chemically less stable than the aromatic membrane (NE90) given the surface characterizations and DFT calculation results.

  3. Improvement of activity and stability of Chondroitinase ABC I by introducing an aromatic cluster at the surface of protein.

    Science.gov (United States)

    Shahaboddin, Mohammad Esmaeil; Khajeh, Khosro; Maleki, Monireh; Golestani, Abolfazl

    2017-10-01

    Chondroitinase ABC I (ChABC I) has been shown to depolymerize a variety of glycosaminoglycan substrates and promote regeneration of damaged spinal cord. However, to date, intrathecal delivery methods have been suboptimal largely due to enzyme instability which necessitates repeated administration to the injured loci. Among the aromatic amino acids, tyrosine has been shown to be more effective in creation of stable clusters and further stabilize of the proteins. Bioinformatics approaches have been used to examine the effect of an extra aromatic cluster at the surface of ChABC I. In this study two amino acids i.e., Asn 806 and Gln 810 were mutated to tyrosine and to alanine as negative control. In this way, four variants i.e., N806Y/Q810Y, N806A/Q810Y, N806Y/Q810A and N806A/Q810A were created. The results showed that N806Y/Q810Y mutation improved both activity and thermal stability of the enzyme while Ala substitution reduced the enzyme activity and destabilized it. Structural analysis of mutants showed an increase in intrinsic fluorescence intensity and secondary structure content of N806Y/Q810Y mutant when compared to the wild type enzyme indicating a more rigid structure of this variant. Moreover, the N806Y/Q810Y enzyme displayed a remarkable resistance against trypsin degradation with a half-life (t 1/2 ) of 45.0min versus 32.5min of wild-type. In conclusion, the data revealed that structural features and activity of ChABC I can be improved by introducing appropriate aromatic clusters at the surface of the enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Immobilization of nanoparticle titanium dioxide membrane on polyamide fabric by low temperature hydrothermal method

    International Nuclear Information System (INIS)

    Zhang Hui; Yang Lu

    2012-01-01

    A thin layer of nanoparticle titanium dioxide was immobilized on polyamide 6 (PA6) fiber using titanium sulfate and urea at low temperature hydrothermal condition. The titanium dioxide loaded fabric was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetry techniques. The optical and mechanical properties, water absorption and degradation of methylene blue dye under ultraviolet (UV) irradiation of the PA6 fabric before and after treatments were also examined. It was found that when PA6 fabric was treated in titanium sulfate and urea aqueous solution, anatase nanocrystalline titanium dioxide was synthesized and simultaneously adhered onto the fiber surface. The average crystal size of titanium dioxide nanoparticles was about 13.2 nm. The thermal behavior of PA6 fiber distinctly changed and the onset decomposition temperature decreased. As compared with the untreated fabric, the protection against UV radiation was improved. The water absorbency increased slightly. As the fabric dimensions were reduced in warp and weft directions, the breaking load and tensile strain increased to some extent. The titanium dioxide coated fabric could degradate methylene blue dye under UV irradiation. - Highlights: ► We employed a method to immobilize TiO 2 nanoparticle on polyamide fiber. ► We fabricated the TiO 2 -coated polyamide fabric with the photocatalytic activity. ► The modification method may be suitable for the potential applications.

  5. Antioxidant activity of selenenamide-based mimic as a function of the aromatic thiols nucleophilicity, a DFT-SAPE model.

    Science.gov (United States)

    Kheirabadi, Ramesh; Izadyar, Mohammad

    2018-05-18

    The mechanism of action of the selenenamide 1 as a mimic of the glutathione peroxidase (GPx) was investigated by the density functional theory. The solvent-assisted proton exchange procedure was applied to model the catalytic behavior and antioxidant activity of this mimic. To have an insight into the charge transfer effect, different aromatic thiols, including electron donating substituents on the phenyl ring were considered. The catalytic behavior of the selenenamide was modeled in a four-step mechanism, described by the oxidation of the mimic, the reduction of the obtained product, selenoxide, the reduction of the selenenylsulfide and dehydration of selenenic acid. On the basis of the activation parameters, the final step of the proposed mechanism is the rate determining states of the catalytic cycle. Turnover frequency (TOF) analysis showed that the electron donating groups at the para-position of the phenyl ring of the PhSH do not affect the catalytic activity of the selenenamide in contrast to p-methyl thiophenol which indicates the highest nucleophilicity. The evaluation of the electronic contribution of the various donating groups on the phenyl ring of the aromatic thiols shows that the antioxidant activity of the selenenamide sufficiently increases in the presence of the electron-donating substitutions. Finally, the charge transfer process at the rate-determining state was investigated based on the natural bond orbital analysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Combining molecular docking and QSAR studies for modeling the anti-tyrosinase activity of aromatic heterocycle thiosemicarbazone analogues

    Science.gov (United States)

    Dong, Huanhuan; Liu, Jing; Liu, Xiaoru; Yu, Yanying; Cao, Shuwen

    2018-01-01

    A collection of thirty-six aromatic heterocycle thiosemicarbazone analogues presented a broad span of anti-tyrosinase activities were designed and obtained. A robust and reliable two-dimensional quantitative structure-activity relationship model, as evidenced by the high q2 and r2 values (0.848 and 0.893, respectively), was gained based on the analogues to predict the quantitative chemical-biological relationship and the new modifier direction. Inhibitory activities of the compounds were found to greatly depend on molecular shape and orbital energy. Substituents brought out large ovality and high highest-occupied molecular orbital energy values helped to improve the activity of these analogues. The molecular docking results provided visual evidence for QSAR analysis and inhibition mechanism. Based on these, two novel tyrosinase inhibitors O04 and O05 with predicted IC50 of 0.5384 and 0.8752 nM were designed and suggested for further research.

  7. Seawater Polluted with Highly Concentrated Polycyclic Aromatic Hydrocarbons Suppresses Osteoblastic Activity in the Scales of Goldfish, Carassius auratus.

    Science.gov (United States)

    Suzuki, Nobuo; Sato, Masayuki; Nassar, Hossam F; Abdel-Gawad, Fagr Kh; Bassem, Samah M; Yachiguchi, Koji; Tabuchi, Yoshiaki; Endo, Masato; Sekiguchi, Toshio; Urata, Makoto; Hattori, Atsuhiko; Mishima, Hiroyuki; Shimasaki, Youhei; Oshima, Yuji; Hong, Chun-Sang; Makino, Fumiya; Tang, Ning; Toriba, Akira; Hayakawa, Kazuichi

    2016-08-01

    We have developed an original in vitro bioassay using teleost scale, that has osteoclasts, osteoblasts, and bone matrix as each marker: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Using this scale in vitro bioassay, we examined the effects of seawater polluted with highly concentrated polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) on osteoblastic and osteoclastic activities in the present study. Polluted seawater was collected from two sites (the Alexandria site on the Mediterranean Sea and the Suez Canal site on the Red Sea). Total levels of PAHs in the seawater from the Alexandria and Suez Canal sites were 1364.59 and 992.56 ng/l, respectively. We were able to detect NPAHs in both seawater samples. Total levels of NPAHs were detected in the seawater of the Alexandria site (12.749 ng/l) and the Suez Canal site (3.914 ng/l). Each sample of polluted seawater was added to culture medium at dilution rates of 50, 100, and 500, and incubated with the goldfish scales for 6 hrs. Thereafter, ALP and TRAP activities were measured. ALP activity was significantly suppressed by both polluted seawater samples diluted at least 500 times, but TRAP activity did not change. In addition, mRNA expressions of osteoblastic markers (ALP, osteocalcin, and the receptor activator of the NF-κB ligand) decreased significantly, as did the ALP enzyme activity. In fact, ALP activity decreased on treatment with PAHs and NPAHs. We conclude that seawater polluted with highly concentrated PAHs and NPAHs influences bone metabolism in teleosts.

  8. Cu(II AND Zn(II COMPLEX COMPOUNDS WITH BIGUANIDES AROMATIC DERIVATIVES. SYNTHESIS, CHARACTERIZATION, BIOLOGICAL ACTIVITY

    Directory of Open Access Journals (Sweden)

    Ticuţa Negreanu-Pîrjol

    2011-05-01

    Full Text Available In this paper we report the synthesis, physical-chemical characterization and antimicrobial activity of some new complex compounds of hetero-aromatic biguanides ligands, chlorhexidine base (CHX and chlorhexidine diacetate (CHXac2 with metallic ions Cu(II and Zn(II, in different molar ratio. The synthesized complexes were characterized by elemental chemical analysis and differential thermal analysis. The stereochemistry of the metallic ions was determined by infrared spectra, UV-Vis, EPR spectroscopy and magnetic susceptibility in the aim to establish the complexes structures. The biological activity of the new complex compounds was identified in solid technique by measuring minimum inhibition diameter of bacterial and fungal culture, against three standard pathogen strains, Escherichia coli ATCC 25922, Staphilococcus aureus ATCC 25923 and Candida albicans ATCC 10231. The results show an increased specific antimicrobial activity for the complexes chlorhexidine:Cu(II 1:1 and 1:2 compared with the one of the Zn(II complexes.

  9. Vieillissement du polyamide 11 utilisé dans les conduites flexibles : influence de la composition du fluide transporté Influence of the Chemical Nature of the Environment on the Aging of Polyamide 11 Used for Offshore Flexible Pipes

    Directory of Open Access Journals (Sweden)

    Ubrich E.

    2006-11-01

    a single type of material or several materials. These materials were analyzed at the same time by thermodesorption coupled with mass spectrometry and by other techniques. The results obtained show that this new method is capable of quantitatively and simultaneous determining : (1 the residual plasticizer content, (2 the water and absorbed-hydrocarbon content, and (3 the distribution, by chemical families, of the absorbed hydrocarbons (alkanes, cycloalkanes, aromatics. In the second phase, since polyamide 11 has varying affinity for the different chemical families present in a petroleum environment, we tried to determine the influence of each type of compound on the mechanical properties (ultimate elongation and physicochemical properties (rate of crystallinity, molecular weight, contents of diffusing materials. Aging was performed in the laboratory in model environments made up in varying proportions, i. e. water, a gas-oil cut composed mainly of aromatic hydrocarbons, a gas-oil cut composed mainly of aliphatic hydrocarbons. The composition of these different aging environments was chosen by means of an experimental plan applied to the mixtures, and a polynomial mathematical model has been postulated. The conditions of temperature, pressure and aging time were set at a constant level for all the tests, i. e. 140°C, 6 bar of nitrogen, 15 days. The model obtained was used to plot isoresponse curves and to predict the properties analyzed as a function of the composition of the environment. The influence of water on the degradation of the mechanical properties (decrease in ultimate elongation and the physicochemical properties (reduction of the molecular weight and increase in the rate of crystallinity was revealed. Likewise, it was shown that, no matter what the aging environment was at 140°C, the plasticizer is extracted and the aromatic environment influences the plastication of the material. By means of mass spectrometry, the chemical nature of the aromatic

  10. Dynamic mechanical properties of toughened polyamide composites

    International Nuclear Information System (INIS)

    Alsewailem, Fares D.

    2008-01-01

    The effect of incorporating thermoplastic rubber on the dynamic mechanical properties, storage and loss moduli, of virgin and recycled glass-fiber-reinforced polyamide 66 has been investigated in this study. Styrene-Ethylene-Styrene and Ethylene-Propylene grafted with maleic anhydride were used as elastomers for toughening. Dynamic mechanical properties of the composites were examined by the rotational rhometry. Shear storage and loss moduli of recycled and virgin materials were measured against frequency. Also the variation of storage modulus of the virgin composites was measured against temperatures by conducting a series of torsion tests. Both dynamic storage and loss moduli of the composites were found to increase with increasing glass fiber and rubber contents. Recycled composites had lower values of dynamic modulus compared that of virgin composites; however by proper combining of fiber and rubber into the recycled material, its modulus fairly matches that of the virgin material. Addition of rubber to virgin composites causes a reduction in G' as temperature increases. Rubber, which acts as a stress concentrator, had a major effect on minimizing the overall modulus of the composites. The in G' versus temperature has been observed for all composites: however the temperature at which the transition G' occurs decreases with increasing rubber content. (author)

  11. Machining of glass fiber reinforced polyamide

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available The machinability of a 30 wt% glass fiber reinforced polyamide (PA was investigated by means of drilling tests. A disk was cut from an extruded rod and drilled on the flat surface: thrust was acquired during drilling at different drilling speed, feed rate and drill diameter. Differential scanning calorimetry (DSC and indentation were used to characterize PA so as to evaluate the intrinsic lack of homogeneity of the extruded material. In conclusion, it was observed that the chip formation mechanism affects the thrust dependence on the machining parameters. A traditional modeling approach is able to predict thrust only in presence of a continuous chip. In some conditions, thrust increases as drilling speed increases and feed rate decreases; this evidence suggests not to consider the general scientific approach which deals the machining of plastics in analogy with metals. Moreover, the thrust can be significantly affected by the workpiece fabrication effect, as well as by the machining parameters; therefore, the fabrication effect is not negligible in the definition of an optimum for the machining process.

  12. Mosquito repellent activity of essential oils of aromatic plants growing in Argentina.

    Science.gov (United States)

    Gillij, Y G; Gleiser, R M; Zygadlo, J A

    2008-05-01

    Mosquitoes are important vectors of diseases and nuisance pests. Repellents minimize contact with mosquitoes. Repellents based on essential oils (EO) are being developed as an alternative to DEET (N,N-diethyl-m-methylbenzamide), an effective compound that has disadvantages including toxic reactions, and damage to plastic and synthetic fabric. This work evaluated the repellency against Aedes aegypti of EO from aromatic plants that grow in Argentina: Acantholippia seriphioides, Achyrocline satureioides, Aloysia citriodora, Anemia tomentosa, Baccharis spartioides, Chenopodium ambrosioides, Eucalyptus saligna, Hyptis mutabilis, Minthostachys mollis, Rosmarinus officinalis, Tagetes minuta and Tagetes pusilla. Most EO were effective. Variations depending on geographic origin of the plant were detected. At a 90% EO concentration, A. satureoides and T. pusilla were the least repellent. At concentrations of 12.5% B. spartioides, R. officinalis and A. citriodora showed the longest repellency times. Comparisons of the principal components of each EO suggest that limonene and camphor were the main components responsible for the repellent effects.

  13. Antibacterial Properties of Functional Polyamide 6.6

    Directory of Open Access Journals (Sweden)

    El Bouchti Mehdi

    2014-06-01

    Full Text Available Polyamide 6.6 multifilaments are grafted with the monomer N-allyliminodiacetic acid for the purpose of removal of some heavy metal ions from their aqueous solutions by forming its metal chelate especially with Ag+ ion. Such a fibrous chelate-forming resin has been used with success due to its large surface area, which contains an important metal chelate-forming functional group, where metal ions are adsorbed or desorbed on its surface, and therefore having an improved adsorption and desorption capability. In previous work, chelate-forming fibre was characterised by ICP-AES analysis according to the digestion method by microwave. The antibacterial activity of the prepared fibre is investigated with Escherichia coli bacteria as reference, according to the zone of inhibition method in agar medium. The material used as reference without metal does not present any effect on E. coli. However, the chelateforming fibres with Ag+ have a strong bactericidal effect, even with a low concentration of silver ions. These modified materials can be used as highly effective bactericidal composites that may be used in future applications for the production of antimicrobial textiles, papers or polymer materials

  14. Extraction and Characterization of Natural Dye from Green Walnut Shells and Its Use in Dyeing Polyamide: Focus on Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Mohammad Mirjalili

    2013-01-01

    Full Text Available Extraction of dyes from walnut using Soxhlet apparatus has been studied. The color components extracted and isolated from walnut shells were characterized by column chromatography, thin layer chromatography (TLC, nuclear magnetic resonance (NMR, mass spectroscopy (MS, and infrared (IR techniques. Natural dye extract obtained from the walnut was used in dyeing polyamide fabrics with different mordants. The dyed fabrics were evaluated for antibacterial activity against pathogenic strains of Gram-positive (Staphylococcus aureus and Gram-negative (Escherichia coli bacteria. As such, the relationship between antibacterial activity and dye concentration is investigated. Durability of antibacterial activity to laundering is also discussed. Results indicate that the polyamide dyed with walnut displayed excellent antibacterial activity in the presence of ferric sulfate, cupric sulfate, and potassium aluminum sulfate and exhibited good and durable fastness properties.

  15. Development of polyamide-6/chitosan membranes for desalination

    Directory of Open Access Journals (Sweden)

    A. EL-Gendi

    2014-06-01

    Full Text Available This article deals with “developing novel polyamide-6/chitosan membranes for water desalting using wet phase inversion technique”, in which novel polyamide-6/chitosan membranes were prepared using an appropriate polymer concerning the national circumferences, along with the definition of different controlling parameters of the preparing processes and their effects on the characteristics of the produced membranes. Further, evaluation process of the fabricated sheets was undertaken. Preparation process was followed by assessment of the membrane structural characteristics; then the desalting performance of each prepared membrane was evaluated under different operating conditions in order to find the structure–property relationship. The results show that the membrane flux increases with the increase of operating pressure. The salt rejection and permeation flux have been enhanced this indicates that the chitosan (CS addition to the polyamide-6 (PA-6 membrane increases the membrane hydrophilic property. Hydraulic permeability coefficient is not stable and varies considerably with the operating pressure.

  16. Enhancement of protocatechuate decarboxylase activity for the effective production of muconate from lignin-related aromatic compounds.

    Science.gov (United States)

    Sonoki, Tomonori; Morooka, Miyuki; Sakamoto, Kimitoshi; Otsuka, Yuichiro; Nakamura, Masaya; Jellison, Jody; Goodell, Barry

    2014-12-20

    The decarboxylation reaction of protocatechuate has been described as a bottleneck and a rate-limiting step in cis,cis-muconate (ccMA) bioproduction from renewable feedstocks such as sugar. Because sugars are already in high demand in the development of many bio-based products, our work focuses on improving protocatechuate decarboxylase (Pdc) activity and ccMA production in particular, from lignin-related aromatic compounds. We previously had transformed an Escherichia coli strain using aroY, which had been used as a protocatechuate decarboxylase encoding gene from Klebsiella pneumoniae subsp. pneumoniae A170-40, and inserted other required genes from Pseudomonas putida KT2440, to allow the production of ccMA from vanillin. This recombinant strain produced ccMA from vanillin, however the Pdc reaction step remained a bottleneck during incubation. In the current study, we identify a way to increase protocatechuate decarboxylase activity in E. coli through enzyme production involving both aroY and kpdB; the latter which encodes for the B subunit of 4-hydroxybenzoate decarboxylase. This permits expression of Pdc activity at a level approximately 14-fold greater than the strain with aroY only. The expression level of AroY increased, apparently as a function of the co-expression of AroY and KpdB. Our results also imply that ccMA may inhibit vanillate demethylation, a reaction step that is rate limiting for efficient ccMA production from lignin-related aromatic compounds, so even though ccMA production may be enhanced, other challenges to overcome vanilate demethylation inhibition still remain.

  17. Irradiation Crosslinking of Polyamides for the Electrical and Automotive Industry

    International Nuclear Information System (INIS)

    Gehring, J.

    2006-01-01

    Irradiation crosslinking of electrical cables and heat shrinkable tubes have been widely accepted in the automotive and electrical industry for a long time. Due higher demands regarding temperature resistance, arc resistance and good chemical resistance against oil and greases crosslinked injection moulded parts made out of polyamid and polybutylentherephtalate become also more and more interesting. Crosslinked polyamide can also replace thermosets for switches and offers therefore additional financial benefits. It will be shown on the basis of already realized projects, which basic requirements exist and how irradiation crosslinking can fulfil these demands

  18. Investigating the property profile of polyamide-alumina nanocomposite materials

    International Nuclear Information System (INIS)

    Sarwar, Muhammad Ilyas; Zulfiqar, Sonia; Ahmad, Zahoor

    2009-01-01

    Transparent sol-gel-derived nanocomposites were prepared by incorporating an alumina network into a polyamide matrix. Different amounts of aluminum butoxide were hydrolyzed and condensed to produce the alumina network. Thin composite films were characterized in terms of their optical, morphological, mechanical and thermomechanical properties. Tensile modulus, stress at both yield and break points, improved for alumina loadings of 5-10 wt.%. The glass transition temperature increased to 140 o C for nanocomposites containing 15 wt.% alumina. Scanning electron microscopy investigations indicated a uniform distribution of alumina in the polyamide matrix.

  19. Indole-3-acetic acid biosynthetic pathway and aromatic amino acid aminotransferase activities in Pantoea dispersa strain GPK.

    Science.gov (United States)

    Kulkarni, G B; Nayak, A S; Sajjan, S S; Oblesha, A; Karegoudar, T B

    2013-05-01

    This investigation deals with the production of IAA by a bacterial isolate Pantoea dispersa strain GPK (PDG) identified by 16S rRNA gene sequence analysis. HPLC and Mass spectral analysis of metabolites from bacterial spent medium revealed that, IAA production by PDG is Trp-dependent and follows indole-3-pyruvic acid (IPyA) pathway. Substrate specificity study of aromatic amino acid aminotransferase (AAT) showed high activities, only when tryptophan (Trp) and α-ketoglutarate (α-kg) were used as substrates. AAT is highly specific for Trp and α-kg as amino group donor and acceptor, respectively. The effect of exogenous IAA on bacterial growth was established. Low concentration of exogenous IAA induced the growth, whereas high concentration decreased the growth of bacterium. PDG treatment significantly increased the root length, shoot length and dry mass of the chickpea and pigeon pea plants. © 2013 The Society for Applied Microbiology.

  20. Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers.

    Science.gov (United States)

    Liu, Zhen-Shu; Li, Wen-Kai; Hung, Ming-Jui

    2014-09-01

    Incineration flue gas contains polycyclic aromatic hydrocarbons (PAHs) and sulfur dioxide (SO2). The effects of SO2 concentration (0, 350, 750, and 1000 ppm), reaction temperature (160, 200, and 280 degrees C), and the type of activated carbon fibers (ACFs) on the removal of SO2 and PAHs by ACFs were examined in this study. A fluidized bed incinerator was used to simulate practical incineration flue gas. It was found that the presence of SO2 in the incineration flue gas could drastically decrease removal of PAHs because of competitive adsorption. The effect of rise in the reaction temperature from 160 to 280 degrees C on removal of PAHs was greater than that on SO2 removal at an SO2 concentration of 750 ppm. Among the three ACFs studied, ACF-B, with the highest microporous volume, highest O content, and the tightest structure, was the best adsorbent for removing SO2 and PAHs when these gases coexisted in the incineration flue gas. Implications: Simultaneous adsorption of sulfur dioxide (SO2) and polycyclic aromatic hydrocarbons (PAHs) emitted from incineration flue gas onto activated carbon fibers (ACFs) meant to devise a new technique showed that the presence of SO2 in the incineration flue gas leads to a drastic decrease in removal of PAHs because of competitive adsorption. Reaction temperature had a greater influence on PAHs removal than on SO2 removal. ACF-B, with the highest microporous volume, highest O content, and tightest structure among the three studied ACFs, was found to be the best adsorbent for removing SO2 and PAHs.

  1. Aromatic residues located close to the active center are essential for the catalytic reaction of flap endonuclease-1 from hyperthermophilic archaeon Pyrococcus horikoshii.

    Science.gov (United States)

    Matsui, Eriko; Abe, Junko; Yokoyama, Hideshi; Matsui, Ikuo

    2004-04-16

    Flap endonuclease-1 (FEN-1) possessing 5'-flap endonuclease and 5'-->3' exonuclease activity plays important roles in DNA replication and repair. In this study, the kinetic parameters of mutants at highly conserved aromatic residues, Tyr33, Phe35, Phe79, and Phe278-Phe279, in the vicinity of the catalytic centers of FEN-1 were examined. The substitution of these aromatic residues with alanine led to a large reduction in kcat values, although these mutants retained Km values similar to that of the wild-type enzyme. Notably, the kcat of Y33A and F79A decreased 333-fold and 71-fold, respectively, compared with that of the wild-type enzyme. The aromatic residues Tyr33 and Phe79, and the aromatic cluster Phe278-Phe279 mainly contributed to the recognition of the substrates without the 3' projection of the upstream strand (the nick, 5'-recess-end, single-flap, and pseudo-Y substrates) for the both exo- and endo-activities, but played minor roles in recognizing the substrates with the 3' projection (the double flap substrate and the nick substrate with the 3' projection). The replacement of Tyr33, Phe79, and Phe278-Phe279, with non-charged aromatic residues, but not with aliphatic hydrophobic residues, recovered the kcat values almost fully for the substrates without the 3' projection of the upstream strand, suggesting that the aromatic groups of Tyr33, Phe79, and Phe278-Phe279 might be involved in the catalytic reaction, probably via multiple stacking interactions with nucleotide bases. The stacking interactions of Tyr33 and Phe79 might play important roles in fixing the template strand and the downstream strand, respectively, in close proximity to the active center to achieve the productive transient state leading to the hydrolysis.

  2. Asymmetric Baylis-Hillman Reaction between Chiral Activated Alkenes and Aromatic Aldehydes in Me3N/H2O/Solvent Medium

    Institute of Scientific and Technical Information of China (English)

    Ke HE; Zheng Hong ZHOU; Hong Ying TANG; Guo Feng ZHAO; Chu Chi TANG

    2005-01-01

    Chiral activated alkene, L-menthyl acrylate and (+)-N-α-phenylethyl acrylamide,induced asymmetric Baylis-Hillman reaction of aromatic aldehydes was realized at 25℃ for 7 days in Me3N/H2O/solvent homogeneous medium. The corresponding Baylis-Hillman adducts were obtained in good chemical yield with moderate to excellent diastereoselectivity (up to 99% de).

  3. Cu-catalyzed C(sp³)-H bond activation reaction for direct preparation of cycloallyl esters from cycloalkanes and aromatic aldehydes.

    Science.gov (United States)

    Zhao, Jincan; Fang, Hong; Han, Jianlin; Pan, Yi

    2014-05-02

    Cu-catalyzed dehydrogenation-olefination and esterification of C(sp(3))-H bonds of cycloalkanes with TBHP as an oxidant has been developed. The reaction involves four C-H bond activations and gives cycloallyl ester products directly from cycloalkanes and aromatic aldehydes.

  4. Highly Active and Specific Tyrosine Ammonia-Lyases from Diverse Origins Enable Enhanced Production of Aromatic Compounds in Bacteria and Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Jendresen, Christian Bille; Stahlhut, Steen Gustav; Li, Mingji

    2015-01-01

    Phenylalanine and tyrosine ammonia-lyases form cinnamic acid and p-coumaric acid, which are precursors of a wide range of aromatic compounds of biotechnological interest. Lack of highly active and specific tyrosine ammonia-lyases has previously been a limitation in metabolic engineering approaches...

  5. DEPENDENCY OF POLYCHLORINATED BIPHENYL AND POLYCYCLIC AROMATIC HYDROCARBON BIOACCUMULATION IN MYA ARENARIA ON BOTH WATER COLUMN AND SEDIMENT BED CHEMICAL ACTIVITIES

    Science.gov (United States)

    The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) by the filter-feeding soft-shell clam Mya arenaria was evaluated at three sites near Boston (MA, USA) by assessing the chemical activities of those hydrophobic organic compounds (H...

  6. Melanogenesis-inhibitory activity of aromatic glycosides from the stem bark of Acer buergerianum.

    Science.gov (United States)

    Akihisa, Toshihiro; Orido, Masashi; Akazawa, Hiroyuki; Takahashi, Akitomo; Yamamoto, Ayako; Ogihara, Eri; Fukatsu, Makoto

    2013-02-01

    A new benzyl glucoside, 3-O-demethylnikoenoside (1), along with eleven known compounds, including seven aromatic glycosides, 2-8, three lignans, 9-11, and one cyclitol, 12, were isolated from the BuOH-soluble fraction of a MeOH extract of Acer buergerianum stem bark. The structures of the new compound were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Upon evaluation of compounds 1-12 on melanogenesis in B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), three compounds, i.e., hovetrichoside B (8), pinoresinol 4-O-β-D-glucopyranoside (9), and pinoresinol 4-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (10), have been found to exhibit inhibitory effects with 41-49% melanin content compared to the control at 100 μM and low cytotoxicity to the cells (81-92% cell viability at 100 μM). Western blot analysis showed that compound 8 reduced the protein levels of MITF (=microphtalmia-associated transcription factor) and tyrosinase, in a concentration-dependent manner, suggesting that 8 inhibits melanogenesis in α-MSH-stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of tyrosinase. On the other hand, upon Western blotting, compound 9 was found to reduce the protein levels of tyrosinase and TRP-2, while it increased MITF and TRP-1 (=tyrosine-related protein 1), in a concentration-dependent manner, indicating that 9 inhibits melanogenesis in α-MSH-stimulated B16 melanoma cells by, at least in part, inhibiting the expression of tyrosinase and TRP-2. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

  7. Development and optimization of methods for the radiofluorination of aromatic compounds with specific, high fluorine-18 activity

    International Nuclear Information System (INIS)

    Franken, K.

    1987-06-01

    The positron emitter fluorine-18 (T 1/2 = 110 min) is an ideal radionuclide for analogue tracers in positron emission tomography (PET). In this study the production of the electrophilic species [ 18 F]-F 2 , [ 18 F]-CH 3 CO 2 F and to some extent [ 18 F]-XeF 2 has been optimized with respect to yield and specific activity. Selectivity and reactivity of these species have been studied in simple aromatic model compounds. Fluorine was produced via the 20 Ne(d,α) 18 F reaction. The effect of target material, dimensions, amount of carrier (F 2 ), pressure, beam current and irradiation time was studied. Reactivity of [ 18 F]-F 2 and [ 18 F]-CH 3 CO 2 F with respect to hydrogen subsitution was systematically studied in a series of benzene derivatives (C 6 H 5 X, X = CF 3 , I, Br, CL, F, H, CH 3 , OCH 3 , OH) in various solvents (CHCl 3 , CFCl 3 , CH 3 CN, CH 3 OH, CF 3 COOH). The radiochemical yield of 18 F-for-H-substitution in the aromatic ring increased with increasing acceptor number (AN) of the solvent. The electrophilic nature of both fluorination agents was confirmed by a Hammett plot. As expected, [ 18 F]-CH 3 CO 2 F showed a higher selectivity than [ 18 F]-F 2 . Direct radiofluorination with [ 18 F]-F 2 and [ 18 F]-CH 3 CO 2 F was successfully applied to the biomolecules phenylalanine, tyrosine and DOPA. As potential methods for no-carrier-added (n.c.a.) radiofluorination some less common dediazoniation reactions were also studied. (orig./RB) [de

  8. Researches on increasing compatibility between mixtures of PPS (poly-phenylene sulfide) and polyamide; Recherches en vue de la compatibilisation de melanges de polyamide et de polysulfure de phenylene

    Energy Technology Data Exchange (ETDEWEB)

    Montagne, O.

    1997-01-08

    This work aims to increase the compatibility between PPS (Poly Phenylene Sulfide) and a Polyamide. In order to do so, a bloc co-polymer was synthesised by the coupling of telechelic oligomers of PPS and PA oligomers. These telechelic oligomers of PPS were synthesised in a single step which a synthesis was made possible were the nitrile and secondary amide functions. These oligomers were characterised by various techniques which lead to a rather good precision (difficult to achieve for insolubility reasons). These oligomers were then coupled with the polyamide oligomers. In order to do so, a new reaction was discovered between an aromatic nitrile and a secondary aliphatic amide. It was assessed both on model molecules and on oligomers. An original mechanism is proposed. Once the characterisation of these copolymers was made, various blends of PPS and PA were studied. At last, the incorporation of the block copolymers in the blend obtained by a twin screw extruder, lead to an improvement of the compatibility between the two polymers and in an increase of the resistance to crack propagation. (author) 314 refs.

  9. A study of thermal reactions of coal with polyamides

    Czech Academy of Sciences Publication Activity Database

    Straka, Pavel; Náhunková, Jana

    2004-01-01

    Roč. 1, č. 2 (2004), s. 239-243 ISSN 1211-1910 R&D Projects: GA AV ČR IAA2046902 Institutional research plan: CEZ:AV0Z3046908 Keywords : coal * kinetics * polyamides Subject RIV: CD - Macromolecular Chemistry

  10. The study of epoxy polyamide and polyvinyl resins as corrosion ...

    African Journals Online (AJOL)

    The corrosion resistance of two commonly used protective coatings (epoxy polyamide and polyvinyl resins) in the Niger Delta area of Nigeria has been assessed. The coatings on low carbon steel were subjected to varying conditions of pH, temperature and exposure time and the corrosion rates calculated. At a pH of 2, 3, 4, ...

  11. Microporous membranes from polyolefin-polyamide blend materials

    Czech Academy of Sciences Publication Activity Database

    Meier-Haack, J.; Valko, M.; Lunkwitz, K.; Bleha, Miroslav

    2004-01-01

    Roč. 163, 1-3 (2004), s. 215-221 ISSN 0011-9164. [Membrane Science and Technology Conference PERMEA 2003. Tatranské Matliare, 07.09.2003-11.09.2003] Institutional research plan: CEZ:AV0Z4050913 Keywords : microporous membranes * polypropylene polyamide blends * reactive extrusion Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.057, year: 2004

  12. Aromatic graphene

    Energy Technology Data Exchange (ETDEWEB)

    Das, D. K., E-mail: gour.netai@gmail.com [Department of Metallurgical and Material Science Engineering, National Institute of Technology Durgapur-713209, West Bengal (India); Sahoo, S., E-mail: sukadevsahoo@yahoo.com [Department of Physics, National Institute of Technology Durgapur-713209, West Bengal (India)

    2016-04-13

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  13. Aromatic graphene

    International Nuclear Information System (INIS)

    Das, D. K.; Sahoo, S.

    2016-01-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  14. An HRE-Binding Py-Im Polyamide Impairs Hypoxic Signaling in Tumors.

    Science.gov (United States)

    Szablowski, Jerzy O; Raskatov, Jevgenij A; Dervan, Peter B

    2016-04-01

    Hypoxic gene expression contributes to the pathogenesis of many diseases, including organ fibrosis, age-related macular degeneration, and cancer. Hypoxia-inducible factor-1 (HIF1), a transcription factor central to the hypoxic gene expression, mediates multiple processes including neovascularization, cancer metastasis, and cell survival. Pyrrole-imidazole polyamide 1: has been shown to inhibit HIF1-mediated gene expression in cell culture but its activity in vivo was unknown. This study reports activity of polyamide 1: in subcutaneous tumors capable of mounting a hypoxic response and showing neovascularization. We show that 1: distributes into subcutaneous tumor xenografts and normal tissues, reduces the expression of proangiogenic and prometastatic factors, inhibits the formation of new tumor blood vessels, and suppresses tumor growth. Tumors treated with 1: show no increase in HIF1α and have reduced ability to adapt to the hypoxic conditions, as evidenced by increased apoptosis in HIF1α-positive regions and the increased proximity of necrotic regions to vasculature. Overall, these results show that a molecule designed to block the transcriptional activity of HIF1 has potent antitumor activity in vivo, consistent with partial inhibition of the tumor hypoxic response. Mol Cancer Ther; 15(4); 608-17. ©2015 AACR. ©2015 American Association for Cancer Research.

  15. Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Fialips, Claire I

    2017-07-01

    Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Effects of fulvic acid concentration and origin on photodegradation of polycyclic aromatic hydrocarbons in aqueous solution: Importance of active oxygen

    International Nuclear Information System (INIS)

    Xia Xinghui; Li Gongchen; Yang Zhifeng; Chen Yumin; Huang, Gordon H.

    2009-01-01

    With an Xe arc lamp house as simulated sunlight, the influences of fulvic acid (FA) concentration and origins on photodegradation of acenaphthene, fluorine, phenanthrene, fluoranthene and pyrene in aqueous solution have been studied. Similar effects of FAs, collected from five places around China, on polycyclic aromatic hydrocarbon (PAH) photodegradation have been observed. Active oxygen was of significance in PAH photodegradation with the presence of FAs. For systems with 1.25 mg L -1 FAs, the contributions of ·OH to PAH photodegradation rates were from 33% to 69%. FAs had two opposite effects, i.e., stimulating the generation of active oxygen and advancing PAH photodegradation; competing with PAHs for energy and photons and restraining PAH photodegradation. Generally, photodegradation rates of the 5 PAHs decreased with the increase of FAs concentration; except fluoranthene and pyrene were advanced in solutions with low FA concentration. The influences of FA concentration on PAH photodegradation were more significant than FA origin. - Influences of fulvic acid (FA) concentration on PAH photodegradation were more significant than FA origin, and active oxygen played an important role in PAH photodegradation

  17. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    KAUST Repository

    Louie, Jennifer Sarah

    2011-02-01

    The application of polymer surface coatings to improve the fouling resistance of reverse osmosis membranes tends to increase flow resistance across the membrane. This paper presents a systematic analysis on how membrane properties and performance are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux, which is attributed to wetting of pores in the selective polyamide layer and to changes in the polymer structure. This flux increase was not readily reversible, based on a 300-h water permeation test. Conversely, drying a wetted membrane led to a decrease in water flux, which we hypothesize is caused by increased interchain hydrogen-bonding in the selective layer. This drop in water flux was not permanent; higher flux was observed if the same wetted/dried membrane was then re-soaked in ethanol prior to the water permeation experiment. An ethanol pre-soaking step also increased water flux of a PEBAX-coated membrane by nearly 70%. In contrast to the reduction in water flux caused by the specific treatment sequence of ethanol-swelling followed by drying, this same sequence actually increased gas transport. The eight- to ten-fold increase in Knudsen diffusion-based gas permeance after this pre-treatment was attributed to an increase in the number or size of membrane defects. © 2010 Elsevier B.V.

  18. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  19. Polycyclic aromatic hydrocarbon-induced CYP1B1 activity is suppressed by perillyl alcohol in MCF-7 cells

    International Nuclear Information System (INIS)

    Chan, Nelson L.S.; Wang Huan; Wang Yun; Leung, H.Y.; Leung, Lai K.

    2006-01-01

    Perillyl alcohol (POH) is a dietary monoterpene with potential applications in chemoprevention and chemotherapy. Although clinical trials are under way, POH's physiological and pharmacological properties are still unclear. In the present study, the effect of POH on polycyclic aromatic hydrocarbon (PAH)-induced genotoxicity, and the related expression were examined in MCF-7 cells. Exposure to environmental toxicant increases the risk of cancer. Many of these compounds are pro-carcinogens and are biotransformed into their ultimate genotoxic structures by xenobiotic metabolizing enzymes. CYP1A1 and 1B1 are enzymes that catalyze the biotransformation of dimethylbenz[a]anthracene (DMBA). Our data revealed that 0.5 μM of POH was effective in blocking DMBA-DNA binding. Ethoxyresorufin-O-deethylase (EROD) assay indicated that the administration of POH inhibited the DMBA-induced enzyme activity in MCF-7 cells. Enzyme kinetic analysis revealed that POH inhibited CYP1B1 but not CYP1A1 activity. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay also demonstrated that the monoterpene reduced CYP1B1 mRNA abundance induced by DMBA. The present study illustrated that POH might inhibit and downregulate CYP1B1, which could protect against PAH-induced carcinogenesis

  20. A critical evaluation of magnetic activated carbon's potential for the remediation of sediment impacted by polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Han, Zhantao; Sani, Badruddeen; Akkanen, Jarkko; Abel, Sebastian; Nybom, Inna; Karapanagioti, Hrissi K; Werner, David

    2015-04-09

    Addition of activated carbon (AC) or biochar (BC) to sediment to reduce the chemical and biological availability of organic contaminants is a promising in-situ remediation technology. But concerns about leaving the adsorbed pollutants in place motivate research into sorbent recovery methods. This study explores the use of magnetic sorbents. A coal-based magnetic activated carbon (MAC) was identified as the strongest of four AC and BC derived magnetic sorbents for polycyclic aromatic hydrocarbons (PAHs) remediation. An 8.1% MAC amendment (w/w, equal to 5% AC content) was found to be as effective as 5% (w/w) pristine AC in reducing aqueous PAHs within three months by 98%. MAC recovery from sediment after three months was 77%, and incomplete MAC recovery had both, positive and negative effects. A slight rebound of aqueous PAH concentrations was observed following the MAC recovery, but aqueous PAH concentrations then dropped again after six months, likely due to the presence of the 23% unrecovered MAC. On the other hand, the 77% recovery of the 8.1% MAC dose was insufficient to reduce ecotoxic effects of fine grained AC or MAC amendment on the egestion rate, growth and reproduction of the AC sensitive species Lumbriculus variegatus. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Effect of Aromatic Essential Oil of Lavender on the Electrical Activity of Healthy Girls’ Heart during Exercise

    Directory of Open Access Journals (Sweden)

    M. Torabi

    2017-02-01

    Full Text Available Aims: Some of the herbal supplementations consumed by the athletes in order to improve their athletic functions are selected to affect the cardio-vascular system. The aim of the study was to investigate the aromatic effects of lavender essential oils on the heart electrical functions during exercises in the healthy girls. Materials & Methods: In the repeated pretest-posttest semi-experimental study, 9 active healthy girls studying sport sciences in Shahid Rajaei University were studied in 2015. The subjects were selected via purposeful sampling method. As counter balance, either ethanol soaked cotton or lavender oil essence were exposed to each subject, and the Conconi test was conducted as a sport activity. Both electrocardiogram waves and blood pressure data were recorded before the activities and immediately after and one minute after the end of the activity (recovery. Data were analyzed by SPSS 20 software using repeated ANOVA and student T tests. Findings: Immediately after the test, the systolic blood pressure in experimental group was significantly higher than control group (p<0.05. In addition, the inhalation of the lavender oil in experimental group increased R wave height during the final moments of exercises compared to control group (p<0.05. Nevertheless, the systolic blood pressure, T wave height, and R-R and Q-T distances did not significantly change in response to the exercises. Conclusion: During the sport activities, the inhalation of lavender affects the heart ventricular function, as well as the heart beat and the systolic blood pressure.

  2. High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite

    Science.gov (United States)

    Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

    2015-01-01

    Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes. PMID:26333385

  3. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  4. Synthesis, characterization and DNA cleavage activity of nickel(II adducts with aromatic heterocyclic bases

    Directory of Open Access Journals (Sweden)

    G. H. PHILIP

    2010-01-01

    Full Text Available Mixed ligand complexes of nickel(II with 2,4-dihydroxyaceto-phenone oxime (DAPO and 2,4-dihydroxybenzophenone oxime (DBPO as primary ligands, and pyridine (Py and imidazole (Im as secondary ligands were synthesized and characterized by molar conductivity, magnetic moments measurements, as well as by electronic, IR, and 1H-NMR spectroscopy. Electrochemical studies were performed by cyclic voltammetry. The active signals are assignable to the NiIII/II and NiII/I redox couples. The binding interactions between the metal complexes and calf thymus DNA were investigated by absorption and thermal denaturation. The cleavage activity of the complexes was determined using double-stranded pBR322 circular plasmid DNA by gel electrophoresis. All complexes showed increased nuclease activity in the presence of the oxidant H2O2. The nuclease activities of mixed ligand complexes were compared with those of the parent copper(II complexes.

  5. Antimicrobial, Antioxidant, and Anti-Inflammatory Activities of Essential Oils of Selected Aromatic Plants from Tajikistan

    OpenAIRE

    Sharopov, Farukh; Braun, Markus Santhosh; Gulmurodov, Isomiddin; Khalifaev, Davlat; Isupov, Salomiddin; Wink, Michael

    2015-01-01

    Antimicrobial, antioxidant, and anti-inflammatory activities of the essential oils of 18 plant species from Tajikistan (Central Asia) were investigated. The essential oil of Origanum tyttanthum showed a strong antibacterial activity with both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 312.5 µg/mL for E. coli, 625 µg/mL (MIC) and 1250 µg/mL (MBC) for MRSA (methicillin-resistant Staphylococcus aureus), respectively. The essential oil of Galagan...

  6. Antimicrobial, Antioxidant, and Anti-Inflammatory Activities of Essential Oils of Selected Aromatic Plants from Tajikistan

    Directory of Open Access Journals (Sweden)

    Farukh Sharopov

    2015-11-01

    Full Text Available Antimicrobial, antioxidant, and anti-inflammatory activities of the essential oils of 18 plant species from Tajikistan (Central Asia were investigated. The essential oil of Origanum tyttanthum showed a strong antibacterial activity with both minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC values of 312.5 µg/mL for E. coli, 625 µg/mL (MIC and 1250 µg/mL (MBC for MRSA (methicillin-resistant Staphylococcus aureus, respectively. The essential oil of Galagania fragrantissima was highly active against MRSA at concentrations as low as 39.1 µg/mL and 78.2 µg/mL for MIC and MBC, respectively. Origanum tyttanthum essential oil showed the highest antioxidant activity with IC50 values of 0.12 mg/mL for ABTS (2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid and 0.28 mg/mL for DPPH (2,2-diphenyl-1-picrylhydrazyl. Galagania fragrantissima and Origanum tyttanthum essential oils showed the highest anti-inflammatory activity; IC50 values of 5-lipoxygenase (5-LOX inhibition were 7.34 and 14.78 µg/mL, respectively. In conclusion, essential oils of Origanum tyttanthum and Galagania fragrantissima exhibit substantial antimicrobial, antioxidant, and anti-inflammatory activities. They are interesting candidates in phytotherapy.

  7. Volatile Profiling of Aromatic Traditional Medicinal Plant, Polygonum minus in Different Tissues and Its Biological Activities

    Directory of Open Access Journals (Sweden)

    Rafidah Ahmad

    2014-11-01

    Full Text Available The aim of this research was to identify the volatile metabolites produced in different organs (leaves, stem and roots of Polygonum minus, an important essential oil producing crop in Malaysia. Two methods of extraction have been applied: Solid Phase Microextraction (SPME and hydrodistillation coupled with Gas Chromatography-Mass Spectrometry (GC-MS. Approximately, 77 metabolites have been identified and aliphatic compounds contribute significantly towards the aroma and flavour of this plant. Two main aliphatic compounds: decanal and dodecanal were found to be the major contributor. Terpenoid metabolites were identified abundantly in leaves but not in the stem and root of this plant. Further studies on antioxidant, total phenolic content, anticholinesterase and antimicrobial activities were determined in the essential oil and five different extracts. The plant showed the highest DPPH radical scavenging activity in polar (ethanol extract for all the tissues tested. For anti-acetylcholinesterase activity, leaf in aqueous extract and methanol extract showed the best acetylcholinesterase inhibitory activities. However, in microbial activity, the non-polar extracts (n-hexane showed high antimicrobial activity against Methicillin-resistant Staphylococcus aureus (MRSA compared to polar extracts. This study could provide the first step in the phytochemical profiles of volatile compounds and explore the additional value of pharmacology properties of this essential oil producing crop Polygonum minus.

  8. Antimicrobial, Antioxidant, and Anti-Inflammatory Activities of Essential Oils of Selected Aromatic Plants from Tajikistan.

    Science.gov (United States)

    Sharopov, Farukh; Braun, Markus Santhosh; Gulmurodov, Isomiddin; Khalifaev, Davlat; Isupov, Salomiddin; Wink, Michael

    2015-11-02

    Antimicrobial, antioxidant, and anti-inflammatory activities of the essential oils of 18 plant species from Tajikistan (Central Asia) were investigated. The essential oil of Origanum tyttanthum showed a strong antibacterial activity with both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 312.5 µg/mL for E. coli , 625 µg/mL (MIC) and 1250 µg/mL (MBC) for MRSA (methicillin-resistant Staphylococcus aureus), respectively. The essential oil of Galagania fragrantissima was highly active against MRSA at concentrations as low as 39.1 µg/mL and 78.2 µg/mL for MIC and MBC, respectively. Origanum tyttanthum essential oil showed the highest antioxidant activity with IC 50 values of 0.12 mg/mL for ABTS (2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid)) and 0.28 mg/mL for DPPH (2,2-diphenyl-1-picrylhydrazyl) . Galagania fragrantissima and Origanum tyttanthum essential oils showed the highest anti-inflammatory activity; IC 50 values of 5-lipoxygenase (5-LOX) inhibition were 7.34 and 14.78 µg/mL, respectively. In conclusion, essential oils of Origanum tyttanthum and Galagania fragrantissima exhibit substantial antimicrobial, antioxidant, and anti-inflammatory activities. They are interesting candidates in phytotherapy.

  9. The polycyclic aromatic hydrocarbons benzo[a]pyrene and phenanthrene inhibit intestinal lipase activity in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    de Gelder, Stefan; Sæle, Øystein; de Veen, Bas T H; Vos, Joëlle; Flik, Gert; Berntssen, Marc H G; Klaren, Peter H M

    2017-08-01

    Elevated levels of polycyclic aromatic hydrocarbons (PAHs) are detected in aquafeeds where fish oils are (partially) replaced by vegetable oils. The highly lipophilic PAHs solubilize readily in oil droplets and micelles in the intestinal lumen that can affect enzymatic lipid digestion by altering lipase activity. We therefore investigated the effect of two PAHs, benzo[a]pyrene (BaP) and phenanthrene (PHE), on bile salt-activated lipase (BAL) activity in desalted luminal extracts of the proximal intestine of rainbow trout (Oncorhynchus mykiss) using the triacylglycerides rapeseed oil and fish oil as substrates. The hydrolysis of rapeseed oil and fish oil measured at a calculated substrate concentration of 2.2mM, increased linearly up to 30min at 15°C. Substrate dependency under initial velocity conditions was described by simple Michaelis-Menten kinetics with a K m value of 1.2mM for rapeseed and fish oil. Rapeseed oil hydrolysis was inhibited by 1nM BaP and 10nM PHE. The hydrolysis of fish oil was only inhibited by 10μM BaP. The in vitro lipase activity data were corroborated by TLC/HPLC analysis of the reaction products, showing that in the presence of BaP and PHE, 46-80% less free fatty acids (FFA) were hydrolysed from rapeseed and fish oil triacylglycerides. The presence of low concentrations of BaP and PHE decreased rapeseed oil hydrolysis by BAL whereas fish oil hydrolysis was not affected. The replacement of fish oil by rapeseed oil in aquafeeds introduces PAHs that could affect lipid digestion. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Studies on low-carrier radiofluorination of non-active aromatics with no-carrier-added [18F]fluoride

    International Nuclear Information System (INIS)

    Cardinale, Jens

    2013-01-01

    In vivo imaging with positron emission tomography generally demands radiotracers with a high specific activity. In case of fluorine-18 the required no-carrier-added (n.c.a.) starting material is only available in form of fluoride. This and the short half-life of 109.7 minutes of the radionuclide lead to the demand of special methods for radiosyntheses. The only practical procedure for manufacturing n.c.a. [ 18 F]fluoro-compounds is therefore nucleophilic substitution. There is, however, still a lack of effective procedures for the labelling of electron rich aromatic molecules starting from n.c.a. [ 18 F]fluoride. A process for n.c.a. radiofluorination of these compounds is offered by the reaction of iodonium compounds as starting materials. In this study modern procedures for the synthesis of iodoniumsalts and -ylides were investigated. Several precursor molecules for the versatile synthetic building block 4-[ 18 F]fluoroiodobenzene were synthesised. In this course, a new one-pot procedure for the synthesis of iodoniumylides was developed. Further on, the syntheses of suitable iodonium precursors for two fluorophenoxy-derivatives, which are possible antidepressants, were investigated. Due to their binding profile these compounds can be considered as ligands for the serotonin reuptake transporter (SERT) and the norepinephrin reuptake transporter (NET), respectively. The preparation of appropriate iodonium salts proved to be too problematic, while the synthesis of suitable iodoniumylides could be accomplished with satisfactory yields of about 30% and 40 %, respectively. Both compounds were labelled with n.c.a. [ 18 F]fluoride and deprotected to the desired target compounds 4-((3-[ 18 F]fluorophenoxy)(phenyl)methyl)piperidine and 4-((4-[ 18 F]fluorophenoxy)(phenyl)methyl)piperidine in radiochemical yields of about 40 % and 25 %, respectively. Those are now available for preclinical evaluation studies. Furthermore, a process for the palladium catalysed synthesis of 18

  11. Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide.

    Directory of Open Access Journals (Sweden)

    Amanda E Hargrove

    Full Text Available Pyrrole-imidazole (Py-Im polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse xenograft model. In addition to the effects on AR regulated transcription, RNA-seq analysis revealed inhibition of topoisomerase-DNA binding as a potential mechanism that contributes to the antitumor effects of polyamides in cell culture and in xenografts. These studies support the therapeutic potential of Py-Im polyamides to target multiple aspects of transcriptional regulation in prostate cancers without genotoxic stress.

  12. Prenatal polycyclic aromatic hydrocarbon, adiposity, peroxisome proliferator-activated receptor (PPAR γ methylation in offspring, grand-offspring mice.

    Directory of Open Access Journals (Sweden)

    Zhonghai Yan

    Full Text Available Greater levels of prenatal exposure to polycyclic aromatic hydrocarbon (PAH have been associated with childhood obesity in epidemiological studies. However, the underlying mechanisms are unclear.We hypothesized that prenatal PAH over-exposure during gestation would lead to weight gain and increased fat mass in offspring and grand-offspring mice. Further, we hypothesized that altered adipose gene expression and DNA methylation in genes important to adipocyte differentiation would be affected.Pregnant dams were exposed to a nebulized PAH mixture versus negative control aerosol 5 days a week, for 3 weeks. Body weight was recorded from postnatal day (PND 21 through PND60. Body composition, adipose cell size, gene expression of peroxisome proliferator-activated receptor (PPAR γ, CCAAT/enhancer-binding proteins (C/EBP α, cyclooxygenase (Cox-2, fatty acid synthase (FAS and adiponectin, and DNA methylation of PPAR γ, were assayed in both the offspring and grand-offspring adipose tissue.Offspring of dams exposed to greater PAH during gestation had increased weight, fat mass, as well as higher gene expression of PPAR γ, C/EBP α, Cox2, FAS and adiponectin and lower DNA methylation of PPAR γ. Similar differences in phenotype and DNA methylation extended through the grand-offspring mice.Greater prenatal PAH exposure was associated with increased weight, fat mass, adipose gene expression and epigenetic changes in progeny.

  13. An active site aromatic triad in Escherichia coli DNA Pol IV coordinates cell survival and mutagenesis in different DNA damaging agents.

    Directory of Open Access Journals (Sweden)

    Ryan W Benson

    Full Text Available DinB (DNA Pol IV is a translesion (TLS DNA polymerase, which inserts a nucleotide opposite an otherwise replication-stalling N(2-dG lesion in vitro, and confers resistance to nitrofurazone (NFZ, a compound that forms these lesions in vivo. DinB is also known to be part of the cellular response to alkylation DNA damage. Yet it is not known if DinB active site residues, in addition to aminoacids involved in DNA synthesis, are critical in alkylation lesion bypass. It is also unclear which active site aminoacids, if any, might modulate DinB's bypass fidelity of distinct lesions. Here we report that along with the classical catalytic residues, an active site "aromatic triad", namely residues F12, F13, and Y79, is critical for cell survival in the presence of the alkylating agent methyl methanesulfonate (MMS. Strains expressing dinB alleles with single point mutations in the aromatic triad survive poorly in MMS. Remarkably, these strains show fewer MMS- than NFZ-induced mutants, suggesting that the aromatic triad, in addition to its role in TLS, modulates DinB's accuracy in bypassing distinct lesions. The high bypass fidelity of prevalent alkylation lesions is evident even when the DinB active site performs error-prone NFZ-induced lesion bypass. The analyses carried out with the active site aromatic triad suggest that the DinB active site residues are poised to proficiently bypass distinctive DNA lesions, yet they are also malleable so that the accuracy of the bypass is lesion-dependent.

  14. New aromatic activated dihalides and bisphenol monomers for the preparation of novel poly(arylene ethers)

    Science.gov (United States)

    Wolfe, James F.

    1993-01-01

    The goal of this research program was to synthesize a series of unique monomers of type I to be utilized at NASA-Langley in the preparation of new poly(arylene ether ketones), poly(arylene ether ketosulfones), and poly(arylene ether ketophosphine oxides). These A-A and A-B monomer systems, which possess activated aryl halide and/or phenolic end groups, are accessible via condensation reactions of appropriately substituted aryl acetonitrile carbanions with activated aryl dihalides followed by oxidative decyanation.

  15. Aromatic C-H bond activation revealed by infrared multiphoton dissociation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Jašíková, L.; Hanikýřová, E.; Schröder, Detlef; Roithová, J.

    2012-01-01

    Roč. 47, č. 4 (2012), s. 460-465 ISSN 1076-5174 Grant - others:GA ČR(CZ) GAP207/11/0338; Seventh Framework Program(XE) 226716 Institutional research plan: CEZ:AV0Z40550506 Keywords : C-H activation * density functional theory calculations * ion spectroscopy * metal oxides * rearrangements Subject RIV: CC - Organic Chemistry Impact factor: 3.214, year: 2012

  16. Engineered P450 biocatalysts show improved activity and regio-promiscuity in aromatic nitration.

    Science.gov (United States)

    Zuo, Ran; Zhang, Yi; Jiang, Chao; Hackett, John C; Loria, Rosemary; Bruner, Steven D; Ding, Yousong

    2017-04-12

    Nitroaromatics are among the most important and commonly used chemicals but their production often suffers from multiple unsolved challenges. We have previously described the development of biocatalytic nitration processes driven by an engineered P450 TxtE fusion construct. Herein we report the creation of improved nitration biocatalysts through constructing and characterizing fusion proteins of TxtE with the reductase domain of CYP102A1 (P450BM3, BM3R). The majority of constructs contained variable linker length while one was rationally designed for optimizing protein-protein interactions. Detailed biochemical characterization identified multiple active chimeras that showed improved nitration activity, increased coupling efficiency and higher total turnover numbers compared with TxtE. Substrate promiscuity of the most active chimera was further assessed with a substrate library. Finally, a biocatalytic nitration process was developed to nitrate 4-Me-DL-Trp. The production of both 4-Me-5-NO 2 -L-Trp and 4-Me-7-NO 2 -L-Trp uncovered remarkable regio-promiscuity of nitration biocatalysts.

  17. Anti-plasmodial and insecticidal activities of the essential oils of aromatic plants growing in the Mediterranean area

    Directory of Open Access Journals (Sweden)

    Dell’Agli Mario

    2012-07-01

    Full Text Available Abstract Background Sardinia is a Mediterranean area endemic for malaria up to the last century. During a screening study to evaluate the anti-plasmodial activity of some aromatic plants traditionally used in Sardinia, Myrtus communis (myrtle, Myrtaceae, Satureja thymbra (savory, Lamiaceae, and Thymus herba-barona (caraway thyme, Lamiaceae were collected in three vegetative periods: before, during and after flowering. Methods The essential oils were obtained by steam distillation, fractionated by silica gel column chromatography and analysed by GC-FID-MS. Total oil and three main fractions were tested on D10 and W2 strains of Plasmodium falciparum in vitro. Larvicidal and adulticidal activities were tested on Anopheles gambiae susceptible strains. Results The essential oil of savory, rich in thymol, was the most effective against P. falciparum with an inhibitory activity independent from the time of collection (IC50 17–26 μg/ml on D10 and 9–11 μg/ml on W2. Upon fractionation, fraction 1 was enriched in mono-sesquiterpenoid hydrocarbons; fraction 2 in thymol (73-83%; and fraction 3 contained thymol, carvacrol and terpinen-4-ol, with a different composition depending on the time of collection. Thymol-enriched fractions were the most active on both strains (IC50 20–22 μg/ml on D10 and 8–10 μg/ml on W2 and thymol was confirmed as mainly responsible for this activity (IC50 19.7± 3.0 and 10.6 ± 2.0 μg/ml on D10 and W2, respectively. The essential oil of S. thymbra L. showed also larvicidal and adulticidal activities. The larvicidal activity, expressed as LC50, was 0.15 ± 0.002; 0.21 ± 0.13; and 0.15 ± 0.09 μg/ml (mean ± sd depending on the time of collection: before, during and after flowering, respectively. Conclusions This study provides evidence for the use of essential oils for treating malaria and fighting the vector at both the larval and adult stages. These findings open the possibility for further

  18. Polyamide 6/clay membranes: effect of precipitation bath in morphology

    International Nuclear Information System (INIS)

    Ferreira, Rodholfo da S.B.; Pereira, Caio H. do O; Leite, Amanda M.D.; Araujo, Edcleide M.; Lira, Helio L.

    2015-01-01

    Polyamide 6 membranes and their nanocomposites with 5% clay were obtained by the phase inversion method and the precipitation was made in distilled water bath and also in the mixture of solvent and distilled water. The nanocomposites were characterized by XRD and membranes by SEM. By XRD analysis, it was found that the obtained nanocomposite presents a structure probably exfoliated and / or partially exfoliated, it was also possible to observe the presence of two characteristic peaks (α and γ) of the polyamide 6 phases. In the SEM micrographs it was seen that the presence of clay promote alterations in morphology, size and distribution of pores. The presence of acid in the precipitation bath leads to a significant decrease in the filter layer, but also an increase in the quantity of pore size. (author)

  19. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

    International Nuclear Information System (INIS)

    Paz, Rene A.; Leite, Amanda M.D.; Medeirosa, Vanessa da N.; Araujo, Edcleide M.; Melo, Tomas J.A.; Pessan, Luiz A.

    2010-01-01

    Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that they affect the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a regional bentonite modified with a quaternary ammonium salt in an amount of 3% by weight. XRD results showed that incorporation of salt among the layers of clay, making it organophilic and obtaining exfoliated and/or partially exfoliated structures. The impact properties of the nanocomposites showed inferior in relation to pure polyamide, in other words, lost of toughness. (author)

  20. Investigation into radiation-chemical transformations of polyamide P-54

    International Nuclear Information System (INIS)

    Khabarov, V.N.; Kozlov, L.L.; Panchenkov, G.M.

    1981-01-01

    Investigation results of alcohol-soluble polyamide P-54 radiolysis by different physicochemical methods are presented. It has been established that under the effect of γ-radiation certain processes take place in polyamide, which are connected with branching, structurization and destruction of macromolecules. Radiation-chemical yields of gaseous products during irradiation in the air and in vacuum at irradiation temperatures from 273 to 393 K are calculated. The ratio of the rates of lacing and destruction processes is found and radiation yields of the processes are determined. Under irradiation in the air at temperatures >333 K chain oxidation of P-54 takes place and the growth of pe-- roxide compounds with 8 molecules/100 eV at 298 K up to 135 mole-- cules/100 eV at irradiation temperature 373 K testifies to the fact

  1. Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide

    OpenAIRE

    Hargrove, Amanda E.; Martinez, Thomas F.; Hare, Alissa A.; Kurmis, Alexis A.; Phillips, John W.; Sud, Sudha; Pienta, Kenneth J; Dervan, Peter B.

    2015-01-01

    Pyrrole-imidazole (Py-Im) polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE)-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse ...

  2. Synthesis and Characterization of New Polyamides from 1,2-Bis hydrazine Derivatives

    International Nuclear Information System (INIS)

    Salaha, A.; Abdel-Bary, E.M.; Kandilea, N.G.

    2005-01-01

    Preparation of polyamides having different chemical structures allows obtaining new materials with different mechanical and physical properties. The difference in the chemical structure depends mainly on the starting reactants used in condensation polymerization of polyamides. In this paper the synthesis of new polyamides based on the condensation polymerization of 1,2- Bis(3-carboxyacryloyl or carboxybenzoyl) hydrazine derivatives and various diamines has been described. The polymers obtained were characterized using spectroscopic and X-ray analysis. Besides thermal stability and electrical conductivity have been evaluated and correlated with the chemical structure of the polyamides obtained

  3. Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers.

    Science.gov (United States)

    Huang, Hai; Lin, Saisai; Zhang, Lin; Hou, Li'an

    2017-03-22

    Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N-H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.

  4. Kinetics of copyrolysis of coal with polyamide 6

    Czech Academy of Sciences Publication Activity Database

    Straka, Pavel; Náhunková, Jana; Brožová, Zuzana

    2004-01-01

    Roč. 71, č. 1 (2004), s. 213-221 ISSN 0165-2370. [Pyrolysis 2002, 15th International Symposium on Analytical and Applied Pyrolysis. Leoben, 17.09.2002-20.09.2002] R&D Projects: GA AV ČR IBS3046004 Institutional research plan: CEZ:AV0Z3046908 Keywords : coal * kinetics * polyamide 6 Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.352, year: 2004

  5. Factors affecting polyamide prototypes design of Albedo dosemeters

    International Nuclear Information System (INIS)

    Martins, M.M.; Mauricio, C.L.P.; Fonseca, E.S.

    1996-01-01

    This work studies the most important factors which affect the response of albedo neutron dosemeters containing LiF TLDs with the aim to improve their sensitivity. It includes tests of thickness and shape of the polyamide moderator body prototypes, albedo window diameter and TLD position inside the moderator. Analyzing the results, an albedo neutron dosemeter prototype, B 4 C covered, was developed. The prototype has a response three times higher than the albedo dosemeter now in use in Brazil. (author)

  6. Antimicrobial Activity and Chemical Composition of Three Essential Oils Extracted from Mediterranean Aromatic Plants.

    Science.gov (United States)

    Elshafie, Hazem S; Sakr, Shimaa; Mang, Stefania M; Belviso, Sandra; De Feo, Vincenzo; Camele, Ippolito

    2016-11-01

    There is a growing interest in essential oils (EOs) as possible alternatives for traditional chemical pesticides. This study was carried out to characterize the chemical composition of the three EOs extracted from Verbena officinalis, Majorana hortensis, and Salvia officinalis using gas chromatography (GC) and GC-mass spectrometry (GC-MS) and to evaluate in vitro their efficacy against some phyto or human pathogens. The antifungal activity was investigated against Colletotrichum acutatum and Botrytis cinerea in comparison with Azoxystrobin as a large spectrum fungicide. Antibacterial activity was evaluated against Bacillus megaterium, Bacillus mojavensis, and Clavibacter michiganensis (G+ve) and Escherichia coli, Xanthomonas campestris, Pseudomonas savastanoi, and P. syringae pv. phaseolicola (G-ve) compared to a synthetic antibiotic tetracycline. Minimum inhibitory concentration was evaluated against the above tested fungi using 96-well microplate method. Results showed that the chemical structure of the three studied EOs was mainly composed of monoterpene compounds and all oils belong to the chemotype carvacrol/thymol. Results of GC analysis identified 64 compounds, which were identified based on their mass to charge ratio. Furthermore, the different concentrations of studied EOs inhibited the growth of tested microorganism in a dose-dependent manner.

  7. Impact of salinity and dispersed oil on adsorption of dissolved aromatic hydrocarbons by activated carbon and organoclay

    Energy Technology Data Exchange (ETDEWEB)

    Younker, Jessica M.; Walsh, Margaret E., E-mail: mwalsh2@dal.ca

    2015-12-15

    Highlights: • Powdered activated carbon (PAC) outperformed organoclay for dissolved aromatics removal • Dispersed oil reduced the adsorption capacity of PAC but not organoclay • Salinity did not affect phenol or naphthalene removal by PAC or BTMA-organoclay • Commercial organoclay had reduced adsorption capacity in saline water due to aggregation • PAC performed better in single solute systems than multi-solute systems - Abstract: Adsorption capacity of phenol and naphthalene by powdered activated carbon (PAC), a commercial organoclay (OC) and a lab synthesized organoclay (BTMA) was studied using batch adsorption experiments under variable feed water quality conditions including single- and multi- solute conditions, fresh water, saline water and oily-and-saline water. Increasing salinity levels was found to reduce adsorption capacity of OC, likely due to destabilization, aggregation and subsequent removal of organoclay from the water column, but did not negatively impact adsorption capacity of PAC or BTMA. Increased dispersed oil concentrations were found to reduce the surface area of all adsorbents. This decreased the adsorption capacity of PAC for both phenol and naphthalene, and reduced BTMA adsorption of phenol, but did not negatively affect naphthalene removals by either organoclay. The presence of naphthalene as a co-solute significantly reduced phenol adsorption by PAC, but had no impact on organoclay adsorption. These results indicated that adsorption by PAC occurred via a surface adsorption mechanism, while organoclay adsorption occurred by hydrophobic or pi electron interactions. In general, PAC was more sensitive to changes in water quality than either of the organoclays evaluated in this study. However, PAC exhibited a higher adsorption capacity for phenol and naphthalene compared to both organoclays even in adverse water quality conditions.

  8. Impact of salinity and dispersed oil on adsorption of dissolved aromatic hydrocarbons by activated carbon and organoclay

    International Nuclear Information System (INIS)

    Younker, Jessica M.; Walsh, Margaret E.

    2015-01-01

    Highlights: • Powdered activated carbon (PAC) outperformed organoclay for dissolved aromatics removal • Dispersed oil reduced the adsorption capacity of PAC but not organoclay • Salinity did not affect phenol or naphthalene removal by PAC or BTMA-organoclay • Commercial organoclay had reduced adsorption capacity in saline water due to aggregation • PAC performed better in single solute systems than multi-solute systems - Abstract: Adsorption capacity of phenol and naphthalene by powdered activated carbon (PAC), a commercial organoclay (OC) and a lab synthesized organoclay (BTMA) was studied using batch adsorption experiments under variable feed water quality conditions including single- and multi- solute conditions, fresh water, saline water and oily-and-saline water. Increasing salinity levels was found to reduce adsorption capacity of OC, likely due to destabilization, aggregation and subsequent removal of organoclay from the water column, but did not negatively impact adsorption capacity of PAC or BTMA. Increased dispersed oil concentrations were found to reduce the surface area of all adsorbents. This decreased the adsorption capacity of PAC for both phenol and naphthalene, and reduced BTMA adsorption of phenol, but did not negatively affect naphthalene removals by either organoclay. The presence of naphthalene as a co-solute significantly reduced phenol adsorption by PAC, but had no impact on organoclay adsorption. These results indicated that adsorption by PAC occurred via a surface adsorption mechanism, while organoclay adsorption occurred by hydrophobic or pi electron interactions. In general, PAC was more sensitive to changes in water quality than either of the organoclays evaluated in this study. However, PAC exhibited a higher adsorption capacity for phenol and naphthalene compared to both organoclays even in adverse water quality conditions.

  9. Phytochemical profiles and antimicrobial activity of aromatic Malaysian herb extracts against food-borne pathogenic and food spoilage microorganisms.

    Science.gov (United States)

    Aziman, Nurain; Abdullah, Noriham; Noor, Zainon Mohd; Kamarudin, Wan Saidatul Syida Wan; Zulkifli, Khairusy Syakirah

    2014-04-01

    Preliminary phytochemical and flavonoid compounds of aqueous and ethanolic extracts of 6 aromatic Malaysian herbs were screened and quantified using Reverse-Phase High Performance Liquid Chromatography (RP-HPLC). The herbal extracts were tested for their antimicrobial activity against 10 food-borne pathogenic and food spoilage microorganisms using disk diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of herbal extracts were determined. In the phytochemical screening process, both aqueous and ethanolic extracts of P. hydropiper exhibited presence of all 7 tested phytochemical compounds. Among all herbal extracts, the aqueous P. hydropiper and E. elatior extracts demonstrated the highest antibacterial activity against 7 tested Gram-positive and Gram-negative bacteria with diameter ranging from 7.0 to 18.5 mm and 6.5 to 19 mm, respectively. The MIC values for aqueous and ethanolic extracts ranged from 18.75 to 175 mg/mL and 0.391 to 200 mg/mL, respectively while the MBC/MFC values for aqueous and ethanolic extracts ranged from 25 to 200 mg/mL and 3.125 to 50 mg/mL, respectively. Major types of bioactive compounds in aqueous P. hydropiper and E. elatior extracts were identified using RP-HPLC instrument. Flavonoids found in these plants were epi-catechin, quercetin, and kaempferol. The ability of aqueous Persicaria hydropiper (L.) H. Gross and Etlingera elatior (Jack) R.M. Sm. extracts to inhibit the growth of bacteria is an indication of its broad spectrum antimicrobial potential. Hence these herbal extracts may be used as natural preservative to improve the safety and shelf-life of food and pharmaceutical products. © 2014 Institute of Food Technologists®

  10. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

    International Nuclear Information System (INIS)

    Paz, Rene Anisio; Araujo, Edcleide Maria; Tomas Jeferson Alves; Amanda Damiao; Medeiros, Vanessa da Nobrega; Pessan, Luiz Antonio

    2012-01-01

    Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that it affects the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a Brazilian bentonite modified with a quaternary ammonium salt. X-Ray Diffraction (XRD) results showed the incorporation of salt among the layers of clay, making it organophilic and that the nanocomposites presented exfoliated and/or partially exfoliated structures and confirmed by transmission electron microscopy (TEM). By thermogravimetry (TG), the results indicated that the presence of clay increased the thermal stability of polyamide 6. The impact properties of the nanocomposites showed inferior values in relation to the pure polyamide, in other words, decrease the toughness. (author)

  11. Structure and mechanical properties of polyamide 6/Brazilian clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Amanda Melissa Damião Leite

    2009-06-01

    Full Text Available Recent interest in polymer/organoclays nanocomposites systems is motivated by the possibility of achieving enhanced properties and added functionality at lower clay loading as compared to conventional micron size fillers. By adding montmorillonite clay to polyamide 6 increases the Young modulus, yield strength and also improves barrier properties. In this work, nanocomposites of polyamide 6 with montmorillonite clay were obtained. The clay was chemically modified with three different quaternary ammonium salts such as: Dodigen, Genamin and Cetremide. In this case, a dispersion of Na-MMT was stirred and a salt equivalent to 1:1 of cation exchange capacity (CEC of Na-MMT was added to the dispersion. The montmorillonite clay (untreated and treated by ammonium salts and nanocomposites were characterized by X ray diffractions. Also the nanocomposites were characterized by transmission electron microscopy and mechanical properties. The results indicated that all the quaternary ammonium salts were intercalated between the layers of clay, leading to an expansion of the interlayer spacing. The obtained nanocomposites showed better mechanical properties when compared to polyamide 6. The clay acted as reinforcing filler, increasing the rigidity of nanocomposites and decreasing its ductility.

  12. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Paz, Rene Anisio; Araujo, Edcleide Maria; Tomas Jeferson Alves; Amanda Damiao; Medeiros, Vanessa da Nobrega [Federal University of Campina Grande (CCT/UFCG), Campina Grande, PB (Brazil). Centro de Ciencias e Tecnologia; Pessan, Luiz Antonio [Federal University of Sao Carlos (DEMa/UFSCar), SP (Brazil). Materials Engineering Department

    2012-07-15

    Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that it affects the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a Brazilian bentonite modified with a quaternary ammonium salt. X-Ray Diffraction (XRD) results showed the incorporation of salt among the layers of clay, making it organophilic and that the nanocomposites presented exfoliated and/or partially exfoliated structures and confirmed by transmission electron microscopy (TEM). By thermogravimetry (TG), the results indicated that the presence of clay increased the thermal stability of polyamide 6. The impact properties of the nanocomposites showed inferior values in relation to the pure polyamide, in other words, decrease the toughness. (author)

  13. Studies on the Simultaneous Formation of Aroma-Active and Toxicologically Relevant Vinyl Aromatics from Free Phenolic Acids during Wheat Beer Brewing.

    Science.gov (United States)

    Langos, Daniel; Granvogl, Michael

    2016-03-23

    During the brewing process of wheat beer, the desired aroma-active vinyl aromatics 2-methoxy-4-vinylphenol and 4-vinylphenol as well as the undesired and toxicologically relevant styrene are formed from their respective precursors, free ferulic acid, p-coumaric acid, and cinnamic acid, deriving from the malts. Analysis of eight commercial wheat beers revealed high concentrations of 2-methoxy-4-vinylphenol and 4-vinylphenol always in parallel with high concentrations of styrene or low concentrations of the odorants in parallel with low styrene concentrations, suggesting a similar pathway. To better understand the formation of these vinyl aromatics, each process step of wheat beer brewing and the use of different strains of Saccharomyces cerevisiae were evaluated. During wort boiling, only a moderate decarboxylation of free phenolic acids and formation of desired and undesired vinyl aromatics were monitored due to the thermal treatment. In contrast, this reaction mainly occurred enzymatically catalyzed during fermentation with S. cerevisiae strain W68 with normal Pof(+) activity (phenolic off-flavor) resulting in a wheat beer eliciting the typical aroma requested by consumers due to high concentrations of 2-methoxy-4-vinylphenol (1790 μg/L) and 4-vinylphenol (937 μg/L). Unfortunately, also a high concentration of undesired styrene (28.3 μg/L) was observed. Using a special S. cerevisiae strain without Pof(+) activity resulted in a significant styrene reduction (beer aroma.

  14. POLYAMIDE 6 WITH A FLAME RETARDANT ENCAPSULATED BY POLYAMIDE 66: FLAME RETARDATION, THERMO-DECOMPOSITION AND THE POTENTIAL MECHANISM

    Institute of Scientific and Technical Information of China (English)

    Wei-cheng Xiong; Li Chen; Bin Zhao; De-yi Wang; Yu-zhong Wang

    2012-01-01

    A novel encapsulated flame retardant containing phosphorus-nitrogen (MSMM-Al-P) was prepared by encapsulating with polyamide 66 (PA66-MSMM-Al-P) for the flame retardation of polyamide 6 (PA6).The structure and thermal properties of PA66-MSMM-Al-P were characterized by Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy and thermogravimetric analysis.The flammability of PA6 containing' flame retardants (MSMMAl-P and PA66-MSMM-Al-P) was investigated by the limiting oxygen index test,vertical burning test and cone calorimeter.The flame retardancy and cone calorimetric analyses suggested a synergistic effect between PA66 and MSMM-Al-P in the flame-retardant PA6.Thermal stability of the flame-retardant PA6 was also investigated.

  15. Breakthrough indicator for aromatic VOCs using needle trap samplers for activated carbon adsorbent.

    Science.gov (United States)

    Cheng, Wen-Hsi; Jiang, Jia-Rong; Huang, Yi-Ning; Huang, Shiun-Chian; Yu, Yan-Pin

    2012-08-01

    Internal circulation cabinets equipped with granular activated carbon (GAC) for adsorbing volatile organic compounds (VOCs) are widely used to store bottles containing organic solvents in universities, colleges, and hospital laboratories throughout Taiwan. This work evaluates the VOC adsorption capacities of GAC using various adsorption times for gas stream mixtures of 100 ppm toluene and 100 ppm o-xylene. Additionally, needle trap sampling (NTS) technology was used to indicate the time for renewing the GAC to avoid VOC breakthrough from adsorbents. Experimental results demonstrate that the proposed models can linearly express toluene and o-xylene adsorption capacities as the natural logarithm of adsorption time (ln(t)) and can accurately simulate the equilibrium adsorption capacities (Qe, g VOCs/g GAC) for gaseous toluene and o-xylene. The NTS, packed with 60-80 mesh divinylbenzene (DVB) particles, was compared in terms of extraction efficiency by simultaneously using the 75-microm Carboxen/polydimethylsiloxane-solid-phase microextraction (Carboxen/PDMS-SPME) fiber for time-weighted average (TWA) sampling, and experimental results indicated that the packed DVB-NTS achieved higher toluene extraction rates. Additionally, the NTS installed in the outlet air stream for adsorbing toluene and o-xylene exhausted through GAC accurately indicated toluene and o-xylene breakthrough times of 4700-5000 min. The GAC-NTS operational instructions to indicate the replacing time of adsorbent in the internal circulation cabinets are also included in this paper.

  16. 1H NMR analysis of complexation of hydrotropic agents nicotinamide and caffeine with aromatic biologically active molecules in aqueous solution

    Science.gov (United States)

    Lantushenko, Anastasia O.; Mukhina, Yulia V.; Veselkov, Kyrill A.; Davies, David B.; Veselkov, Alexei N.

    2004-07-01

    NMR spectroscopy has been used to elucidate the molecular mechanism of solubilization action of hydrotropic agents nicotinamide (NA) and caffeine (CAF). Hetero-association of NA with riboflavine-mononucleotide (FMN) and CAF with low soluble in aqueous solution synthetic analogue of antibiotic actinomycin D, actinocyl-bis-(3-dimethylaminopropyl) amine (Actill), has been investigated by 500 MHz 1H NMR spectroscopy. Concentration and temperature dependences of proton chemical shifts have been analysed in terms of a statistical-thermodynamic model of indefinite self- and heteroassociation of aromatic molecules. The obtained results enable to conclude that NA-FMN and CAF-Actill intermolecular complexes are mainly stabilized by the stacking interactions of the aromatic chromophores. Hetero-association of the investigated molecules plays an important role in solubilization of aromatic drugs by hydrotropic agents nicotinamide and caffeine.

  17. Aromatic polyamide short fibres-reinforced elastomers: adhesion mechanisms and the composite's performance properties

    NARCIS (Netherlands)

    Sadatshirazi, S.

    2012-01-01

    The current thesis consists of a chapter as literature review in which different scientific sources and the results of investigation of various researchers are reviewed, followed by 5 chapters (2 to 6) and an appendix covering the results of the experimental work performed. The results can be

  18. Effect of activated carbon and biochars on the bioavailability of polycyclic aromatic hydrocarbons in different industrially contaminated soils.

    Science.gov (United States)

    Kołtowski, Michał; Hilber, Isabel; Bucheli, Thomas D; Oleszczuk, Patryk

    2016-06-01

    Coal production negatively affects the environment by the emission of polycyclic aromatic hydrocarbons (PAHs). Two soils (KOK and KB) from a coking plant area was investigated and their total PAH concentration was 40 and 17 mg/kg for the sum (∑) 16 US EPA PAHs, respectively. A third soil was sampled from a bitumen plant area and was characterized by 9 mg/kg ∑16 US EPA PAHs. To reduce the freely dissolved concentration (Cfree) of the PAHs in the soil pore water, active carbon (AC) and two biochars pyrolysed from wheat straw (biochar-S) and willow (biochar-W) were added to the soils at 0.5-5 % (w/w), each. The AC performed best and reduced the Cfree by 51-98 % already at the lowest dose. The biochars needed doses up to 2.5 % to significantly reduce the Cfree by 44-86 % in the biochar-S and by 37-68 % in the biochar-W amended soils. The high black carbon (BC) content of up to 2.3 % in the Silesian soils competed with the sorption sites of the carbon amendments and the performance of the remediation was a consequence of the contaminant's source and the distribution between the BC and the AC/biochars. In contrast, the carbon amendment could best reduce the Cfree in the Lublin soil where the BC content was normal (0.05 %). It is therefore crucial to know the contaminant's source and history of a sample/site to choose the appropriate carbon amendment not only for remediation success but also for economic reasons.

  19. Measurements of activity coefficients at infinite dilution of aromatic and aliphatic hydrocarbons, alcohols, and water in the new ionic liquid [EMIM][SCN] using GLC

    International Nuclear Information System (INIS)

    Domanska, Urszula; Marciniak, Andrzej

    2008-01-01

    A new ionic liquid was chosen for the separation of aromatic hydrocarbons from aliphatic hydrocarbons. The activity coefficients at infinite dilution, γ 13 ∞ for 29 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, and water in the ionic liquid 1-ethyl-3-methyl-imidazolium thiocyanate [EMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15 K to 368.15 K. The values of the partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for the hexane/benzene and cyclohexane/benzene separation problems were calculated from the γ 13 ∞ and compared to the other ionic liquids, NMP and sulfolane, taken from the recent literature. This work demonstrates that with chosen ionic liquid it is possible to separate different organic compounds with the highest selectivity ever published

  20. Characteristics of polycyclic aromatic hydrocarbons in PM2.5 emitted from different cooking activities in China.

    Science.gov (United States)

    Li, Yun-Chun; Qiu, Jia-Qian; Shu, Man; Ho, Steven Sai Hang; Cao, Jun-Ji; Wang, Ge-Hui; Wang, Xian-Xiang; Zhao, Xiao-Qing

    2018-02-01

    Nineteen polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 emitted from five different cooking activities were characterized, and their influencing factors were determined. The total quantified particle-bounded PAH concentrations (ΣPAHs) in the airs from the cooking activities were 4.2-36.5-fold higher than those in corresponding backgrounds. The highest ΣPAHs were seen in cafeteria frying (783 ± 499 ng/m 3 ), followed by meat roasting (420 ± 191 ng/m 3 ), fish roasting (210 ± 105 ng/m 3 ), snack-street boiling (202 ± 230 ng/m 3 ), and cafeteria boiling (150 ± 65 ng/m 3 ). The main influencing factors on the PAH emissions were cooking methods, fat contents in raw materials, and oil consumptions. Four- to six-ringed PAHs had the highest contributions to the ΣPAHs (avg. 87.5%). Diagnostic ratios of individual PAH were similar between the two charbroiling and other three conventional Chinese cooking methods, respectively, demonstrating the dominance of cooking methods in the PAH emissions. Remarkably high benzo(b)fluoranthene/benzo(k)fluoranthene (BbF/BkF) ratio (8.31) was seen in the snack-street boiling, attributed to the coal combustion as cooking fuel. Both fluoranthene/(fluoranthene + pyrene) [FLT/(FLT + PYR)] and benzo(a)anthracene/(benzo(a)anthracene + chrysene) [BaA/(BaA + CHR)] ratios were higher for the oil-based cooking than those from the water-based ones. In addition, two ratios of indeno(1,2,3-cd)pyrene/(indeno(1,2,3-cd)pyrene + benzo(g,h,i)perylene) [IPY/(IPY + BPE)] and benzo(a)pyrene/(benzo(a)pyrene + benzo(g,h,i)perylene) [BaP/(BaP + BPE)] were higher for two charbroiling than the three conventional Chinese cooking methods. The characterization work in this study is particularly important since cooking is a potential contributor of atmospheric PAHs in urban China. Carcinogenic potencies of PAHs were assessed by comparison with the air quality guideline and health risk estimation. The BaP and BaP equivalent were

  1. Metal-ligand cooperative activation of nitriles by a ruthenium complex with a de-aromatized PNN pincer ligand

    NARCIS (Netherlands)

    Eijsink, Linda E; Perdriau, Sébastien C P; de Vries, Johannes G; Otten, Edwin

    2016-01-01

    The pincer complex (PNN)RuH(CO), with a de-aromatized pyridine in the ligand backbone, is shown to react with nitriles in a metal-ligand cooperative manner. This leads to the formation of a series of complexes with new Ru-N(nitrile) and C(ligand)-C(nitrile) bonds. The initial nitrile cycloaddition

  2. Removal of Intermediate Aromatic Halogenated DBPs by Activated Carbon Adsorption: A New Approach to Controlling Halogenated DBPs in Chlorinated Drinking Water.

    Science.gov (United States)

    Jiang, Jingyi; Zhang, Xiangru; Zhu, Xiaohu; Li, Yu

    2017-03-21

    During chlorine disinfection of drinking water, chlorine may react with natural organic matter (NOM) and bromide ion in raw water to generate halogenated disinfection byproducts (DBPs). To mitigate adverse effects from DBP exposure, granular activated carbon (GAC) adsorption has been considered as one of the best available technologies for removing NOM (DBP precursor) in drinking water treatment. Recently, we have found that many aromatic halogenated DBPs form in chlorination, and they act as intermediate DBPs to decompose and form commonly known DBPs including trihalomethanes and haloacetic acids. In this work, we proposed a new approach to controlling drinking water halogenated DBPs by GAC adsorption of intermediate aromatic halogenated DBPs during chlorination, rather than by GAC adsorption of NOM prior to chlorination (i.e., traditional approach). Rapid small-scale column tests were used to simulate GAC adsorption in the new and traditional approaches. Significant reductions of aromatic halogenated DBPs were observed in the effluents with the new approach; the removals of total organic halogen, trihalomethanes, and haloacetic acids by the new approach always exceeded those by the traditional approach; and the effluents with the new approach were considerably less developmentally toxic than those with the traditional approach. Our findings indicate that the new approach is substantially more effective in controlling halogenated DBPs than the traditional approach.

  3. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: Linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units

    DEFF Research Database (Denmark)

    Schmidt, Stine Nørgaard; Holmstrup, Martin; Smith, Kilian E. C.

    2013-01-01

    treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑Clipid eq.), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments...... could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LClipid eq...

  4. Inhibition of peripheral aromatization in baboons by an enzyme-activated aromatase inhibitor (MDL 18,962)

    International Nuclear Information System (INIS)

    Longcope, C.; Femino, A.; Johnston, J.O.

    1988-01-01

    The peripheral aromatization ([rho]BM) of androstenedione (A) and testosterone (T) was measured before and after administration of the aromatase inhibitor 10-(2 propynyl)estr-4-ene-3,17-dione (MDL-18,962) to five mature female baboons, Papio annubis. The measurements were made by infusing [3H]androstenedione/[14C]estrone or [3H]testosterone/[14C]estradiol for 3.5 h and collecting blood samples during the infusions and all urine for 96 h from the start of the infusion. Blood samples were analyzed for radioactivity as infused and product steroids, and the data were used to calculate MCRs. An aliquot of the pooled urine was analyzed for the glucuronides of estrone and estradiol and used to calculate the [rho]BM. MDL-18,962 was administered as a pulse in polyethylene glycol-400 (1-5 ml) either iv or via gastric tube 30 min before administration of the radiolabeled steroids. Control studies were done with and without polyethylene glycol-400 administration. When MDL-18,962 was given iv at 4 mg/kg, the aromatization of A was decreased 91.8 +/- 0.9% from the control value of 1.23 +/- 0.13% to 0.11 +/- 0.01%. At the same dose, aromatization of T was decreased 82.0 +/- 7.1%, from a control value of 0.20 +/- 0.03% to 0.037 +/- 0.018%. When MDL-18,962 was given iv at doses of 0.4, 0.1, 0.04, and 0.01 mg/kg, the values for aromatization of A were 0.16 +/- 0.03%, 0.18 +/- 0.06%, 0.37 +/- 11%, and 0.65 +/- 0.09%, respectively. The administration of MDL-18,962 via gastric tube at 4 mg/kg as a pulse decreased the aromatization of A from 1.35 +/- 0.06% to 0.43 +/- 0.12%, an inhibition of 67.2 +/- 10.7%. When administered via gastric tube daily for 5 days at 4 mg/kg, the aromatization of A fell from 1.35 +/- 0.06% to 0.063 +/- 0.003%, an inhibition of 84.4 +/- 0.5%

  5. Polyamide membranes with nanoscale Turing structures for water purification

    Science.gov (United States)

    Tan, Zhe; Chen, Shengfu; Peng, Xinsheng; Zhang, Lin; Gao, Congjie

    2018-05-01

    The emergence of Turing structures is of fundamental importance, and designing these structures and developing their applications have practical effects in chemistry and biology. We use a facile route based on interfacial polymerization to generate Turing-type polyamide membranes for water purification. Manipulation of shapes by control of reaction conditions enabled the creation of membranes with bubble or tube structures. These membranes exhibit excellent water-salt separation performance that surpasses the upper-bound line of traditional desalination membranes. Furthermore, we show the existence of high water permeability sites in the Turing structures, where water transport through the membranes is enhanced.

  6. Morphology study of polyamide 6/bentonite clay nanocomposites

    International Nuclear Information System (INIS)

    Paz, Rene A.; Araujo, Edcleide M.; Melo, Tomas J.A.; Leite, Amanda M.D.; Medeiros, Vanessa Nobrega; Pessan, Luiz A.; Passador, Fabio R.

    2011-01-01

    Polymer/clay nanocomposites have had much attention in recent years, especially those developed with layered silicates, due to the need for engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in the crystalline structure of polymer matrices has been studied and it has been observed that it affects the behavior of crystalline and therefore the mechanical and physical properties. In this study, polyamide 6 nanocomposites were obtained by the melt intercalation technique, using regional bentonite clay modified with a quaternary ammonium salt in an amount of 3% by weight. XRD and TEM tests showed obtaining nanocomposites with exfoliated structures (author)

  7. Experimental comparison of manufacturing techniques of toughened and nanoreinforced polyamides

    Science.gov (United States)

    Siengchin, S.; Bergmann, C.; Dangtungee, R.

    2011-11-01

    Composites consisting of polyamide-6 (PA-6), nitrile rubber (NBR), and sodium fluorohectorite (FH) or alumina silicate (Sungloss; SG) were produced by different techniques with latex precompounding. Their tensile and thermomechanical properties were determined by using tensile tests and a dynamic-mechanical analysis, performed at various temperatures. The PA-6/NBR composite systems produced by the direct melt compounding outperformed those obtained by using the masterbatch technique with respect to the strength and ductility, but the latter ones had a higher storage modulus.

  8. Grafting of acrylamide onto synthetic co polyamide by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hamoud, M R; Qamhieyh, E A [Chemistry Dept., College of Ibn Al-Haitham Baghdad university-Adhamiyah-Baghdad- (Iraq)

    1995-10-01

    Grafted copolymer was prepared by using gamma irradiation to graft acrylamide onto polymeric molecule prepared by interfacial condensation between two diamine molecules like 1,2 diamino propane and 1,6 diamino-hexane in aqueous layer with sebacoyl chloride in organic layer. The resulted co polyamide was grafted with acrylamide using gamma irradiation. The optimum conditions of grafting reaction were found, also various factors such as the effect of solvents, redox systems and the role water on the radiochemical grafting were studied. Many techniques were used in the characterization of the copolymer before and after grafting. 8 figs.,.

  9. Synthesis of New Macrocyclic Polyamides as Antimicrobial Agent Candidates

    Directory of Open Access Journals (Sweden)

    Osama I. Abd El-Salam

    2012-12-01

    Full Text Available A series of macrocyclic imides and Schiff-bases have been prepared via the cyclocondensation of pyridine-2,6-dicarbonyl dichloride (1 with L-ornithine methyl ester to give the corresponding macrocyclic bisester 2. Treatment of 2 with hydrazine hydrate gave macrocyclic bisacid hydrazide 3, which was used as starting material. Condensation of bishydrazide 3 with diacid anhydrides or aromatic aldehydes in refluxing acetic acid or ethanol gave the corresponding macrocyclic bisimides 4, 5a,b and macrocyclic bis- hydrazones 6a–j, respectively. The structure assignments of the new compounds were based on chemical and spectroscopic evidence. The antimicrobial screening showed that many of these newly synthesized compounds have good antimicrobial activities, comparable to ampicillin and ketaconazole used as reference drugs.

  10. The surface characteristics of hyperbranched polyamide modified corncob and its adsorption property for Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hai, E-mail: linhai@ces.ustb.edu.cn [School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants, Beijing 100083 (China); Han, Shaoke; Dong, Yingbo; He, Yinhai [School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory on Resource-oriented Treatment of Industrial Pollutants, Beijing 100083 (China)

    2017-08-01

    Highlights: • An anion adsorbent was synthesized by hyperbranched polyamide modified corncob (HPMC). • The surface characteristics of samples (RCC, HPMC, HPMC-Cr) were studied. • Langmuir isotherm provided more fit and maximum adsorption capacity was 131.6 mg/g. • The adsorption process was chemisorption, controlled by intra-particle diffusion and film diffusion. • Adsorption is fast, stable, spontaneous and endothermic. - Abstract: A low-cost anion adsorbent for Cr(VI) effectively removing was synthesized by hyperbranched polyamide modified corncob (HPMC). Samples were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy, Fourier transform infrared (FTIR) and zeta potential analysis. Kinetics, isotherms and thermodynamics studies of HPMC for Cr(VI) adsorption were investigated in batch static experiments, in the temperature range of 25–45 °C, pH = 2.0. Results showed that the adsorption was rapid and stable, with the uptake capacity higher than 80% after 30 min. Adsorption behavior and rate-controlling mechanisms were analyzed using three kinetic models (pseudo-first order, pseudo-second order, intra-particle kinetic model). Kinetic studies showed that the adsorption of HPMC to Cr(VI) relied the pseudo-second-order model, and controlled both by the intra-particle diffusion and film diffusion. Equilibrium data was tested by Langmuir and Freundlich adsorption isotherm models. Langmuir model was more suitable to indicate a homogeneous distribution of active sites on HPMC and monolayer adsorption. The maximum adsorption capacity from the Langmuir model, q{sub max}, was 131.6 mg/g at pH 2.0 and 45 °C for HPMC. Thermodynamic parameters revealed spontaneous and endothermic nature of the Cr(VI) adsorption onto HPMC.

  11. Electron beam radiation effects on recycled polyamide-6

    International Nuclear Information System (INIS)

    Evora, Maria Cecilia; Silva, Leonardo G. de Andrade e

    2001-01-01

    Applications of electron beam processing in the treatment of polymers are commonly used. The interaction of high energy radiation with polymers may cause permanent modifications in the polymer's physicochemical structure. The induced modifications may result in degradation of the polymer or in improvement of its properties (crosslinking), which are simultaneous and competing processes, depending on the radiation dose utilized. Crosslinking occurs more readily in the polymer's amorphous content and this process makes the glass transition temperature (Tg) of the polymers to increase. Successive recycling cycles promote changes in polymers properties, such as breaking of structure, molecular weight reduction, melt index increase and mechanical resistance reduction. The polyamide-6 resin was recycled for three successive recycling cycles and thi polyamide-6 specimens were molded by the process of injection molding. These specimens were irradiated at the Nuclear Energetic Research Institute (IPEN) radiation facility, on a JOB 188 model accelerator, with a 1.5 MeV electron beam, doses of 200, 300, 400, 500 and 600 kGy, and dose rate of 22.61 kGy/s. The DMA tests were performed using DMA-983 equipment from TA Instruments and two heatings were adopted in order to eliminate the moisture absorption. The X-ray diffraction analysis wa carried out at the Philips PW 1830 model equipment

  12. Characterization of isolated polyamide thin films of RO and NF membranes using novel TEM techniques

    KAUST Repository

    Pacheco, Federico A.; Pinnau, Ingo; Reinhard, Martin; Leckie, James O.

    2010-01-01

    Achieving a better understanding of transport and rejection mechanisms in RO and NF membranes requires more detailed information of the nanostructure of polyamide thin films. This study reports on two novel transmission electron microscopy (TEM) techniques for characterizing polyamide nanostructure. The first technique produces cross-sectional images of isolated polyamide thin films by removing the polysulfone support from regular TEM cross-sections. In the second technique called " projected area" TEM (PA-TEM), isolated polyamide thin films are placed with their surface perpendicular to the electron beam. The resulting images capture the thickness, morphology and mass density of the entire thin film. In combination, these new techniques provide information on polyamide nanostructure that is not evident using conventional methods. For the commercial RO membrane ESPA3, the cross-sectional view of the isolated polyamide thin film shows a 30-60. nm thick base of nodular polyamide (presumably the separation barrier) that forms a relatively smooth interface with the polysulfone support. Above this, a more open structure of loose polyamide extends outward giving rise to the ridge-and-valley surface structure. In PA-TEM images, the ridges and valleys correspond to the dark and bright regions, respectively; the polyamide nodular base appears as round features forming an irregular honeycomb pattern throughout the images. Membrane cross-sections were prepared with a simple resin embedding protocol using the acrylic resin LR White. The protocol did not require dehydration steps, and was applicable to both dry and wet membrane samples. Artifacts that may be produced during sample preparation were also documented. © 2010 Elsevier B.V.

  13. Characterization of isolated polyamide thin films of RO and NF membranes using novel TEM techniques

    KAUST Repository

    Pacheco, Federico A.

    2010-08-15

    Achieving a better understanding of transport and rejection mechanisms in RO and NF membranes requires more detailed information of the nanostructure of polyamide thin films. This study reports on two novel transmission electron microscopy (TEM) techniques for characterizing polyamide nanostructure. The first technique produces cross-sectional images of isolated polyamide thin films by removing the polysulfone support from regular TEM cross-sections. In the second technique called " projected area" TEM (PA-TEM), isolated polyamide thin films are placed with their surface perpendicular to the electron beam. The resulting images capture the thickness, morphology and mass density of the entire thin film. In combination, these new techniques provide information on polyamide nanostructure that is not evident using conventional methods. For the commercial RO membrane ESPA3, the cross-sectional view of the isolated polyamide thin film shows a 30-60. nm thick base of nodular polyamide (presumably the separation barrier) that forms a relatively smooth interface with the polysulfone support. Above this, a more open structure of loose polyamide extends outward giving rise to the ridge-and-valley surface structure. In PA-TEM images, the ridges and valleys correspond to the dark and bright regions, respectively; the polyamide nodular base appears as round features forming an irregular honeycomb pattern throughout the images. Membrane cross-sections were prepared with a simple resin embedding protocol using the acrylic resin LR White. The protocol did not require dehydration steps, and was applicable to both dry and wet membrane samples. Artifacts that may be produced during sample preparation were also documented. © 2010 Elsevier B.V.

  14. Synthesis of nanosilver on polyamide fabric using silver/ammonia complex

    Energy Technology Data Exchange (ETDEWEB)

    Montazer, Majid, E-mail: tex5mm@aut.ac.ir [Textile Department, Functional Fibrous Structures and Environmental Enhancement (FFSEE), Amirkabir University of Technology, Hafez Avenue, Tehran (Iran, Islamic Republic of); Shamei, Ali; Alimohammadi, Farbod [Young Researchers Club, Tehran South Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2014-05-01

    In this paper, a novel synthesis method for nanosilver has been introduced on or within the polymeric chains of polyamide 6 fabric by using silver/ammonia complex [Ag(NH{sub 3}){sub 2}]{sup +}. The silver complex was reduced directly by functional groups of polyamide chains without using any additional chemical reducing agents. The polyamide fabric was also stabilized with formation of new linkages between the polymeric chains of the nylon fabric through silver nanoparticle synthesis. The presence of nanosilver on the fabric was confirmed by UV–vis spectra, EDX patterns and XRD patterns. In addition, X-ray photoelectron spectroscopy (XPS) was utilized to identify the chemical state of silver in a range of silver oxide and silver metal. The SEM images confirmed the presence of nanosilver on the polyamide within the size of 20 and 150 nm. Excellent antibacterial properties were achieved with the treated fabrics against Staphylococcus aureus and Escherichia coli. Further, the antibacterial properties of the polyamide fabric treated with 35 mg/L silver/ammonia were durable against washing as they only decreased to 98.6% after 20 washes. In addition, some other properties of the treated fabrics including color changes, dimensional stability, water droplet adsorption, and reflectance spectrum are reported and thoroughly discussed. - Highlights: • Novel in situ synthesis of nanosilver on polyamide 6 • Synthesis of nanosilver without using external stabilizing and reducing agent • Synthesis of nanosilver particles within molecular chains of polyamide 6 • Producing antibacterial polyamide 6 using 35 mg/L Ag/ammonia complex • Obtaining durable antibacterial properties on polyamide 6 by this method.

  15. Synthesis of nanosilver on polyamide fabric using silver/ammonia complex

    International Nuclear Information System (INIS)

    Montazer, Majid; Shamei, Ali; Alimohammadi, Farbod

    2014-01-01

    In this paper, a novel synthesis method for nanosilver has been introduced on or within the polymeric chains of polyamide 6 fabric by using silver/ammonia complex [Ag(NH 3 ) 2 ] + . The silver complex was reduced directly by functional groups of polyamide chains without using any additional chemical reducing agents. The polyamide fabric was also stabilized with formation of new linkages between the polymeric chains of the nylon fabric through silver nanoparticle synthesis. The presence of nanosilver on the fabric was confirmed by UV–vis spectra, EDX patterns and XRD patterns. In addition, X-ray photoelectron spectroscopy (XPS) was utilized to identify the chemical state of silver in a range of silver oxide and silver metal. The SEM images confirmed the presence of nanosilver on the polyamide within the size of 20 and 150 nm. Excellent antibacterial properties were achieved with the treated fabrics against Staphylococcus aureus and Escherichia coli. Further, the antibacterial properties of the polyamide fabric treated with 35 mg/L silver/ammonia were durable against washing as they only decreased to 98.6% after 20 washes. In addition, some other properties of the treated fabrics including color changes, dimensional stability, water droplet adsorption, and reflectance spectrum are reported and thoroughly discussed. - Highlights: • Novel in situ synthesis of nanosilver on polyamide 6 • Synthesis of nanosilver without using external stabilizing and reducing agent • Synthesis of nanosilver particles within molecular chains of polyamide 6 • Producing antibacterial polyamide 6 using 35 mg/L Ag/ammonia complex • Obtaining durable antibacterial properties on polyamide 6 by this method

  16. Preparation and water desalination properties of POSS-polyamide nanocomposite reverse osmosis membranes

    KAUST Repository

    Duan, Jintang

    2015-01-01

    The application of nanotechnology to thin-film nanocomposites (TFN) is a new route to enhance membrane performance in water desalination. Here, the potential of polyhedral oligomeric silsesquioxane (POSS) as the nanofiller in polyamide (PA) reverse osmosis membranes was systematically investigated. Four POSS materials (P-8Phenyl, P-8NH3Cl, P-8NH2 and P-1NH2) were introduced into the selective layer by physical blending or chemical fixation during standard interfacial polymerization. Water flux and NaCl rejection were measured with 2000ppm NaCl solution under 15.5bar pressure, and SEM and TEM images of membrane selective layers were obtained. Membranes prepared without POSS showed water flux of 20.0±0.5L/m2·h and salt rejection of 98.0±0.2%. TFN membranes prepared with 0.4% (w/v) P-8Phenyl in the organic phase showed a 65% increase in water flux compared to the pristine PA membrane while maintaining high salt rejection. The selective layer of this membrane maintained the typical ridge-and-valley structure of aromatic PA. Results with P-8NH3Cl and P-8NH2 added to the organic phase were similar. TFN membranes prepared with monoamine P-1NH2 in the organic phase had poor water flux of 3.2L/m2·h, a smooth and more hydrophobic surface, and a much thicker (~400nm) selective layer. One of the four POSS compounds studied, P-8NH3Cl, is sufficiently soluble in water for incorporation into the selective layer via the aqueous phase. Membranes were prepared with P-8NH3Cl in the aqueous phase at varying reaction time, loading, and additive (triethylamine) concentration. With these parameters optimized, water flux increased to 35.4L/m2·h.

  17. Hemoglobin binding of aromatic amines: molecular dosimetry and quantitative structure-activity relationships for N-oxidation.

    Science.gov (United States)

    Sabbioni, G

    1993-01-01

    Aromatic amines are important intermediates in industrial manufacturing. N-Oxidation to N-hydroxyarylamines is a key step in determining the genotoxic properties of aromatic amines. N-Hydroxyarylamines can form adducts with DNA, with tissue proteins, and with the blood proteins albumin and hemoglobin in a dose-dependent manner. The determination of hemoglobin adducts is a useful tool for biomonitoring exposed populations. We have established the hemoglobin binding index (HBI) [(mmole compound/mole hemoglobin)/(mmole compound/kg body weight)] of several aromatic amines in female Wistar rats. Including the values from other researchers obtained in the same rat strain, the logarithm of hemoglobin binding (logHBI) was plotted against the following parameters: the sum of the Hammett constants(sigma sigma = sigma p + sigma m), pKa, logP (octanol/water), the half-wave oxidation potential (E1/2), and the electronic descriptors of the amines and their corresponding nitrenium ions obtained by semi-empirical calculations (MNDO, AMI, and PM3), such as atomic charge densities, energies of the highest occupied molecular orbit and lowest occupied molecular orbit and their coefficients, the bond order of C-N, the dipole moments, and the reaction enthalpy [MNDOHF, AM1HF or PM3HF = Hf(nitrenium) - Hf(amine)]. The correlation coefficients were determined from the plots of all parameters against log HBI for all amines by means of linear regression analysis. The amines were classified in three groups: group 1, all parasubstituted amines (maximum, n = 9); group 2, all amines with halogens (maximun, n = 11); and group 3, all amines with alkyl groups (maximum, n = 13).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8319626

  18. SiRNAs conjugated with aromatic compounds induce RISC-mediated antisense strand selection and strong gene-silencing activity

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Takanori, E-mail: kubo-t@yasuda-u.ac.jp [Faculty of Pharmacy, Yasuda Women' s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153 (Japan); Yanagihara, Kazuyoshi [Faculty of Pharmacy, Yasuda Women' s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153 (Japan); Division of Genetics, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Takei, Yoshifumi [Department of Biochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumi-cho, Showa-ku, Nagoya 466-8550 (Japan); Mihara, Keichiro [Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Sato, Yuichiro; Seyama, Toshio [Faculty of Pharmacy, Yasuda Women' s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153 (Japan)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer SiRNAs conjugated with aromatic compounds (Ar-siRNAs) at 5 Prime -sense strand were synthesized. Black-Right-Pointing-Pointer Ar-siRNAs increased resistance against nuclease degradation. Black-Right-Pointing-Pointer Ar-siRNAs were thermodynamically stable compared with the unmodified siRNA. Black-Right-Pointing-Pointer High levels of cellular uptake and cytoplasmic localization were found. Black-Right-Pointing-Pointer Strong gene-silencing efficacy was exhibited in the Ar-siRNAs. -- Abstract: Short interference RNA (siRNA) is a powerful tool for suppressing gene expression in mammalian cells. In this study, we focused on the development of siRNAs conjugated with aromatic compounds in order to improve the potency of RNAi and thus to overcome several problems with siRNAs, such as cellular delivery and nuclease stability. The siRNAs conjugated with phenyl, hydroxyphenyl, naphthyl, and pyrenyl derivatives showed strong resistance to nuclease degradation, and were thermodynamically stable compared with unmodified siRNA. A high level of membrane permeability in HeLa cells was also observed. Moreover, these siRNAs exhibited enhanced RNAi efficacy, which exceeded that of locked nucleic acid (LNA)-modified siRNAs, against exogenous Renilla luciferase in HeLa cells. In particular, abundant cytoplasmic localization and strong gene-silencing efficacy were found in the siRNAs conjugated with phenyl and hydroxyphenyl derivatives. The novel siRNAs conjugated with aromatic compounds are promising candidates for a new generation of modified siRNAs that can solve many of the problems associated with RNAi technology.

  19. Impact of aromaticity on anticancer activity of polypyridyl ruthenium(II) complexes: synthesis, structure, DNA/protein binding, lipophilicity and anticancer activity.

    Science.gov (United States)

    Čanović, Petar; Simović, Ana Rilak; Radisavljević, Snežana; Bratsos, Ioannis; Demitri, Nicola; Mitrović, Marina; Zelen, Ivanka; Bugarčić, Živadin D

    2017-10-01

    With the aim of assessing how the aromaticity of the inert chelating ligand can influence the activity of ruthenium(II) polypyridyl complexes, two new monofunctional ruthenium(II) complexes, [Ru(Cl-Ph-tpy)(phen)Cl]Cl (1) and [Ru(Cl-Ph-tpy)(o-bqdi)Cl]Cl (2) (where Cl-Ph-tpy = 4'-(4-chlorophenyl)-2,2':6',2″-terpyridine, phen = 1,10-phenanthroline, o-bqdi = o-benzoquinonediimine), were synthesized. All complexes were fully characterized by elemental analysis and spectroscopic techniques (IR, UV-Vis, 1D and 2D NMR, XRD). Their chemical behavior in aqueous solution was studied by UV-Vis and NMR spectroscopy showing that both compounds are relatively labile leading to the formation of the corresponding aqua species 1a and 2a. 1 H NMR spectroscopy studies performed on complexes 1 and 2 demonstrated that after the hydrolysis of the Cl ligand, they are capable to interact with guanine derivatives (i.e., 9-methylguanine (9MeG) and 5'-GMP) through the N7, forming monofunctional adduct. The kinetics and the mechanism of the reaction of complexes 1 and 2 with the biologically more relevant 5'-GMP ligand were studied by UV-Vis spectroscopy. DNA/protein interactions of the complexes have been examined by photophysical studies, which demonstrated a bifunctional binding mode of the complexes with DNA and the complexes strongly quench the fluorescence intensity of bovine serum albumin (BSA) through the mechanism of both static and dynamic quenching. Complexes 1 and 2 strongly induced apoptosis of treated cancer cells with high percentages of apoptotic cells and negligible percentage of necrotic cells. In addition, both ruthenium complexes decreased Bcl-2/Bax ratio causing cytochrome c mitochondrial release, the activation of caspase-3 and induction of apoptosis.

  20. Novel bio-composite of hydroxyapatite reinforced polyamide and polyethylene: Composition and properties

    International Nuclear Information System (INIS)

    Zuo Yi; Li Yubao; Li Jidong; Zhang Xiang; Liao Hongbing; Wang Yuanyuan; Yang Weihu

    2007-01-01

    A new bio-composite of hydroxyapatite reinforced polyamide 66 and high density polyethylene was prepared using melt mixing in a co-rotation twin screw extruder. Two series of composites with different composition were investigated using scanning electronic microscopy, mechanical testing, water absorption and infrared spectrometer. The results showed that the change of composition influenced significantly the properties of the composites by different mechanism. Polyethylene mixing with polyamide matrix induced different microstructure and adjusted water absorption and manufacturability. Hydrogen bonding between hydroxyapatite and the polar groups of polyamide improved the adhesion of interface

  1. Voltammetry coupled to mass spectrometry in the presence of isotope {sup 18}O labeled water for the prediction of oxidative transformation pathways of activated aromatic ethers: Acebutolol

    Energy Technology Data Exchange (ETDEWEB)

    Bussy, Ugo; Tea, Illa [LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Ferchaud-Roucher, Véronique; Krempf, Michel [Université de Nantes, Plateforme Spectrométrie de Masse, CRNH, SFR Santé F. Bonamy, Institut du Thorax, UMR S1087, IRT-UN, BP 70721, 8 Quai Moncousu, 44007 Nantes cedex 1 (France); Silvestre, Virginie; Galland, Nicolas [LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Jacquemin, Denis [LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Institut Universitaire de France, 103, Boulevard Saint-Michel, 75005 Cedex 5 France (France); Andresen-Bergström, Moa; Jurva, Ulrik [CVGI iMed DMPK, AstraZeneca R and D Mölndal, Mölndal (Sweden); and others

    2013-01-31

    Highlights: ► Voltammetry coupled to mass spectrometry method as a useful tool for on-line predictions of electrochemical transformations. ► Evidence of the O-dealkoxylation reaction pathway of acebutolol in the presence of labeled water. ► New approach for on line EC-MS applications. -- Abstract: The coupling between an electrochemical cell (EC) and a mass spectrometer (MS) is a useful screening tool (EC-MS) to study the oxidative transformation pathways of various electroactive species. For that purpose, we showed that the EC-MS method, carried out in the presence and absence of isotope {sup 18}O labeled water leads not only to a fast identification of oxidation products but also leads to a fast elucidation of the mechanism pathway reaction. We examined herein the case of the electrochemical hydrolysis of activated aromatic ether. Acebutolol (β-blockers) was selected herein as model of activated aromatic ether, and its electrochemical oxidation was examined in both the presence and absence of isotope {sup 18}O labeled water. To elucidate electrochemical hydrolysis pathway reaction: O-dealkylation or O-dealkoxylation, our approach was used to prove its applicability. The electrochemical oxidation mechanism was then elucidated showing an O-dealkoxylation reaction. In addition, density functional theory (DFT) calculations fully support the experimental conclusions.

  2. Enhanced adsorbability and photocatalytic activity of TiO2-graphene composite for polycyclic aromatic hydrocarbons removal in aqueous phase.

    Science.gov (United States)

    Bai, Hongzhen; Zhou, Jun; Zhang, Hongjian; Tang, Guping

    2017-02-01

    Photodegradation via titanium dioxide (TiO 2 ) has been used to remove polycyclic aromatic hydrocarbons (PAHs) from environmental media broadly. In this study, a series of TiO 2 -graphene composites (P25-GR) with different GR weight ratios were synthesized via hydrothermal reaction of graphene oxide (GO) and P25. Their structures were characterized and the proprieties were tested in aqueous phase. Phenanthrene (PHE), fluoranthene (FLAN), and benzo[a]pyrene (BaP) were selected as models of PAHs. The experiment indicated that P25-2.5%GR exhibited enhancement in both adsorption and photodegradation, ∼80% of PAHs were removed after 2h photocatalysis. The influence of photodegradation rate was studied, including PAHs initial concentration and pH. Aromatic intermediates were identified during the reaction process and the degradation pathways were portrayed. This work explored the enhanced photocatalysis performance was attributed to the PAH-selective adsorbability and the strong electron transfer ability of the composite. The analysis of the degradation intermediates confirmed that the reaction proceeded with the formation of free radicals, leading to the gradual PAH mineralization. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The Role of Human Aldo-Keto Reductases in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH Catechols and PAH o-Quinones

    Science.gov (United States)

    Zhang, Li; Jin, Yi; Huang, Meng; Penning, Trevor M.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR) catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quinones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox-cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis. PMID:23162467

  4. Identification and characterization of epoxide hydrolase activity of polycyclic aromatic hydrocarbon-degrading bacteria for biocatalytic resolution of racemic styrene oxide and styrene oxide derivatives.

    Science.gov (United States)

    Woo, Jung-Hee; Kwon, Tae-Hyung; Kim, Jun-Tae; Kim, Choong-Gon; Lee, Eun Yeol

    2013-04-01

    A novel epoxide hydrolase (EHase) from polycyclic aromatic hydrocarbon (PAH)-degrading bacteria was identified and characterized. EHase activity was identified in four strains of PAH-degrading bacteria isolated from commercial gasoline and oil-contaminated sediment based on their growth on styrene oxide and its derivatives, such as 2,3- and 4-chlorostyrene oxides, as a sole carbon source. Gordonia sp. H37 exhibited high enantioselective hydrolysis activity for 4-chlorostyrene oxide with an enantiomeric ratio of 27. Gordonia sp. H37 preferentially hydrolyzed the (R)-enantiomer of styrene oxide derivatives resulting in the preparation of a (S)-enantiomer with enantiomeric excess greater than 99.9 %. The enantioselective EHase activity was identified and characterized in various PAH-degrading bacteria, and whole cell Gordonia sp. H37 was employed as a biocatalyst for preparing enantiopure (S)-styrene oxide derivatives.

  5. Degradation in tensile properties of aromatic polymers by electron beam irradiation

    International Nuclear Information System (INIS)

    Sasuga, T.; Hayakawa, N.; Yoshida, K.; Hagiwara, M.

    1985-01-01

    Electron beam irradiation effects of ten kinds of polymers containing various aromatic rings linked by functional groups in the main chain (aromatic polymer) were studied with reference to change in tensile properties. The polymers studied were polyimides 'Kapton H', and 'UPILEX', polyetherimide 'ULTEM', polyamides 'A-Film' and 'APH-50 (nomex type paper)', poly-ether-ether-ketone 'PEEK', polyarylate 'U-Polymer', polysulphones 'Udel-Polysulphone' and 'PES', and modified poly(phenylene oxide) 'NORYL'. Irradiation was carried out by use of electron beam at a dose rate of 5 x 10 3 Gy s -1 at room temperature. The elongation at break was the most severely influenced by the irradiation and it decreased with increasing dose. The order of radiation resistivity which was evaluated from the dose required for the elongation to become 50% and 20% of the initial value was as follows: Polyimide > PEEK > polyamide > polyetherimide > polyarylate > polysulphone, poly(phenylene oxide). Based on the above experimental results, an order is proposed for the radiation stability of the aromatic repeating units composing the main chain. (author)

  6. Ultrathin Polyamide Membranes Fabricated from Free-Standing Interfacial Polymerization: Synthesis, Modifications, and Post-treatment

    KAUST Repository

    Cui, Yue; Liu, Xiang-Yang; Chung, Neal Tai-Shung

    2016-01-01

    ) membranes. The polyamide selective layer usually possesses a high selectivity and permeability, making it the heart of this membrane technology. To further improve and understand its formation, with entirely excluding the effect of substrate, an ultrathin

  7. Free volume sizes in intercalated polyamide 6/clay nanocomposites

    DEFF Research Database (Denmark)

    Wiinberg, P.; Eldrup, Morten Mostgaard; Pedersen, N.J.

    2005-01-01

    The effect of incorporating modified clay into a polyamide 6 (PA6) matrix, on the free volume cavity sizes and the thermal and viscoelastic properties of the resulting nanocomposite, was studied with positron annihilation lifetime spectroscopy, differential scanning calorimetry and dynamic...... response of PA6/clay nanocomposites, as compared to unfilled PA6, pointed towards a changed mobility in the non-crystalline regions. At high concentrations of clay (> 19 wt%) an increase of the free volume cavity diameter was observed, indicating a lower chain packing efficiency in the PA6/clay...... nanocomposites. The increased free volume sizes were present both above and below the glass transition temperature of PA6. (c) 2005 Elsevier Ltd. All rights reserved....

  8. Stiffening mechanisms in amorphous polyamide bio-nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Focke, Walter W. [Institute of Applied Materials, Department of Chemical Engineering, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria (South Africa); Macheca, Afonso D. [Institute of Applied Materials, Department of Chemical Engineering, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria (South Africa); Department of Chemical Engineering, Eduardo Mondlane University, P.O. Box 257, Maputo (Mozambique); Benhamida, Aida; Kaci, Mustapha [Laboratoire des Matériaux Polymères Avancés (LMPA), Université de Bejaia 06000 (Algeria)

    2016-05-18

    Dimer fatty acid polyamide nanocomposites based on flake- or needle-shaped nanoparticles were prepared via melt compounding. Transmission electron microscopy showed the presence of both individually dispersed particles and particle agglomerates in the polymer matrix. Dynamic mechanical analysis suggests that three stiffening mechanisms were operating. The reinforcing effect of the high stiffness inorganic filler particles is the primary contributor. Together with the chain confinement effect, that expresses itself in an apparent increase in the glass transition temperature, this provided an adequate rationalization of the stiffness variation below Tg. However, an additional stiffening effect is indicated at temperatures above Tg. The mechanism may involve dynamic network formation based on fluctuating hydrogen bonding interactions between the polymer chains and the filler particles.

  9. Processing and Mechanical Properties of Macro Polyamide Fiber Reinforced Concrete.

    Science.gov (United States)

    Jeon, Joong Kyu; Kim, WooSeok; Jeon, Chan Ki; Kim, Jin Cheol

    2014-11-26

    This study developed a macro-sized polyamide (PA) fiber for concrete reinforcement and investigated the influence of the PA fiber on flexural responses in accordance with ASTM standards. PA fibers are advantageous compared to steel fibers that are corrosive and gravitated. The macro-sized PA fiber significantly improved concrete ductility and toughness. Unlike steel fibers, the PA fibers produced two peak bending strengths. The first-peaks occurred near 0.005 mm of deflection and decreased up to 0.5 mm of deflection. Then the bending strength increased up to second-peaks until the deflections reached between 1.0 and 1.5 mm. The averaged flexural responses revealed that PA fiber content did not significantly influence flexural responses before L /600, but had significant influence thereafter. Toughness performance levels were also determined, and the results indicated more than Level II at L /600 and Level IV at others.

  10. Strain rate dependency of laser sintered polyamide 12

    Directory of Open Access Journals (Sweden)

    Cook J.E.T.

    2015-01-01

    Full Text Available Parts processed by Additive Manufacturing can now be found across a wide range of applications, such as those in the aerospace and automotive industry in which the mechanical response must be optimised. Many of these applications are subjected to high rate or impact loading, yet it is believed that there is no prior research on the strain rate dependence in these materials. This research investigates the effect of strain rate and laser energy density on laser sintered polyamide 12. In the study presented here, parts produced using four different laser sintered energy densities were exposed to uniaxial compression tests at strain rates ranging from 10−3 to 10+3 s−1 at room temperature, and the dependence on these parameters is presented.

  11. Research on mechanical properties of carbon fiber /polyamide reinforced PP composites

    Science.gov (United States)

    Chen, Xinghui; Yu, Qiang; Liu, Lixia; Ji, Wenhua; Yang, Li; Fan, Dongli

    2017-10-01

    The polyamide composites reinforced by carbon fiber/polypropylene are produced by injection molding processing. The flow abilities and mechanical properties of the CF/PA/PP composite materials are studied by the fusion index instrument and the universal testing machine. The results show that with the content of carbon fiber/polyamide increase, the impact breaking strength and the tensile property of the composite materials increase, which is instructive to the actual injection production of polypropylene products.

  12. Ultrathin Polyamide Membranes Fabricated from Free-Standing Interfacial Polymerization: Synthesis, Modifications, and Post-treatment

    KAUST Repository

    Cui, Yue

    2016-12-21

    The thin film composite (TFC) membrane synthesized via interfacial polymerization is the workhorse of the prevalent membrane technologies such as nanofiltration (NF), reverse osmosis (RO), forward osmosis (FO), and pressure retarded osmosis (PRO) membranes. The polyamide selective layer usually possesses a high selectivity and permeability, making it the heart of this membrane technology. To further improve and understand its formation, with entirely excluding the effect of substrate, an ultrathin membrane which consists of only the polyamide selective layer has been fabricated via free-standing interfacial polymerization between M-phenylenediamine (MPD) and trimesoyl chloride (TMC) in this study. The influences of monomer concentration on polyamide layer formation is first examined. Different from previous studies which indicated that the variation of MPD concentration might affect the polyamide layer formation even when in excess, the MPD concentration when in excess does not affect membrane properties significantly, while increasing the TMC concentration gradually densifies the polyamide layer and enhances its transport resistance. Adding lithium bromide (LiBr) and sodium dodecyl sulfate (SDS) in MPD solutions is found to facilitate the reaction between the two phases and result in a significant improvement in water permeability. However, a high amount of additives leads to an augmentation in transport resistance. The N,N-dimethylformamide (DMF) treatment on the polyamide membrane shows pronounced improvements on water flux under FO tests and water permeability under RO tests without compromising reverse salt flux and salt rejection because the dense polyamide core stays intact. This study may offer a different perspective on membrane formation and intrinsic properties of the polyamide selective layer and provide useful insights for the development of next-generation TFC membranes.

  13. The Effect of Silane Coupling Agents on a Composite Polyamide-6/Talc

    Directory of Open Access Journals (Sweden)

    H. Wiebeck

    1998-12-01

    Full Text Available This paper evaluates the effect of the addition of silane agents on the mechanical properties (tensile strength, hardness and flexibility of the composite polyamide-6/talc. For this purpose, 30% and 40% of a talc with and without the addition of silane agents were incorporated into polyamide-6. Three kinds of silane agents were used, resulting in nine formulations. Comparing the experimental results, it is concluded that the silane agents improve the mechanical properties of the composite material.

  14. Analysis of primary aromatic amines (PAA) in black nylon kitchenware 2014

    DEFF Research Database (Denmark)

    Trier, Xenia; Granby, Kit

    is 0,01 mg of substance per kg of food or food simulant. The detection limit applies to the sum of primary aromatic amines released’ Since July 1st 2011, an additional EU regulation has come into place, which states that each consignment of polyamide (nylon) kitchen utensils from China and Hong Kong......% acetic acid as food simulant at an exposure temperature of 100°C and time from ½-4 hours, depending on the foreseeable use of the utensil. The samples were collected by the Norwegian Food Safety Authority at importers and retail shops. Of the 20 PAAs analysed. four PAAs were detected, being aniline (ANL...

  15. Formation of high aspect ratio polyamide-6 nanofibers via electrically induced double layer during electrospinning

    International Nuclear Information System (INIS)

    Nirmala, R.; Nam, Ki Taek; Park, Soo-Jin; Shin, Yu-Shik; Navamathavan, R.; Kim, Hak Yong

    2010-01-01

    In the present study, the formation of high aspect ratio nanofibers in polyamide-6 was investigated as a function of applied voltage ranging from 15 to 25 kV using electrospinning technique. All other experimental parameters were kept constant. The electrospun polyamide-6 nanofibers were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). FE-SEM images of polyamide-6 nanofibers showed that the diameter of the electrospun fiber was decreased with increasing applied voltage. At the critical applied voltage, the polymer solution was completely ionized to form the dense high aspect ratio nanofibers in between the main nanofibers. The diameter of the polyamide-6 nanofibers was observed to be in the range of 75-110 nm, whereas the high aspect ratio structures consisted of regularly distributed very fine nanofibers with diameters of about 9-28 nm. Trends in fiber diameter and diameter distribution were discussed for the high aspect ratio nanofibers. TEM results revealed that the formation of double layers in polyamide-6 nanofibers and then split-up into ultrafine fibers. The electrically induced double layer in combination with the polyelectrolytic nature of solution is proposed as the suitable mechanisms for the formation of high aspect ratio nanofibers in polyamide-6.

  16. Synthesis and characterizations of Pt nanorods on electrospun polyamide-6 nanofibers templates

    International Nuclear Information System (INIS)

    Nirmala, R.; Navamathavan, R.; Won, Jeong Jin; Jeon, Kyung Soo; Yousef, Ayman; Kim, Hak Yong

    2012-01-01

    Highlights: ► Electrospun polyamide-6 nanofibers were used as the templates for synthesis Pt nanorods. ► Polyamide-6 nanofibers surfaces were plasma treated to coat Pt. ► High quality Pt nanorods were obtained by calcinations process. ► Pt nanorods with a diameter of few hundred nanometers were obtained. ► Polyamide-6 nanofibers template based Pt nanorods synthesis are a feasible method. - Abstract: We report on the synthesis of platinum (Pt) nanorods by using ultrafine polyamide-6 nanofibers templates produced via electrospinning technique. These ultrafine polyamide-6 nanofibers can be utilized as the templates for growing Pt nanorods after modifying them optimally by plasma passivations. The morphological, structural, optical and electrical properties of the template assisted Pt nanorods were studied by field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), photoluminescence (PL) and current–voltage (I–V) characteristics. The ability to fabricate the ultrafine size controlled Pt nanorods on polyamide-6 templates with optimized growth parameters in real time can be utilized for the variety of technological applications. Therefore, it is possible to obtain high quality with size control Pt nanorods. Once obtaining the high quality metal nanorods on polymer templates, the same can be adapted for the electronic device fabrication.

  17. Polyamide nanocapsules and nano-emulsions containing Parsol® MCX and Parsol® 1789: in vitro release, ex vivo skin penetration and photo-stability studies.

    Science.gov (United States)

    Hanno, Ibrahim; Anselmi, Cecilia; Bouchemal, Kawthar

    2012-02-01

    To prepare polyamide nanocapsules for skin photo-protection, encapsulating α-tocopherol, Parsol®MCX (ethylhexyl methoxycinnamate) and/or Parsol®1789 (butyl methoxydibenzoylmethane). Nanocapsules were obtained by combining spontaneous emulsification and interfacial polycondensation reaction between sebacoyl chloride and diethylenetriamine. Nano-emulsions used as control were obtained by the same process without monomers. The influence of carrier on release rate was studied in vitro with a membrane-free model. Epidermal penetration of encapsulated sunscreens was ex vivo evaluated using Franz diffusion cells. Ability of encapsulated sunscreens to improve photo-stability was verified by comparing percentage of degradation after UV radiation exposure. Sunscreen-containing nanocapsules (260-400 nm) were successfully prepared; yield of encapsulation was >98%. Parsol®MCX and Parsol®1789 encapsulation led to decreased release rate by up to 60% in comparison with nano-emulsion and allowed minimum penetration through pig ear epidermis. Presence of polyamide shell protected encapsulated sunscreen filters from photo-degradation without affecting their activity. Encapsulation of Parsol®MCX and Parsol®1789 into oil-core of polyamide nanocapsules allowed protection from photo-degradation, controlled release from nanocapsules, and limited penetration through pig ear epidermis.

  18. Sequence-specific DNA alkylation targeting for Kras codon 13 mutation by pyrrole-imidazole polyamide seco-CBI conjugates.

    Science.gov (United States)

    Taylor, Rhys Dylan; Asamitsu, Sefan; Takenaka, Tomohiro; Yamamoto, Makoto; Hashiya, Kaori; Kawamoto, Yusuke; Bando, Toshikazu; Nagase, Hiroki; Sugiyama, Hiroshi

    2014-01-27

    Hairpin N-methylpyrrole-N-methylimidazole polyamide seco-CBI conjugates 2-6 were designed for synthesis by Fmoc solid-phase synthesis, and their DNA-alkylating activities against the Kras codon 13 mutation were compared by high-resolution denaturing gel electrophoresis with 225 base pair (bp) DNA fragments. Conjugate 5 had high reactivity towards the Kras codon 13 mutation site, with alkylation occurring at the A of the sequence 5'-ACGTCACCA-3' (site 2), including minor 1 bp-mismatch alkylation against wild type 5'-ACGCCACCA-3' (site 3). Conjugate 6, which differs from conjugate 5 by exchanging one Py unit with a β unit, showed high selectivity but only weakly alkylated the A of 5'-ACGTCACCA-3' (site 2). The hairpin polyamide seco-CBI conjugate 5 thus alkylates according to Dervan's pairing rule with the pairing recognition which β/β pair targets T-A and A-T pairs. SPR and a computer-minimized model suggest that 5 binds to the target sequence with high affinity in a hairpin conformation, allowing for efficient DNA alkylation. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Measurements of activity coefficients at infinite dilution of aliphatic and aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, MTBE, and water in ionic liquid [BMIM][SCN] using GLC

    International Nuclear Information System (INIS)

    Domanska, Urszula; Laskowska, Marta

    2009-01-01

    The activity coefficients at infinite dilution, γ 13 ∞ for 32 solutes: alkanes, alken-1-es, alkyn-1-es, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, tert-butyl methyl ether, and water in the ionic liquid 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15 K to 368.15 K. The values of the partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for the hexane/benzene, cyclohexane/benzene, hexane/thiophene, and other separation problems were calculated from the γ 13 ∞ and compared to the other ionic liquids, N-methyl-2-pyrrolidinone, and sulfolane, taken from the recent literature. This work demonstrates that with chosen ionic liquid it is possible to separate different organic compounds with the highest selectivity, ever published

  20. Water Diffusion Mechanism in Carbon Nanotube and Polyamide Nanocomposite Reverse Osmosis Membranes: A Possible Percolation-Hopping Mechanism

    Science.gov (United States)

    Araki, Takumi; Cruz-Silva, Rodolfo; Tejima, Syogo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Terrones, Mauricio; Endo, Morinobu

    2018-02-01

    This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. The mechanism of water diffusion across reverse osmosis nanocomposite membranes made of carbon nanotubes (CNTs) and aromatic polyamide is not completely understood despite its high potential for desalination applications. While most of the groups have proposed that superflow inside the CNT might positively impact the water flow across membranes, here we show theoretical evidence that this is not likely the case in composite membranes because CNTs are usually oriented parallel to the membrane surface, not to mention that sometimes the nanotube cores are occluded. Instead, we propose an oriented diffusion mechanism that explains the high water permeation by decreasing the diffusion path of water molecules across the membranes, even in the presence of CNTs that behave as impermeable objects. Finally, we provide a comprehensive description of the molecular dynamics occurring in water desalination membranes by considering the bond polarizability caused by dynamic charge transfer and explore the use of molecular-dynamics-derived stochastic diffusion simulations. The proposed water diffusion mechanism offers an alternative and most likely explanation for the high permeation phenomena observed in CNTs and PA nanocomposite membranes, and its understanding can be helpful to design the next generation of reverse osmosis desalination membranes.

  1. Aromater i drikkevand

    DEFF Research Database (Denmark)

    Nyeland, B. A.; Hansen, A. B.

    DMU har den 10. Juni 1997 afholdt en præstationsprøvning: Aromater i drikkevand. Der deltog 21 laboratorier i præstationsprøvningen. Prøvningen omfattede 6 vandige prøver og 6 ampuller indeholdende 6 aromater. Laboratorierne spikede de tilsendte vandprøver med indholdet fra ampullerne...

  2. Modulation of ethoxyresorufin O-deethylase and glutathione S-transferase activities in Nile tilapia (Oreochromis niloticus) by polycyclic aromatic hydrocarbons containing two to four rings: implications in biomonitoring aquatic pollution.

    Science.gov (United States)

    Pathiratne, Asoka; Hemachandra, Chamini K

    2010-08-01

    Despite ubiquity of polycyclic aromatic hydrocarbons (PAHs) in the tropical environments, little information is available concerning responses of tropical fish to PAHs and associated toxicity. In the present study, effects of five PAHs containing two to four aromatic rings on hepatic CYP1A dependent ethoxyresorufin O-deethylase (EROD), glutathione S-transferase (GST) and serum sorbitol dehydrogenase (SDH) activities in Nile tilapia, a potential fish species for biomonitoring pollution in tropical waters, were evaluated. Results showed that EROD activities were induced by the PAHs containing four aromatic rings (pyrene and chrysene) in a dose dependent manner. However PAHs with two to three aromatic rings (naphthalene, phenanthrene and fluoranthene) caused no effect or inhibition of EROD activities depending on the dose and the duration. Fluoranthene was the most potent inhibitor. SDH results demonstrated that high doses of fluoranthene induced hepatic damage. GST activity was induced by the lowest dose of phenanthrene, fluoranthene and chrysene but high doses had no effect. The results indicate that induction of EROD enzyme in Nile tilapia is a useful biomarker of exposure to PAHs such as pyrene and chrysene. However EROD inhibiting PAHs such as fluoranthene in the natural environment may modulate the EROD inducing potential of other PAHs thereby influencing PAH exposure assessments.

  3. Aromatic inhibitors derived from ammonia-pretreated lignocellulose hinder bacterial ethanologenesis by activating regulatory circuits controlling inhibitor efflux and detoxification

    Directory of Open Access Journals (Sweden)

    David H. Keating

    2014-08-01

    Full Text Available Efficient microbial conversion of lignocellulosic hydrolysates to biofuels is a key barrier to the economically viable deployment of lignocellulosic biofuels. A chief contributor to this barrier is the impact on microbial processes and energy metabolism of lignocellulose-derived inhibitors, including phenolic carboxylates, phenolic amides (for ammonia-pretreated biomass, phenolic aldehydes, and furfurals. To understand the bacterial pathways induced by inhibitors present in ammonia-pretreated biomass hydrolysates, which are less well studied than acid-pretreated biomass hydrolysates, we developed and exploited synthetic mimics of ammonia-pretreated corn stover hydrolysate (ACSH. To determine regulatory responses to the inhibitors normally present in ACSH, we measured transcript and protein levels in an Escherichia coli ethanologen using RNA-seq and quantitative proteomics during fermentation to ethanol of synthetic hydrolysates containing or lacking the inhibitors. Our study identified four major regulators mediating these responses, the MarA/SoxS/Rob network, AaeR, FrmR, and YqhC. Induction of these regulons was correlated with a reduced rate of ethanol production, buildup of pyruvate, depletion of ATP and NAD(PH, and an inhibition of xylose conversion. The aromatic aldehyde inhibitor 5-hydroxymethylfurfural appeared to be reduced to its alcohol form by the ethanologen during fermentation, whereas phenolic acid and amide inhibitors were not metabolized. Together, our findings establish that the major regulatory responses to lignocellulose-derived inhibitors are mediated by transcriptional rather than translational regulators, suggest that energy consumed for inhibitor efflux and detoxification may limit biofuel production, and identify a network of regulators for future synthetic biology efforts.

  4. Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Nirmala, R. [Bio-nano System Engineering, College of Engineering, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of); Park, Hye-Min [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Navamathavan, R. [School of Advanced Materials Engineering, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Kang, Hyung-Sub [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); El-Newehy, Mohamed H. [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Kim, Hak Yong, E-mail: khy@jbnu.ac.kr [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Center for Healthcare Technology and Development, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of)

    2011-03-12

    In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

  5. Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

    International Nuclear Information System (INIS)

    Nirmala, R.; Park, Hye-Min; Navamathavan, R.; Kang, Hyung-Sub; El-Newehy, Mohamed H.; Kim, Hak Yong

    2011-01-01

    In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

  6. Sugar-Based Polyamides: Self-Organization in Strong Polar Organic Solvents.

    Science.gov (United States)

    Rosu, Cornelia; Russo, Paul S; Daly, William H; Cueto, Rafael; Pople, John A; Laine, Roger A; Negulescu, Ioan I

    2015-09-14

    Periodic patterns resembling spirals were observed to form spontaneously upon unassisted cooling of d-glucaric acid- and d-galactaric acid-based polyamide solutions in N-methyl-N-morpholine oxide (NMMO) monohydrate. Similar observations were made in d-galactaric acid-based polyamide/ionic liquid (IL) solutions. The morphologies were investigated by optical, polarized light and confocal microscopy assays to reveal pattern details. Differential scanning calorimetry was used to monitor solution thermal behavior. Small- and wide-angle X-ray scattering data reflected the complex and heterogeneous nature of the self-organized patterns. Factors such as concentration and temperature were found to influence spiral dimensions and geometry. The distance between rings followed a first-order exponential decay as a function of polymer concentration. Fourier-Transform Infrared Microspectroscopy analysis of spirals pointed to H-bonding between the solvent and the pendant hydroxyl groups of the glucose units from the polymer backbone. Tests on self-organization into spirals of ketal-protected d-galactaric acid polyamides in NMMO monohydrate confirmed the importance of the monosaccharide's pendant free hydroxyl groups on the formation of these patterns. Rheology performed on d-galactaric-based polyamides at high concentration in NMMO monohydrate solution revealed the optimum conditions necessary to process these materials as fibers by spinning. The self-organization of these sugar-based polyamides mimics certain biological materials.

  7. Synthesis of nanosilver on polyamide fabric using silver/ammonia complex.

    Science.gov (United States)

    Montazer, Majid; Shamei, Ali; Alimohammadi, Farbod

    2014-05-01

    In this paper, a novel synthesis method for nanosilver has been introduced on or within the polymeric chains of polyamide 6 fabric by using silver/ammonia complex [Ag(NH3)2](+). The silver complex was reduced directly by functional groups of polyamide chains without using any additional chemical reducing agents. The polyamide fabric was also stabilized with formation of new linkages between the polymeric chains of the nylon fabric through silver nanoparticle synthesis. The presence of nanosilver on the fabric was confirmed by UV-vis spectra, EDX patterns and XRD patterns. In addition, X-ray photoelectron spectroscopy (XPS) was utilized to identify the chemical state of silver in a range of silver oxide and silver metal. The SEM images confirmed the presence of nanosilver on the polyamide within the size of 20 and 150 nm. Excellent antibacterial properties were achieved with the treated fabrics against Staphylococcus aureus and Escherichia coli. Further, the antibacterial properties of the polyamide fabric treated with 35 mg/L silver/ammonia were durable against washing as they only decreased to 98.6% after 20 washes. In addition, some other properties of the treated fabrics including color changes, dimensional stability, water droplet adsorption, and reflectance spectrum are reported and thoroughly discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Tribological properties of nanosized calcium carbonate filled polyamide 66 nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Itagaki, Kaito [Department of Mechanical Engineering, Graduate School of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 Japan (Japan); Nishitani, Yosuke [Department of Mechanical Engineering, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015 Japan (Japan); Kitano, Takeshi [Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, T.G.M. 275, Zlin, 767 72 Czech Republic (Czech Republic); Eguchi, Kenichiro [Shiraishi Central Laboratories, 4-78 Motohama,Amagasaki,Hyogo,660-0085 Japan (Japan)

    2016-03-09

    For the purpose of developing high performance tribomaterials for mechanical sliding parts such as gears, bearings and so on, nanosized calcium carbonate (nano-CaCO{sub 3}) filled polyamide 66 (PA66) nanocomposites were investigated. The nano-CaCO{sub 3} was a kind of precipitated (colloid typed) CaCO{sub 3}, and its average particle size was 40, 80 and 150 nm. Surface treatment was performed by fatty acid on the nano-CaCO{sub 3} and its volume fraction in the nanocomposite was varied from 1 to 20vol.%. These nanocomposites were melt-mixed by a twin screw extruder and injection-molded. Tribological properties were measured by two types of sliding wear testers such as ring-on-plate type and ball-on-plate type one under dry condition. The counterface, worn surface and wear debris were observed by digital microscope and scanning electron microscope. It was found that the nano-CaCO{sub 3} has a good effect on the tribological properties, although the effect on the frictional coefficient and specific wear rate is differed by the volume fraction and the type of sliding wear modes. This is attributed to the change of wear mechanisms, which is the change of form of the transfer films on the counterface and the size of wear debris. It follows from these results that PA66/nano-CaCO{sub 3} nanocomposites may be possible to be the high performance tribomaterials.

  9. Ionic Liquids Incorporating Polyamide 6: Miscibility and Physical Properties

    Directory of Open Access Journals (Sweden)

    Xin Zheng

    2018-05-01

    Full Text Available The effects of 1-vinyl-3-butyl imidazole chloride (VBIM on the structure and properties of Polyamide 6 (PA6 were investigated systematically. It was found that PA6/VBIM blends were homogeneous without phase separation. The glass transition temperature (Tg of PA6 increased with small VBIM loadings followed by the decreasing in Tg with further increasing the amount of VBIM. The crystallization temperature decreased with the addition of VBIM because of the strong interactions between VBIM and the PA6 matrix, as well as the dilution effect when large amounts of VBIM was introduced to the matrix. According to rheological testing, small amounts of VBIM enhanced the storage modulus and melt viscosity of PA6. Tensile tests also show an increase in strength and modulus at relatively low loadings of VBIM. The strength of PA6 with only 1 wt % VBIM improved by 108% compared to that of neat PA6. Fourier transform infrared (FTIR investigations revealed that the ions of VBIM preferred to form hydrogen bonds with amide groups in PA6. Therefore, VBIM acts as physical connection point for the neighboring PA6 molecular chains. The specific interactions between VBIM and PA6 account not only for the enhanced melt viscosity of PA6, but also for the improved mechanical properties. Moreover, outstanding antistatic property was also observed. The surface resistivity of the sample with 1 wt % VBIM was 1.50 × 1010 Ω/sq, which means good electric dissipation property.

  10. Flame retardancy of highly filled polyamide 6/clay nanocomposites

    International Nuclear Information System (INIS)

    Dasari, Aravind; Yu Zhongzhen; Mai Yiuwing; Liu Songlin

    2007-01-01

    To obtain an in-depth physical knowledge of the protective barrier stability and uniformity under fire conditions, we prepared highly filled polyamide 6/organoclay nanocomposites and characterized their thermal and flammability properties. The objectives were to identify a critical composition that is needed to form a stable char with no apertures or cracks and to gain a thorough understanding of the mechanisms of flame retardancy. It was shown that there is no need for higher percentages of clay and even smaller amounts of clay (<10 wt%) should be enough to achieve good fire performance. Factors such as incoherency, poor stability and non-uniformity of the char or the presence of large cracks and formation of island-like structures were insignificant in slowing down the heat release and mass loss rates. Nevertheless, there was no stage during the flammability test where the fire completely extinguished even when the protective layer was stable and free from major cracks/apertures. Based on these results, new insights and approaches to process better flame retardant polymer nanocomposites are discussed

  11. Hybrid membranes of polyamide applied in treatment of waste water

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Keila Machado de; Araujo, Edcleide Maria; Lira, Helio de Lucena, E-mail: keilamachadodemedeiros@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Lima, Diego de Farias; Lima, Carlos Antonio Pereira de [Universidade Estadual da Paraiba (UEPB), Campina Grande, PB (Brazil). Departamento de Engenharia Sanitaria e Ambiental

    2017-03-15

    In this work, it was prepared hybrid membranes of polyamide6 (PA6) with montmorillonite (MMT) and porogenic agent (CaCl{sub 2} ). The hybrid membranes with CaCl{sub 2} were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), porosimetry by mercury intrusion (PMI), flux measurements and rejection. By means of X-ray diffraction, it was revealed that the hybrid membranes with CaCl{sub 2} have an exfoliated and/or partially exfoliated structure. For FTIR and DSC of hybrid membranes with CaCl{sub 2} , it was found that the spectra and the crystalline melting temperature remained virtually unchanged compared to PA6 membrane. From the SEM images, it was observed that the addition of the MMT and the CaCl{sub 2} in the membrane of PA6 caused an increase in the amount of pores the surface and cross section of these membranes. By PMI, it was observed that the presence of MMT and CaCl{sub 2} in the membrane caused an increase in the average diameters of pores. The water-oil separation tests, indicated a significant reduction of oil in the permeate, allowing treatment of wastewater contaminated with oil. (author)

  12. Hybrid membranes of polyamide applied in treatment of waste water

    International Nuclear Information System (INIS)

    Medeiros, Keila Machado de; Araujo, Edcleide Maria; Lira, Helio de Lucena; Lima, Diego de Farias; Lima, Carlos Antonio Pereira de

    2017-01-01

    In this work, it was prepared hybrid membranes of polyamide6 (PA6) with montmorillonite (MMT) and porogenic agent (CaCl 2 ). The hybrid membranes with CaCl 2 were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), porosimetry by mercury intrusion (PMI), flux measurements and rejection. By means of X-ray diffraction, it was revealed that the hybrid membranes with CaCl 2 have an exfoliated and/or partially exfoliated structure. For FTIR and DSC of hybrid membranes with CaCl 2 , it was found that the spectra and the crystalline melting temperature remained virtually unchanged compared to PA6 membrane. From the SEM images, it was observed that the addition of the MMT and the CaCl 2 in the membrane of PA6 caused an increase in the amount of pores the surface and cross section of these membranes. By PMI, it was observed that the presence of MMT and CaCl 2 in the membrane caused an increase in the average diameters of pores. The water-oil separation tests, indicated a significant reduction of oil in the permeate, allowing treatment of wastewater contaminated with oil. (author)

  13. Improved Mechanical Properties of Compatibilized Polypropylene/Polyamide-12 Blends

    Directory of Open Access Journals (Sweden)

    Nora Aranburu

    2015-01-01

    Full Text Available Compatibilized blends of polypropylene (PP and polyamide-12 (PA12 as a second component were obtained by direct injection molding having first added 20% maleic anhydride-modified copolymer (PP-g-MA to the PP, which produced partially grafted PP (gPP. A nucleating effect of the PA12 took place on the cooling crystallization of the gPP, and a second crystallization peak of the gPP appeared in the PA12-rich blends, indicating changes in the crystalline morphology. There was a slight drop in the PA12 crystallinity of the compatible blends, whereas the crystallinity of the gPP increased significantly in the PA12-rich blends. The overall reduction in the dispersed phase particle size together with the clear increase in ductility when gPP was used instead of PP proved that compatibilization occurred. Young’s modulus of the blends showed synergistic behavior. This is proposed to be both due to a change in the crystalline morphology of the blends on the one hand and, on the other, in the PA12-rich blends, to the clear increase in the crystallinity of the gPP phase, which may, in turn, have been responsible for the increase in its continuity and its contribution to the modulus.

  14. Fluorescent detection of C-reactive protein using polyamide beads

    Science.gov (United States)

    Jagadeesh, Shreesha; Chen, Lu; Aitchison, Stewart

    2016-03-01

    Bacterial infection causes Sepsis which is one of the leading cause of mortality in hospitals. This infection can be quantified from blood plasma using C - reactive protein (CRP). A quick diagnosis at the patient's location through Point-of- Care (POC) testing could give doctors the confidence to prescribe antibiotics. In this paper, the development and testing of a bead-based procedure for CRP quantification is described. The size of the beads enable them to be trapped in wells without the need for magnetic methods of immobilization. Large (1.5 mm diameter) Polyamide nylon beads were used as the substrate for capturing CRP from pure analyte samples. The beads captured CRP either directly through adsorption or indirectly by having specific capture antibodies on their surface. Both methods used fluorescent imaging techniques to quantify the protein. The amount of CRP needed to give a sufficient fluorescent signal through direct capture method was found suitable for identifying bacterial causes of infection. Similarly, viral infections could be quantified by the more sensitive indirect capture method. This bead-based assay can be potentially integrated as a disposable cartridge in a POC device due to its passive nature and the small quantities needed.

  15. Quantitative structure-activity relationship (QSAR) models for polycyclic aromatic hydrocarbons (PAHs) dissipation in rhizosphere based on molecular structure and effect size

    International Nuclear Information System (INIS)

    Ma Bin; Chen Huaihai; Xu Minmin; Hayat, Tahir; He Yan; Xu Jianming

    2010-01-01

    Rhizoremediation is a significant form of bioremediation for polycyclic aromatic hydrocarbons (PAHs). This study examined the role of molecular structure in determining the rhizosphere effect on PAHs dissipation. Effect size in meta-analysis was employed as activity dataset for building quantitative structure-activity relationship (QSAR) models and accumulative effect sizes of 16 PAHs were used for validation of these models. Based on the genetic algorithm combined with partial least square regression, models for comprehensive dataset, Poaceae dataset, and Fabaceae dataset were built. The results showed that information indices, calculated as information content of molecules based on the calculation of equivalence classes from the molecular graph, were the most important molecular structural indices for QSAR models of rhizosphere effect on PAHs dissipation. The QSAR model, based on the molecular structure indices and effect size, has potential to be used in studying and predicting the rhizosphere effect of PAHs dissipation. - Effect size based on meta-analysis was used for building PAHs dissipation quantitative structure-activity relationship (QSAR) models.

  16. Quantitative structure-activity relationship (QSAR) models for polycyclic aromatic hydrocarbons (PAHs) dissipation in rhizosphere based on molecular structure and effect size

    Energy Technology Data Exchange (ETDEWEB)

    Ma Bin; Chen Huaihai; Xu Minmin; Hayat, Tahir [Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Natural Resource Sciences, Zhejiang University, Hangzhou 310029 (China); He Yan, E-mail: yhe2006@zju.edu.c [Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Natural Resource Sciences, Zhejiang University, Hangzhou 310029 (China); Xu Jianming, E-mail: jmxu@zju.edu.c [Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Natural Resource Sciences, Zhejiang University, Hangzhou 310029 (China)

    2010-08-15

    Rhizoremediation is a significant form of bioremediation for polycyclic aromatic hydrocarbons (PAHs). This study examined the role of molecular structure in determining the rhizosphere effect on PAHs dissipation. Effect size in meta-analysis was employed as activity dataset for building quantitative structure-activity relationship (QSAR) models and accumulative effect sizes of 16 PAHs were used for validation of these models. Based on the genetic algorithm combined with partial least square regression, models for comprehensive dataset, Poaceae dataset, and Fabaceae dataset were built. The results showed that information indices, calculated as information content of molecules based on the calculation of equivalence classes from the molecular graph, were the most important molecular structural indices for QSAR models of rhizosphere effect on PAHs dissipation. The QSAR model, based on the molecular structure indices and effect size, has potential to be used in studying and predicting the rhizosphere effect of PAHs dissipation. - Effect size based on meta-analysis was used for building PAHs dissipation quantitative structure-activity relationship (QSAR) models.

  17. Comparison of the Emission of Aromatic Hydrocarbons from Moulding Sands with Furfural Resin with the Low Content of Furfuryl Alcohol and Different Activators

    Directory of Open Access Journals (Sweden)

    Żymankowska-Kumon S.

    2016-12-01

    Full Text Available No-bake process refers to the use of chemical binders to bond the moulding sand. Sand is moved to the mould fill station in preparation for filling of the mould. A mixer is used to blend the sand with the chemical binder and activator. As the sand exits the mixer, the binder begins the chemical process of hardening. This paper presents the results of decomposition of the moulding sands with modified urea-furfuryl resin (with the low content of furfuryl alcohol below 25 % and different activators: organic and inorganic on a quartz matrix, under semi-industrial conditions. Investigations of the gases emission in the test foundry plant were executed according to the method extended in the Faculty of Foundry Engineering (AGH University of Science and Technology. Article presents the results of the emitted chosen aromatic hydrocarbons and loss on ignition compared with the different activators used to harden this resin. On the bases of the data, it is possible to determine the content of the emitted dangerous substances from the moulding sand according to the content of loss on ignition.

  18. Polycyclic aromatic hydrocarbons and trace elements bounded to airborne PM10 in the harbor of Volos, Greece: Implications for the impact of harbor activities

    Science.gov (United States)

    Manoli, E.; Chelioti-Chatzidimitriou, A.; Karageorgou, K.; Kouras, A.; Voutsa, D.; Samara, C.; Kampanos, I.

    2017-10-01

    Harbors are often characterized by high levels of air pollutants that are emitted from ship traffic and other harbor activities. In the present study, the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and trace elements (As, Cd, Ni, Pb, Cr, Mn, Zn, and Fe) bounded to the inhalable particulate matter PM10 were studied in the harbor of Volos, central Greece, during a 2-year period (2014-2015). Seasonal and daily variations were investigated. Moreover, total carcinogenic and mutagenic activities of PAHs were calculated. The effect of major wind sectors (sea, city, industrial, harbor) was estimated to assess the potential contribution of ship traffic and harbor activities, such as scrap metal handling operations. Results showed that the harbor sector (calm winds ≤ 0.5 m s-1) was associated with the highest concentrations of PM10. The harbor sector was also associated with relatively increased levels of trace elements (As, Fe, Cr, Mn, Ni), however the effect of this sector was lower than the corresponding effect of the industrial wind sector. The sea sector showed only a slight increase in B[a]Py and Σ12PAHs, whereas the highest increasing effect for PAHs and traffic-related elements, such as Pb and Zn, was evidenced for the city sector.

  19. Structural comparison of nanocomposites membranes of polyamide 6 and polyamide 6.6 with a regional clay; Comparacao estrutural de membranas de nanocompositos de poliamida 6 e poliamida 6.6 com uma argila regional

    Energy Technology Data Exchange (ETDEWEB)

    Leite, A M.D.; Medeiros, V N; Paz, R A; Araujo, E M; Lira, H.L., E-mail: amandamelissa.lins@yahoo.com.b [Universidade Federal de Campina Grande (UAEMa/UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Ito, Edson N [Universidade Federal do Rio Grande do Norte (DEMat/UFRN), Natal, RN (Brazil). dept. de Engenharia de Materiais

    2010-07-01

    Polyamide membranes do not require wetting agents because they are hydrophilic membranes and show great interest in the separation of aqueous solutions. With this, there is the interest to produce membranes from nanocomposites (polyamide 6 and polyamide 6.6)/organoclay), using the technique of isothermal immersion-precipitation in a bath with distilled water. The objective of this work was to produce, characterize and compare nanocomposites of polyamide 6 and polyamide 6.6/organoclay for use in the preparation of membranes. The nanocomposites were produced with 3 wt% of clay organically modified by quaternary ammonium salt (Cetremide) and were characterized by XRD and TEM. The nanocomposites presented an exfoliated/partially exfoliated structure. The membranes were characterized by SEM and presented a dense layer (selective skin) and another layer with uniform pores distributed along the membrane. (author)

  20. Flame Retardant Polyamide Fibres: The Challenge of Minimising Flame Retardant Additive Contents with Added Nanoclays

    Directory of Open Access Journals (Sweden)

    Richard Horrocks

    2016-08-01

    Full Text Available This work shows that halogen-free, flame retarded polyamide 6 (PA6, fabrics may be produced in which component fibres still have acceptable tensile properties and low levels (preferably ≤10 wt % of additives by incorporating a nanoclay along with two types of flame retardant formulations. The latter include (i aluminium diethyl phosphinate (AlPi at 10 wt %, known to work principally in the vapour phase and (ii ammonium sulphamate (AS/dipentaerythritol (DP system present at 2.5 and 1 wt % respectively, believed to be condense phase active. The nanoclay chosen is an organically modified montmorillonite clay, Cloisite 25A. The effect of each additive system is analysed in terms of its ability to maximise both filament tensile properties relative to 100% PA6 and flame retardant behaviour of knitted fabrics in a vertical orientation. None of the AlPi-containing formulations achieved self-extinguishability, although the presence of nanoclay promoted lower burning and melt dripping rates. The AS/DP-containing formulations with total flame retardant levels of 5.5 wt % or less showed far superior properties and with nanoclay, showed fabric extinction times ≤ 39 s and reduced melt dripping. The tensile and flammability results, supported by thermogravimetric analysis, have been interpreted in terms of the mechanism of action of each flame retardant/nanoclay type.

  1. Triclosan-immobilized polyamide thin film composite membranes with enhanced biofouling resistance

    Science.gov (United States)

    Park, Sang-Hee; Hwang, Seon Oh; Kim, Taek-Seung; Cho, Arah; Kwon, Soon Jin; Kim, Kyoung Taek; Park, Hee-Deung; Lee, Jung-Hyun

    2018-06-01

    We report on a strategy to improve biofouling resistance of a polyamide (PA) thin-film composite (TFC) reverse osmosis (RO) membrane via chemically immobilizing triclosan (TC), known as a common organic biocide, on its surface. To facilitate covalent attachment of TC on the membrane surface, TC was functionalized with amine moiety to prepare aminopropyl TC. Then, the TC-immobilized TFC (TFC-TC) membranes were fabricated through a one-step amide formation reaction between amine groups of aminopropyl TC and acyl chloride groups present on the PA membrane surface, which was confirmed by high-resolution XPS. Strong stability of the immobilized TC was also confirmed by a hydraulic washing test. Although the TFC-TC membrane showed slightly reduced separation performance compared to the pristine control, it still maintained a satisfactory RO performance level. Importantly, the TFC-TC membrane exhibited excellent antibacterial activity against both gram negative (E. coli and P. aeruginosa) and gram positive (S. aureus) bacteria along with greatly enhanced resistance to biofilm formation. Our immobilization approach offers a robust and relatively benign strategy to control biofouling of functional surfaces, films and membranes.

  2. Preparation and characterisation of polyamide 11/montmorillonite (MMT) nanocomposites for use in angioplasty balloon applications

    International Nuclear Information System (INIS)

    Halim, Khairul Anwar A.; Farrell, Joseph B.; Kennedy, James E.

    2013-01-01

    With increased demands on catheter balloon functionality, there is an emphasis to blend new materials which can improve mechanical performance. Polymer nanocomposites were prepared by melt blending polyamide 11 (PA 11) with organically modified montmorillonite nanoclay. The effects of incorporating the nanoclay on the short-term mechanical properties of PA 11 were assessed using a design of experiments (DoEs) approach. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis techniques (DMA) were used to characterise the morphology of the nanocomposites. Design of experiments studies revealed that the optimum nanocomposites properties can be achieved by carefully controlling the melt compounding parameters. XRD and TEM data proved that exfoliated clay morphologies existed within the matrix at low clay loading (2%). Whereas the interaction between the polymer matrix and nanoclay was quantified in the DMA spectra, showed a significant increase in storage modulus (up to 80%). The reinforcing effect of nanoclay within the PA 11 was further investigated using mechanical testing, where significant increases in the ultimate tensile strength and strain at break of reinforced tri-layer balloon tubing were observed. - Highlights: • TEM reveals the coexistence of exfoliated and intercalated nanostructures. • Isothermal crystallisation studies found that the nano-clays reduced the crystallisation time. • Significant increase in the storage modulus was due to the reinforcing effect of the nano-clay platelets. • It was observed that the activation energy values decreased due to the presence of nanoclay

  3. Preparation and characterisation of polyamide 11/montmorillonite (MMT) nanocomposites for use in angioplasty balloon applications

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Khairul Anwar A. [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland); School of Materials Engineering, Universiti Malaysia Perlis, Perlis (Malaysia); Farrell, Joseph B. [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland); Kennedy, James E., E-mail: jkennedy@ait.ie [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland)

    2013-12-16

    With increased demands on catheter balloon functionality, there is an emphasis to blend new materials which can improve mechanical performance. Polymer nanocomposites were prepared by melt blending polyamide 11 (PA 11) with organically modified montmorillonite nanoclay. The effects of incorporating the nanoclay on the short-term mechanical properties of PA 11 were assessed using a design of experiments (DoEs) approach. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis techniques (DMA) were used to characterise the morphology of the nanocomposites. Design of experiments studies revealed that the optimum nanocomposites properties can be achieved by carefully controlling the melt compounding parameters. XRD and TEM data proved that exfoliated clay morphologies existed within the matrix at low clay loading (2%). Whereas the interaction between the polymer matrix and nanoclay was quantified in the DMA spectra, showed a significant increase in storage modulus (up to 80%). The reinforcing effect of nanoclay within the PA 11 was further investigated using mechanical testing, where significant increases in the ultimate tensile strength and strain at break of reinforced tri-layer balloon tubing were observed. - Highlights: • TEM reveals the coexistence of exfoliated and intercalated nanostructures. • Isothermal crystallisation studies found that the nano-clays reduced the crystallisation time. • Significant increase in the storage modulus was due to the reinforcing effect of the nano-clay platelets. • It was observed that the activation energy values decreased due to the presence of nanoclay.

  4. Control of biofouling on reverse osmosis polyamide membranes modified with biocidal nanoparticles and antifouling polymer brushes

    KAUST Repository

    Rahaman, Md. Saifur

    2014-01-01

    Thin-film composite (TFC) polyamide reverse osmosis (RO) membranes are prone to biofouling due to their inherent physicochemical surface properties. In order to address the biofouling problem, we have developed novel surface coatings functionalized with biocidal silver nanoparticles (AgNPs) and antifouling polymer brushes via polyelectrolyte layer-by-layer (LBL) self-assembly. The novel surface coating was prepared with polyelectrolyte LBL films containing poly(acrylic acid) (PAA) and poly(ethylene imine) (PEI), with the latter being either pure PEI or silver nanoparticles coated with PEI (Ag-PEI). The coatings were further functionalized by grafting of polymer brushes, using either hydrophilic poly(sulfobetaine) or low surface energy poly(dimethylsiloxane) (PDMS). The presence of both LBL films and sulfobetaine polymer brushes at the interface significantly increased the hydrophilicity of the membrane surface, while PDMS brushes lowered the membrane surface energy. Overall, all surface modifications resulted in significant reduction of irreversible bacterial cell adhesion. In microbial adhesion tests with E. coli bacteria, a normalized cell adhesion in the range of only 4 to 16% on the modified membrane surfaces was observed. Modified surfaces containing silver nanoparticles also exhibited strong antimicrobial activity. Membranes coated with LBL films of PAA/Ag-PEI achieved over 95% inactivation of bacteria attached to the surface within 1 hour of contact time. Both the antifouling and antimicrobial results suggest the potential of using these novel surface coatings in controlling the fouling of RO membranes. © The Royal Society of Chemistry 2014.

  5. Polyamide Microparticles Containing Vitamin C by Interfacial Polymerization: An Approach by Design of Experimentation

    Directory of Open Access Journals (Sweden)

    Lionel Ripoll

    2016-11-01

    Full Text Available Vitamin C is widely use in cosmetics and pharmaceutics products for its active properties. However ascorbic acid shows unfavourable chemical instability such as oxidation leading to formulation problems. Therefore, carriers, such as micro- and nanoparticles, have been widely investigated as delivery systems for vitamin C to improve its beneficial effects in skin treatment. However, none of the previous studies have been able to produce microparticles with a high encapsulation entrapment of vitamin C. The aim of the present study is to use an experimental design to optimize the synthesis of polyamide microparticles for the delivery of ascorbic acid. The effect of four formulation parameters on microparticles properties (size and morphology, encapsulation efficiency and yield, release kinetics were investigated using a surface response design. Finally, we were able to obtain stable microparticles containing more than 65% of vitamin C. This result confirms the effectiveness of using design of experiments for the optimisation of microparticle formulation and supports the proposal of using them as candidate for the delivery of vitamin C in skin treatment.

  6. Effect of repair resin type and surface treatment on the repair strength of polyamide denture base resin.

    Science.gov (United States)

    Gundogdu, Mustafa; Yanikoglu, Nuran; Bayindir, Funda; Ciftci, Hilal

    2015-01-01

    The purpose of the present study was to evaluate the effects of different repair resins and surface treatments on the repair strength of a polyamide denture base material. Polyamide resin specimens were prepared and divided into nine groups according to the surface treatments and repair materials. The flexural strengths were measured with a 3-point bending test. Data were analyzed with a 2-way analysis of variance, and the post-hoc Tukey test (α=0.05). The effects of the surface treatments on the surface of the polyamide resin were examined using scanning electron microscopy. The repair resins and surface treatments significantly affected the repair strength of the polyamide denture base material (p0.05). The flexural strength of the specimens repaired with the polyamide resin was significantly higher than that of those repaired with the heat-polymerized and autopolymerizing acrylic resins.

  7. Antioxidant activity, phenolic content, and peroxide value of essential oil and extracts of some medicinal and aromatic plants used as condiments and herbal teas in Turkey.

    Science.gov (United States)

    Ozcan, Mehmet Musa; Erel, Ozcan; Herken, Emine Etöz

    2009-02-01

    The antioxidant activity, total peroxide values, and total phenol contents of several medicinal and aromatic plant essential oil and extracts from Turkey were examined. Total phenolic contents were determined using a spectrophotometric technique and calculated as gallic acid equivalents. Total antioxidant activity of essential oil and extracts varied from 0.6853 to 1.3113 and 0.3189 to 0.6119 micromol of Trolox equivalents/g, respectively. The total phenolic content of essential oil ranged from 0.0871 to 0.5919 mg of gallic acid/g dry weight. However, the total phenolic contents of extracts were found to be higher compared with those of essential oils. The amount of total peroxide values of oils varied from 7.31 (pickling herb) to 58.23 (bitter fennel flower) mumol of H(2)O(2)/g. As a result, it is shown that medicinal plant derivatives such as extract and essential oils can be useful as a potential source of total phenol, peroxide, and antioxidant capacity for protection of processed foods.

  8. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    Science.gov (United States)

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-02

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  9. MRI diagnosis of the complications of polyamide hydrogel injection for augmentation mammoplasty

    International Nuclear Information System (INIS)

    Chen Xueqiang; Chen Pingyou; Zhang Yunshu; Luo Qinghua; Xu Rong

    2005-01-01

    Objective: To analyze MRI findings and its clinical significance in complications of polyamide hydrogel injection for augmentation mammoplasty. Methods: The complication findings of MR imaging in 20 cases with polyamide hydrogel injection for augmentation mammoplasty were retrospectively reviewed and analyzed. Results: In 20 patients, 26 breasts suffered from complications, including infection (n=5) with pieces of long T 1 and long T 2 signals, aseptic inflammation (n=2) with pieces of slight long T 1 and moderate T 2 signals, hard nodule (n=10) with long T 1 and long T 2 signals, and rupture (n=5) with pieces and nodes of long T 1 and long T 2 signals on MR images. Conclusion: MRI has the great diagnostic value in the detection of complications after polyamide hydrogel injection for augmentation mammoplasty, and it should be taken as the first diagnostic choice. (authors)

  10. Retention and Deformation of Cobalt-Chromium and High-Impact Polyamide Clasps

    Directory of Open Access Journals (Sweden)

    Övül Kümbüloğlu

    2018-04-01

    Full Text Available Objective: The use of metal clasps especially in anterior region may cause aesthetic problems. Polyamide resin has been suggested as an alternative aesthetic denture clasp material. This study compared the retentive force and deformation of cobalt-chromium and polyamide clasps after 36 months of simulated clinical use. Materials and Methods: The retentive force for clasp removal was measured in distilled water using a custom-made apparatus with intervals corresponding to 0, 6, 12, 18, 24, 30 and 36 months of simulated clinical use. The distance (mm between the retentive and reciprocal clasp tips was measured using a microscope before and after the insertion-removal procedures. Results: Significant difference was observed in distance between clasp tips for metal clasps between baseline and 36 months for molars and premolars (p0.05. Conclusion: Polyamide clasps could be alternative to metal clasps particularly on premolars with reliable retention and deformation.

  11. Orientation and the extent of exfoliation of clay on scratch damage in polyamide 6 nanocomposites

    International Nuclear Information System (INIS)

    Dasari, Aravind; Yu Zhongzhen; Mai Yiuwing; Kim, Jang-Kyo

    2008-01-01

    The major objectives of this work are to understand the effects of organoclay, its extent of exfoliation and orientation, and indenter geometry on the scratch characteristics of polyamide 6/organoclay nanocomposites. Two different organically treated clays are used for this purpose and their structural parameters in a polyamide 6 matrix quantified. It is shown that, while the material properties are important for scratching resistance, they are not the only determinants of the scratch performance of materials. Further, despite proving beneficial to scratch resistance, in terms of residual depth, the presence (and exfoliation) of organoclay promotes the formation of brittle cracks during scratching. But with no organoclay layers, plastic flow controls the scratch damage in neat polyamide 6 with large residual depths. Factors such as orientation of clay layers and variations of indenter tip geometry also exert dominant effects on scratch penetration resistance and damage. Additionally, significant plastic flow and rotation of organoclay layers from the original configuration are observed underneath the sliding indenter

  12. Mechanical and rheological properties of nanocomposites of polyamide 6 with national organoclay

    International Nuclear Information System (INIS)

    Paz, Rene Anisio da; Leite, Amanda Melissa Damiao; Araujo, Edcleide Maria; Melo, Tomas Jeferson Alves de; Pessan, Luiz Antonio; Passador, Fabio Roberto

    2013-01-01

    Nanocomposites of polyamide 6 with organoclay were prepared by melt intercalation and their rheological and mechanical properties were studied. The clay was treated with the quaternary ammonium salt (Cetremide) and characterized by Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed the incorporation of salt in the clay and its organophilization. A master was prepared with PA6/clay (1:1) by weight and this was added to the pure polyamide 6 to reach the nominal proportion of 3% of clay, using a co-rotational twin screw extruder. The samples were molded by injection and characterized by: capillary rheometry, XRD, TEM and mechanical testing (tensile and impact). The results of capillary rheometry showed that the presence of organoclay in the PA6 increased the viscosity of the systems. With XRD and TEM, it was verified that all systems presented predominantly exfoliated structure. The tensile properties of the nanocomposites were better than those of pure polyamide 6. (author)

  13. Morphologic characterization for XRD and TEM of polyamide 6 and 66 nanocomposites with bentonite regional clay

    International Nuclear Information System (INIS)

    Leite, Amanda M.D.; Medeiros, Vanessa da N.; Maia, Larissa F.; Araujo, Edcleide M.; Lira, Helio L.

    2009-01-01

    Polyamide 6 and 66 nanocomposites with clay consisting of silicates layer from Paraiba were produced. The clay was modified being used the quaternary salt of ammonium Cetremide, this so there is a better interaction of the clay with polymeric matrix. The clay without treatment (MMT) and treated clay was evaluated by XRD that showed the insertion of the salt molecules into silicates layer. The nanocomposites were obtained from polyamide 6 and 66 were verified that these presented morphological structure composed of exfoliated/partially exfoliated, analyzed by XRD and TEM. (author)

  14. Mechanisms of formation and destruction of nitrogen oxides during polyamide incineration in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Hahnel, F; Gadiou, R; Prado, G [Univ. de Haute Alsace, Mulhouse (France). Lab. de Gestion des Risques et Environnement

    1998-09-01

    In order to study the incineration of nitrogen-containing polymers, a fludized bed has been built. This paper reports the results for polyamide 6-6 incineration. The main nitrogen containing species have been identified, and the axial profiles of concentration of nitrogen oxides, HCN and NH3 have been measured. The main steps of decomposition of the polyamide were identified. We present an experimental investigation of the influence of operating parameters (temperature, excess air) on the formation and reduction of polymer combustion products. The yields of conversion of nitrogen to the different N-species have been calculated as a function of excess air in the fluidized bed. (orig.)

  15. Rapid microwave hydrothermal synthesis of ZnGa2O4 with high photocatalytic activity toward aromatic compounds in air and dyes in liquid water

    International Nuclear Information System (INIS)

    Sun Meng; Li Danzhen; Zhang Wenjuan; Chen Zhixin; Huang Hanjie; Li Wenjuan; He Yunhui; Fu Xianzhi

    2012-01-01

    ZnGa 2 O 4 was synthesized from Ga(NO 3 ) 3 and ZnCl 2 via a rapid and facile microwave-assisted hydrothermal method. The photocatalytic properties of the as-prepared ZnGa 2 O 4 were evaluated by the degradation of pollutants in air and aqueous solution under ultraviolet (UV) light illumination. The results demonstrated that ZnGa 2 O 4 had exhibited efficient photocatalytic activities higher than that of commercial P25 (Degussa Co.) in the degradation of benzene, toluene, and ethylbenzene, respectively. In the liquid phase degradation of dyes (methyl orange, Rhodamine B, and methylene blue), ZnGa 2 O 4 has also exhibited remarkable activities higher than that of P25. After 32 min of UV light irradiation, the decomposition ratio of methyl orange (10 ppm, 150 mL) over ZnGa 2 O 4 (0.06 g) was up to 99%. The TOC tests revealed that the mineralization ratio of MO (10 ppm, 150 mL) was 88.1% after 90 min of reaction. A possible mechanism of the photocatalysis over ZnGa 2 O 4 was also proposed. - Graphical abstract: In the degradation of RhB under UV light irradiation, ZnGa 2 O 4 had exhibited efficient photo-activity, and after only 24 min of irradiation the decomposition ratio was up to 99.8%. Highlights: ► A rapid and facile M–H method to synthesize ZnGa 2 O 4 photocatalyst. ► The photocatalyst exhibits high activity toward benzene and dyes. ► The catalyst possesses more surface hydroxyl sites than TiO 2 (P25). ► Deep oxidation of different aromatic compounds and dyes over catalyst.

  16. Polycyclic Aromatic Hydrocarbons (PAHs) Mediate Transcriptional Activation of the ATP Binding Cassette Transporter ABCB6 Gene via the Aryl Hydrocarbon Receptor (AhR)*

    Science.gov (United States)

    Chavan, Hemantkumar; Krishnamurthy, Partha

    2012-01-01

    Liver is endowed with a mechanism to induce hepatic cytochromes P450 (CYP450s) in response to therapeutic drugs and environmental contaminants, leading to increased detoxification and elimination of the xenobiotics. Each CYP450 is composed of an apoprotein moiety and a heme prosthetic group, which is required for CYP450 activity. Thus, under conditions of CYP450 induction, there is a coordinate increase in heme biosynthesis to compensate for the increased expression of CYP450s. ABCB6, a mitochondrial ATP binding cassette transporter, which regulates coproporphyrinogen transport from the cytoplasm into the mitochondria to complete heme biosynthesis, represents a previously unrecognized rate-limiting step in heme biosynthesis. However, it is not known if exposure to drugs and environmental contaminants induces ABCB6 expression, to assure an adequate and apparently coordinated supply of heme for the generation of functional cytochrome holoprotein. In the present study, we demonstrate that polycyclic aromatic hydrocarbons (PAHs), the widely distributed environmental toxicants shown to induce porphyrin accumulation causing hepatic porphyria, up-regulate ABCB6 expression in both mice and humans. Using siRNA technology and Abcb6 knock-out mice, we demonstrate that PAH-mediated increase in hepatic porphyrins is compromised in the absence of ABCB6. Moreover, in vivo studies in aryl hydrocarbon receptor (AhR) knock-out mice demonstrate that PAH induction of ABCB6 is mediated by AhR. Promoter activation studies combined with electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrate direct interactions between the AhR binding sites in the ABCB6 promoter and the AhR receptor, implicating drug activation mechanisms for ABCB6 similar to those found in inducible cytochrome P450s. These studies are the first to describe direct transcriptional activation of both mouse and human ABCB6 by xenobiotics. PMID:22761424

  17. Rheological changes of polyamide 12 under oscillatory shear

    Science.gov (United States)

    Mielicki, C.; Gronhoff, B.; Wortberg, J.

    2014-05-01

    Changes in material properties as well as process deviation prevent Laser Sintering (LS) technology from manufacturing of quality assured parts in a series production. In this context, the viscosity of Polyamide 12 (PA12) is assumed to possess the most significant influence, as it determines the sintering velocity, the resistance towards melt formation and the bonding strength of sintered layers. Moreover, the viscosity is directly related to the structure of the molten polymer. In particular, it has been recently reported that LS process conditions lead to structural changes of PA12 affecting viscosity and coalescence of adjacent polymer particles, i.e. melt formation significantly. Structural change of PA12 was understood as a post condensation. Its influence on viscosity was described by a time and temperature depending rheological model whereas time dependence was considered by a novel structural change shift factor which was derived from melt volume rate data. In combination with process data that was recorded using online thermal imaging, the model is suitable to control the viscosity (processability of the material) as result of material and process properties. However, as soon as laser energy is exposed to the powder bed PA12 undergoes a phase transition from solid to molten state. Above the melting point, structural change is expected to occur faster due to a higher kinetic energy and free volume of the molten polymer. Oscillatory shear results were used to study the influence of aging time and for validation of the novel structural change shift factor and its model parameters which were calibrated based on LS processing condition.

  18. Constituents and Pharmacological Activities of Myrcia (Myrtaceae): A Review of an Aromatic and Medicinal Group of Plants.

    Science.gov (United States)

    Cascaes, Márcia Moraes; Guilhon, Giselle Maria Skelding Pinheiro; Andrade, Eloisa Helena de Aguiar; Zoghbi, Maria das Graças Bichara; Santos, Lourivaldo da Silva

    2015-10-09

    Myrcia is one of the largest genera of the economically important family Myrtaceae. Some of the species are used in folk medicine, such as a group known as "pedra-hume-caá" or "pedra-ume-caá" or "insulina vegetal" (insulin plant) that it is used for the treatment of diabetes. The species are an important source of essential oils, and most of the chemical studies on Myrcia describe the chemical composition of the essential oils, in which mono- and sesquiterpenes are predominant. The non-volatile compounds isolated from Myrcia are usually flavonoids, tannins, acetophenone derivatives and triterpenes. Anti-inflammatory, antinociceptive, antioxidant, antimicrobial activities have been described to Myrcia essential oils, while hypoglycemic, anti-hemorrhagic and antioxidant activities were attributed to the extracts. Flavonoid glucosides and acetophenone derivatives showed aldose reductase and α-glucosidase inhibition, and could explain the traditional use of Myrcia species to treat diabetes. Antimicrobial and anti-inflammatory are some of the activities observed for other isolated compounds from Myrcia.

  19. Constituents and Pharmacological Activities of Myrcia (Myrtaceae: A Review of an Aromatic and Medicinal Group of Plants

    Directory of Open Access Journals (Sweden)

    Márcia Moraes Cascaes

    2015-10-01

    Full Text Available Myrcia is one of the largest genera of the economically important family Myrtaceae. Some of the species are used in folk medicine, such as a group known as “pedra-hume-caá” or “pedra-ume-caá” or “insulina vegetal” (insulin plant that it is used for the treatment of diabetes. The species are an important source of essential oils, and most of the chemical studies on Myrcia describe the chemical composition of the essential oils, in which mono- and sesquiterpenes are predominant. The non-volatile compounds isolated from Myrcia are usually flavonoids, tannins, acetophenone derivatives and triterpenes. Anti-inflammatory, antinociceptive, antioxidant, antimicrobial activities have been described to Myrcia essential oils, while hypoglycemic, anti-hemorrhagic and antioxidant activities were attributed to the extracts. Flavonoid glucosides and acetophenone derivatives showed aldose reductase and α-glucosidase inhibition, and could explain the traditional use of Myrcia species to treat diabetes. Antimicrobial and anti-inflammatory are some of the activities observed for other isolated compounds from Myrcia.

  20. Effects of reuse and bleach/formaldehyde reprocessing on polysulfone and polyamide hemodialyzers.

    Science.gov (United States)

    Cornelius, Rena M; McClung, W Glenn; Barre, Paul; Esguerra, Fe; Brash, John L

    2002-01-01

    The surface features, morphology, and blood interactions of fibers from pristine, bleach/formaldehyde reprocessed, and reused Fresenius Polysulfone High Flux (Hemoflow F80B) hemodialyzers and Gambro Polyflux 21S Polyamide hemodialyzers have been studied. SEM images of fibers from both hemodialyzer types revealed a dense skin layer on the inner surface and a relatively thick porous layer on the outer surface. The 21S polyamide support layer consisted of interconnected highly porous structures. Environmental scanning electron microscopy and atomic force microscopy images of both membrane types showed alterations in morphology due to reprocessing and reuse; however the changes were more marked for the 21S polyamide dialyzers. Fluorescence microscopy images showed only minimal fluorescence associated with the fibers after patient use and reprocessing, suggesting that blood derived deposits were removed by processing. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were studied using SDS-PAGE and immunoblotting. Before bleach/formaldehyde treatment, protein layers of considerable amount and complexity were found on the blood side of singly and multiply used dialyzers. Proteins adsorbed on the dialysate side were predominantly in the molecular mass region below 30 kDa. However, some higher molecular mass proteins were detected on the dialysate side of the 21 S polyamide dialyzers. Very little protein was detected on dialyzers that were treated with bleach/formaldehyde after dialysis, regardless of whether they had been used/reprocessed once or 12 times.

  1. Comparison of Three Different Methods for Pile Integrity Testing on a Cylindrical Homogeneous Polyamide Specimen

    Science.gov (United States)

    Lugovtsova, Y. D.; Soldatov, A. I.

    2016-01-01

    Three different methods for pile integrity testing are proposed to compare on a cylindrical homogeneous polyamide specimen. The methods are low strain pile integrity testing, multichannel pile integrity testing and testing with a shaker system. Since the low strain pile integrity testing is well-established and standardized method, the results from it are used as a reference for other two methods.

  2. Influence of moisture absorption on properties of fiber reinforced polyamide 6 composites

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Løgstrup Andersen, Tom; Lystrup, Aage

    2011-01-01

    sensitive to moisture, and if PA6 is used as matrix material in a fiber composite, the properties of the fiber composite will depend on the moisture content of the material. At standard condition (23 °C and 50% RH) polyamide6 absorbs about 3 weight-% of water, whereas the PA6 material is dry right after...

  3. Applications of polyamide/cellulose fiber/wollastonite composites for microcellular injection molding

    Science.gov (United States)

    Herman Winata; Lih-Sheng Turng; Daniel F. Caulfield; Tom Kuster; Rick Spindler; Rod Jacobson

    2003-01-01

    In this study, a cellulose-fiber-reinforced Polyamide-6 (PA-6) composite, a hybrid composite (PA-6/cellulose/Wollastonite), and the neat PA-6 resin were injection molded into ASTM test–bar samples with conventional and microcellular injection molding. The impact and tensile strengths of molded samples were measured and the Scanning Electron Microscopy (SEM) images were...

  4. Mechanical Characterization and Fractography of Glass Fiber/Polyamide (PA6) Composites

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Pillai, Saju; Charca, Samuel

    2015-01-01

    The mechanical properties of the glass fiber reinforced Polyamide (PA6) composites made by prepreg tapes and commingled yarns were studied by in-plane compression, short-beam shear, and flexural tests. The composites were fabricated with different fiber volume contents (prepregs—47%, 55%, 60%, an...

  5. Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Hua [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Tang, Gang [School of Architecture and Civil Engineering, Anhui University of Technology, 59 Hudong Road, Ma’anshan, Anhui 243002 (China); Hu, Wei-Zhao; Wang, Bi-Bo; Pan, Ying [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Song, Lei, E-mail: leisong@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren’ai Road, Suzhou, Jiangsu 215123 (China)

    2015-08-30

    Highlights: • MCAHP was prepared and applied in polyamide 6. • MCA as the capsule material can improve the fire safety of AHP. • Flame retardant polyamide 6 composites with MCAHP show good flame retardancy. - Abstract: Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy.

  6. Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6

    International Nuclear Information System (INIS)

    Ge, Hua; Tang, Gang; Hu, Wei-Zhao; Wang, Bi-Bo; Pan, Ying; Song, Lei; Hu, Yuan

    2015-01-01

    Highlights: • MCAHP was prepared and applied in polyamide 6. • MCA as the capsule material can improve the fire safety of AHP. • Flame retardant polyamide 6 composites with MCAHP show good flame retardancy. - Abstract: Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy

  7. Sequence-specific 1H-NMR assignments for the aromatic region of several biologically active, monomeric insulins including native human insulin.

    Science.gov (United States)

    Roy, M; Lee, R W; Kaarsholm, N C; Thøgersen, H; Brange, J; Dunn, M F

    1990-06-12

    The aromatic region of the 1H-FT-NMR spectrum of the biologically fully-potent, monomeric human insulin mutant, B9 Ser----Asp, B27 Thr----Glu has been investigated in D2O. At 1 to 5 mM concentrations, this mutant insulin is monomeric above pH 7.5. Coupling and amino acid classification of all aromatic signals is established via a combination of homonuclear one- and two-dimensional methods, including COSY, multiple quantum filters, selective spin decoupling and pH titrations. By comparisons with other insulin mutants and with chemically modified native insulins, all resonances in the aromatic region are given sequence-specific assignments without any reliance on the various crystal structures reported for insulin. These comparisons also give the sequence-specific assignments of most of the aromatic resonances of the mutant insulins B16 Tyr----Glu, B27 Thr----Glu and B25 Phe----Asp and the chemically modified species des-(B23-B30) insulin and monoiodo-Tyr A14 insulin. Chemical dispersion of the assigned resonances, ring current perturbations and comparisons at high pH have made possible the assignment of the aromatic resonances of human insulin, and these studies indicate that the major structural features of the human insulin monomer (including those critical to biological function) are also present in the monomeric mutant.

  8. Ultrahigh gas storage both at low and high pressures in KOH-activated carbonized porous aromatic frameworks.

    KAUST Repository

    Li, Yanqiang; Ben, Teng; Zhang, Bingyao; Fu, Yao; Qiu, Shilun

    2013-01-01

    The carbonized PAF-1 derivatives formed by high-temperature KOH activation showed a unique bimodal microporous structure located at 0.6 nm and 1.2 nm and high surface area. These robust micropores were confirmed by nitrogen sorption experiment and high-resolution transmission electron microscopy (TEM). Carbon dioxide, methane and hydrogen sorption experiments indicated that these novel porous carbon materials have significant gas sorption abilities in both low-pressure and high-pressure environments. Moreover the methane storage ability of K-PAF-1-750 is among the best at 35 bars, and its low-pressure gas adsorption abilities are also comparable to the best porous materials in the world. Combined with excellent physicochemical stability, these materials are very promising for industrial applications such as carbon dioxide capture and high-density clean energy storage.

  9. Diversity of organotrophic bacteria, activity of dehydrogenases and urease as well as seed germination and root growth Lepidium sativum, Sorghum saccharatum and Sinapis alba under the influence of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Lipińska, Aneta; Wyszkowska, Jadwiga; Kucharski, Jan

    2015-12-01

    Polycyclic aromatic hydrocarbons are organic compounds with highly toxic, carcinogenic, and mutagenic properties, which adversely affect the basic biological parameters of the soil, including the count of microorganisms, and the enzymatic activity. In addition to disturbances to the biological activity of the soil, PAHs may also exhibit toxic effects on plants. In view of the above, the study involved testing aimed at the determination of the effects of polycyclic aromatic hydrocarbons in a form of naphthalene, phenanthrene, anthracene and pyrene on the count, colony development (CD) index, ecophysiological (EP) diversity index of organotrophic bacteria, and the activity of soil dehydrogenases and soil urease. Moreover, an attempt was made to determine the soil's resistance based on the activity of the above-listed enzymes, and the effect of polycyclic aromatic hydrocarbons on seed germination and root growth was assessed by Lepidium sativum, Sorghum saccharatum, and Sinapis alba. In addition, the species of bacteria found in a soil subjected to strong pressure of polycyclic aromatic hydrocarbons were isolated. The experiment was performed in a laboratory on samples of loamy sand. Polycyclic aromatic hydrocarbons were introduced into the soil in an amount of 0, 1000, 2000, and 4000 mg kg(-1) of soil dry matter. Germination and growth of cress (L. sativum), white mustard (S. alba), and sweet sorghum (S. saccharatum) were determined using Phytotoxkit tests. It was found that the tested PAHs increased the average colony counts of organotrophic soil bacteria; pyrene did so to the greatest extent (2.2-fold relative to non-contaminated soil), phenanthrene to the smallest extent (1.4-fold relative to non-contaminated soil). None of the PAHs changed the value of the bacterial colony development (CD) index, while anthracene and pyrene increased the value of the eco-physiological (EP) diversity indicator. PAHs lowered the activity of the tested enzymes. The activity of

  10. Drug-DNA adducts as biomarkers for metabolic activation of the nitro-aromatic nitrogen mustard prodrug PR-104A.

    Science.gov (United States)

    Stornetta, Alessia; Deng, Kai-Cheng Kieren; Danielli, Sara; Liyanage, H D Sarath; Sturla, Shana J; Wilson, William R; Gu, Yongchuan

    2018-04-07

    PR-104A is a clinical-stage nitrogen mustard prodrug that is activated for DNA alkylation by reduction of a nitro group to the corresponding hydroxylamine (PR-104H) or amine (PR-104M). Metabolic reduction is catalysed by flavoreductases such as cytochrome P450 oxidoreductase (POR) under hypoxia, or by aldo-ketoreductase 1C3 (AKR1C3) independently of hypoxia. The unstable reduced metabolites are challenging to measure in biological samples, and biomarkers of the metabolic activation of PR-104A have not been used in the clinical evaluation of PR-104 to date. Here, we employ a selected reaction monitoring mass spectrometry assay for DNA crosslinks to assess the capacity of human cancer cells to bioactivate PR-104A. We also test whether the more abundant DNA monoadducts could be used for the same purpose. DNA monoadducts and crosslinks from PR-104A itself, and from its reduced metabolites, accumulated over 4 h in AKR1C3-expressing TF1 erythroleukaemia cells under hypoxia, whereas intracellular concentrations of unstable PR-104H and PR-104M reached steady state within 1 h. We then varied rates of PR-104A reduction by manipulating hypoxia or reductase expression in a panel of cell lines, in which AKR1C3 and POR were quantified by targeted proteomics. Hypoxia or reductase overexpression induced large increases in PR-104A sensitivity (inhibition of proliferation), DNA damage response (γH2AX formation), steady-state concentrations of PR-104H/M and formation of reduced drug-DNA adducts but not DNA adducts retaining the dinitro groups of PR-104A. The fold-change in the sum of PR-104H and PR-104M correlated with the fold-change in reduced crosslinks or monoadducts (R 2  = 0.87 for both), demonstrating their potential for assessing the capacity of cancer cells to bioactivate PR-104A. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Technical guidelines on testing the migration of primary aromatic amines from polyamide kitchenware and of formaldehyde from melamine kitchenware

    DEFF Research Database (Denmark)

    Simoneau, C.; Hoekstra, E.; Bradley, E.

    Comparability of results is an important feature of the measurements carried out for official controls purposes. In the area of food contact materials and articles comparability of results is dependent on the availability of samples representative of a consignment, the type of exposure and the te...

  12. Microbial and molecular techniques to evaluate and to implement in-situ biodegradation potential and activity at sites contaminated with aromatic and chlorinated hydrocarbons

    International Nuclear Information System (INIS)

    Karg, F.; Henkler, Ch.

    2005-01-01

    Intrinsic bio-remediation harnesses the ability of indigenous microorganisms to degrade contaminants that are present in soil and groundwater. Over the past decade many environmental regulatory agencies especially in Europe have come to recognize the importance of these natural processes in contaminant attenuation. In order to use in-situ bio-remediation to clean up a site successfully it is necessary to investigate the indigenous microbial population and its potential activity to degrade the contaminants of concern (COCs). The evaluation of naturally-occurring degradative activity in initial screening of soil and groundwater samples using recently developed molecular and microbial methods may allow for the implementation of a contaminant reduction and management program without the need for fully engineered remediation intervention. Limited engineering approaches (nutrient delivery etc.) can be implemented to support naturally-occurring bio-restoration processes to achieve a controlled, dynamic attenuation of COCs. Techniques for monitoring pollutant-degrading microorganisms were previously limited to standard culturing techniques. More recently, techniques based upon detection of genetic elements and metabolic activities have been developed in collaboration with university partners Europe, especially in France. The modern techniques are more sensitive for monitoring microbial populations, metabolic activity and the genetic potential to degrade the COCs, and avoid the need for cultivation of microbes under artificial conditions in the laboratory. Especially the application of PCR-Tests (Polymerase Chain Reaction) are able to quantify the Genetic Potential of Pollutant Microbiological Degradation on a contaminated site. This enables to use very economic in-situ site rehabilitation strategies as for example (Dynamic Natural Attenuation). For this modern application of these new strategies PLANREAL created with HPC Envirotec and together with a French University

  13. Impact of Increased Thermokarst Activity on Polycyclic Aromatic Compound (PAC) Accumulation in Sediment of Lakes in the Hydrocarbon-Rich Uplands Adjacent to the Mackenzie Delta, NT, Canada

    Science.gov (United States)

    Eickmeyer, D.; Thienpont, J. R.; Blais, J. M.

    2017-12-01

    In ecologically sensitive, hydrocarbon-rich regions like the western Canadian Arctic, environmental monitoring of oil and gas development often focuses on both direct and unintentional consequences of increased exploration and extraction of hydrocarbon resources. However, proper assessments of impact from these activities could be confounded by natural petrogenic sources in permafrost-rich regions where increased thermokarst activity results in permafrost exposure and erosion of hydrocarbon-rich deposits. Using a paired-lake design in the tundra uplands adjacent to the Mackenzie Delta, NT, we examined 4 lakes with retrogressive thaw slump scars along their shores, and 4 nearby undisturbed reference lakes, focusing on polycyclic aromatic compound (PAC) deposition and composition in the sediment. Total organic carbon (TOC)-normalized concentrations for parent and alkylated PACs were higher in surface sediments of slump-affected lakes than the reference lakes. This followed the pattern previously observed for persistent organic pollutants in these lakes where presence of thaw slumps on the lake shore was associated with lower TOC content in the water column, resulting in a smaller pool of available organic carbon, leading to higher PAC concentrations. Diagnostic ratios of specific PACs also suggested the sediment of slump-affected lakes had greater influence from petroleum-based PAC sources than their reference counterparts. This interpretation was corroborated by a principle components analysis of the metal content in the sediment. Slump-affected lakes were enriched in metals related to shale-based, Quaternary deposits of the Mackenzie Basin (e.g. Ca, Sr, Mg) when compared to reference lakes where these surficial materials were not exposed by thermokarst activity. Higher PAC concentrations and composition indicative of petrogenic sources observed in sediment of slump-affected lakes were best explained as a combination of low TOC availability and increased inputs of

  14. High-performance polyamide thin-film-nanocomposite reverse osmosis membranes containing hydrophobic zeolitic imidazolate framework-8

    KAUST Repository

    Duan, Jintang; Pan, Yichang; Pacheco Oreamuno, Federico; Litwiller, Eric; Lai, Zhiping; Pinnau, Ingo

    2015-01-01

    A hydrophobic, hydrothermally stable metal-organic framework (MOF) - zeolitic imidazolate framework-8 (ZIF-8) was successfully incorporated into the selective polyamide (PA) layer of thin-film nanocomposite (TFN) membranes for water desalination

  15. Investigations on the remains of polycyclic aromatic hydrocarbons in contaminated soils after the addition of micro-organisms active in decomposition

    International Nuclear Information System (INIS)

    Mahro, B.; Kaestner, M.; Breuer-Jammali, M.; Schaefer, G.; Kasche, V.

    1993-01-01

    The microbial decomposition of polycyclic aromatic hydrocarbons (PAH's) by bacteria and fungi was previously mainly examined in liquid cultures. In examining the microbial decomposition of PAH's in the soil, analytical problems arise. The disappearance of the PAH's or other xenobiotica in soil cultures cannot be regarded as equivalent to biological decomposition, as absorption phenomena in the soil also have to be regarded. (orig.) [de

  16. The Homocoupling Reaction of Aromatic Terminal Alkynes by a Highly Active Palladium(II)/AgNO₃ Cocatalyst in Aqueous Media Under Aerobic Conditions.

    Science.gov (United States)

    Guo, Mengping; Chen, Bo; Lv, Meiyun; Zhou, Xiuling; Wen, Yongju; Shen, Xiuli

    2016-05-10

    A new and efficient Pd(II)/AgNO₃-cocatalyzed homocoupling of aromatic terminal alkynes is described. Various symmetrical 1,4-disubstituted-1,3-diynes are obtained in good to excellent yields. This protocol employs a loading with relatively low palladium(II) in aqueous media under aerobic conditions.

  17. UV excimer laser and low temperature plasma treatments of polyamide materials

    Science.gov (United States)

    Yip, Yiu Wan Joanne

    Polyamides have found widespread application in various industrial sectors, for example, they are used in apparel, home furnishings and similar uses. However, the requirements for high quality performance products are continually increasing and these promote a variety of surface treatments for polymer modification. UV excimer laser and low temperature plasma treatments are ideally suited for polyamide modification because they can change the physical and chemical properties of the material without affecting its bulk features. This project aimed to study the modification of polyamides by UV excimer laser irradiation and low temperature plasma treatment. The morphological changes in the resulting samples were analysed by scanning electron microscopy (SEM) and tapping mode atomic force microscopy (TM-AFM). The chemical modifications were studied by x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and chemical force microscopy (CFM). Change in degree of crystallinity was examined by differential scanning calorimetry (DSC). After high-fluence laser irradiation, topographical results showed that ripples of micrometer size form on the fibre surface. By contrast, sub-micrometer size structures form on the polyamide surface when the applied laser energy is well below its ablation threshold. After high-fluence laser irradiation, chemical studies showed that the surface oxygen content of polyamide is reduced. A reverse result is obtained with low-fluence treatment. The DSC result showed no significant change in degree of crystallinity in either high-fluence or low-fluence treated samples. The same modifications in polyamide surfaces were studied after low temperature plasma treatment with oxygen, argon or tetrafluoromethane gas. The most significant result was that the surface oxygen content of polyamide increased after oxygen and argon plasma treatments. Both treatments induced many hydroxyl (-OH) and carboxylic acid (-COOH

  18. Electronic properties of polyamide-PPy/metal junction and electrical conductivity of a typical sample at low temperatures

    International Nuclear Information System (INIS)

    Suenel, N.; Sedef, A.G.; Parlak, M.; Toppare, L.

    2005-01-01

    Electronic properties of junctions fabricated by polyamide-polypyrrole composite films polymerized with adjusted doping concentration and various metal contacts (In, Al, Au and Ag) were investigated. For the junctions giving good rectification I 0 , n and φ b were specified. Conductivity of polyamide-polypyrrole composite polymer was obtained as a function of temperature in the 70-320 K range and was found to obey the VRH model. In addition the Mott parameters were evaluated

  19. Electronic properties of polyamide-PPy/metal junction and electrical conductivity of a typical sample at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Suenel, N. [Gaziosmanpasa University, Physics Department, Tasliciftlik Kampasu, Tokat (Turkey)]. E-mail: nsunel@gop.edu.tr; Sedef, A.G. [Gaziosmanpasa University, Physics Department, Tasliciftlik Kampasu, Tokat (Turkey); Parlak, M. [Middle East Technical University, Physics Department, Ankara (Turkey); Toppare, L. [Middle East Technical University, Chemistry Department, Ankara (Turkey)

    2005-05-15

    Electronic properties of junctions fabricated by polyamide-polypyrrole composite films polymerized with adjusted doping concentration and various metal contacts (In, Al, Au and Ag) were investigated. For the junctions giving good rectification I{sub 0}, n and {phi}{sub b} were specified. Conductivity of polyamide-polypyrrole composite polymer was obtained as a function of temperature in the 70-320 K range and was found to obey the VRH model. In addition the Mott parameters were evaluated.

  20. Preparation and Characterization of Polyurethane-Polydimethylsiloxane/Polyamide12-b-Polytetramethylene Glycol Blend Membranes for Gas Separation

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Semsarzadeh*

    2013-07-01

    Full Text Available Blend membranes of synthesized polyurethane based on toluene diisocyanate (TDI, polydimethylsiloxane (PDMS and polytetramethylene glycol (PTMG with polyamide12-b-PTMG were prepared by solution casting technique. The synthesized polyurethane-polydimethylsiloxane and PU-PDMS/polyamide12-b-PTMG blend membranes were characterized by Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC and scanning electron microscopy (SEM. In the FTIR spectrum of the synthesized PU-PDMS, the disappearance of NCO stretching vibration at 2270 cm−1 was used to confirm the completion of the reaction. According to our DSC results, the use of higher polyamide12-b-PTMG content in PU-PDMS/polyamide12-b-PTMG blends led to greater compatibility between the two phases. The SEM images showed that the blends with polyamide12-b-PTMG (20 wt% were significantly more homogeneous in the micrometric scale compared to other samples. Gas transport properties have been determined for N2, CO2 and He gases and the obtained permeability values were correlated with the properties of the blends. The comparison of the results with that of the pure PU-PDMS membrane showed that the blend membranes had a higher permeability toward CO2 and lower toward N2 gas. The blend membrane with 20 wt% polyamide12-b-PTMG showed higher CO2 permeability (≈105 Barrer compared to PU-PDMS membrane. By introduction of polyamide12-b-PTMG into PU-PDMS matrix a perceptible rise in helium ideal selectivity of the blend membranes was observed. In blend membranes with 5-20 wt% polyamide12-b-PTMG contents, an enhancement of CO2/N2 (244%, He/N2 (20% and CO2/He (103% selectivity factor was observed. The experimental permeability values of the blend membranes were compared with the calculated permeability based on a modified additive logarithmic model.

  1. Discovering Chemical Aromaticity Using Fragrant Plants

    Science.gov (United States)

    Schneider, Tanya L.

    2010-01-01

    Introductory organic chemistry is often perceived as inaccessible by students. This article describes a method used to link organic chemistry to everyday experience, asking students to explore whether fragrant molecules are also aromatic in the chemical sense. Students were engaged in this activity, excited about their results, and performed well…

  2. Aromatization of propane over MFI-gallosilicates

    NARCIS (Netherlands)

    Bayense, C.R.; vd Pol, A.J.H.P.; Hooff, van J.H.C.

    1991-01-01

    The results of propane aromatization over gallium containing HZSM-5 zeolites are described. Highly dispersed gallium in the zeolite (framework or extra-framework) was found to possess dehydrogenation activity, especially in the presence of strong Brønsted acid sites. The extra-framework gallium was

  3. Reactive microencapsulation of carbon allotropes in polyamide shell-core structures and their transformation in hybrid composites with tailored electrical properties

    Directory of Open Access Journals (Sweden)

    F. Oliveira

    2016-02-01

    Full Text Available Polyamide 6 microcapsules (PAMC loaded with 2–10 wt% of different carbon allotropes: carbon black, multiwalled carbon nanotubes, carbon nanofibers and graphite were synthesized via activated anionic polymerization (AAROP of ε-caprolactam in solution performed in the presence of the respective micro- or nanosized loads. The forming high-molecular weight microporous PAMC showed typical diameters of 15–35 µm, the filler particles being entrapped in the core as proven by microscopy methods. The melt processing of the loaded microcapsules produced PA6/C-filler hybrid thermoplastic composites with homogeneous distribution of one or two C-fillers even at loads of up to 10% without any functionalization. The crystalline structure of all PAMC and molded composites was studied by thermal and X-ray diffraction methods focusing on possible structure modification during the transition from PAMC to molded plates. Mechanical tests in tension and electrical conductivity measurements showed that transforming loaded PAMC into composites by melt processing could be a facile and rapid method to fabricate polyamide composites with improved mechanical performance and tailored electrical and dielectric properties.

  4. Controlled Surface Modification of Polyamide 6.6 Fibres Using CaCl2/H2O/EtOH Solutions

    Directory of Open Access Journals (Sweden)

    Barbara Rietzler

    2018-02-01

    Full Text Available Polyamide 6.6 is one of the most widely used polymers in the textile industry due to its durability; however, it has rather limited modification potential. In this work, the controlled surface modification of polyamide 6.6 fibres using the solvent system CaCl2/H2O/EtOH was studied. The effects of solvent composition (relative proportions of the three components and treatment time on fibre properties were studied both in situ (with fibres in solvent and ex situ (after the solvent was washed off. The fibres swell and/or dissolve in the solvent depending on its composition and the treatment time. We believe that the fibre–solvent interaction is through complex formation between the fibre carbonyl groups and the CaCl2. On washing, there is decomplexation and precipitation of the polymer. The treated fibres exhibit greater diameters and surface roughness, structural difference between an outer shell and an inner core is observable, and water retention is higher. The solvent system is more benign than current alternatives, and through suitable tailoring of the treatment conditions, e.g., composition and time, it may be used in the design of advanced materials for storage and release of active substances.

  5. Birds and polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Albers, P.H.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAH) are present throughout the global environment and are produced naturally and by activities of humans. Effects of PAH on birds have been determined by studies employing egg injection, egg immersion, egg shell application, single and multiple oral doses, subcutaneous injection, and chemical analysis of field-collected eggs and tissue. The four-to six-ring aromatic compounds are the most toxic to embryos, young birds, and adult birds. For embryos, effects include death, developmental abnormalities, and a variety of cellular and biochemical responses. For adult and young birds, effects include reduced egg production and hatching, increased clutch or brood abandonment, reduced growth, increased organweights, and a variety of biochemical responses. Trophic level accumulation is unlikely. Environmental exposure to PAH in areas of high human population or habitats affected by recent petroleum spills might be sufficient to adversely affect reproduction. Evidence of long-term effects of elevated concentrations of environmental PAH on bird populations is very limited and the mechanisms of effect are unclear.

  6. Mixed field radiation effects on dry and acidic solution saturated polyamide 6,6

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ont., K7K 7B4 (Canada); Bonin, H.W. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ont., K7K 7B4 (Canada)]. E-mail: bonin-h@rmc.ca; Bui, V.T. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ont., K7K 7B4 (Canada)

    2005-05-15

    The disposal of Canada's radioactive waste materials has been the focus of ongoing research at the Royal Military College of Canada, in the use of polymer-based composite materials for the fabrication of disposal containers. An evaluation of the performance of polyamide 6,6 after exposure to radiation and acidic aqueous solutions provides the basis for the assessment of the lifetime performance of a polymeric-based storage container. This work demonstrates the importance of the combined effects of aqueous solution diffusion and radiation exposure on the mechanical performance and molecular structure of polyamide 6,6. Irradiation of dry samples initially results in a marked reduction of mechanical performance, however, post-irradiation aging allows for the return to pre-irradiation mechanical strength. Samples irradiated after exposure to either distilled water or 0.1 M sulfuric acid solutions exhibited increases in mechanical performance upon exposure to a mixed field radioactive environment.

  7. Mixed field radiation effects on dry and acidic solution saturated polyamide 6,6

    International Nuclear Information System (INIS)

    Brown, L.; Bonin, H.W.; Bui, V.T.

    2005-01-01

    The disposal of Canada's radioactive waste materials has been the focus of ongoing research at the Royal Military College of Canada, in the use of polymer-based composite materials for the fabrication of disposal containers. An evaluation of the performance of polyamide 6,6 after exposure to radiation and acidic aqueous solutions provides the basis for the assessment of the lifetime performance of a polymeric-based storage container. This work demonstrates the importance of the combined effects of aqueous solution diffusion and radiation exposure on the mechanical performance and molecular structure of polyamide 6,6. Irradiation of dry samples initially results in a marked reduction of mechanical performance, however, post-irradiation aging allows for the return to pre-irradiation mechanical strength. Samples irradiated after exposure to either distilled water or 0.1 M sulfuric acid solutions exhibited increases in mechanical performance upon exposure to a mixed field radioactive environment

  8. Preparation and characterization of new polyamide/montmorillonite nanocomposites containing azo moiety in the main chain

    Directory of Open Access Journals (Sweden)

    Khalil Faghihi

    2016-11-01

    Full Text Available Two new samples of polyamide/montmorillonite reinforced nanocomposites containing 4,4′-azobenzoic acid moiety in the main chain were synthesized by a convenient solution intercalation technique. Polyamide (PA 4 as a source of polymer matrix was synthesized by the direct polycondensation reaction of 4,4′-azobenzoic acid 2 with 4,4′-diamino diphenyl ether 3 in the presence of triphenyl phosphite (TPP, CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP. Morphology and structure of the resulting PA-nanocomposite films 4a and 4b with 10 and 20% silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV–vis spectroscopy, thermogravimetric analysis (TGA and water uptake measurements.

  9. Evaluation of rheological behavior and structure of nanocomposites with polymer matrices of polyamide 6 and polyethylene

    International Nuclear Information System (INIS)

    Cavalcanti, Shirley N.; Araujo, Edcleide M.; Paz, Rene A.; Gouveia, Taciana R.; Oliveira, Sara V.; Souza, Dayanne D. de

    2009-01-01

    The objective of this study was to evaluate the results of the obtention of nanocomposites from the system of high density polyethylene (PEAD)/polyamide 6/organoclay, using concentrations of (5 and 10wt.%) compatibilizer PE-g-MA, the organoclay was organophilizate with the quaternary ammonium salt Genamin and mixtures were prepared in a twin screw counter rotating extruder, coupled to a Haake torque rheometer. The rheological behavior of the blends and the nanocomposites was evaluated by torque rheometer. The degree of dispersion of clay in the blend (polyamide 6 and PE) was evaluated by x-ray diffraction (XRD). In general, it was observed an increase in viscosity for the compositions containing the compatibilizer, and the results of XRD showed that the systems presented an intercalated and/or exfoliated structure. (author)

  10. Preparation and Characterization of Silica/Polyamide-imide Nanocomposite Thin Films

    Directory of Open Access Journals (Sweden)

    Hwang Jong-Sun

    2010-01-01

    Full Text Available Abstract The functional silica/polyamide-imide composite films were prepared via simple ultrasonic blending, after the silica nanoparticles were modified by cationic surfactant—cetyltrimethyl ammonium bromide (CTAB. The composite films were characterized by scanning electron microscope (SEM, thermo gravimetric analysis (TGA and thermomechanical analysis (TMA. CTAB-modified silica nanoparticles were well dispersed in the polyamide-imide matrix, and the amount of silica nanoparticles to PAI was investigated to be from 2 to 10 wt%. Especially, the coefficients of thermal expansion (CET continuously decreased with the amount of silica particles increasing. The high thermal stability and low coefficient of thermal expansion showed that the nanocomposite films can be widely used in the enamel wire industry.

  11. Optical, thermal and combustion properties of self-colored polyamide nanocomposites reinforced with azo dye surface modified ZnO nanoparticles

    Science.gov (United States)

    Hajibeygi, Mohsen; Shabanian, Meisam; Omidi-Ghallemohamadi, Mehrdad; Khonakdar, Hossein Ali

    2017-09-01

    New self-colored aromatic-polyamide (PA) nanocomposites containing azo and naphthalene chromophores were prepared with azo-dye surface-modified ZnO nanoparticles (SMZnO) using solution method in dimethylformamide. The X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results showed the uniform distribution for ZnO nanoparticles in the PA matrix. The UV-vis spectra of PA/ZnO nanocomposites (PANC) showed a blue shift as well as reduction in absorbance intensities and the photoluminescence studies revealed that the increasing intensities of the violet emission in SMZnO loading. From thermo gravimetric analysis (TGA), the temperature at 10% mass loss (T10) increased from 291.8 °C to 387.6 °C for PANC containing 8 mass% of SMZnO, as well as the char yield enhanced significantly, which was about 23.5% higher than the neat PA. The peak heat release rate resulted from microscale combustion calorimeter (MCC), by 8 mass% loading of SMZnO, decreased about 56.9% lower than the neat PA.

  12. Combined Experimental and Theoretical Investigations on Optical Activities of Möbius Aromatic and Möbius Antiaromatic Hexaphyrin Phosphorus Complexes.

    Science.gov (United States)

    Mori, Tadashi; Tanaka, Takayuki; Higashino, Tomohiro; Yoshida, Kota; Osuka, Atsuhiro

    2016-06-23

    Intrinsically chiral Möbius aromatic [28]hexaphyrin monophosphorus(V) and Möbius antiaromatic [30]hexaphyrin bisphosphorus(V) complexes have been optically resolved and their absolute configurations (ACs) were determined by combined experimental and theoretical investigations on their circular dichroisms (CDs). First elutes in chiral HPLC exhibited strong positive Cotton effects (CEs) at the B-band, characteristic for the ML configurations in their Möbius strips. Weak CEs at the Q-band, if attainable, complemented their AC assignment. The whole CD pattern and intensity were well reproduced by time-dependent approximate coupled cluster theory using model systems that omit five outward meso-aryl substituents (inward-meso-retained model), providing a solid basis for AC assignment. The cost efficient TD-DFT method with appropriate functionals for fully substituted (nontruncated) complexes well reproduced CEs around the B-band (but less satisfactory at the Q-band), also allows the rapid AC estimation for their Möbius strips. Observed difference in CDs between aromatic and antiaromatic hexaphyrins were better interpreted by their shifts in energy levels and altered interactions of relevant molecular orbitals, rather than small differences in Möbius geometries nor aromatic/antiaromatic character, despite the correlations recently claimed in planar π-systems.

  13. Enhancing the cellular uptake of Py–Im polyamides through next-generation aryl turns

    OpenAIRE

    Meier, Jordan L.; Montgomery, David C.; Dervan, Peter B.

    2012-01-01

    Pyrrole–imidazole (Py–Im) hairpin polyamides are a class of programmable, sequence-specific DNA binding oligomers capable of disrupting protein–DNA interactions and modulating gene expression in living cells. Methods to control the cellular uptake and nuclear localization of these compounds are essential to their application as molecular probes or therapeutic agents. Here, we explore modifications of the hairpin γ-aminobutyric acid turn unit as a means to enhance cellular uptake and biologica...

  14. Study of the effect of ionizing radiation on properties of polyamide 6 with fibreglass reinforcement

    International Nuclear Information System (INIS)

    Pinto, Clovis

    2007-01-01

    It is each time more common the use of polymers reinforced with fibreglass in the domestic market. Between them it is used polyamide 6 that it presents good tension resistance, to the impact and the humidity absorption compared with non-reinforced, being also at the present time used in the automobile industry in parts underneath the hood, especially in the radiator frames. The aim of this work is to study the effect of ionizing radiation on properties of polyamide 6 with fibreglass reinforcement, undergone to different radiation doses. Samples were prepared and irradiated on JOB 188 accelerator with an electron beam energy of 1.5 MeV in air with different doses (100 to 600 kGy) and a dose rate of 22.61 kGy/h. Afterward the irradiation, the properties of the samples of irradiated polyamide 6 with fibreglass reinforcement were evaluated and compared with the samples non-irradiated. It evidenced that the mechanical properties flexural resistance and tension resistance increased and the resistance to the impact decreased. Regarding the thermal properties of the temperature of fusing decreased of 224,4 deg C for 212,5 deg C but the loss of mass ahead of the constant increase of the temperature also decreased. In the property of resistance to the glow wire the polyamide 6 with fibreglass reinforcement had a good performance. The images caught for Scanning Electronic Microscopy show that the irradiation provoked a good integration enters the fibreglass and polymer what was responsible for the good performance in the property of resistance to the glow wire. (author)

  15. Effect of graphene oxide on structure and properties of impact-modified polyamide 6

    Czech Academy of Sciences Publication Activity Database

    Kelnar, Ivan; Kratochvíl, Jaroslav; Kaprálková, Ludmila; Špitálsky, Z.; Ujčić, Massimo; Zhigunov, Alexander; Nevoralová, Martina

    2018-01-01

    Roč. 57, č. 9 (2018), s. 827-835 ISSN 0360-2559 R&D Projects: GA ČR(CZ) GA16-03194S Institutional support: RVO:61389013 Keywords : graphene oxide * morphology * polyamide 6 Subject RIV: JI - Composite Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 1.232, year: 2016

  16. Study of nanocomposites prepared from polyamides and biodegradable polyesters and poly(ester amide)s

    OpenAIRE

    Morales Gámez, Laura Teresa

    2012-01-01

    Premi extraordinari doctorat curs 2011-2012, àmbit d’Enginyeria Industrial Polymer clay nanocomposites of polyamides and biodegradable polymers with three kinds of organomodified clays were prepared by different techniques (in situ polymerization, solution casting, and melt mixing). The polymers used in this research were nylons 56, 65 and 47 and the biodegradable polymers: poly (glycolic acid-alt-6-hydrohexanoic acid) and poly(glycolic acid-alt-6-aminohexanoic acid). The developmen...

  17. An electron beam irradiation method for modification of surface electrical resistivity of polyamides

    International Nuclear Information System (INIS)

    Brasoveanu, M. M.; Timus, D.; Nemtanu, M. R.

    2002-01-01

    The synthetic textiles which have mechanical and processing properties and a low price are very useful and consequently in high demand. The low antistatic qualities are an important disadvantage, but not impossible to eliminate. The aim of paper is the study of modification the antistatic properties of polyamide by grafting of monomers by irradiation. Twisted and unthermofixed polyamide-6 fibre from CFS Savinesti were investigated. The samples of polyamide were irradiated with an electron beam from the ALIN-7 linear accelerator of Electron Accelerators Laboratory of National Institute for Lasers, Plasma and Radiation Physics, Bucharest. Immediately after irradiation, the samples were measured by electron spin resonance (ESR). ESR spectra were recorded at room temperature using a Jeol spectrometer, JES-ME-3X, with 100 kHz modulation. In polyamide-6 at least two irradiation defect types occurred which present EPR signal by electron beam irradiation. Unstable centres of type A presenting an incompletely resolved hyperfine structure can be attributed to radicals -N-CH 2 - or -NH-CH-CH 2 -. Both radicals can present at room temperature a five-line spectrum like the radical formed in this work. First radical appears with very low probability and if the free bond is at one of carbon atoms then it will be stabilized immediately in a position from nitrogen. These type A radicals can appear in same zone and then they can react and form unsaturated bonds or bridge between the polymeric chains. Thus, it will appear the type B defects which were more stabile and without structure. On these double chains one can graft vinylic monomers even after time intervals longer from irradiation. (authors)

  18. Reuse of effluent from dyeing process of polyamide fibers modified by double barrier discharge (DBD) plasma

    OpenAIRE

    Oliveira, Fernando Ribeiro; Steffens, F.; Souto, A. Pedro; Zille, Andrea

    2016-01-01

    Published online: 27 Feb 2015 Low-temperature plasma technology becomes more and more attractive compared with traditional wet processes in textile preparation and finishing due to its high efficiency and low environmental impact. The objective of this study was to investigate the influence of dielectric barrier discharge plasma treatment on the trichromic dyeing process of polyamide 6.6 (PA66) and the reuse of the generated effluents for new dyeing processes. Chemical and physical charact...

  19. Optimization of preparation conditions of polyamide thin film composite membrane for organic solvent nanofiltration

    International Nuclear Information System (INIS)

    Namvar-Mahboub, Mahdieh; Pakizeh, Majid

    2014-01-01

    Separation performance of polyamide composite membranes is affected by several parameters during formation of thin upper layer via interfacial polymerization. We investigated the effect of various polyamide synthesis conditions on the performance of organic solvent resistant polyamide composite membranes through the model equations designed by 2-level fractional factorial design. The dewaxing solvent recovery was selected as separation process. Five factors were changed in two level includin; TMC concentration (0.05-0.1%), MPD concentration (1-2%), support immersion time in organic solution (2-4 min), support immersion time in aqueous solution (1-2 min), and curing temperature (70-80 .deg. C). The resultant equations showed 93.48% and 94.82% of the variability (R 2 adj ) in data used to fit oil rejection and permeate flux models, respectively. The analysis of variance revealed that both models were high significant. It was also observed that TMC concentration, MPD concentration and immersion time in TMC have more pronounced effect on the oil rejection and permeate flux than other factors and interactions. Optimal polyamide preparation conditions were obtained using multiple response method for 94% oil rejection as target value. According to the results, the best value of permeate flux (8.86 l/(m 2 ·h)) was found at TMC concentration of 0.1%, MPD concentration of 1.94%, immersion time in TMC of 3.88 min, immersion time in MPD of 1.95 min and curing temperature of 71.96 .deg. C with desirability factor of 1

  20. Study of the ionizing radiation effect on the polyamide 6,6 mechanical properties

    International Nuclear Information System (INIS)

    Colombo, Maria Aparecida da Silva

    2004-01-01

    Polyamide 6,6 due to its excellent mechanical, thermal and electrical properties and its great performance in multiple industrial applications is considered one of the most important engineering polymers. However, in specific applications, some of its properties need to be improved by means additives or fillers to reach the required properties increasing its final cost. By these considerations, the aim of this work was to apply the ionizing radiation to improve the natural mechanical properties of polyamide 6,6. Also, to evaluate the irradiation parameters, and the mechanical performance of the irradiated polymer in order to use the cross-linking, induced by ionizing radiation, as substitute of additives and fillers. Row polyamide 6,6 samples, for mechanical tests, were prepared by injection molded and then irradiated with high energetic electrons to reach doses of 70, 100, 150, and 200 kGy. The mechanical performance, of non-irradiated and irradiated samples, was evaluated by tensile strength, impact, hardness and wear measurements. Furthermore, hardness and wear tests were carried out with samples, which were immersed in petroleum and sea water for 6 months. The experimental results have shown that, in the studied dose range, the tensile strength increases 25%, the hardness Shore D 15%, the impact values diminished by 80% and the wear values decreased 20 times between 0 and 200 kGy. The effect of the petroleum and sea water were shown mainly in the nonirradiated samples. (author)

  1. Proton Conductive Channel Optimization in Methanol Resistive Hybrid Hyperbranched Polyamide Proton Exchange Membrane

    Directory of Open Access Journals (Sweden)

    Liying Ma

    2017-12-01

    Full Text Available Based on a previously developed polyamide proton conductive macromolecule, the nano-scale structure of the self-assembled proton conductive channels (PCCs is adjusted via enlarging the nano-scale pore size within the macromolecules. Hyperbranched polyamide macromolecules with different size are synthesized from different monomers to tune the nano-scale pore size within the macromolecules, and a series of hybrid membranes are prepared from these two micromoles to optimize the PCC structure in the proton exchange membrane. The optimized membrane exhibits methanol permeability low to 2.2 × 10−7 cm2/s, while the proton conductivity of the hybrid membrane can reach 0.25 S/cm at 80 °C, which was much higher than the value of the Nafion 117 membrane (0.192 S/cm. By considering the mechanical, dimensional, and the thermal properties, the hybrid hyperbranched polyamide proton exchange membrane (PEM exhibits promising application potential in direct methanol fuel cells (DMFC.

  2. Primary aromatic amines (PAAs) in black nylon and other food-contact materials, 2004-2009

    DEFF Research Database (Denmark)

    Trier, Xenia Thorsager; Okholm, B.; Foverskov, Annie

    2010-01-01

    Primary aromatic amines (PAAs) were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in migrates from 234 samples of food-contact materials, including black nylon (polyamide) kitchen utensils (n = 136), coloured plastics (28), and clear/printed multilayer film/laminates (41......), from retailers, importers, and food producers. A further 29 utensils in use were obtained from colleagues. Very high PAA migration was found from black nylon kitchen utensils to the food simulant 3% acetic acid: the 'non-detectable' limit (20 mu g aniline equivalents kg-1 food) was exceeded by up...... migration test conditions influenced the final test results. Long-term release of PAAs was fitted by diffusion modelling experiments and long-term release was also seen as expected from used utensils. Toxicologists consider these migration levels of the suspected carcinogenic PAAs as a problem of major...

  3. Allosteric analysis of glucocorticoid receptor-DNA interface induced by cyclic Py-Im polyamide: a molecular dynamics simulation study.

    Directory of Open Access Journals (Sweden)

    Yaru Wang

    Full Text Available BACKGROUND: It has been extensively developed in recent years that cell-permeable small molecules, such as polyamide, can be programmed to disrupt transcription factor-DNA interfaces and can silence aberrant gene expression. For example, cyclic pyrrole-imidazole polyamide that competes with glucocorticoid receptor (GR for binding to glucocorticoid response elements could be expected to affect the DNA dependent binding by interfering with the protein-DNA interface. However, how such small molecules affect the transcription factor-DNA interfaces and gene regulatory pathways through DNA structure distortion is not fully understood so far. METHODOLOGY/PRINCIPAL FINDINGS: In the present work, we have constructed some models, especially the ternary model of polyamides+DNA+GR DNA-binding domain (GRDBD dimer, and carried out molecular dynamics simulations and free energy calculations for them to address how polyamide molecules disrupt the GRDBD and DNA interface when polyamide and protein bind at the same sites on opposite grooves of DNA. CONCLUSIONS/SIGNIFICANCE: We found that the cyclic polyamide binding in minor groove of DNA can induce a large structural perturbation of DNA, i.e. a >4 Å widening of the DNA minor groove and a compression of the major groove by more than 4 Å as compared with the DNA molecule in the GRDBD dimer+DNA complex. Further investigations for the ternary system of polyamides+DNA+GRDBD dimer and the binary system of allosteric DNA+GRDBD dimer revealed that the compression of DNA major groove surface causes GRDBD to move away from the DNA major groove with the initial average distance of ∼4 Å to the final average distance of ∼10 Å during 40 ns simulation course. Therefore, this study straightforward explores how small molecule targeting specific sites in the DNA minor groove disrupts the transcription factor-DNA interface in DNA major groove, and consequently modulates gene expression.

  4. Activation of the aryl hydrocarbon receptor is the major toxic mode of action of an organic extract of a reference urban dust particulate matter mixture: The role of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Andrysik, Zdenek; Vondracek, Jan; Marvanova, Sona; Ciganek, Miroslav; Neca, Jiri; Pencikova, Katerina; Mahadevan, Brinda; Topinka, Jan; Baird, William M.; Kozubik, Alois; Machala, Miroslav

    2011-01-01

    Highlights: → SRM1649a extract and its fractions are potent activators of AhR in a model of epithelial cells. → AhR-dependent effects include both induction of CYP1 enzymes and disruption of cell proliferation control. → Polycyclic aromatic hydrocarbons present in the neutral SRM1649a fraction are major contributors to the AhR-mediated toxic effects. → Activation of AhR and related nongenotoxic effects occur at significantly lower doses than the formation of DNA adducts and activation of DNA damage response. → More attention should be paid to the AhR-dependent nongenotoxic events elicited by urban particulate matter constituents. - Abstract: Many of the toxic and carcinogenic effects of urban air pollution have been linked to polycyclic aromatic hydrocarbons (PAHs) adsorbed to airborne particulate matter (PM). The carcinogenic properties of PAHs in complex organic mixtures derived from PM have been chiefly attributed to their mutagenicity. Nevertheless, PAHs are also potent activators of the aryl hydrocarbon receptor (AhR), which may contribute to their nongenotoxic effects, including tumor promotion. As the genotoxicity of carcinogenic PAHs in complex mixtures derived from urban PM is often inhibited by other mixture constituents, the AhR-mediated activity of urban PM extracts might significantly contribute to the carcinogenic activity of such mixtures. In the present study, we used an organic extract of the urban dust standard reference material, SRM1649a, as a model mixture to study a range of toxic effects related to DNA damage and AhR activation. Both the organic extract and its neutral aromatic fraction formed a low number of DNA adducts per nucleotide in the liver epithelial WB-F344 cells model, without inducing DNA damage response, such as tumor suppressor p53 activation and apoptosis. In contrast, we found that this extract, as well as its neutral and polar fractions, were potent inducers of a range of AhR-mediated responses, including induction

  5. Polyamide desalination membrane characterization and surface modification to enhance fouling resistance.

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mukul M. (Univeristy of Texas at Austin, Austin, TX); Freeman, Benny D. (Univeristy of Texas at Austin, Austin, TX); Van Wagner, Elizabeth M. (Univeristy of Texas at Austin, Austin, TX); Hickner, Michael A. (Pennsylvania State University, University Park, PA); Altman, Susan Jeanne

    2010-08-01

    The market for polyamide desalination membranes is expected to continue to grow during the coming decades. Purification of alternative water sources will also be necessary to meet growing water demands. Purification of produced water, a byproduct of oil and gas production, is of interest due to its dual potential to provide water for beneficial use as well as to reduce wastewater disposal costs. However, current polyamide membranes are prone to fouling, which decreases water flux and shortens membrane lifetime. This research explored surface modification using poly(ethylene glycol) diglycidyl ether (PEGDE) to improve the fouling resistance of commercial polyamide membranes. Characterization of commercial polyamide membrane performance was a necessary first step before undertaking surface modification studies. Membrane performance was found to be sensitive to crossflow testing conditions. Concentration polarization and feed pH strongly influenced NaCl rejection, and the use of continuous feed filtration led to higher water flux and lower NaCl rejection than was observed for similar tests performed using unfiltered feed. Two commercial polyamide membranes, including one reverse osmosis and one nanofiltration membrane, were modified by grafting PEGDE to their surfaces. Two different PEG molecular weights (200 and 1000) and treatment concentrations (1% (w/w) and 15% (w/w)) were studied. Water flux decreased and NaCl rejection increased with PEGDE graft density ({micro}g/cm{sup 2}), although the largest changes were observed for low PEGDE graft densities. Surface properties including hydrophilicity, roughness and charge were minimally affected by surface modification. The fouling resistance of modified and unmodified membranes was compared in crossflow filtration studies using model foulant solutions consisting of either a charged surfactant or an oil in water emulsion containing n-decane and a charged surfactant. Several PEGDE-modified membranes demonstrated improved

  6. Aromatic chemical feedstocks from coal

    Energy Technology Data Exchange (ETDEWEB)

    Collin, G

    1982-06-01

    Liquid byproducts of coal carbonization meet some 25% of the world demand for aromatic chemicals, currently at approx. 30 million t/a, in particular 15% of the demand for benzene and over 95% of the demand for condensed aromatics and heteroaromatics. Industrial processing of the aromatic byproducts of coal pressure gasification is carried out to only a minor extent. Other methods that may be employed in future to obtain carbochemical aromatic compounds are solvolysis and supercritical gas extraction, the catalytic liquid-phase hydrogenation and hydropyrolysis of coal, which also permit recovery of benzene and homologues, phenols, and condensed and partially hydrogenated aromatics, and the synthesis of aromatics using methanol as the key compound. As with the present means of obtaining aromatic chemicals from coal, the processes that may in the future be applied on an industrial scale to obtain pure aromatics will only be economically feasible if linked with the manufacture of other mass products and combined with the present production of carbochemical aromatics.

  7. Aromatic raw materials from coal

    Energy Technology Data Exchange (ETDEWEB)

    Collin, G

    1982-06-01

    Liquid byproducts of coal carbonization meet some 25% of the world demand for aromatic chemicals, currently at approx. 30 million t/a, in particular 15% of the demand for benzene and over 95% of the demand for condensed aromatics and heteroaromatics. Industrial processing of the aromatic byproducts of coal pressure gasification is carried out to only a minor extent. Other methods that may be employed in future to obtain carbochemical aromatic compounds are solvolysis and supercritical gas extraction, the catalytic liquid-phase hydrogenation and hydropyrolysis of coal, which also permit recovery of benzene and homologues, phenols, and condensed and partially hydrogenated aromatics, and the synthesis of aromatics using methanol as the key compound. As with the present means of obtaining aromatic chemicals from coal, the processes that may in future be applied on an industrial scale to obtain pure aromatics will only be economically feasible if linked with the manufacture of other mass products and combined with the present production of carbochemical aromatics. (In German)

  8. Analysis of Polycyclic Aromatic Hydrocarbon (PAH Mixtures Using Diffusion-Ordered NMR Spectroscopy and Adsorption by Powdered Activated Carbon and Biochar

    Directory of Open Access Journals (Sweden)

    Dong An

    2018-03-01

    Full Text Available Analysis of polycyclic aromatic hydrocarbons (PAHs in air and water sources is a key part of environmental chemistry research, since most PAHs are well known to be associated with negative health impacts on humans. This study explores an approach for analyzing PAH mixtures with advanced nuclear magnetic resonance (NMR spectroscopic techniques including high-resolution one-dimensional (1D NMR spectroscopy and diffusion-ordered NMR spectroscopy (DOSY NMR. With this method, different kinds of PAHs can be detected and differentiated from a mixture with high resolution. The adsorption process of PAH mixtures by PAC and biochar was studied to understand the mechanism and assess the method.

  9. Searching for new sources of innovative products for the food industry within halophyte aromatic plants: In vitro antioxidant activity and phenolic and mineral contents of infusions and decoctions of Crithmum maritimum L.

    Science.gov (United States)

    Pereira, Catarina Guerreiro; Barreira, Luísa; da Rosa Neng, Nuno; Nogueira, José Manuel Florêncio; Marques, Cátia; Santos, Tamára F; Varela, João; Custódio, Luísa

    2017-09-01

    Aromatic halophyte plants are an outstanding source of bioactive compounds and natural products with potential use in the food industry. This work reports the in vitro antioxidant activity, toxicity, polyphenolic profile and mineral contents of infusions and decoctions from stems, leaves and flowers of Crithmum maritimum L., an aromatic and edible maritime halophyte (sea fennel). Aspalathus linearis (Burm.f.) Dahlg. (rooibos) herbal tea was used as a reference. Sea fennel's tisanes, particularly from leaves, were rich in phenolic compounds and five of them (p-hydroxybenzoic and ferulic acids, epicatechin, pyrocatechol and 4-hydroxybenzaldehyde) were here described in C. maritimum for the first time. Chlorogenic acid was the dominant phenolic determined. Na was the most abundant mineral in all tisanes followed by Ca and Mg in leaves' tisanes and K in flowers. Sea fennel's samples had a similar antioxidant activity than those from A. linearis, and had no significant toxicity towards four different mammalian cell lines. Altogether, our results suggest that sea fennel can be a source of products and/or molecules for the food industry with antioxidant properties and minerals in the form, for example, of innovative health-promoting herbal beverages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The effect of gamma irradiation in air and inert atmosphere on structure and properties of unfilled or glass fibre-reinforced polyamide 6

    Czech Academy of Sciences Publication Activity Database

    Porubská, M.; Babić, D.; Janigová, I.; Šlouf, Miroslav; Jomová, K.; Chodák, I.

    2016-01-01

    Roč. 73, č. 6 (2016), s. 1775-1794 ISSN 0170-0839 Institutional support: RVO:61389013 Keywords : polyamide 6 * glass fibre-reinforced polyamide 6 * gamma beam irradiation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.430, year: 2016

  11. The Role of Human Aldo-Keto Reductases (AKRs in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH-catechols and PAH o-Quinones

    Directory of Open Access Journals (Sweden)

    Li eZhang

    2012-11-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAH are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quiniones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis.

  12. Double dielectric barrier (DBD) plasma-assisted deposition of chemical stabilized nanoparticles on polyamide 6,6 and polyester fabrics

    Science.gov (United States)

    Ribeiro, A. I.; Modic, M.; Cvelbar, U.; Dinescu, G.; Mitu, B.; Nikiforov, A.; Leys, C.; Kuchakova, I.; Vanneste, M.; Heyse, P.; De Vrieze, M.; Carneiro, N.; Souto, A. P.; Zille, A.

    2017-10-01

    The development of new multifunctional textiles containing nanoparticles (NPs) has a special interest in several applications for pharmaceutical and medical products. Cu, Zn and Ag are the most promising antimicrobial NPs, exhibiting strong antibacterial activities. However, most of antimicrobial textiles coated with NPs are not able to perform a controlled release of NPs because of the high degree of aggregation. The aim of this study is to assess the effect of NPs stabilizers such as citrate, alginate and polyvinyl alcohol (PVA) in Cu, Zn and Ag NPs dispersions. The obtained dispersions were used to develop a new class of antibacterial NPs coatings onto polyamide 6,6 (PA66) and polyester fabrics (PES) by Double Dielectric Barrier (DBD) plasma discharge. Dynamic light scattering (DLS) was used to evaluate the best dispersing agent in terms of size, polydispersity index and zeta potential. Coating efficiency was evaluated by SEM, XPS and FTIR. The washing fastness of the coatings developed was also tested. The results show that the best dispersions were obtained using 2.5% of citrate for ZnO, 5% Alginate for Cu and 2.5% alginate for Ag NPs. SEM, XPS and FTIR analysis shows that DBD is an efficient deposition technique only for Ag and Cu NPs and that better perform in PA66 than PES fabric. The DBD deposition in air display similar results in term of NPS deposition of usually more efficient plasma jets using carrier gas such as N2 and Ar.

  13. Laser surface treatment of polyamide and NiTi alloy and the effects on mesenchymal stem cell response

    Science.gov (United States)

    Waugh, D. G.; Lawrence, J.; Shukla, P.; Chan, C.; Hussain, I.; Man, H. C.; Smith, G. C.

    2015-07-01

    Mesenchymal stem cells (MSCs) are known to play important roles in development, post-natal growth, repair, and regeneration of mesenchymal tissues. What is more, surface treatments are widely reported to affect the biomimetic nature of materials. This paper will detail, discuss and compare laser surface treatment of polyamide (Polyamide 6,6), using a 60 W CO2 laser, and NiTi alloy, using a 100 W fiber laser, and the effects of these treatments on mesenchymal stem cell response. The surface morphology and composition of the polyamide and NiTi alloy were studied by scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS), respectively. MSC cell morphology cell counting and viability measurements were done by employing a haemocytometer and MTT colorimetric assay. The success of enhanced adhesion and spreading of the MSCs on each of the laser surface treated samples, when compared to as-received samples, is evidenced in this work.

  14. A comparison of transmission, reflection and photoacoustic FTIR techniques in the analysis of recycled and irradiated polyamide-6

    International Nuclear Information System (INIS)

    Evora, Maria C.; Goncalez, Odair L.

    2002-01-01

    A comparative study involving transmission, reflection and photoacoustic FTIR techniques is presented with analysis of polyamide-6. The potential and limitations of these methods are investigated by analyzing structural variations that take place at the surface in the bulk in recycled and irradiated polyamide-6 with a 1.5 MeV electron beam with a 500kGY dose, in the presence of O 2 . FTIR techniques appear to be sensitive in detecting small structural changes that occur in recycled and irradiated polyamide-6. The analysis of samples indicated the formation of OH, HOC=O-, - C=O groups. Also, small structural changes were detected which are characterisitic of NH and CN-C=O groups. Transmission techniques show better the structural changes in the bulk, and microscopy-FTIR appears to be more sensitive in detecting what occurs at the sample surface. (author)

  15. Environmental effect on the mechanical properties of commingled-yarn-based carbon fibre/polyamide 6 composites

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack

    2014-01-01

    The main objective of this experimental investigation was to evaluate the changes from accelerated ageing on selected properties of carbon fibre/polyamide 6 composites based on hybrid yarns. In this study, two types of mechanical tests were performed to measure the environmental influence...... on the material properties. They are three-point bending to measure the flexural strength and stiffness, and short beam three-point bending to measure the interlaminar shear strength. The 10-mm-thick quasi-isotropic carbon fibre/polyamide 6 composites with 52% volume fraction of carbon fibre to be tested were...... temperature. The interlaminar shear strength values also drop to about 75% at both −45 and 115. Extreme temperatures and long-time exposure to humidity of quasi-isotropic carbon fibre/polyamide 6 laminates can thus reduce the bending stiffness and strength by up to 35% and the interlaminar shear strength...

  16. Polyamide 6/nickel ferrite composites: morphological and structural evaluation; Compositos poliamida 6 /ferrita de niquel: avaliacao morfologica e estrutural

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, P.C.F.; Santos, P.T.A.; Wanderley, A.S.D.; Costa, A.C.F.M.; Araujo, E.M., E-mail: patricia.fernandes24@hotmail.com [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Unidade Academica de Engenharia de Materiais

    2011-07-01

    This study aims to evaluate the influence of particle size of the load on the structure and morphology of polyamide composite 6/ferrita nickel. To obtain the composite, the polyamide 6 was previously vacuum dried at 80 ° C/48h to eliminate moisture, and then the load was incorporated as powders and as synthesized after calcination at 900°C in the mass concentration of 50%. Subsequently, the mixture was compressed using three tons to obtain the composites, which were characterized by XRD and SEM. XRD results showed the characteristic peaks of polyamide 6 and ferrite. An increase in crystallinity was observed for the composite loaded calcined at 900° C. SEM results showed a good dispersion of nickel ferrite loading in the matrix, the presence of larger clusters and evenly distributed load for the composite calcined at 900 ° C. (author)

  17. Evaluation of Shear Resisting Capacity of a Prestressed Concrete Containment Building with Steel or Polyamide Fiber Reinforcement

    International Nuclear Information System (INIS)

    Choun, Youngsun; Park, Junhee

    2014-01-01

    Conventional reinforced concrete (RC) members generally show a rapid deterioration in shear resisting mechanisms under a reversed cyclic load. However, the use of high-performance fiber-reinforced cement composites provides excellent damage tolerance under large displacement reversals compared with regular concrete. Previous experimental studies have indicated that the use of fibers in conventional RC can enhance the structural and functional performance of prestressed concrete containment buildings (PCCBs) in nuclear power plants. This study evaluates the shear resisting capacity for a PCCB constructed using steel fiber reinforced concrete (SFRC) or polyamide fiber reinforced concrete (PFRC). The effects of steel and polyamide fibers on the shear performance of a PCCB were investigated. It was revealed that steel fibers are more effective to enhance the shear resisting capacity of a PCCB than polyamide fibers. The ductility and energy dissipation increase significantly in fiber reinforced PCCBs

  18. Evaluation of Shear Resisting Capacity of a Prestressed Concrete Containment Building with Steel or Polyamide Fiber Reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Youngsun; Park, Junhee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Conventional reinforced concrete (RC) members generally show a rapid deterioration in shear resisting mechanisms under a reversed cyclic load. However, the use of high-performance fiber-reinforced cement composites provides excellent damage tolerance under large displacement reversals compared with regular concrete. Previous experimental studies have indicated that the use of fibers in conventional RC can enhance the structural and functional performance of prestressed concrete containment buildings (PCCBs) in nuclear power plants. This study evaluates the shear resisting capacity for a PCCB constructed using steel fiber reinforced concrete (SFRC) or polyamide fiber reinforced concrete (PFRC). The effects of steel and polyamide fibers on the shear performance of a PCCB were investigated. It was revealed that steel fibers are more effective to enhance the shear resisting capacity of a PCCB than polyamide fibers. The ductility and energy dissipation increase significantly in fiber reinforced PCCBs.

  19. Aromatic hydrocarbon concentrations in sediments of Placentia Bay, Newfoundland

    International Nuclear Information System (INIS)

    Kiceniuk, J.W.

    1992-01-01

    A study was conducted to examine the potential for contamination of recent sediments with polycyclic aromatic hydrocarbons due to tanker and refinery activity in Placentia Bay, Newfoundland, an area without large local anthropogenic sources of aromatics. Sediment samples were taken from the vicinity of the Come By Chance refinery, Woody Island, Wild Cove, and Port Royal Arm, all in the north end of the bay. The samples were extracted by two methods, dichloromethane extraction of dried sediment for determination of total aromatic hydrocarbon content and hexane extraction of wet sediment for estimation of the bioavailability of hydrocarbons and determination of more volatile compounds. Class analysis of aromatic hydrocarbons was conducted on a NH 2 column with detection at 255 nm. Total concentrations of di-tricyclic aromatics were highest at the Woody Island site (0.6 μg/g). The sediments from the Come By Chance site, Wild Cove, and Port Royal Arm sediments contained 0.3, 0.1, and 0.2 μg/g respectively. The hexane extracts from Come By Chance were lowest in di-tricyclic aromatics (0.007 μg/g), with the other sites being equal in concentration (0.01 μg/g). It is evident from the study that aromatic hydrocarbon concentrations in Placentia Bay are elevated in some parts of the bay in the absence of local combustion sources, and that the most likely source is petroleum. 12 refs., 5 figs., 2 tabs

  20. Synthesis and characterization of new polyamides derived from alanine and valine derivatives

    Directory of Open Access Journals (Sweden)

    El-Faham Ayman

    2012-11-01

    Full Text Available Abstract Background Many efforts have been recently devoted to design, investigate and synthesize biocompatible, biodegradable polymers for applications in medicine for either the fabrication of biodegradable devices or as drug delivery systems. Many of them consist of condensation of polymers having incorporated peptide linkages susceptible to enzymatic cleavage. Polyamides (PAs containing α-amino acid residues such as L-leucine, L-alanine and L-phenylalanine have been reported as biodegradable materials. Furthermore, polyamides (PAs derived from C10 and C14 dicarboxylic acids and amide-diamines derived from 1,6-hexanediamine or 1,12-dodecanediamine and L-phenylalanine, L-valyl-L-phenylalanine or L-phenylalanyl-L-valine residues have been reported as biocompatible polymers. We have previously described the synthesis and thermal properties of a new type of polyamides-containing amino acids based on eight new symmetric meta-oriented protected diamines derived from coupling of amino acids namely; Fomc-glycine, Fmoc-alanine, Fomc-valine and Fomc-leucine with m-phenylene diamine or 2,6-diaminopyridine. Results revealed that incorporation of pyridine onto the polymeric backbone of all series decreases the thermal stability. Here we describe another family of polyamides based on benzene dicarboxylic acid, pyridine dicarboxylic acid, and α-amino acid linked to benzidine and 4,4′-oxydianiline to study the effect of the dicarboxylic acid as well as the amino acids on the nature and thermal stability of the polymers. Results We report here the preparation of a new type of polyamides based on benzene dicarboxylic acid, pyridine dicarboxylic acid, and α-amino acid linked to benzidine and 4,4′-oxydianiline to study the effect of the dicarboxylic acid as well as the amino acids on the nature and thermal stability of polymers. The thermal properties of the polymers were evaluated by different techniques. Results revealed that structure-thermal property

  1. Sequence-selective single-molecule alkylation with a pyrrole-imidazole polyamide visualized in a DNA nanoscaffold.

    Science.gov (United States)

    Yoshidome, Tomofumi; Endo, Masayuki; Kashiwazaki, Gengo; Hidaka, Kumi; Bando, Toshikazu; Sugiyama, Hiroshi

    2012-03-14

    We demonstrate a novel strategy for visualizing sequence-selective alkylation of target double-stranded DNA (dsDNA) using a synthetic pyrrole-imidazole (PI) polyamide in a designed DNA origami scaffold. Doubly functionalized PI polyamide was designed by introduction of an alkylating agent 1-(chloromethyl)-5-hydroxy-1,2-dihydro-3H-benz[e]indole (seco-CBI) and biotin for sequence-selective alkylation at the target sequence and subsequent streptavidin labeling, respectively. Selective alkylation of the target site in the substrate DNA was observed by analysis using sequencing gel electrophoresis. For the single-molecule observation of the alkylation by functionalized PI polyamide using atomic force microscopy (AFM), the target position in the dsDNA (∼200 base pairs) was alkylated and then visualized by labeling with streptavidin. Newly designed DNA origami scaffold named "five-well DNA frame" carrying five different dsDNA sequences in its cavities was used for the detailed analysis of the sequence-selectivity and alkylation. The 64-mer dsDNAs were introduced to five individual wells, in which target sequence AGTXCCA/TGGYACT (XY = AT, TA, GC, CG) was employed as fully matched (X = G) and one-base mismatched (X = A, T, C) sequences. The fully matched sequence was alkylated with 88% selectivity over other mismatched sequences. In addition, the PI polyamide failed to attach to the target sequence lacking the alkylation site after washing and streptavidin treatment. Therefore, the PI polyamide discriminated the one mismatched nucleotide at the single-molecule level, and alkylation anchored the PI polyamide to the target dsDNA.

  2. Catalytic aromatization of methane.

    Science.gov (United States)

    Spivey, James J; Hutchings, Graham

    2014-02-07

    Recent developments in natural gas production technology have led to lower prices for methane and renewed interest in converting methane to higher value products. Processes such as those based on syngas from methane reforming are being investigated. Another option is methane aromatization, which produces benzene and hydrogen: 6CH4(g) → C6H6(g) + 9H2(g) ΔG°(r) = +433 kJ mol(-1) ΔH°(r) = +531 kJ mol(-1). Thermodynamic calculations for this reaction show that benzene formation is insignificant below ∼600 °C, and that the formation of solid carbon [C(s)] is thermodynamically favored at temperatures above ∼300 °C. Benzene formation is insignificant at all temperatures up to 1000 °C when C(s) is included in the calculation of equilibrium composition. Interestingly, the thermodynamic limitation on benzene formation can be minimized by the addition of alkanes/alkenes to the methane feed. By far the most widely studied catalysts for this reaction are Mo/HZSM-5 and Mo/MCM-22. Benzene selectivities are generally between 60 and 80% at methane conversions of ∼10%, corresponding to net benzene yields of less than 10%. Major byproducts include lower molecular weight hydrocarbons and higher molecular weight substituted aromatics. However, carbon formation is inevitable, but the experimental findings show this can be kinetically limited by the use of H2 or oxidants in the feed, including CO2 or steam. A number of reactor configurations involving regeneration of the carbon-containing catalyst have been developed with the goal of minimizing the cost of regeneration of the catalyst once deactivated by carbon deposition. In this tutorial review we discuss the thermodynamics of this process, the catalysts used and the potential reactor configurations that can be applied.

  3. Effect of Polyamide 6 on Crystalline Structure of Polymer in PVDF-Nanoclay Nanocomposite

    Directory of Open Access Journals (Sweden)

    Ali Akbar Yousefi

    2012-12-01

    Full Text Available The  effect  of  nanocaly  on  crystalline  structure  of  poly(vinylidene  fuoride, PVDF, and the morphology of the resulting nano-composite were investigated using  different  characterization  techniques.  The  presence  of  3wt%  Cloisite 30B in PVDF matrix results in 11 fold increase in the percentage of beta crystalline content of the polymer. This was found to be attributed to the epitaxial effect of the clay  surface. The  beta  crystalline  content  of  the  pure  polymer  (6% was  raised  to 68% in the composite. Addition of 5wt% polyamide 6 (PA6 improved dispersion of nanoclay which led to augmentation of the viscosity and displacement of the crossover frequency of the compatibilized composite towards lower frequencies. However, due to stronger affnity of the PA6 towards organically modifed clay the epitaxial effect of  the  clay on  crystalline  structure of PVDF was  totally  eliminated. The  reduction of  viscosity  in  incompatibilized  nanocomposite was  attributed  to  reduced  number of PVDF chain entanglements  in  the presence of nanoclay. Meanwhile,  increase  in viscosity and displacement of crossover  frequency  towards  lower  frequencies were attributed to formation of clay-PA nanoparticles and PVDF-polyamide 6 interactions. It is expected that the presence of polyamide 6 promotes the formation of oriented-beta crystals in PVDF, which in turn improves the piezoelectric properties of the polymer.

  4. Synthesis and Properties of New Polyamides Based on 4-Phenylenediacrylic Acid and Hydantoin Derivatives in the Main Chain

    OpenAIRE

    FAGHIHI, Khalil

    2008-01-01

    Six new polyamides (5a-f) containing p-phenylenediacrylic and hydantoin moieties in the main chain were prepared by direct polycondensation reaction of 4-phenylenediacrylic acid (3) with 6 different hydantoin derivatives (4a-f) using thionyl chloride and pyridine as condensing agents and N-methyl-2-pyrolidone as solvent. These new polymers (5a-f) were obtained in high yield and inherent viscosity between 0.35-0.55 dL/g. The resulting polyamides were characterized by elemental analysi...

  5. Evaluation of ionizing radiation effects on recycled polyamide-6 by infrared spectroscopy and measures of fluidity index

    International Nuclear Information System (INIS)

    Evora, Maria Cecilia; Goncalez, Odair Lelis

    2000-01-01

    In this work are presented partial results from a set of experiments and analyses performed at CTA and IPEN laboratories for the characterization of the polyamide-6, recycled and irradiated with a 1.5 MeV electron beam with a 500 kGy dose. The experimental determinations were carried out using infrared spectroscopy with Fourier transform (FTIR), in the medium infrared region (MIR) and in the far infrared region (FAR), to evaluate if exist significant changes in the infrared absorption region of the amide groups due to the polyamide irradiation. Characteristics relative to the measured fluidity index were used to evaluate the irradiated material crosslinking. (author)

  6. Effect of Graphene Nanoplatelets (GNPs on Tribological and Mechanical Behaviors of Polyamide 6 (PA6

    Directory of Open Access Journals (Sweden)

    F. Mindivan

    2017-09-01

    Full Text Available The effects of Graphene Nanoplatelet (GNP on mechanical and tribological properties of Polyamide 6 (PA6 were studied. The composites were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of microhardness, scratch hardness and Young’s modulus measurements and tensile test. The tribological behavior of composites was studied by using ball-on-disc reciprocating tribometer. Recent studies showed that the addition of GNP in PA6 matrix resulted in enhancement of mechanical and tribological properties.

  7. Mechanical thermal evaluation of polyamide 6 with bentonite organo clay nanocomposites

    International Nuclear Information System (INIS)

    Paz, Rene Anisio da; Araujo, Edcleide M.; Melo, Tomas Jeferson Alves de; Leite, Amanda M.D.; Cavalcanti, Shirley Nobrega; Pessan, Luiz Antonio

    2009-01-01

    This work had for objective to obtain polymeric nanocomposites of polyamide 6 and a clay consisting of silicates layer from of Paraiba mines and to evaluate evaluation mechanical thermal in different processing conditions. The clay was organically modified using a quaternary ammonium salt (Cetremide), so that there is a larger interaction of the clay with the polymer. The obtained nanocomposites showed the morphological structure composed exfoliated/partially exfoliated, as shown XRD. The results of HDT it because the clay increases the dimensional stability of PA6 in high temperatures, making possible the use of the nanocomposites for making of pieces with good resistance to the heat distortion. (author)

  8. Polyamide microcapsules containing jojoba oil prepared by inter-facial polymerization.

    Science.gov (United States)

    Persico, P; Carfagna, C; Danicher, L; Frere, Y

    2005-08-01

    Jojoba oil containing polyamide microcapsules having diameter of approximately 5 microm were prepared by inter-facial polycondensation by direct method (oil-in-water). Qualitative effects of both the formulation and the process parameters on microcapsules characteristics were investigated by SEM observations. Morphological analysis showed the dependence of the external membrane compactness on the chemical nature of the water-soluble polyamine and the oil-soluble acid polychloride: 1,6-hexamethylenediamine (HMDA) and terephthaloyl dichloride (TDC) were found to favour the production of smooth and dense surfaces. The use of ultrasonic irradiations during the dispersion step to get a further reduction of microcapsules size was also evaluated.

  9. Synthesis and characterization of lead oxides for preparation of nanocomposites with polyamide

    International Nuclear Information System (INIS)

    Cado, Ronan Gorski; Severo, Vinicius A.; Bulhores, Luis Otavio S.

    2016-01-01

    Lead oxide nanoparticles with diameters between 100 to 250 nm were obtained using a polymeric precursor method in the presence of citric acid and ethylene glycol. X-ray diffraction (XRD) and dynamic light scattering to measure the size and zeta potential in solution in dispersions with different pH were used to characterize the as-obtained samples. The nanoparticles were incorporated into polyamide 6.6 and composite films were prepared by electrospinning being evaluated the variation of the mechanical properties of the polymer and its effectiveness in attenuation of X-rays. (author)

  10. Morphology and transport in biodegradable polymer compositions based on poly(3-hydroxybutyrate) and polyamide 54C

    Energy Technology Data Exchange (ETDEWEB)

    Zhul' kina, A. L.; Ivantsova, E. L.; Filatova, A. G.; Kosenko, R. Yu.; Gumargalieva, K. Z.; Iordanskii, A. L., E-mail: iordan@chph.ras.ru [Russian Academy of Sciences, Semenov Institute of Chemical Physics (Russian Federation)

    2009-05-15

    Complex investigation of the equilibrium sorption of water, diffusive transport of antiseptic, and morphology of mixed compositions based on polyoxybutirate and polyamide resin 54C has been performed to develop and analyze new biodegradable polymer compositions for controlled release of medicinal substances. Samples of mixtures were prepared by two methods: pressing under pressure and solvent evaporation from a polymer solution. The samples were compared and their morphology was analyzed by scanning electron microscopy. It is shown that the component ratio in the obtained mixtures affects their morphological, transport, and sorption characteristics.

  11. Morphology and transport in biodegradable polymer compositions based on poly(3-hydroxybutyrate) and polyamide 54C

    International Nuclear Information System (INIS)

    Zhul'kina, A. L.; Ivantsova, E. L.; Filatova, A. G.; Kosenko, R. Yu.; Gumargalieva, K. Z.; Iordanskii, A. L.

    2009-01-01

    Complex investigation of the equilibrium sorption of water, diffusive transport of antiseptic, and morphology of mixed compositions based on polyoxybutirate and polyamide resin 54C has been performed to develop and analyze new biodegradable polymer compositions for controlled release of medicinal substances. Samples of mixtures were prepared by two methods: pressing under pressure and solvent evaporation from a polymer solution. The samples were compared and their morphology was analyzed by scanning electron microscopy. It is shown that the component ratio in the obtained mixtures affects their morphological, transport, and sorption characteristics.

  12. Metabolism and Biomarkers of Heterocyclic Aromatic Amines in Molecular Epidemiology Studies: Lessons Learned from Aromatic Amines

    Science.gov (United States)

    2011-01-01

    Aromatic amines and heterocyclic aromatic amines (HAAs) are structurally related classes of carcinogens that are formed during the combustion of tobacco or during the high-temperature cooking of meats. Both classes of procarcinogens undergo metabolic activation by N-hydroxylation of the exocyclic amine group, to produce a common proposed intermediate, the arylnitrenium ion, which is the critical metabolite implicated in toxicity and DNA damage. However, the biochemistry and chemical properties of these compounds are distinct and different biomarkers of aromatic amines and HAAs have been developed for human biomonitoring studies. Hemoglobin adducts have been extensively used as biomarkers to monitor occupational and environmental exposures to a number of aromatic amines; however, HAAs do not form hemoglobin adducts at appreciable levels and other biomarkers have been sought. A number of epidemiologic studies that have investigated dietary consumption of well-done meat in relation to various tumor sites reported a positive association between cancer risk and well-done meat consumption, although some studies have shown no associations between well-done meat and cancer risk. A major limiting factor in most epidemiological studies is the uncertainty in quantitative estimates of chronic exposure to HAAs and, thus, the association of HAAs formed in cooked meat and cancer risk has been difficult to establish. There is a critical need to establish long-term biomarkers of HAAs that can be implemented in molecular epidemioIogy studies. In this review article, we highlight and contrast the biochemistry of several prototypical carcinogenic aromatic amines and HAAs to which humans are chronically exposed. The biochemical properties and the impact of polymorphisms of the major xenobiotic-metabolizing enzymes on the biological effects of these chemicals are examined. Lastly, the analytical approaches that have been successfully employed to biomonitor aromatic amines and HAAs, and

  13. Aromatic Plants as a Source of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Panagiota Florou-Paneri

    2012-09-01

    Full Text Available Aromatic plants, also known as herbs and spices, have been used since antiquity as folk medicine and as preservatives in foods. The best known aromatic plants, such as oregano, rosemary, sage, anise, basil, etc., originate from the Mediterranean area. They contain many biologically active compounds, mainly polyphenolics, which have been found to possess antimicrobial, antioxidant, antiparasitic, antiprotozoal, antifungal, and anti-inflammatory properties. Currently, the demand for these plants and their derivatives has increased because they are natural, eco-friendly and generally recognized as safe products. Therefore, aromatic plants and their extracts have the potential to become new generation substances for human and animal nutrition and health. The purpose of this review is to provide an overview of the literature surrounding the in vivo and in vitro use of aromatic plants.

  14. Fabrication of Electrospun Polyamide-6/Chitosan Nanofibrous Membrane toward Anionic Dyes Removal

    Directory of Open Access Journals (Sweden)

    Mozhdeh Ghani

    2014-01-01

    Full Text Available Nanofibrous filter media of polyamide-6/chitosan were fabricated by electrospinning onto a satin fabric substrate and characterized by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, and water contact angle (WCA. Anionic dye removal capability of the filter was investigated for Solophenyl Red 3BL and Polar Yellow GN, respectively, as acidic and direct dyes were investigated with respect to solution parameters (pH and initial dye concentration and membrane parameters (electrospinning time and chitosan ratio through filtration system. Experiments were designed using response surface methodology (RSM based on five-level central composite design (CCD with four parameters to maximize removal efficiency of the filter media. Moreover, the effect of parameters and their likely interactions on dye removal were investigated by mathematically developed models. The optimum values for solution pH, initial dye concentration, electrospinning time, and chitosan ratio were predicted to be 5, 50 mg/L, 4 hr, 30% and 5, 100 mg/L, 4 hr, 10%, respectively, for achieving 96% and 95% removal of Solophenyl Red 3BL and Polar Yellow GN. Evaluation of the estimation capability of applied models revealed that the models have a good agreement with experimental values. This study demonstrated that polyamide-6/chitosan nanofibrous membrane has an enormous applicable potential in dye removal from aqueous solutions.

  15. Modelling mechanical properties of the multilayer composite materials with the polyamide core

    Directory of Open Access Journals (Sweden)

    Talaśka Krzysztof

    2018-01-01

    Full Text Available Due to the wide range of application for belt conveyors, engineers look for many different combinations of mechanical properties of conveyor and transmission belts. It can be made by creating multilayer or fibre reinforced composite materials from base thermoplastic or thermosetting polymers. In order to gain high strength with proper elasticity and friction coefficient, the core of the composite conveyor belt is made of polyamide film core, which can be combined with various types of polymer fabrics, films or even rubbers. In this paper authors show the complex model of multilayer composite belt with the polyamide core, which can be used in simulation analyses. The following model was derived based on the experimental research, which consisted of tensile, compression and shearing tests. In order to achieve the most accurate model, proper simulations in ABAQUS were made and then the results were compared with empirical mechanical characteristics of a conveyor belt. The main goal of this research is to fully describe the perforation process of conveyor and transmission belts for vacuum belt conveyors. The following model will help to develop design briefs for machines used for mechanical perforation.

  16. Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

    Directory of Open Access Journals (Sweden)

    Jonas Matulevicius

    2014-01-01

    Full Text Available Electrospun polyamide 6 (PA 6 and polyamide 6/6 (PA 6/6 nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer concentration, ratio of solvents, nanofiber media collection time, tip-to-collector distance, and the deposition voltage. The average diameter of the fibers, their morphology, basis weight, thickness, and resulting media solidity were investigated. Effects of each variable on the essential characteristics of PA 6/6 and PA 6 nanofiber media were studied. The comparative analysis of the obtained PA 6/6 and PA 6 nanofiber characteristics revealed that PA 6/6 had higher potential to be used in filtration applications. Based on the experimental results, the graphical representation—response surfaces—for obtaining nanofiber media with the desirable fiber diameter and basis weight characteristics were derived. Based on the modelling results the nanofiber filter media (mats were fabricated. Filtration results revealed that nanofiber filter media electrospun from PA6/6 8% (w/vol solutions with the smallest fiber diameters (62–66 nm had the highest filtration efficiency (PA6/6_30 = 84.9–90.9% and the highest quality factor (PA6/6_10 = 0.0486–0.0749 Pa−1.

  17. Advances towards aromatic oligoamide foldamers

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Plesner, Malene; Dissing, Mette Marie

    2014-01-01

    We have efficiently synthesized 36 arylopeptoid dimers with ortho-, meta-, and para-substituted aromatic backbones and tert-butyl or phenyl side chains. The dimers were synthesized by using a "submonomer method" on solid phase, by applying a simplified common set of reaction conditions. X......-ray crystallographic analysis of two of these dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a comparatively more closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation with a more open, extended structure...... of the surrounding aromatic backbone. Investigation of the X-ray structures of two arylopeptoid dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation...

  18. Three-dimensional aromatic networks.

    Science.gov (United States)

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  19. Positron emission tomographic studies on aromatic L-amino acid decarboxylase activity in vivo for L-dopa and 5-hydroxy-L-tryptophan in the monkey brain

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig, P; Tedroff, J; Lindner, K J; Bjurling, P; Chang, C W; Laangstroem, B [Uppsala Univ. (Sweden); Tsukada, H [Central Research Lab., Hamamatsu Photonics Shizuoka, Osaka (Japan); Watanabe, Y [Dept. of Neuroscience, Osaka Bioscience Inst., Osaka (Japan)

    1993-01-01

    The regional brain kinetics following 5-hydroxy-L-([beta]-11 C)tryptophan and L-([beta]-11 C)DOPA intravenous injection was measured in twelve Rhesus monkeys using positron emission tomography (PET). The radiolabelled compounds were also injected together with various doses of unlabelled 5-hydroxy-L-tryptophan or L-DOPA. The radioactivity accumulated in the striatal region and the rate of increased utilization with time was calculated using a graphical method with back of the brain as a reference region. The rate constants for decarboxylation were 0.0070 [+-] 0.0007 (S. D) and 0.0121 [+-] 0.0010 min[sup -1] for 5-hydroxy-L-([beta]-11 C)tryptophan and L-([beta]-11 C)DOPA, respectively. After concomitant injection with unlabelled 5-hydroxy-L-tryptophan, the rate constant of 5-hydroxy-L-([beta]-11 C)tryptophan decreased dose-dependently and a 50 percent reduction was seen with a dose of about 4 mg/kg of unlabelled compound. A decreased utilization rate of L-([beta]-11 C)DOPA was seen only after simultaneous injection of 30 mg/kg of either L-DOPA or 5-hydroxy-L-tryptophan. This capacity limitation was most likely interpreted as different affinity of the striatal aromatic amino acid decarboxylase for L-DOPA and 5-hydroxy-L-tryptophan, respectively.

  20. Fire resistant polyamide based on 1-(diorganooxyphosphonyl)methyl-2,4- and -2,6diamino benzene

    Science.gov (United States)

    Mikroyannidis, J. A. (Inventor); Kourtides, D. A. (Inventor)

    1986-01-01

    1-(Diorganooxyphosphonyl)methyl2,4- and-2,6diamino benzenes are reacted with polyacylhalides and optionally comonomers to produce polyamides which have desirable heat and fire resistance properties. These polymers are used to form fibers and fabrics where fire resistance properties are important, e.g., aircraft equipment and structures.

  1. Rigid, bio-based polyamides from galactaric acid derivatives with elevated glass transition temperatures and their characterization

    NARCIS (Netherlands)

    Wróblewska, Aleksandra A.; Bernaerts, Katrien; de Wildeman, Stefaan

    2017-01-01

    A comparative study was prepared investigating the synthesis of polyamides using bio-based building blocks derived from sugar beet pulp, namely 2,3:4,5-di-O-methylene-galactarate (GalXH) and 2,3:4,5-di-O-isopropylidene-galactarate (GalXMe) derivatives. Two different approaches towards the synthesis

  2. Thermo-oxidative degradation study of melt-processed polyethylene and its blend with polyamide using time-resolved rheometry

    CSIR Research Space (South Africa)

    Salehiyan, Reza

    2017-05-01

    Full Text Available Time-resolved mechanical spectroscopy (TRMS) was conducted to study the thermo-oxidative degradation of linear low density polyethylene (LLDPE) samples with different thermal histories and their blends with a polyamide (PA6) in the melt state. Neat...

  3. Correlating PSf Support Physicochemical Properties with the Formation of Piperazine-Based Polyamide and Evaluating the Resultant Nanofiltration Membrane Performance

    Directory of Open Access Journals (Sweden)

    Micah Belle Marie Yap Ang

    2017-10-01

    Full Text Available Membrane support properties influence the performance of thin-film composite nanofiltration membranes. We fabricated several polysulfone (PSf supports. The physicochemical properties of PSf were altered by adding polyethylene glycol (PEG of varying molecular weights (200–35,000 g/mol. This alteration facilitated the formation of a thin polyamide layer on the PSf surface during the interfacial polymerization reaction involving an aqueous solution of piperazine containing 4-aminobenzoic acid and an organic solution of trimesoyl chloride. Attenuated total reflectance-Fourier transform infrared validated the presence of PEG in the membrane support. Scanning electron microscopy and atomic force microscopy illustrated that the thin-film polyamide layer morphology transformed from a rough to a smooth surface. A cross-flow filtration test indicated that a thin-film composite polyamide membrane comprising a PSf support (TFC-PEG20k with a low surface porosity, small pore size, and suitable hydrophilicity delivered the highest water flux and separation efficiency (J = 81.1 ± 6.4 L·m−2·h−1, RNa2SO4 = 91.1% ± 1.8%, and RNaCl = 35.7% ± 3.1% at 0.60 MPa. This membrane had a molecular weight cutoff of 292 g/mol and also a high rejection for negatively charged dyes. Therefore, a PSf support exhibiting suitable physicochemical properties endowed a thin-film composite polyamide membrane with high performance.

  4. COMPOSITE POLYMERICADDITIVESDESIGNATED FORCONCRETEMIXES BASED ONPOLYACRYLATES, PRODUCTS OF THERMAL DECOMPOSITION OF POLYAMIDE-6 AND LOW-MOLECULAR POLYETHYLENE

    Directory of Open Access Journals (Sweden)

    Polyakov Vyacheslav Sergeevich

    2012-07-01

    4 the optimal composite additive that increases the time period of stiffening of the cement grout , improves the water resistance and the compressive strength of concrete, represents the composition of polyacrylates and polymethacrylates, products of thermal decomposition of polyamide-6 and low-molecular polyethylene in the weight ratio of 1:1:0.5.

  5. Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Salama, Farid

    2010-01-01

    Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

  6. Bio-Based Aromatic Epoxy Monomers for Thermoset Materials

    Directory of Open Access Journals (Sweden)

    Feifei Ng

    2017-01-01

    Full Text Available The synthesis of polymers from renewable resources is a burning issue that is actively investigated. Polyepoxide networks constitute a major class of thermosetting polymers and are extensively used as coatings, electronic materials, adhesives. Owing to their outstanding mechanical and electrical properties, chemical resistance, adhesion, and minimal shrinkage after curing, they are used in structural applications as well. Most of these thermosets are industrially manufactured from bisphenol A (BPA, a substance that was initially synthesized as a chemical estrogen. The awareness on BPA toxicity combined with the limited availability and volatile cost of fossil resources and the non-recyclability of thermosets implies necessary changes in the field of epoxy networks. Thus, substitution of BPA has witnessed an increasing number of studies both from the academic and industrial sides. This review proposes to give an overview of the reported aromatic multifunctional epoxide building blocks synthesized from biomass or from molecules that could be obtained from transformed biomass. After a reminder of the main glycidylation routes and mechanisms and the recent knowledge on BPA toxicity and legal issues, this review will provide a brief description of the main natural sources of aromatic molecules. The different epoxy prepolymers will then be organized from simple, mono-aromatic di-epoxy, to mono-aromatic poly-epoxy, to di-aromatic di-epoxy compounds, and finally to derivatives possessing numerous aromatic rings and epoxy groups.

  7. Aromatization of n-octane over Pd/C catalysts

    KAUST Repository

    Yin, Mengchen; Natelson, Robert H.; Campos, Andrew A.; Kolar, Praveen; Roberts, William L.

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  8. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic compounds has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  9. Highly Porous, Rigid-Rod Polyamide Aerogels with Superior Mechanical Properties and Unusually High Thermal Conductivity.

    Science.gov (United States)

    Williams, Jarrod C; Nguyen, Baochau N; McCorkle, Linda; Scheiman, Daniel; Griffin, Justin S; Steiner, Stephen A; Meador, Mary Ann B

    2017-01-18

    We report here the fabrication of polyamide aerogels composed of poly-p-phenylene-terephthalamide, the same backbone chemistry as DuPont's Kevlar. The all-para-substituted polymers gel without the use of cross-linker and maintain their shape during processing-an improvement over the meta-substituted cross-linked polyamide aerogels reported previously. Solutions containing calcium chloride (CaCl 2 ) and para-phenylenediamine (pPDA) in N-methylpyrrolidinone (NMP) at low temperature are reacted with terephthaloyl chloride (TPC). Polymerization proceeds over the course of 5 min resulting in gelation. Removal of the reaction solvent via solvent exchange followed by extraction with supercritical carbon dioxide provides aerogels with densities ranging from 0.1 to 0.3 g/cm 3 , depending on the concentration of calcium chloride, the formulated number of repeat units, n, and the concentration of polymer in the reaction mixture. These variables were assessed in a statistical experimental study to understand their effects on the properties of the aerogels. Aerogels made using at least 30 wt % CaCl 2 had the best strength when compared to aerogels of similar density. Furthermore, aerogels made using 30 wt % CaCl 2 exhibited the lowest shrinkage when aged at elevated temperatures. Notably, whereas most aerogel materials are highly insulating (thermal conductivities of 10-30 mW/m K), the polyamide aerogels produced here exhibit remarkably high thermal conductivities (50-80 mW/(m K)) at the same densities as other inorganic and polymer aerogels. These high thermal conductivities are attributed to efficient phonon transport by the rigid-rod polymer backbone. In conjunction with their low cost, ease of fabrication with respect to other polymer aerogels, low densities, and high mass-normalized strength and stiffness properties, these aerogels are uniquely valuable for applications such as lightweighting in consumer electronics, automobiles, and aerospace where weight reduction is

  10. Toughened nanocomposites of polyamide-6 and polyepichlorohydrin elastomer: mechanical and morphological properties

    International Nuclear Information System (INIS)

    Pinotti, Caio A.; Goncalves, Maria C.; Felisberti, Maria I.

    2009-01-01

    Blends of polyamide 6, P A6, and polyepichlorohydrin elastomer, PE Pi, nano composites of P A6 and OMMT and toughened nano composites, P A6/PE Pi/OMMT were prepared by twin-screw extrusion. Nanocomposites of P A6 and organophilic clay presented morphology of exfoliated clay with the presence of some tactoids, which were investigated by XRD and TEM. The blends P A6/PE Pi are immiscible with morphology of elastomer disperse phase. The size of the elastomer phase in the PA6 matrix and a better distribution of these phase were achieved with the incorporation of the clay in the ternary nanocomposites. Toughened nano composites presented increases in Young's modulus, Izod impact strength and yield stress, comparing with the blends of P A6 and polyepichlorohydrin elastomer. (author)

  11. Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

    International Nuclear Information System (INIS)

    Ugucioni, J.C.; Ghilardi Netto, T.; Mulato, M.

    2010-01-01

    Mercuric iodide (HgI 2 ) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI 2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 o C, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI 2 crystalline device.

  12. The Development of Biomimetic Spherical Hydroxyapatite/Polyamide 66 Biocomposites as Bone Repair Materials

    Directory of Open Access Journals (Sweden)

    Xuesong Zhang

    2014-01-01

    Full Text Available A novel biomedical material composed of spherical hydroxyapatite (s-HA and polyamide 66 (PA biocomposite (s-HA/PA was prepared, and its composition, mechanical properties, and cytocompatibility were characterized and evaluated. The results showed that HA distributed uniformly in the s-HA/PA matrix. Strong molecule interactions and chemical bonds were presented between the s-HA and PA in the composites confirmed by IR and XRD. The composite had excellent compressive strength in the range between 95 and 132 MPa, close to that of natural bone. In vitro experiments showed the s-HA/PA composite could improve cell growth, proliferation, and differentiation. Therefore, the developed s-HA/PA composites in this study might be used for tissue engineering and bone repair.

  13. Surface modification of polyamide thin film composite membrane by coating of titanium dioxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Thu Hong Anh Ngo

    2016-12-01

    Full Text Available In this paper, the coating of TiO2 nanoparticles onto the surface of a polyamide thin film composite nanofiltration membrane has been studied. Changes in the properties and separation performance of the modified membranes were systematically characterized. The experimental results indicated that the membrane surface hydrophilicity was significantly improved by the presence of the coated TiO2 nanoparticles with subsequent UV irradiation. The separation performance of the UV-irradiated TiO2-coated membranes was improved with a great enhancement of flux and a very high retention for removal of residual dye in an aqueous feed solution. The antifouling property of the UV-irradiated TiO2-coated membranes was enhanced with higher maintained flux ratios and lower irreversible fouling factors compared with an uncoated membrane.

  14. Thermal and mechanical properties of polyamide 6/compatibilizer/clay nano composites

    International Nuclear Information System (INIS)

    Agrawal, P.; Brito, G.F.; Cunha, C.T.C.; Araujo, E.M.; Melo, T.J.A.

    2010-01-01

    In this work, the thermal and mechanical properties of Polyamide 6 (PA6)/compatibilizer/clay (CL20A) nanocomposites were investigated. The nanocomposites were prepared in a counter-rotating twin screw extruder at 240 deg C and 50 rpm, and characterized by X-Ray Diffraction (XRD), Thermogravimetry (TG) and mechanical properties. XRD results showed that when the clay is mixed with PA6, the clay peak is shifted to lower 2θ angles, indicating that PA6 was intercalated between the clay platelets. For PA6/compatibilizer/clay system, the results indicated that a nanocomposite with exfoliated structure was formed. TG results showed that the thermal stability of PA6/CL20A and PA6/compatibilizer/CL20A was higher than that of neat PA6. The mechanical properties results showed that the addition of the compatibilizer to PA6/CL20A substantially increased the impact strength and decreased the stiffness. (author)

  15. Characterization of an aluminum-filled polyamide powder for applications in selective laser sintering

    International Nuclear Information System (INIS)

    Mazzoli, Alida; Moriconi, Giacomo; Pauri, Marco Giuseppe

    2007-01-01

    Solid free-form fabrication (SFF) techniques use layer-based manufacturing to create physical objects directly from computer-generated models. Using an additive approach to manufacture shapes, SFF systems join liquid, powder or sheet materials. Selective laser sintering (SLS) is a SFF technique by which parts are built layer-by-layer offering the key advantage of the direct manufacturing of functional parts. In SLS, a laser beam is traced over the surface of a tightly compacted powder made of thermoplastic material. In this paper is characterized a new aluminum-filled polyamide powder developed for applications in SLS. This material is promising for many applications that require a metallic look of the part, good finishing properties, high stiffness and higher part quality

  16. Preliminary biocompatible evaluation of nano-hydroxyapatite/polyamide 66 composite porous membrane

    Directory of Open Access Journals (Sweden)

    Yili Qu

    2010-06-01

    Full Text Available Yili Qu1,3, Ping Wang1,3, Yi Man1, Yubao Li2, Yi Zuo2, Jidong Li21State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064, China; 2Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu 610064, China; 3These authors contributed equally to this workAbstract: Nano-hydroxyapatite/polyamide 66 (nHA/PA66 composite with good bioactivity and osteoconductivity was employed to develop a novel porous membrane with asymmetric structure for guided bone regeneration (GBR. In order to test material cytotoxicity and to investigate surface-dependent responses of bone-forming cells, the morphology, proliferation, and cell cycle of bone marrow stromal cells (BMSCs of rats cultured on the prepared membrane were determined. The polygonal and fusiform shape of BMSCs was observed by scanning electronic microscopy (SEM. The proliferation of BMSCs cultured on nHA/PA66 membrane tested by the MTT method (MTT: [3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazoliumbromide] was higher than that of negative control groups for 1 and 4 days’ incubation and had no significant difference for 7 and 11 days’ culture. The results of cell cycle also suggested that the membrane has no negative influence on cell division. The nHA/PA66 membranes were then implanted into subcutaneous sites of nine Sprague Dawley rats. The wounds and implant sites were free from suppuration and necrosis in all periods. All nHA/PA66 membranes were surrounded by a fibrous capsule with decreasing thickness 1 to 8 weeks postoperatively. In conclusion, the results of the in vitro and in vivo studies reveal that nHA/PA66 membrane has excellent biocompatibility and indicate its use in guided tissue regeneration (GTR or GBR.Keywords: hydroxyapatite/polyamide, barrier membrane, biocompatibility, guided bone regeneration

  17. Novel thermoplastic vulcanizates (TPVs based on silicone rubber and polyamide exploring peroxide cross-linking

    Directory of Open Access Journals (Sweden)

    K. Naskar

    2014-04-01

    Full Text Available Novel thermoplastic vulcanizates (TPVs based on silicone rubber (PDMS and polyamide (PA12 have been prepared by dynamic vulcanization process. The effect of dynamic vulcanization and influence of various types of peroxides as cross-linking agents were studied in detail. All the TPVs were prepared at a ratio of 50/50 wt% of silicone rubber and polyamide. Three structurally different peroxides, namely dicumyl peroxide (DCP, 3,3,5,7,7-pentamethyl 1,2,4-trioxepane (PMTO and cumyl hydroperoxide (CHP were taken for investigation. Though DCP was the best option for curing the silicone rubber, at high temperature it suffers from scorch safety. An inhibitor 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO was added with DCP to stabilize the radicals in order to increase the scorch time. Though CHP (hydroperoxide had higher half life time than DCP at higher temperature, it has no significant effect on cross-linking of silicone rubber. PMTO showed prolonged scorch safety and better cross-linking efficiency rather than the other two. TPVs of DCP and PMTO were made up to 11 minutes of mixing. Increased values of tensile strength and elongation at break of PMTO cross-linked TPV indicate the superiority of PMTO. Scanning electron micrographs correlate with mechanical properties of the TPVs. High storage modulus (E' and lower loss tangent value of the PMTO cross-linked TPV indicate the higher degree of cross-linking which is also well supported by the overall cross-link density value. Thus PMTO was found to be the superior peroxide for cross-linking of silicone rubber at high temperature.

  18. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2011-09-01

    Full Text Available We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42−. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization

  19. Measurements of mass-fraction activity coefficient at infinite dilution of aliphatic and aromatic hydrocarbons, thiophene, alcohols, water, ethers, and ketones in hyperbranched polymer, Boltorn H2004, using inverse gas chromatography

    International Nuclear Information System (INIS)

    Domanska, Urszula; Zolek-Tryznowska, Zuzanna

    2010-01-01

    Thermodynamic properties of the hyperbranched polymer, Boltorn H2004 (B-H2004), were investigated by inverse gas chromatography with 42 different solvents: n-alkanes (C 5 -C 10 ), cycloalkanes (C 5 -C 8 ), alkenes (C 5 -C 8 ), alkynes (C 5 -C 8 ), aromatic hydrocarbons (benzene, toluene, ethylbenzene, o-, m-, p-xylene, thiophene), alcohols (C 1 -C 5 ), water, ethers (tetrahydrofuran (THF), methyl-tert-butylether (MTBE), diethyl-, di-n-propyl-, di-n-butyl ether), and ketones (acetone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, cyclopentanone) at the temperatures from (308.15 to 348.15) K using the inverse gas chromatography (IGC). The density and thermophysical properties of polymer were described. The specific retention volume (V g ), the mass-fraction activity coefficient at infinite dilution (Ω 13 ∞ ), the Flory-Huggins interaction parameter (χ 13 ∞ ), the molar enthalpy of sorption in the polymer (Δ s H), the partial molar excess enthalpy at infinite dilution (ΔH 1 E,∞ ), the molar enthalpy of vaporization to the ideal-gas state for the pure solutes (Δ vap H 0 ), the partial molar Gibbs excess energy at infinite dilution (ΔG 1 E,∞ ), and the solubility parameter of the polymer (δ 3 ), were calculated. The UNIFAC-FV model was used to predict the mass-fraction activity coefficient at infinite dilution for different solutes in the B-H2004 polymer.

  20. Fused aromatic thienopyrazines: structure, properties and function

    KAUST Repository

    Mondal, Rajib; Ko, Sangwon; Bao, Zhenan

    2010-01-01

    Recent development of a fused aromatic thieno[3.4-b]pyrazine system and their application in optoelectronic devices are reviewed. Introduction of a fused aromatic unit followed by side chain engineering, dramatically enhanced the charge carrier

  1. Converting lignin to aromatics: step by step

    NARCIS (Netherlands)

    Strassberger, Z.I.

    2014-01-01

    Lignin, the glue that holds trees together, is the most abundant natural resource of aromatics. In that respect, it is a far more advanced resource than crude oil. This is because lignin already contains the aromatic functional groups. Thus, catalytic conversion of lignin to high-value aromatics is

  2. Design and screening of ASIC inhibitors based on aromatic diamidines for combating neurological disorders.

    Science.gov (United States)

    Chen, Xuanmao; Orser, Beverley A; MacDonald, John F

    2010-12-01

    Acid sensing ion channels (ASICs) are implicated in various brain functions including learning and memory and are involved in a number of neurological disorders such as pain, ischemic stroke, depression, and multiple sclerosis. We have recently defined ASICs as one of receptor targets of aromatic diamidines in neurons. Aromatic diamidines are DNA-binding agents and have long been used in the treatment of leishmaniasis, trypanosomiasis, pneumocystis pneumonia and babesiosis. Moreover, some aromatic diamidines are used as skin-care and baby products and others have potential to suppress tumor growth or to combat malaria. A large number of aromatic diamidines or analogs have been synthesized. Many efforts are being made to optimize the therapeutic spectrum of aromatic diamidines, i.e. to reduce toxicity, increase oral bioavailability and enhance their penetration of the blood-brain barrier. Aromatic diamidines therefore provide a shortcut of screening for selective ASIC inhibitors with therapeutic potential. Intriguingly nafamostat, a protease inhibitor for treating acute pancreatitis, also inhibits ASIC activities. Aromatic diamidines and nafamostat have many similarities although they belong to distinct classes of medicinal agents for curing different diseases. Here we delineate background, clinical application and drug development of aromatic diamidines that could facilitate the screening for selective ASIC inhibitors for research purposes. Further studies may lead to a drug with therapeutic value and extend the therapeutic scope of aromatic diamidines to combat neurological diseases. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. An ethnopharmacological study of aromatic Uyghur medicinal plants in Xinjiang, China.

    Science.gov (United States)

    Zhao, Lu; Tian, Shuge; Wen, E; Upur, Halmuart

    2017-12-01

    An ethnobotanical survey was completed in a remote village and surrounding country of Xinjiang, where most Uyghur medicinal plants could be collected. This work clarifies and increases ethnobotanical data. We surveyed and organized aromatic medicinal plants that are commonly used in clinical settings to provide a significant reference for studying new medical activities. In the survey, informants who have traditional knowledge on aromatic Uyghur medicinal plants were interviewed between March 2014 and September 2014. Aromatic medicinal plant species and pertinent information were collected. Some therapeutic methods and modes of preparation of traditional aromatic medicinal plants were found. A total of 86 aromatic medicinal plant species belonging to 36 families were included in our study. We identified 34 plant species introduced from different regions such as Europe, India and Mediterranean areas. Fruits and whole plants were the most commonly used parts of plant, and most aromatic medicinal plants could be applied as medicine and food. We assigned the medicinal plants a use value (UV). Knowing the UV of species is useful in determining the use reliability and pharmacological features of related plants. Xinjiang is an area in which indigenous aromatic medicinal plants are diversely used and has therefore established a sound dimensional medical healthcare treatment system. Some aromatic Uyghur medicinal plants are on the verge of extinction. Hence, further strategies for the conservation of these aromatic medicinal plants should be prioritized.

  4. Synthesis and characterization of novel polyamide-ethers based on bis-imidazole containing bulky aryl pendant groups

    Directory of Open Access Journals (Sweden)

    Seyed Mahdi Saadati

    2013-01-01

    Full Text Available A series of novel polyamide-ethers (PAEs based on bis-imidazole containing bulky aryl pendant groups was prepared by direct polycondensation of a diamine, 4-(1-(4-(4-(2-(4-aminophenyl-4,5-diphenyl-1H-imidazol-1-ylphenoxyphenyl-4,5-diphenyl-1H-imidazol-2-ylbenzenamine (DABI, and various dicarboxylic acids. All the resulting polyamide-ethers were amorphous with inherent viscosities ranged from 0.52 to 0.61 dL/g and were readily soluble in many organic solvents which could be solution-cast into transparent and tough films. The glass transition temperatures (Tg of these polymers were affected considerably by their chemical structure and ranged from 230 to 310 ºC. They had useful levels of thermal stability associated with relatively high temperatures of 10% weight loss (T10 in the range of 329-399 ºC in air atmosphere.

  5. The influence of sterilisation on the macromechanical properties of polyamide fibre-reinforced PDMS composites for orthopaedic applications

    Czech Academy of Sciences Publication Activity Database

    Sedláček, R.; Suchý, Tomáš; Sucharda, Zbyněk; Balík, Karel; Sochor, M.; Šepitka, J.; Lukeš, J.

    2012-01-01

    Roč. 15, S1 (2012), s. 91-92 ISSN 1025-5842. [Congress of the Société de Biomécanique /37./. Toulouse, 16.10.2012-19.10.2012] R&D Projects: GA ČR(CZ) GAP108/10/1457 Institutional research plan: CEZ:AV0Z30460519 Keywords : composite material * polymer matrix * polyamide Subject RIV: JI - Composite Materials Impact factor: 1.393, year: 2012

  6. The mutagenic potential of high flash aromatic naphtha.

    Science.gov (United States)

    Schreiner, C A; Edwards, D A; McKee, R H; Swanson, M; Wong, Z A; Schmitt, S; Beatty, P

    1989-06-01

    Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent--high-flash aromatic naphtha. A program was initiated to assess the toxicological properties of high-flash aromatic naphtha since there may be human exposure through inhalation or external body contact. The current study was conducted partly to assess the potential for mutagenic activity and also to assist in an assessment of carcinogenic potential. The specific tests utilized included the Salmonella/mammalian microsome mutagenicity assay, the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) forward mutation assay in CHO cells, in vitro chromosome aberration and sister chromatid exchange (SCE) assays in CHO cells, and an in vivo chromosome aberration assay in rat bone marrow.

  7. Studies on low-carrier radiofluorination of non-active aromatics with no-carrier-added [{sup 18}F]fluoride; Untersuchungen zur traegerarmen Radiofluorierung nicht-aktiver Aromaten mit n.c.a. [{sup 18}F]Fluorid

    Energy Technology Data Exchange (ETDEWEB)

    Cardinale, Jens

    2013-01-15

    In vivo imaging with positron emission tomography generally demands radiotracers with a high specific activity. In case of fluorine-18 the required no-carrier-added (n.c.a.) starting material is only available in form of fluoride. This and the short half-life of 109.7 minutes of the radionuclide lead to the demand of special methods for radiosyntheses. The only practical procedure for manufacturing n.c.a. [{sup 18}F]fluoro-compounds is therefore nucleophilic substitution. There is, however, still a lack of effective procedures for the labelling of electron rich aromatic molecules starting from n.c.a. [{sup 18}F]fluoride. A process for n.c.a. radiofluorination of these compounds is offered by the reaction of iodonium compounds as starting materials. In this study modern procedures for the synthesis of iodoniumsalts and -ylides were investigated. Several precursor molecules for the versatile synthetic building block 4-[{sup 18}F]fluoroiodobenzene were synthesised. In this course, a new one-pot procedure for the synthesis of iodoniumylides was developed. Further on, the syntheses of suitable iodonium precursors for two fluorophenoxy-derivatives, which are possible antidepressants, were investigated. Due to their binding profile these compounds can be considered as ligands for the serotonin reuptake transporter (SERT) and the norepinephrin reuptake transporter (NET), respectively. The preparation of appropriate iodonium salts proved to be too problematic, while the synthesis of suitable iodoniumylides could be accomplished with satisfactory yields of about 30% and 40 %, respectively. Both compounds were labelled with n.c.a. [{sup 18}F]fluoride and deprotected to the desired target compounds 4-((3-[{sup 18}F]fluorophenoxy)(phenyl)methyl)piperidine and 4-((4-[{sup 18}F]fluorophenoxy)(phenyl)methyl)piperidine in radiochemical yields of about 40 % and 25 %, respectively. Those are now available for preclinical evaluation studies. Furthermore, a process for the palladium

  8. Phytochemical profile and biological activities of Deverra tortuosa (Desf.)DC.: a desert aromatic shrub widespread in Northern Region of Saudi Arabia.

    Science.gov (United States)

    Guetat, Arbi; Boulila, Abdennacer; Boussaid, Mohamed

    2018-04-16

    The present study describes the chemical composition of the essential oil of different plant parts of Devrra tortuosa; in vivo and in vitro biological activities of plant extract and essential oils. Apiol was found to be the major component of the oil (between 65.73% and 74.41%). The best antioxidant activities were observed for the oil of flowers (IC50 = 175 μg/ml). The samples of stems and roots exhibit lower antioxidant activity (IC50 = 201 μg/ml and 182 μg/ml, respectively). The values of IC50 showed that the extracts of methanol exhibit the highest antioxidants activities (IC50 = 64.8 102 μg/ml). EOs showed excellent antifungal activity against yeasts with low azole susceptibilities (i.e. Malassezia spp. and Candida krusei). The MIC values of oils varied between 2.85 mg/mL and 27 mg/mL. The obtained results also showed that the plant extracts inhibited the germination and the shoot and root growth of Triticum æstivum seedlings.

  9. New polyamides based on 1,3-bis(4-carboxy phenoxy propane and hydantoin derivatives: synthesis and properties

    Directory of Open Access Journals (Sweden)

    Khalil Faghihi

    2010-04-01

    Full Text Available Six new polyamides 5a-f containing flexible trimethylene segments in the main chain were synthesized through the direct polycondensation reaction of 1,3-bis(4-carboxy phenoxy propane 3 with six derivatives of hydantoins 5a-f in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosphite, calcium chloride and pyridine. The polycondensation reaction produced a series of novel polyamides in high yield with inherent viscosities between 0.30-0.47 dL/g. The resulted polymers were fully characterized by means of FT-IR, 1H-NMR spectroscopy, elemental analyses, inherent viscosity, solubility tests and gel permeation chromatography (GPC. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA and differential thermal gravimetry (DTG. The glass-transition temperatures of these polyamides were recorded between 130 and 155 oC by differential scanning calorimetry (DSC, and the 5% weight loss temperatures were ranging from 325 to 415 oC under nitrogen. 1,3-bis(4-Carboxy phenoxy propane 3 was prepared from the reaction of 4-hydroxy benzoic acid 1 with 1,3-dibromo propane 2 in the presence of NaOH solution.

  10. Utilization of rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite

    International Nuclear Information System (INIS)

    Ferro, Waldir Pedro

    2009-01-01

    In order to improve the dimensional stability, as well as, electrical, mechanical and thermal properties of polymers, new filler to this purpose has been developed. The mos applied filler to propitiate the features previously mentioned are the glass and carbon fibers, the mineral filler as the calcium carbonate, the talc and the micro glass sphere. The main aim of this work was to study the rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite, irradiated by electron beam at different doses, since it is constituted of at least 90% of silicon dioxide, and compared with the talc which is the most applied mineral filler. This comparison was made from a compound made through the refined rice husk ash and the polyamide 6 (PA 6), which is one of the main engineering plastic with applications in several productive areas. The samples were injected and irradiated in a electron accelerator. Afterwards, their mechanical and thermal properties were measured. It was also inject automotive parts to verify the processing of the PA 6 with CCA. The results showed that the use of the rice husk ash as filler for polyamide 6 composite is technically and economically viable. The irradiation of the studied composite (PA 6 with 30% of rice husk ash) did not provide any improvement for the mechanical and thermal properties previously appraised. (author)

  11. Effect of fiber content on flexural properties of glass fiber-reinforced polyamide-6 prepared by injection molding.

    Science.gov (United States)

    Nagakura, Manamu; Tanimoto, Yasuhiro; Nishiyama, Norihiro

    2017-07-26

    The use of non-metal clasp denture (NMCD) materials may seriously affect the remaining tissues because of the low rigidity of NMCD materials such as polyamides. The purpose of this study was to develop a high-rigidity glass fiber-reinforced thermoplastic (GFRTP) composed of E-glass fiber and polyamide-6 for NMCDs using an injection molding. The reinforcing effects of fiber on the flexural properties of GFRTPs were investigated using glass fiber content ranging from 0 to 50 mass%. Three-point bending tests indicated that the flexural strength and elastic modulus of a GFRTP with a fiber content of 50 mass% were 5.4 and 4.7 times higher than those of unreinforced polyamide-6, respectively. The result showed that the physical characteristics of GFRTPs were greatly improved by increasing the fiber content, and the beneficial effects of fiber reinforcement were evident. The findings suggest that the injection-molded GFRTPs are adaptable to NMCDs because of their excellent mechanical properties.

  12. Effect of ultraviolet light irradiation and sandblasting treatment on bond strengths between polyamide and chemical-cured resin.

    Science.gov (United States)

    Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

    2014-01-01

    The aim of this study was to evaluate the effects of ultraviolet light (UV) irradiation and sandblasting treatment on the shear bond strength between polyamide and chemical-cured resin. Three types of commercial polyamides were treated using UV irradiation, sandblasting treatment, and a combining sandblasting and UV irradiation. The shear bond strength was measured and analyzed using the Kruskal-Wallis test (α=0.05). Comparing shear bond strengths without surface treatment, from 4.1 to 5.7 MPa, the UV irradiation significantly increased the shear bond strengths except for Valplast, whose shear bond strengths ranged from 5.2 to 9.3 MPa. The sandblasting treatment also significantly increased the shear bond strengths (8.0 to 11.4 MPa). The combining sandblasting and UV irradiation significantly increased the shear bond strengths (15.2 to 18.3 MPa) comparing without surface treatment. This combined treatment was considered the most effective at improving the shear bond strength between polyamide and chemical-cured resin.

  13. Improvement of surface wettability and interfacial adhesion of poly-(p-phenylene terephthalamide) by incorporation of the polyamide benzimidazole segment

    International Nuclear Information System (INIS)

    Cai Renqin; Peng Tao; Wang Fengde; Ye Guangdou; Xu Jianjun

    2011-01-01

    In order to investigate the effect of the polyamide benzimidazole group on the surface wettability and interfacial adhesion of fiber/matrix composites, surface features of two kinds of aramid fibers, poly (p-phenylene terephthalamide) fiber (Kevlar-49) and poly-(polyamide benzimidazole-co-p-phenylene terephthalamide) (DAFIII), have been analyzed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis (CAA) system, respectively. The results show that with the incorporation of the polyamide benzimidazole segment, more polar functional groups exist on DAFIII surface. The contact angles of water and diiodomethane on DAFIII surface get smaller. The surface free energy of DAFIII increases to 36.5 mJ/m 2 , which is 2.3% higher than that of Kevlar-49. In addition, DAFIII has a larger rough surface compared with that of Kevlar-49 due to different spinning processes. The interfacial shear strength (IFSS) of DAFIII/matrix composite is 25.7% higher than that of Kevlar-49/matrix composite, in agreement with the observed results from surface feature tests. SEM micrographs of failed micro-droplet specimens reveal a strong correlation between the fracture features and the observed test data.

  14. Ligand-Controlled Chemoselective C(acyl)–O Bond vs C(aryl)–C Bond Activation of Aromatic Esters in Nickel Catalyzed C(sp2)–C(sp3) Cross-Couplings

    KAUST Repository

    Chatupheeraphat, Adisak

    2018-02-20

    A ligand-controlled and site-selective nickel catalyzed Suzuki-Miyaura cross-coupling reaction with aromatic esters and alkyl organoboron reagents as coupling partners was developed. This methodology provides a facile route for C(sp2)-C(sp3) bond formation in a straightforward fashion by successful suppression of the undesired β-hydride elimination process. By simply switching the phosphorus ligand, the ester substrates are converted into the alkylated arenes and ketone products, respectively. The utility of this newly developed protocol was demonstrated by its wide substrate scope, broad functional group tolerance and application in the synthesis of key intermediates for the synthesis of bioactive compounds. DFT studies on the oxidative addition step helped rationalizing this intriguing reaction chemoselectivity: whereas nickel complexes with bidentate ligands favor the C(aryl)-C bond cleavage in the oxidative addition step leading to the alkylated product via a decarbonylative process, nickel complexes with monodentate phosphorus ligands favor activation of the C(acyl)-O bond, which later generates the ketone product.

  15. New optically active and thermally stable poly(amide-imide)s containing N,N'-(Bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-L-alanine and aromatic diamines: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Faghihi, Khalil; Absalar, Morteza; Hajibeygi, Mohsen [Arak University (Iran, Islamic Republic of). Faculty of Science. Organic Polymer Chemistry Research Lab.

    2009-07-01

    Five new optically active poly(amide-imide)s (PAIs) 6a-e were prepared by direct polycondensation reaction of the newly synthesized N,N'-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-alanine 4 with various aromatic diamines 5a-e using polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP). In this technique triphenyl phosphite (TPP) and pyridine were used as condensing agents to form poly(amide-imide)s through the N-phosphonium salts of pyridine. All of the polymers were obtained in quantitative yields with inherent viscosities between 0.29-0.46 dL g{sup -1} and were highly soluble in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl- 2-pyrrolidone (NMP) and solvents such as sulfuric acid. They were fully characterized by means of {sup 1}H NMR, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of these polymers were investigated using thermogravimetric analysis techniques (TGA and DTG). (author)

  16. New optically active and thermally stable poly(amide-imide)s containing N,N'-(Bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-L-alanine and aromatic diamines: synthesis and characterization

    International Nuclear Information System (INIS)

    Faghihi, Khalil; Absalar, Morteza; Hajibeygi, Mohsen

    2009-01-01

    Five new optically active poly(amide-imide)s (PAIs) 6a-e were prepared by direct polycondensation reaction of the newly synthesized N,N'-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-alanine 4 with various aromatic diamines 5a-e using polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP). In this technique triphenyl phosphite (TPP) and pyridine were used as condensing agents to form poly(amide-imide)s through the N-phosphonium salts of pyridine. All of the polymers were obtained in quantitative yields with inherent viscosities between 0.29-0.46 dL g -1 and were highly soluble in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl- 2-pyrrolidone (NMP) and solvents such as sulfuric acid. They were fully characterized by means of 1 H NMR, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of these polymers were investigated using thermogravimetric analysis techniques (TGA and DTG). (author)

  17. Toxicity and antifeedant activity of essential oils from three aromatic plants grown in Colombia against Euprosterna elaeasa and Acharia fusca(Lepidoptera:Limacodidae)

    Institute of Scientific and Technical Information of China (English)

    Ricardo; Hernández-Lambrao; Karina; Caballero-Gallardo; Jesus; Olivero-Verbel

    2014-01-01

    Objective:To determine the biological effects of essential oils(EOs) isolated from Cymbopogon iiardus,Cymbopogon Jlexuosus and Cvrnbopogon marlinii grown in Colombia against two Lepidoptera larvae,common pests in the oil palm.Methods:Specimens were captured in the field and the antifeedant activity and dermal contact lethality of EOs were measured against Acharia fusca and Euprosterna elaeasa(Lepidoptera:I.imacodidae) at various concentrations 0.002-0.600 μL/cm~3 and 0.002-8 μL/g,respectively.Results:All EOs exhibited strong antifeedant and toxicity activity toward Acharia fusca and Euprosterna elaeasa larvae.Cymbopogon marlinii oil was llie most active againsl both pest insect species,although all tested EOs were better than the synthetic;repellent IR535 on both insects.Conclusions:Colombian EOs have potential for integrated pest management programs in the oil palm industry.

  18. Toxicity and antifeedant activity of essential oils from three aromatic plants grown in Colombia against Euprosterna elaeasa and Acharia fusca (Lepidoptera:Limacodidae)

    Institute of Scientific and Technical Information of China (English)

    Ricardo Hernández-Lambraño; Karina Caballero-Gallardo; Jesus Olivero-Verbel

    2014-01-01

    Objective:To determine the biological effects of essential oils (EOs) isolated from Cymbopogon nardus, Cymbopogon flexuosus and Cymbopogon martinii grown in Colombia against two Lepidoptera larvae, common pests in the oil palm. Methods:Specimens were captured in the field and the antifeedant activity and dermal contact lethality of EOs were measured against Acharia fusca and Euprosterna elaeasa (Lepidoptera:Limacodidae) at various concentrations 0.002-0.600 μL/cm2 and 0.002-8 μL/g, respectively. Results: All EOs exhibited strong antifeedant and toxicity activity toward Acharia fusca and Euprosterna elaeasa larvae. Cymbopogon martinii oil was the most active against both pest insect species, although all tested EOs were better than the synthetic repellent IR3535 on both insects. Conclusions:Colombian EOs have potential for integrated pest management programs in the oil palm industry.

  19. A Comprehensive Review on the Phytochemical Constituents and Pharmacological Activities of Pogostemon cablin Benth.: An Aromatic Medicinal Plant of Industrial Importance.

    Science.gov (United States)

    Swamy, Mallappa Kumara; Sinniah, Uma Rani

    2015-05-12

    Pogostemon cablin Benth. (patchouli) is an important herb which possesses many therapeutic properties and is widely used in the fragrance industries. In traditional medicinal practices, it is used to treat colds, headaches, fever, nausea, vomiting, diarrhea, abdominal pain, insect and snake bites. In aromatherapy, patchouli oil is used to relieve depression, stress, calm nerves, control appetite and to improve sexual interest. Till now more than 140 compounds, including terpenoids, phytosterols, flavonoids, organic acids, lignins, alkaloids, glycosides, alcohols, aldehydes have been isolated and identified from patchouli. The main phytochemical compounds are patchouli alcohol, α-patchoulene, β-patchoulene, α-bulnesene, seychellene, norpatchoulenol, pogostone, eugenol and pogostol. Modern studies have revealed several biological activities such as antioxidant, analgesic, anti-inflammatory, antiplatelet, antithrombotic, aphrodisiac, antidepressant, antimutagenic, antiemetic, fibrinolytic and cytotoxic activities. However, some of the traditional uses need to be verified and may require standardizing and authenticating the bioactivity of purified compounds through scientific methods. The aim of the present review is to provide comprehensive knowledge on the phytochemistry and pharmacological activities of essential oil and different plant extracts of patchouli based on the available scientific literature. This information will provide a potential guide in exploring the use of main active compounds of patchouli in various medical fields.

  20. Generalized cytochrome P450-mediated oxidation and oxygenation reactions in aromatic substrates with activated N-H, O-H, C-H, or S-H substituents

    NARCIS (Netherlands)

    Koymans, L.; Donné-Op den Kelder, G M; te Koppele, J.M.; Vermeulen, N P

    1. The general mechanism of metabolic oxidation of substrates by cytochromes P450 (P450s) appears to consist of sequential one-electron oxidation steps rather than of a single concerted transfer of activated oxygen species from P450 to substrates. 2. In case of the acetanilides paracetamol (PAR),

  1. A Comprehensive Review on the Phytochemical Constituents and Pharmacological Activities of Pogostemon cablin Benth.: An Aromatic Medicinal Plant of Industrial Importance

    Directory of Open Access Journals (Sweden)

    Mallappa Kumara Swamy

    2015-05-01

    Full Text Available Pogostemon cablin Benth. (patchouli is an important herb which possesses many therapeutic properties and is widely used in the fragrance industries. In traditional medicinal practices, it is used to treat colds, headaches, fever, nausea, vomiting, diarrhea, abdominal pain, insect and snake bites. In aromatherapy, patchouli oil is used to relieve depression, stress, calm nerves, control appetite and to improve sexual interest. Till now more than 140 compounds, including terpenoids, phytosterols, flavonoids, organic acids, lignins, alkaloids, glycosides, alcohols, aldehydes have been isolated and identified from patchouli. The main phytochemical compounds are patchouli alcohol, α-patchoulene, β-patchoulene, α-bulnesene, seychellene, norpatchoulenol, pogostone, eugenol and pogostol. Modern studies have revealed several biological activities such as antioxidant, analgesic, anti-inflammatory, antiplatelet, antithrombotic, aphrodisiac, antidepressant, antimutagenic, antiemetic, fibrinolytic and cytotoxic activities. However, some of the traditional uses need to be verified and may require standardizing and authenticating the bioactivity of purified compounds through scientific methods. The aim of the present review is to provide comprehensive knowledge on the phytochemistry and pharmacological activities of essential oil and different plant extracts of patchouli based on the available scientific literature. This information will provide a potential guide in exploring the use of main active compounds of patchouli in various medical fields.

  2. Phytochemical Profile and Evaluation of the Biological Activities of Essential Oils Derived from the Greek Aromatic Plant Species Ocimum basilicum, Mentha spicata, Pimpinella anisum and Fortunella margarita

    Directory of Open Access Journals (Sweden)

    Eleni Fitsiou

    2016-08-01

    Full Text Available Natural products, known for their medicinal properties since antiquity, are continuously being studied for their biological properties. In the present study, we analyzed the composition of the volatile preparations of essential oils of the Greek plants Ocimum basilicum (sweet basil, Mentha spicata (spearmint, Pimpinella anisum (anise and Fortunella margarita (kumquat. GC/MS analyses revealed that the major components in the essential oil fractions, were carvone (85.4% in spearmint, methyl chavicol (74.9% in sweet basil, trans-anethole (88.1% in anise, and limonene (93.8% in kumquat. We further explored their biological potential by studying their antimicrobial, antioxidant and antiproliferative activities. Only the essential oils from spearmint and sweet basil demonstrated cytotoxicity against common foodborne bacteria, while all preparations were active against the fungi Saccharomyces cerevisiae and Aspergillus niger. Antioxidant evaluation by DPPH and ABTS radical scavenging activity assays revealed a variable degree of antioxidant potency. Finally, their antiproliferative potential was tested against a panel of human cancer cell lines and evaluated by using the sulforhodamine B (SRB assay. All essential oil preparations exhibited a variable degree of antiproliferative activity, depending on the cancer model used, with the most potent one being sweet basil against an in vitro model of human colon carcinoma.

  3. Phytochemical Profile and Evaluation of the Biological Activities of Essential Oils Derived from the Greek Aromatic Plant Species Ocimum basilicum, Mentha spicata, Pimpinella anisum and Fortunella margarita.

    Science.gov (United States)

    Fitsiou, Eleni; Mitropoulou, Gregoria; Spyridopoulou, Katerina; Tiptiri-Kourpeti, Angeliki; Vamvakias, Manolis; Bardouki, Haido; Panayiotidis, Mihalis Ι; Galanis, Alex; Kourkoutas, Yiannis; Chlichlia, Katerina; Pappa, Aglaia

    2016-08-16

    Natural products, known for their medicinal properties since antiquity, are continuously being studied for their biological properties. In the present study, we analyzed the composition of the volatile preparations of essential oils of the Greek plants Ocimum basilicum (sweet basil), Mentha spicata (spearmint), Pimpinella anisum (anise) and Fortunella margarita (kumquat). GC/MS analyses revealed that the major components in the essential oil fractions, were carvone (85.4%) in spearmint, methyl chavicol (74.9%) in sweet basil, trans-anethole (88.1%) in anise, and limonene (93.8%) in kumquat. We further explored their biological potential by studying their antimicrobial, antioxidant and antiproliferative activities. Only the essential oils from spearmint and sweet basil demonstrated cytotoxicity against common foodborne bacteria, while all preparations were active against the fungi Saccharomyces cerevisiae and Aspergillus niger. Antioxidant evaluation by DPPH and ABTS radical scavenging activity assays revealed a variable degree of antioxidant potency. Finally, their antiproliferative potential was tested against a panel of human cancer cell lines and evaluated by using the sulforhodamine B (SRB) assay. All essential oil preparations exhibited a variable degree of antiproliferative activity, depending on the cancer model used, with the most potent one being sweet basil against an in vitro model of human colon carcinoma.

  4. Chemical composition and biological activity of essential oils from wild growing aromatic plant species of Skimmia laureola and Juniperus macropoda from Western Himalaya

    Science.gov (United States)

    The Himalayan region is very rich in a great variety of medicinal plants. In this investigation the essential oils of two selected species are described for their antimicrobial and larvicidal as well as biting deterrent activities. Additionally, the odors are characterized. Analyzed by simultaneous ...

  5. Quantification of functional groups and modeling of their ionization behavior in the active layer of FT30 reverse osmosis membrane.

    Science.gov (United States)

    Coronell, Orlando; Mariñas, Benito J; Zhang, Xijing; Cahill, David G

    2008-07-15

    A new experimental approach was developed to measure the concentration of charged functional groups (FGs) in the active layer of thin-film composite reverse osmosis (RO) and nanofiltration (NF) membranes as a function of solution pH. FT30 RO membrane, with a fully aromatic polyamide (PA) active layer sandwiched between a polysulfone support and a coating layer, was used. The experiments consisted of saturating charged FGs with heavy ion probes, and determining the ion probe concentration by Rutherford backscattering spectrometry (RBS). Deprotonated carboxylic groups were saturated with Ag+, and protonated amine groups with W04(2-). The ionization behavior of carboxylic and amine groups was modeled based on acid-base equilibrium theory. While the ionization behavior of amine groups was satisfactorily described by one dissociation constant (pKa = 4.74), two pKa values (5.23 and 8.97) were necessary to describe the titration curve of carboxylic groups. These results were consistent with the bimodal pore size distribution (PSD) of FT30 active layer reported in the literature. The calculated total concentrations of carboxylic and amine groups in the active layer of the FT30 RO membrane studied were 0.432 and 0.036 M, respectively, and the isoelectric point (IEP) was 4.7. The total concentration of carboxylic and amine groups revealed that the degree of cross-linking of the PA active layer of the FT30 RO membrane studied was 94%.

  6. Supported manganese oxide on TiO{sub 2} for total oxidation of toluene and polycyclic aromatic hydrocarbons (PAHs): Characterization and catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Aboukaïs, Antoine, E-mail: aboukais@univ-littoral.fr [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, EA 4492, MREI, ULCO, 59140 Dunkerque (France); Abi-Aad, Edmond [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, EA 4492, MREI, ULCO, 59140 Dunkerque (France); Taouk, Bechara [Laboratoire de Sécurité des procédés Chimiques (LSPC), EA 4704, INSA Rouen, Avenue de l' Université, 76801 Saint Etienne du Rouvray (France)

    2013-11-01

    Manganese oxide catalysts supported on titania (TiO{sub 2}) were prepared by incipient wetness impregnation method in order to elaborate catalysts for total oxidation of toluene and PAHs. These catalysts have been characterized by means of X-ray diffraction (XRD), electron paramagnetic resonance (EPR), temperature programmed reduction (TPR) and temperature programmed desorption (TPD). It has been shown that for the 5%Mn/TiO{sub 2} catalyst the reducibility and the mobility of oxygen are higher compared, in one side, to other x%Mn/TiO{sub 2} samples and, in another side, to catalysts where TiO{sub 2} support was replaced by γ-Al{sub 2}O{sub 3} or SiO{sub 2}. It has been shown that the content of manganese loading on TiO{sub 2} has an effect on the catalytic activity in the toluene oxidation. A maximum of activity was obtained for the 5%Mn/TiO{sub 2} catalyst where the total conversion of toluene was reached at 340 °C. This activity seems to be correlated to the presence of the Mn{sup 3+}/Mn{sup 4+} redox couple in the catalyst. When the Mn content increases, large particles of Mn{sub 2}O{sub 3} appear leading then to the decrease in the corresponding activity. In addition, compared to both other supports, TiO{sub 2} seems to be the best to give the best catalytic activity for the oxidation of toluene when it is loaded with 5% of manganese. For this reason, the latter catalyst was tested for the abatement of some PAHs. The light off temperature of PAHs compounds increases with increasing of benzene rings number and with decreasing of H/C ratio. All of PAHs are almost completely oxidized and converted at temperatures lower than 500 °C. - Highlights: • Preparation of x%MnO{sub 2}/TiO{sub 2} catalysts. • Catalytic oxidation tests of toluene and PAHs. • EPR, TPR and TPD characterizations of Mn(II) and Mn(IV) ions.

  7. Double-Layer Surface Modification of Polyamide Denture Base Material by Functionalized Sol-Gel Based Silica for Adhesion Improvement.

    Science.gov (United States)

    Hafezeqoran, Ali; Koodaryan, Roodabeh

    2017-09-21

    Limited surface treatments have been proposed to improve the bond strength between autopolymerizing resin and polyamide denture base materials. Still, the bond strength of autopolymerizing resins to nylon polymer is not strong enough to repair the fractured denture effectively. This study aimed to introduce a novel method to improve the adhesion of autopolymerizing resin to polyamide polymer by a double layer deposition of sol-gel silica and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (AE-APTMS). The silica sol was synthesized by acid-catalyzed hydrolysis of tetraethylorthosilicate (TEOS) as silica precursors. Polyamide specimens were dipped in TEOS-derived sol (TS group, n = 28), and exposed to ultraviolet (UV) light under O 2 flow for 30 minutes. UV-treated specimens were immersed in AE-APTMS solution and left for 24 hours at room temperature. The other specimens were either immersed in AE-APTMS solution (AP group, n = 28) or left untreated (NT group, n = 28). Surface characterization was investigated by fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Two autopolymerizing resins (subgroups G and T, n = 14) were bonded to the specimens, thermocycled, and then tested for shear bond strength with a universal testing machine. Data were analyzed with one-way ANOVA followed by Tukey's HSD (α = 0.05). FTIR spectra of treated surfaces confirmed the chemical modification and appearance of functional groups on the polymer. One-way ANOVA revealed significant differences in shear bond strength among the study groups. Tukey's HSD showed that TS T and TS G groups had significantly higher shear bond strength than control groups (p = 0.001 and p < 0.001, respectively). Moreover, bond strength values of AP T were statistically significant compared to controls (p = 0.017). Amino functionalized TEOS-derived silica coating is a simple and cost-effective method for improving the bond strength between the autopolymerizing resin and polyamide

  8. Conformationally restrained aromatic analogues of fosmidomycin and FR900098.

    Science.gov (United States)

    Kurz, Thomas; Schlüter, Katrin; Pein, Miriam; Behrendt, Christoph; Bergmann, Bärbel; Walter, Rolf D

    2007-07-01

    The synthesis and in-vitro antimalarial activity of conformationally restrained bis(pivaloyloxymethyl) ester analogues of the natural product fosmidomycin is presented. In contrast to alpha-aryl-substituted analogues, conformationally restrained aromatic analogues exhibit only moderate in-vitro antimalarial activity against the chloroquine-sensitive strain 3D7 of Plasmodium falciparum. The most active derivative displays an IC(50) value of 47 microM.

  9. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  10. Alkylation of organic aromatic compounds

    Science.gov (United States)

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  11. Performance Enhancement of Silicon Alloy-Based Anodes Using Thermally Treated Poly(amide imide) as a Polymer Binder for High Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Yang, Hwi Soo; Kim, Sang-Hyung; Kannan, Aravindaraj G; Kim, Seon Kyung; Park, Cheolho; Kim, Dong-Won

    2016-04-05

    The development of silicon-based anodes with high capacity and good cycling stability for next-generation lithium-ion batteries is a very challenging task due to the large volume changes in the electrodes during repeated cycling, which results in capacity fading. In this work, we synthesized silicon alloy as an active anode material, which was composed of silicon nanoparticles embedded in Cu-Al-Fe matrix phases. Poly(amide imide)s, (PAI)s, with different thermal treatments were used as polymer binders in the silicon alloy-based electrodes. A systematic study demonstrated that the thermal treatment of the silicon alloy electrodes at high temperature made the electrodes mechanically strong and remarkably enhanced the cycling stability compared to electrodes without thermal treatment. The silicon alloy electrode thermally treated at 400 °C initially delivered a discharge capacity of 1084 mAh g(-1) with good capacity retention and high Coulombic efficiency. This superior cycling performance was attributed to the strong adhesion of the PAI binder resulting from enhanced secondary interactions, which maintained good electrical contacts between the active materials, electronic conductors, and current collector during cycling. These findings are supported by results from X-ray photoelectron spectroscopy, scanning electron microscopy, and a surface and interfacial cutting analysis system.

  12. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

    1995-12-31

    The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

  13. Bicyclic Baird-type aromaticity

    Science.gov (United States)

    Cha, Won-Young; Kim, Taeyeon; Ghosh, Arindam; Zhang, Zhan; Ke, Xian-Sheng; Ali, Rashid; Lynch, Vincent M.; Jung, Jieun; Kim, Woojae; Lee, Sangsu; Fukuzumi, Shunichi; Park, Jung Su; Sessler, Jonathan L.; Chandrashekar, Tavarekere K.; Kim, Dongho

    2017-12-01

    Classic formulations of aromaticity have long been associated with topologically planar conjugated macrocyclic systems. The theoretical possibility of so-called bicycloaromaticity was noted early on. However, it has yet to be demonstrated by experiment in a simple synthetic organic molecule. Conjugated organic systems are attractive for studying the effect of structure on electronic features. This is because, in principle, they can be modified readily through dedicated synthesis. As such, they can provide useful frameworks for testing by experiment with fundamental insights provided by theory. Here we detail the synthesis and characterization of two purely organic non-planar dithienothiophene-bridged [34]octaphyrins that permit access to two different aromatic forms as a function of the oxidation state. In their neutral forms, these congeneric systems contain competing 26 and 34 π-electronic circuits. When subject to two-electron oxidation, electronically mixed [4n+1]/[4n+1] triplet biradical species in the ground state are obtained that display global aromaticity in accord with Baird's rule.

  14. Spectroscopic Diagnosis of Excited-State Aromaticity: Capturing Electronic Structures and Conformations upon Aromaticity Reversal.

    Science.gov (United States)

    Oh, Juwon; Sung, Young Mo; Hong, Yongseok; Kim, Dongho

    2018-03-06

    Aromaticity, the special energetic stability derived from cyclic [4 n + 2]π-conjugated electronic structures, has been the topic of intense interest in chemistry because it plays a critical role in rationalizing molecular stability, reactivity, and physical/chemical properties. Recently, the pioneering work by Colin Baird on aromaticity reversal, postulating that aromatic (antiaromatic) character in the ground state reverses to antiaromatic (aromatic) character in the lowest excited triplet state, has attracted much scientific attention. The completely reversed aromaticity in the excited state provides direct insight into understanding the photophysical/chemical properties of photoactive materials. In turn, the application of aromatic molecules to photoactive materials has led to numerous studies revealing this aromaticity reversal. However, most studies of excited-state aromaticity have been based on the theoretical point of view. The experimental evaluation of aromaticity in the excited state is still challenging and strenuous because the assessment of (anti)aromaticity with conventional magnetic, energetic, and geometric indices is difficult in the excited state, which practically restricts the extension and application of the concept of excited-state aromaticity. Time-resolved optical spectroscopies can provide a new and alternative avenue to evaluate excited-state aromaticity experimentally while observing changes in the molecular features in the excited states. Time-resolved optical spectroscopies take advantage of ultrafast laser pulses to achieve high time resolution, making them suitable for monitoring ultrafast changes in the excited states of molecular systems. This can provide valuable information for understanding the aromaticity reversal. This Account presents recent breakthroughs in the experimental assessment of excited-state aromaticity and the verification of aromaticity reversal with time-resolved optical spectroscopic measurements. To

  15. Noncomparative scaling of aromaticity through electron itinerancy

    International Nuclear Information System (INIS)

    Paul, Satadal; Goswami, Tamal; Misra, Anirban

    2015-01-01

    Aromaticity is a multidimensional concept and not a directly observable. These facts have always stood in the way of developing an appropriate theoretical framework for scaling of aromaticity. In the present work, a quantitative account of aromaticity is developed on the basis of cyclic delocalization of π-electrons, which is the phenomenon leading to unique features of aromatic molecules. The stabilization in molecular energy, caused by delocalization of π-electrons is obtained as a second order perturbation energy for archetypal aromatic systems. The final expression parameterizes the aromatic stabilization energy in terms of atom to atom charge transfer integral, onsite repulsion energy and the population of spin orbitals at each site in the delocalized π-electrons. An appropriate computational platform is framed to compute each and individual parameter in the derived equation. The numerical values of aromatic stabilization energies obtained for various aromatic molecules are found to be in close agreement with available theoretical and experimental reports. Thus the reliable estimate of aromaticity through the proposed formalism renders it as a useful tool for the direct assessment of aromaticity, which has been a long standing problem in chemistry

  16. Tribological and mechanical behaviors of polyamide 6/glass fiber composite filled with various solid lubricants.

    Science.gov (United States)

    Li, Duxin; Xie, Ying; Li, Wenjuan; You, Yilan; Deng, Xin

    2013-01-01

    The effects of polytetrafluoroethylene (PTFE), graphite, ultrahigh molecular weight polyethylene (UHMWPE), and their compounds on mechanical and tribological properties of glass-fiber-reinforced polyamide 6 (PA6/GF) were studied. The polymeric materials were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of hardness, tensile strength, and impact strength. Friction and wear experiments were run under ambient conditions at a rotating speed of 200 rpm and load of 100 N. The morphologies of the worn surfaces were also observed with scanning electron microscope. The results showed that graphite could increase the tensile strength of PA6/GF-15 composite, but the material became soft. Graphite/UHMWPE complex solid lubricants were effective in increasing the already high impact strength of PA6/GF-15 composite. 5% PTFE gave the maximum reduction in the coefficient of friction. However, PTFE/UHMWPE complex solid lubricants were the best choice for improving both friction and wear behaviors due to the lower friction coefficient and mass wear rate. Moreover, the worn surface of PA6 composites revealed that adhesive wear, abrasive wear, and fatigue wear occurred in this study.

  17. Synergistic Flame Retardancy of Aluminium Dipropylphosphinate and Melamine in Polyamide 6

    Directory of Open Access Journals (Sweden)

    Linsheng Tang

    2013-01-01

    Full Text Available The synergistic flame retardancy of aluminium dipropylphosphinate (ADPP and melamine (ME in polyamide 6 (PA6 was studied by the limiting oxygen index (LOI measurement, the vertical burning test, and the cone calorimeter test, and the mechanism was also discussed by thermogravimetric and residual analyses. The experimental results indicated that there was obvious synergistic flame retardancy between ADPP and ME under their appropriate weight ratios. The thermogravimetric results and the analysis of the residues obtained in cone calorimeter test showed that ADPP and ADPP/ME played the role of flame retardance by gaseous- and condensed-phase mechanisms, where, on one hand, they were decomposed into nonvolatile aluminum phosphate and promoted the carbonization of PA6, and the formed intumescent layer resulted in flame retardancy by the barrier effect on heat, air, and decomposition products, and on the other hand, they were decomposed into volatile phosphorus compounds which bring about flame retardancy by flame inhibition. Using a combination of ADPP and ME improved charring of PA6 and raised the residual rate of P and Al, thus, improving the barrier effect in the condensed phase.

  18. Multifunctional glass fiber/polyamide composites with thermal energy storage/release capability

    Directory of Open Access Journals (Sweden)

    G. Fredi

    2018-04-01

    Full Text Available Thermoplastic composite laminates with thermal energy storage (TES capability were prepared by combining a glass fabric, a polyamide 12 (PA12 matrix and two different phase change materials (PCMs, i.e. a paraffinic wax microencapsulated in melamine-formaldehyde shells and a paraffin shape stabilized with carbon nanotubes. The melt flow index of the PA12/PCM blends decreased with the PCM concentration, especially in the systems with shape stabilized wax. Differential scanning calorimetry showed that, for the matrices with microcapsules, the values of enthalpy were approximately the 70% of the theoretical values, which was attributed to the fracture of some microcapsules. Nevertheless, most of the energy storage capability was preserved. On the other hand, much lower relative enthalpy values were measured on the composites with shape stabilized wax, due to a considerable paraffin leakage or degradation. The subsequent characterization of the glass fabric laminates highlighted that the fiber and void volume fractions were comparable for all the laminates except for that with the higher amount of shape stabilized wax, where the high viscosity of the matrix led to a low fiber volume fraction and higher void content. The mechanical properties of the laminates were only slightly impaired by PCM addition, while a more sensible drop of the elastic modulus, of the stress at break and of the interlaminar shear strength could be observed in the shape stabilized wax systems.

  19. CRYSTALLIZATION KINETICS OF POLYMERIC NANOCOMPOSITES BASED ON POLYAMIDE 12 MODIFIED BY Cr2O3 NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    E. S. Shapoval

    2014-09-01

    Full Text Available In situ polymerization method is used for obtaining polymeric composites based on polyamide12 matrix (PA 12, filled with Cr2O3 nanoparticles. The carried out researches result in synthesis method development for polymeric nanocomposites based on PA 12 matrix filled with nano-sized Cr2O3magnetic particles providing uniform embedding of the filler into polymeric matrix without formation of nanoparticles agglomerates. Mechanical tests on samples compression are carried out. It is shown that mechanical properties of polymeric composites (Young’s modulus, durability limit are decreased for 20-30 % as compared with not modified PA 12 synthesized by means of the chosen method. The influence of the filler on crystallization morphology and kinetics of polymeric nanocomposites is determined by electron microscopy and differential scanning calorimetry. The values of crystallization degree, crystallization rate constant for different supercooling intervals and parameters of Avrami equation are obtained. The initial nucleation is shown to be going on according to non-thermal mechanism, and nanoparticles are not the germs of crystallization. It is stated that nanoparticles are embedded into polymeric matrix and uniformly allocated in crystallites. Research results can find their application at creation of electric and magnetic fields, micro-sized mechanical devices, and at development of new materials for 3D printers.

  20. Selenopentathionic and Telluropentathionic Acids as Precursors for Formation of Semiconducting Layers on the Surface of Polyamide

    Directory of Open Access Journals (Sweden)

    Skirma Zalenkiene

    2007-01-01

    Full Text Available The layers of copper chalcogenides, which were formed on the surface of semihydrophilic polymer—polyamide 6 (PA using monoselenopentathionic H2SeS4O6 and monotelluropentathionic H2TeS4O6 acids as precursors of chalcogens, were characterized. Fourier transform infrared (FT-IR and UV spectroscopy were used to monitor the effect of chalcogens on the changes in structure of PA corresponding to the concentration of the precursor's solution and an exposure time. The IR spectra of modified PA were completely different from that of the initial PA. Further interaction of chalcogenized PA with copper (II/I salt solution leads to the formation of CuxS, CuxSe, CuxTe, and mixed –CuxS–CuySe and CuxS–CuyTe layers which have different electric transport properties. The surface properties of PA after treatment are studied using AFM and XRD. The electrical resistances of layers with various composition formed over a wide concentration range 0.01–0.5 mol⋅dm−3 of precursor's solution were measured. Variation in the conductivity of layers of Cu–Se–S and Cu–Te–S on the surface of PA shows an evident increase with the increasing of the mass fraction of selenium or tellurium.

  1. Tensile fracture behaviors of T-ZnOw/polyamide 6 composites

    International Nuclear Information System (INIS)

    Shi Jing; Wang Yong; Liu Li; Bai Hongwei; Wu Jun; Jiang Chongxi; Zhou, Zuowan

    2009-01-01

    As a part of serial work about the application of tetra-needle-shaped zinc oxide whisker (T-ZnOw) in polymer composites, this work is focused on the crystallization and tensile fracture behaviors of T-ZnOw/polyamide 6 (T-ZnOw/PA6) composites. Our results show that the addition of T-ZnOw improves the composites tensile strength greatly. For virgin PA6, the stress-strain curve exhibits double-yielding phenomenon. Surface modified T-ZnOw reinforced PA6 composites exhibit higher yield stress and smaller strain-to-fracture compared with virgin PA6. The morphologies of tensile-fractured surfaces show that, addition of T-ZnOw changes the fracture mode from crazing-tearing/brittle fracture mode of virgin PA6 into fibrillation/brittle fracture mode of PA6 composites. Especially, the fracture process of T-ZnOw in composites during the tensile test has been characterized by scanning electronic microscope (SEM) and the corresponding reinforcement mechanism has been discussed.

  2. Study on thermal stability and chemical structure of polyamide blended with small amount of Cu

    International Nuclear Information System (INIS)

    Arai, Tsuyoshi; Ueno, Tomonaga; Kajiya, Takafumi; Ishikawa, Tomoyuki; Takeda, Kunihiko

    2007-01-01

    The thermal stability and the chemical structure of Polyamide 66 (PA66) blended with a small amount of copper have been studied. The thermal degradation of the blend with 35 ppm or more of copper was restrained and no strong influence of the concentration of copper was observed. The molecular weight of PA66 decreased by the thermal aging process but the amount of decrease of the blend was smaller than that of the non-blend. The water uptake of the blend increased. The chemical structure, which was observed by IR and NMR, changed slightly by blending with copper after aging at higher temperatures. Multiple items influenced the thermal stability of PA66 blended with a small amount of copper instead of just one. Namely, the main chain of PA66 is cut by heat and the degree of the cut is restrained by the copper. The diffusion time of copper atoms that disperse uniformly in the PA66 matrix is short enough to cover the individual amide groups and the effect enlarges the entire configuration of the PA66 chain to enhance the thermal stability. (author)

  3. Evaluation of the permeability of microporous membranes polyamide 6 / clay bentonite for water-oil separation

    International Nuclear Information System (INIS)

    Medeiros, P.S.S.; Medeiros, K.M.; Araujo, E.M.; Lira, H.L.

    2014-01-01

    The petroleum refining industries have faced major problems in relation to the treatment of their effluents before disposal into the environment. Among the conventional technologies treatment of these effluents, the process of oil-water separation by means of membranes has been extensively used, for having enormous potentiality. Therefore, in this study, hybrid membranes of polyamide 6/ bentonite clay were produced by the technique of phase inversion and by precipitation of the solution from the nanocomposites obtained by melt intercalation. The clay was organically modified with the quaternary ammonium salt (Cetremide®). The nanocomposites were obtained from (PA6) with untreated (AST) and treated clay (ACT), which were subsequently characterized by X-ray diffraction (XRD). Already membranes were characterized by XRD, scanning electron microscopy (SEM) and flow measurements. From the XRD results, it was observed an exfoliated and/or partially exfoliated structure for the nanocomposites and for the membranes. From SEM images it was observed that the presence of AST and ACT clays in the polymeric matrix caused changes in membrane morphology and pore formation. The flow with distilled water in the membranes showed a decrease initially and then followed by stability. All membranes tested in the process of separating emulsions of oil in water, particularly those of nanocomposites obtained a significant reduction of oil concentration in the permeate, thus showing that these membranes have a great potential to be applied to the water-oil separation. (author)

  4. Tribological and Mechanical Behaviors of Polyamide 6/Glass Fiber Composite Filled with Various Solid Lubricants

    Directory of Open Access Journals (Sweden)

    Duxin Li

    2013-01-01

    Full Text Available The effects of polytetrafluoroethylene (PTFE, graphite, ultrahigh molecular weight polyethylene (UHMWPE, and their compounds on mechanical and tribological properties of glass-fiber-reinforced polyamide 6 (PA6/GF were studied. The polymeric materials were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of hardness, tensile strength, and impact strength. Friction and wear experiments were run under ambient conditions at a rotating speed of 200 rpm and load of 100 N. The morphologies of the worn surfaces were also observed with scanning electron microscope. The results showed that graphite could increase the tensile strength of PA6/GF-15 composite, but the material became soft. Graphite/UHMWPE complex solid lubricants were effective in increasing the already high impact strength of PA6/GF-15 composite. 5% PTFE gave the maximum reduction in the coefficient of friction. However, PTFE/UHMWPE complex solid lubricants were the best choice for improving both friction and wear behaviors due to the lower friction coefficient and mass wear rate. Moreover, the worn surface of PA6 composites revealed that adhesive wear, abrasive wear, and fatigue wear occurred in this study.

  5. Thermal conductivity of plasma modified polyethylene terephthalate and polyamide-6 layers

    Directory of Open Access Journals (Sweden)

    G. Kalacska

    2016-05-01

    Full Text Available Tribological performance of the materials greatly depends on the temperature of the contacting zones and surfaces and hence on the heat conducting behaviour of the materials. Heat conduction of polymers is, however, greatly affected even by a very narrow (few tens of nm modified layer formed on the surface after subjecting the polymer to plasma treatment. In this article the heat flow inhibiting properties of plasma modified surface layers were investigated on polyethylene terephthalate (PET and polyamide-6 (PA6 engineering polymers. Nitrogen Plasma Immersion Ion Implantation gave rise to compositional and structural changes of the polymers in a depth of 110 nm. It was found that even this thin layer exhibited significant heat flow inhibiting effect. The modified layer considerably decreased the thermal conductivity coefficient of the treated polymer and resulted in a reduced heat transmission for PET and PA6 by 33 and 28%, respectively. This new information supports and is in accordance with the former tribological results about extra friction heat generation experienced under NPIII surface layer of PA6 and PET during dry sliding.

  6. Durability Characteristics Analysis of Plastic Worm Wheel with Glass Fiber Reinforced Polyamide.

    Science.gov (United States)

    Kim, Gun-Hee; Lee, Jeong-Won; Seo, Tae-Il

    2013-05-10

    Plastic worm wheel is widely used in the vehicle manufacturing field because it is favorable for weight lightening, vibration and noise reduction, as well as corrosion resistance. However, it is very difficult for general plastics to secure the mechanical properties that are required for vehicle gears. If the plastic resin is reinforced by glass fiber in the fabrication process of plastic worm wheel, it is possible to achieve the mechanical properties of metallic material levels. In this study, the mechanical characteristic analysis of the glass-reinforced plastic worm wheel, according to the contents of glass fiber, is performed by analytic and experimental methods. In the case of the glass fiber-reinforced resin, the orientation and contents of glass fibers can influence the mechanical properties. For the characteristic prediction of plastic worm wheel, computer-aided engineering (CAE) analysis processes such as structural and injection molding analysis were executed with the polyamide resin reinforcement glass fiber (25 wt %, 50 wt %). The injection mold for fabricating the prototype plastic worm wheel was designed and made to reflect the CAE analysis results. Finally, the durability of prototype plastic worm wheel fabricated by the injection molding process was evaluated by the experimental method and the characteristics according to the glass fiber contents.

  7. Generation of conductivity through transfer charge properties, for polyesters and polyamides with characteristic functional groups

    Science.gov (United States)

    Gonzalez, Carmen; Tagle, Luis Hernan; Terraza, Claudio A.; Barriga, Andres; Cabrera, A. L.; Volkmann, Ulrich G.

    2011-03-01

    Electro-optic properties of σ -conjugated polymers, as polysilylene; are associated with electron conjugation in the silicon atom, which allows a significant delocalization of electrons along of the chain. Thus, the conductivity is intimately connected to the mobility of charge carriers, which in turn depends on the structure and morphology of the system. We report the characterization of polyesters (PEFs) and polyamides (PAFs). Film thicknesses were obtained by ellipsometry. The vibration frequencies of the groups were determined by FT-IR and corroborated by Raman spectroscopy. Structural information was obtained from X-Ray diffraction (XRD). The structural and surface morphology were studied by scanning electron microscope (SEM). Electrical conductivity of the polymers was measured before and after exposure to iodine vapor, for films of different thicknesses. Morphological differentiation was studied by energy dispersive microscopy (EDX), showing a regular distribution of iodine within the polymer. Preliminary conductivity measurements showed adverse effects when oxidation of the polymer films is induced These effects are related to a certain grade of disorder within the system

  8. Preparation of Polyamide-6 Submicrometer-Sized Spheres by In Situ Polymerization.

    Science.gov (United States)

    Zhao, Xingke; Xia, Housheng; Fu, Xubing; Duan, Jianping; Yang, Guisheng

    2015-11-01

    Polyamide-6 (PA6) submicron-sized spheres are prepared by two steps: (1) anionic ring-opening polymerization of ε-caprolactam in the presence of poly(ethylene glycol)-block-poly-(propylene glycol)-block-poly(ethylene glycol)(PEG-b-PPG-b-PEG) and (2) separation of PA6 spheres by dissolving PEG-b-PPG-b-PEG from the prepared blends. The PA6 microspheres obtained are regular spherical, with diameter ranging from 200 nm to 2 μm and narrow size distribution, as confirmed by scanning electron microscopy. By comparison with PA6/PS and PA6/PEG systems, it is denominated that the PEG blocks in PEG-b-PPG-b-PEG can effectively reduce the surface tension of PA6 droplets and further decrease the diameter of the PA6 microspheres. The PPG block in PEG-b-PPG-b-PEG can prevent the PA6 droplets coalescing with each other, and isolated spherical particles can be obtained finally. The phase inversion of the PA6/PEG-b-PPG-b-PEG blends occurs at very low PEG-b-PPG-b-PEG content; the PEG-b-PPG-b-PEG phase can be removed by water easily. The whole experiment can be finished in a short time (approximately in half an hour) without using any organic solvents; it is an efficient strategy for the preparation of submicron-sized PA6 microspheres. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Natural organic matter interactions with polyamide and polysulfone membranes: Formation of conditioning film

    KAUST Repository

    Gutierrez, Leonardo

    2015-03-31

    A conditioning film changes the physicochemical properties of the membrane surface and strongly affects subsequent fouling behavior. Results from this Atomic Force Microscopy study indicate that Natural Organic Matter (NOM) characteristics, membrane surface properties, and solution chemistry are fundamental during conditioning film formation. Repulsive forces were observed between HUM (humic-NOM) and Polyamide (PA) or Polysulfone (PS) membranes during approach in Na+ and Ca2+ solutions. However, repulsive and attractive forces were randomly recorded during BIOP (biopolymer-NOM) approach to both membranes, possibly caused by low electrostatic repulsion, hydrogen bonding, and presence of chemically/physically heterogeneous regions on membrane surfaces. During retracting, Ca2+ ions increased HUM adhesion to PA and PS membrane, indicating cation bridging/complexation as dominant interacting mechanism for this isolate. BIOP adsorption on PS and PA membrane was stronger than HUM under similar solution conditions, where hydrogen bonding would play an important role. Additionally, irrespective of solution conditions, higher adhesion energy was recorded on PS than on PA membrane for both NOM isolates, indicating membrane hydrophobicity as an important interacting factor. Results from this research will advance our understanding of conditioning film formation for NOM isolates and membranes of different physicochemical characteristics.

  10. Synergistically improved thermal conductivity of polyamide-6 with low melting temperature metal and graphite

    Directory of Open Access Journals (Sweden)

    Y. C. Jia

    2016-08-01

    Full Text Available Low melting temperature metal (LMTM-tin (Sn was introduced into polyamide-6 (PA6 and PA6/graphite composites respectively to improve the thermal conductivity of PA6 by melt processing (extruding and injection molding. After introducing Sn, the thermal conductivity of PA6/Sn was nearly constant because of the serious agglomeration of Sn. However, when 20 wt% (5.4 vol% of Sn was added into PA6 containing 50 wt% (33.3 vol% of graphite, the thermal conductivity of the composite was dramatically increased to 5.364 versus 1.852 W·(m·K–1 for the PA6/graphite composite, which suggests that the incorporation of graphite and Sn have a significant synergistic effect on the thermal conductivity improvement of PA6. What is more, the electrical conductivity of the composite increased nearly 8 orders of magnitudes after introducing both graphite and Sn. Characterization of microstructure and energy dispersive spectrum analysis (EDS indicates that the dispersion of Sn in PA6/graphite/Sn was much more uniform than that of PA6/Sn composite. According to Differential Scanning Calorimetry measurement and EDS, the uniform dispersion of Sn in PA6/graphite/Sn and the high thermal conductivity of PA6/graphite/Sn are speculated to be related with the electron transfer between graphite and Sn, which makes Sn distribute evenly around the graphite layers.

  11. Processing – morphology – property relationships of polyamide 6/polyethylene blend–clay nanocomposites

    Directory of Open Access Journals (Sweden)

    R. Scaffaro

    2013-10-01

    Full Text Available In this work, we studied the effect of the method of preparation and of reprocessing on the morphology and, consequently, on the physical properties of polyamide 6 (PA6/ high density polyethylene (HDPE-clay nanocomposite blends in the presence of different compatibilizers. In particular, the nanocomposites were obtained by melt mixing using a corotating twin screw extruder (E1. The blends thus obtained were re-extruded (E2 under the same operating conditions. Moreover, blends with the same final composition were produced using a masterbatch of the compatibilizer with the clay prepared in a separated stage in a batch mixer (MB. All the materials were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM and X-ray diffractometry (XRD analyses. In addition, the rheological behaviour and the, tensile and impact, properties were evaluated. The XRD and TEM analysis showed that re-extrusion slightly improves the morphology of the nanocomposites. A further improvement of the morphology, in terms of lower clay dimension and better dispersion, was observed in the MB blends. The results of the mechanical tests showed that reprocessing (E2 induced an increase of all the properties for all the three systems. A further general increase of the mechanical properties was showed by the MB blends.

  12. Diffuse plasma treatment of polyamide 66 fabric in atmospheric pressure air

    International Nuclear Information System (INIS)

    Li, Lee; Peng, Ming-yang; Teng, Yun; Gao, Guozhen

    2016-01-01

    Graphical abstract: - Highlights: • A cylindrical-electrode nanosecond-pulse diffuse-discharge reactor is presented. • Large-scale non-thermal plasmas were generated steadily in atmospheric air. • Treated PA66 fabric is etched with oxygen-containing group increases. • The hydrophily of treated PA66 fabric improves effectively. • Extending the treatment time is a method to reduce the treatment frequency. - Abstract: The polyamide 66 (PA66) fabrics are hard to be colored or glued in industrial production due to the poor hydrophily. Diffuse plasma is a kind of non-thermal plasma generated at atmospheric pressure in air. This paper proposes that large-scale diffuse plasma generated between wire electrodes can be employed for improving the hydrophily of PA66 fabrics. A repetitive nanosecond-pulse diffuse-discharge reactor using a cylindrical wire electrode configuration is presented, which can generate large-scale non-thermal plasmas steadily at atmospheric pressure without any barrier dielectric. Then the reactor is used to treat PA66 fabrics in different discharge conditions. The hydrophilicity property of modified PA66 is measured by wicking test method. The modified PA66 is also analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to prove the surface changes in physical microstructure and chemical functional groups, respectively. What's more, the effects of treatment time and treatment frequency on surface modification are investigated and discussed.

  13. Reinforced nanohydroxyapatite/polyamide66 scaffolds by chitosan coating for bone tissue engineering.

    Science.gov (United States)

    Huang, Di; Zuo, Yi; Zou, Qin; Wang, Yanying; Gao, Shibo; Wang, Xiaoyan; Liu, Haohuai; Li, Yubao

    2012-01-01

    High porosity of scaffold is always accompanied by poor mechanical property; the aim of this study was to enhance the strength and modulus of the highly porous scaffold of nanohydroxyapatite/polyamide66 (n-HA/PA66) by coating chitosan (CS) and to investigate the effect of CS content on the scaffold physical properties and cytological properties. The results show that CS coating can reinforce the scaffold effectively. The compress modulus and strength of the CS coated n-HA/PA66 scaffolds are improved to 32.71 and 2.38 MPa, respectively, being about six times and five times of those of the uncoated scaffolds. Meanwhile, the scaffolds still exhibit a highly interconnected porous structure and the porosity is approximate about 78%, slightly lower than the value (84%) of uncoated scaffold. The cytological properties of scaffolds were also studied in vitro by cocultured with osteoblast-like MG63 cells. The cytological experiments demonstrate that the reinforced scaffolds display favorable cytocompatibility and have no significant difference with the uncoated n-HA/PA66 scaffolds. The CS reinforced n-HA/PA66 scaffolds can meet the basic mechanical requirement of bone tissue engineering scaffold, presenting a potential for biomedical application in bone reconstruction and repair. Copyright © 2011 Wiley Periodicals, Inc.

  14. Viscosity of nanoconfined polyamide-6,6 oligomers: atomistic reverse nonequilibrium molecular dynamics simulation.

    Science.gov (United States)

    Eslami, Hossein; Müller-Plathe, Florian

    2010-01-14

    Our new simulation scheme in isosurface-isothermal-isobaric ensemble [Eslami, H.; Mozaffari, F.; Moghadasi, J.; Müller-Plathe, F. J. Chem. Phys. 2008, 129, 194702], developed to simulate confined fluids in equilibrium with bulk, is applied to simulate polyamide-6,6 oligomers confined between graphite surfaces. The reverse nonequilibrium molecular dynamics simulation technique is employed to shear the graphite surfaces. In this work, six confined systems, with different surface separations, as well as the bulk fluid are simulated. Our results show a viscosity increase with respect to the bulk fluid, with decreasing distance between surfaces. Also, the calculated viscosities of the confined systems show an oscillatory behavior with maxima corresponding to well-formed layers between the surfaces. We observe a substantial slip at the surfaces, with the slip length depending on the shear rate and on the slit width. The slip length and the slip velocity show oscillatory behavior with out-of-phase oscillations with respect to the solvation force oscillations. Moreover, the temperature difference between coldest and hottest parts of the simulation box depends on the shear rate and on the layering effect (solvation force oscillations). An analysis of oligomer deformation under flow shows preferential alignment of oligomers parallel to the surfaces with increasing shear rate.

  15. Microporous membranes from polyamide 6/national clay nanocomposites - Part 2: microstructural and permeability evaluation

    International Nuclear Information System (INIS)

    Leite, Amanda M.D.; Araujo, Edcleide M.; Lira, Helio de L.; Paz, Rene Anisio da; Medeiros, Vanessa da Nobrega

    2014-01-01

    Organic/inorganic hybrid membranes of polyamide 6 and mineral clay containing layers of silicate were prepared and compared to those of the pure polymer. Use was made of an as-received sodium clay from industry and another organophilized with ammonium quaternary salts (Dodigen and Cetremide). The salts make the clays surface hydrophobic and improve their incorporation into the polymer matrix in the molten state. Membranes were prepared with these nanocomposites using the immersion-precipitation technique with formic acid as a solvent, and precipitation in a water bath as non-solvent. The acid concentration in the solution containing the polymer and the hybrids was varied to study its influence in morphology and permeability of the membranes. An asymmetric morphology consisting of a filter skin and a porous support was observed, with pores both on the surface and in the cross section being affected by the different salts. This asymmetric morphology was also affected significantly by the acid concentration, with thicker filter skins for higher concentrations. The acid concentration affected the pores size and their distribution. The clay particles probably acted as a barrier to the flow. The permeating flux for the two acid concentrations varied as a function of the distinct morphologies. (author)

  16. Effect of activated carbon or biochars on toxicity of different soils contaminated by mixture of native polycyclic aromatic hydrocarbons and heavy metals.

    Science.gov (United States)

    Kołtowski, Michał; Oleszczuk, Patryk

    2016-05-01

    Activated carbon (AC), biochar from wheat straw (BCS), and biochar from willow (BCW) were added to the soils sampled from areas of strong anthropogenic influence at doses of 0.5%, 1%, 2.5%, or 5% (w/w) and incubated for 2 mo. At the end of this period, the toxicity of the soils was measured. The effect of AC and biochars on the toxicity of the soils varied based on soil, type of amendment, dose, and test organism. For most of the parameters tested, the highest effectiveness of AC in terms of reduction of toxicity was observed in soil POPI (from bitumen processing plant area). In the case of the remaining soils, after the addition of AC varied results were observed, in which a reduction or an increase of toxicity, relative to the control soil, occurred. As in the case of AC, biochars also caused a significant reduction of phytotoxicity of soil POPI. In soils KB (from coking plant area, industrial waste deposit) and KOK (from coking plant area, coking battery), the reduction or increase of toxicity depended on biochar dose. Compared with the biochars, the effectiveness of AC in the reduction of toxicity depended also on soil, type of amendment, dose, and test organism. Generally, the AC was more effective than biochars in relation to mortality and reproduction of Folsomia candida (in all soils) and for reduction of luminescence inhibition of Vibrio fischeri (in POPI soil). © 2015 SETAC.

  17. r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene in humanurine: A potential biomarker for assessing polycyclic aromatic hydrocarbon metabolic activation

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, S.S.; Chen, M.L.; Yagi, H.; Jerina, D.M.; Carmella, S.G. [University of Minnesota, Minneapolis, MN (United States)

    2003-12-01

    Carcinogen metabolite phenotyping is proposed as a more reliable way to determinethe role of host metabolism in PAH-related cancer. Phenanthrene,is the simplest PAH with a bay region and is metabolized to diol epoxides by the same enzymes and with the same stereochemistry as the prototypic carcinogenic PAH, benzo(a)pyrene. The major end product of this metabolic activation pathway is r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (trans, anti-PheT). We have developed a method for the analysis of trans, anti-PheT in human urine. r-1,t-2,4,c-3,-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (trans,syn-PheT) was used as internal standard. After hydrolysis by beta-glucuronidase and sulfatase, solid phase extraction, and high-performance liquid chromatography collection, the sample was silylated and analyzed by gas chromatography-negative ion chemical ionization-mass spectrometry-selected ion monitoring. Thechromatograms were clean and trans, anti-PheT was detected in all human urine samples. Levels of trans, anti-PheT were 791 {+-} 363 pmol/mg creatinine (n = 20) in psoriasis patients treated with a PAH-containing ointment, 25.7 {+-} 16.8 pmol/mg creatinine (n = 32) in coke oven workers exposed to PAH, 4.58 {+-} 2.95 pmol/mg creatinine (n = 31) in smokers, and 1.51 {+-} 1.15 pmol/mg creatinine (n = 30) in nonsmokers. Levels of trans, anti-PheT correlated with levels of 1-hydroxypyrene in the urine of coke oven workers, smokers, and nonsmokers. Trans, anti-PheT appears to be an excellent biomarker of PAH uptake. Levels of trans, anti-PheT were 8,000-19,000 times higher than those can be detected in human urine.

  18. Production of alkyl-aromatics from light oxygenates over zeolite catalysts for bio-oil refining

    Science.gov (United States)

    Hoang, Trung Q.

    Upgrading of light oxygenates derived from biomass conversion, such as propanal and glycerol, to more valuable aromatics for biofuels has been demonstrated on zeolite catalysts. Aromatics with a high ratio of C 9/(C8+C7) and little benzene are produced at much higher yield from oxygenates than from olefins at mild conditions over HZSM-5. It is proposed that C9 aromatics are predominantly produced via acid-catalyzed aldol condensation. This reaction pathway is different from the pathway of propylene and other hydrocarbon aromatization that occurs via a hydrocarbon pool at more severe conditions with major aromatic products C6 and C7. In fact, investigation on the effect of crystallite size HZSM-5 has shown a higher ratio of C9/(C8+C 7) aromatics on small crystallite. This is due to faster removal of products from the shorter diffusion path length. As a result, a longer catalyst lifetime, less isomerization, and less cracking were observed on small crystallites. Beside crystallite size, pore geometry of zeolites was also found to significantly affect aromatic production for both conversion of propanal and glycerol. It is shown that the structure of the HZSM-22, with a one-dimensional and narrower channel system, restricts the formation of aromatics. In contrast, a higher yield of aromatic products is observed over HZSM-5 with its three-dimensional channel system. By increasing channel dimension and connectivity of the channels, increasing catalyst activity was also observed due to more accessible acid sites. It was also found that glycerol is highly active for dehydration on zeolites to produce high yields of acrolein (propenal), a high value chemical. To maximize aromatics from glycerol conversion, HZSM-5 and HY were found to be effective. A two-bed reactor of Pd/ZnO and HZSM-5 was used to first deoxygenate/hydrogenate glycerol over Pd/ZnO to intermediate oxygenates that can further aromatize on HZSM-5. The end results are very promising with significant improvement

  19. Superficial distribution of aromatic compounds and geomicrobiology of sediments from Suruí Mangrove, Guanabara Bay, RJ, Brazil

    OpenAIRE

    Fontana,Luiz F.; Silva,Frederico S. da; Figueiredo,Natália G. de; Brum,Daniel M.; Netto,Annibal D. Pereira; Gigueiredo Junior,Alberto G. de; Crapez,Mirian A.C.

    2010-01-01

    The distribution of selected aromatic compounds and microbiology were assessed in superficial sediments from Suruí Mangrove, Guanabara Bay. Samples were collected at 23 stations, and particle size, organic matter, aromatic compounds, microbiology activity, biopolymers, and topography were determined. The concentration of aromatic compounds was distributed in patches over the entire mangrove, and their highest total concentration was determinated in the mangrove's central area. Particle size d...

  20. A novel reduced graphene oxide decorated with halloysite nanotubes (HNTs-d-rGO hybrid composite and its flame-retardant application for polyamide 6

    Directory of Open Access Journals (Sweden)

    M. F. Zhu

    2014-06-01

    Full Text Available The improvement of flame-retardant properties of polyamide 6 (PA6 was achieved by using reduced graphene oxide decorated with halloysite nanotubes (HNTs-d-rGO hybrid composite as the additive in PA6 matrix. The intimate integration of reduced graphene oxide (rGO and halloysite nanotubes (HNTs through a three-step chemical functionalization, enabled the combination of their unique physical and chemical characteristics together. The nanostructure of HNTs-d-rGO was determined by Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS and transmission electron microscopy (TEM. A morphological study revealed that HNTs-d-rGO was dispersed uniformly in PA6 matrix. From the results of cone calorimetry measurements, the fire retardant properties of PA6 were further improved with the addition of HNTs-d-rGO when compared with that of either HNTs, or GO, or a mixture of HNTs and GO (HNTs-m-GO used in PA6 matrix. The results indicate clearly that higher flame-retardant activity of the integrated HNTs-d-rGO nanostructures than that of the simple mixture verifies the importance of the intimate integration between HNTs and rGO, which ascribe to the combination of the stable silica layer created by HNT and the barrier effect of rGO.

  1. Integrated effect of supramolecular self-assembled sandwich-like melamine cyanurate/MoS{sub 2} hybrid sheets on reducing fire hazards of polyamide 6 composites

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xiaming [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Wang, Xin, E-mail: wxcmx@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Cai, Wei; Hong, Ningning [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Liew, Kim Meow [Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Department of Architectural and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2016-12-15

    A novel strategy of using supramolecular self-assembly for preparing sandwich-like melamine cyanurate/MoS{sub 2} sheets as the hybrid flame retardants for polyamide 6 (PA6) is reported for the first time. The introduction of MoS{sub 2} sheets function not only as a template to induce the formation of two-dimensional melamine cyanurate capping layers but also as a synergist to generate integrated flame-retarding effect of hybrid sheets, as well as a high-performance smoke suppressor to reduce fire hazards of PA6 materials. Once incorporating this well-designed structures (4 wt%) into PA6 matrix, there resulted in a remarkable drop (40%) in the peak heat release rate and a 25% reduction in total heat release. Moreover, the smoke production and pyrolysis gaseous products were efficiently suppressed by the addition of sandwich-like hybrid sheets. The integrated functions consisting of inherent flame retarding effect, physical barrier performance and catalytic activity are believed to the crucial guarantee for the reduced fire hazards of PA6 nanocomposites. Furthermore, this novel strategy with facile and scalable features may provide reference for developing various kinds of MoS{sub 2} based hybrid sheets for diverse applications.

  2. Ex-situ bioremediation of polycyclic aromatic hydrocarbons in sewage sludge

    DEFF Research Database (Denmark)

    Schmidt, Jens Ejbye; Larsen, S.B.; Karakashev, Dimitar Borisov

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAH) are naturally occurring organic compounds. As a result of anthropogenic activities, PAH concentration has increased in the environment considerably. PAH are regarded as environmental pollutants because they have toxic, mutagenic and carcinogenic effects on l...

  3. Mechanical and rheological properties of nanocomposites of polyamide 6 with national organoclay; Propriedades mecanicas e reologicas de nanocompositos de poliamida 6 com argila organofilica nacional

    Energy Technology Data Exchange (ETDEWEB)

    Paz, Rene Anisio da; Leite, Amanda Melissa Damiao; Araujo, Edcleide Maria; Melo, Tomas Jeferson Alves de, E-mail: rene@cct.ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Pessan, Luiz Antonio; Passador, Fabio Roberto [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2013-07-01

    Nanocomposites of polyamide 6 with organoclay were prepared by melt intercalation and their rheological and mechanical properties were studied. The clay was treated with the quaternary ammonium salt (Cetremide) and characterized by Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed the incorporation of salt in the clay and its organophilization. A master was prepared with PA6/clay (1:1) by weight and this was added to the pure polyamide 6 to reach the nominal proportion of 3% of clay, using a co-rotational twin screw extruder. The samples were molded by injection and characterized by: capillary rheometry, XRD, TEM and mechanical testing (tensile and impact). The results of capillary rheometry showed that the presence of organoclay in the PA6 increased the viscosity of the systems. With XRD and TEM, it was verified that all systems presented predominantly exfoliated structure. The tensile properties of the nanocomposites were better than those of pure polyamide 6. (author)

  4. Comparative study by TG and DSC Of membranes polyamide66/bentonite clay nanocomposite; Estudo comparativo por TG e DSC de membranas de nanocompositos poliamida66/argila bentonitica

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, K.M. de; Kojuch, L R; Araujo, E M; Lira, H.L., E-mail: keilamm@ig.com.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Lima, F [Universidade Estadual da Paraiba (UEPB), Campina Grande, PB (Brazil). Dept. de Quimica

    2010-07-01

    In this study, it was obtained membranes of nanocomposites polyamide66 with 3 and 5% bentonite clay consists of silicates in layers from the interior of Paraiba. The clay was treated with a quaternary ammonium salt in order to make it organophilic. The membranes were prepared by phase inversion technique from the nanocomposites in solution. The clays were characterized by X-ray diffraction (XRD) and thermogravimetry (TG). Also the membranes were characterized by differential scanning calorimetry (DSC) and TG. The XRD and TG confirmed the presence of salt in the clay and thermal stability of the treated clay. For DSC, it was observed that there was no change in melting temperature of the membranes of nanocomposites compared to membrane pure polyamide66. By TG, it was found that the decomposition of the membranes of polyamide66 with treated clay were higher compared with the untreated clay. (author)

  5. Substrate specific hydrolysis of aromatic and aromatic-aliphatic esters in orchid tissue cultures

    Directory of Open Access Journals (Sweden)

    Agnieszka Mironowicz

    2014-01-01

    Full Text Available We found that tissue cultures of higher plants were able, similarly as microorganisms, to transform low-molecular-weight chemical compounds. In tissue cultures of orchids (Cymbidium 'Saint Pierre' and Dendrobium phalaenopsis acetates of phenols and aromatic-aliphatic alcohols were hydrolyzed, whereas methyl esters of aromatic and aromatic-aliphatic acids did not undergo this reaction. Acetates of racemic aromatic-aliphatic alcohols were hydrolyzed with distinct enantiospecificity.

  6. Modulation of estrogen receptor-dependent reporter construct activation and G0/G1-S-phase transition by polycyclic aromatic hydrocarbons in human breast carcinoma MCF-7 cells

    Czech Academy of Sciences Publication Activity Database

    Vondráček, Jan; Kozubík, Alois; Machala, M.

    2002-01-01

    Roč. 70, č. 2 (2002), s. 193-201 ISSN 1096-6080 R&D Projects: GA ČR GP525/01/D076; GA MZe QC0194 Institutional research plan: CEZ:AV0Z5004920 Keywords : polycyclic aromatic hydrocarbons * estrogenicity * proliferation Subject RIV: BO - Biophysics Impact factor: 3.367, year: 2002

  7. Palladium-catalysed electrophilic aromatic C-H fluorination

    Science.gov (United States)

    Yamamoto, Kumiko; Li, Jiakun; Garber, Jeffrey A. O.; Rolfes, Julian D.; Boursalian, Gregory B.; Borghs, Jannik C.; Genicot, Christophe; Jacq, Jérôme; van Gastel, Maurice; Neese, Frank; Ritter, Tobias

    2018-02-01

    Aryl fluorides are widely used in the pharmaceutical and agrochemical industries, and recent advances have enabled their synthesis through the conversion of various functional groups. However, there is a lack of general methods for direct aromatic carbon-hydrogen (C-H) fluorination. Conventional methods require the use of either strong fluorinating reagents, which are often unselective and difficult to handle, such as elemental fluorine, or less reactive reagents that attack only the most activated arenes, which reduces the substrate scope. A method for the direct fluorination of aromatic C-H bonds could facilitate access to fluorinated derivatives of functional molecules that would otherwise be difficult to produce. For example, drug candidates with improved properties, such as increased metabolic stability or better blood-brain-barrier penetration, may become available. Here we describe an approach to catalysis and the resulting development of an undirected, palladium-catalysed method for aromatic C-H fluorination using mild electrophilic fluorinating reagents. The reaction involves a mode of catalysis that is unusual in aromatic C-H functionalization because no organometallic intermediate is formed; instead, a reactive transition-metal-fluoride electrophile is generated catalytically for the fluorination of arenes that do not otherwise react with mild fluorinating reagents. The scope and functional-group tolerance of this reaction could provide access to functional fluorinated molecules in pharmaceutical and agrochemical development that would otherwise not be readily accessible.

  8. Adsorption of aromatic hydrocarbons and ozone at environmental aqueous surfaces.

    Science.gov (United States)

    Vácha, Robert; Cwiklik, Lukasz; Rezác, Jan; Hobza, Pavel; Jungwirth, Pavel; Valsaraj, Kalliat; Bahr, Stephan; Kempter, Volker

    2008-06-05

    Adsorption of environmentally important aromatic molecules on a water surface is studied by means of classical and ab initio molecular dynamics simulations and by reflection-absorption infrared spectroscopy. Both techniques show strong activity and orientational preference of these molecules at the surface. Benzene and naphthalene, which bind weakly to water surface with a significant contribution of dispersion interactions, prefer to lie flat on water but retain a large degree of orientational flexibility. Pyridine is more rigid at the surface. It is tilted with the nitrogen end having strong hydrogen bonding interactions with water molecules. The degree of adsorption and orientation of aromatic molecules on aqueous droplets has atmospheric implications for heterogeneous ozonolysis, for which the Langmuir-Hinshelwood kinetics mechanism is discussed. At higher coverages of aromatic molecules the incoming ozone almost does not come into contact with the underlying aqueous phase. This may rationalize the experimental insensitivity of the ozonolysis on the chemical nature of the substrate on which the aromatic molecules adsorb.

  9. A neurotoxicity assessment of high flash aromatic naphtha.

    Science.gov (United States)

    Douglas, J F; McKee, R H; Cagen, S Z; Schmitt, S L; Beatty, P W; Swanson, M S; Schreiner, C A; Ulrich, C E; Cockrell, B Y

    1993-01-01

    Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide-boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 Aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent also known as High Flash Aromatic Naphtha (HFAN). A program was initiated to assess the toxicological properties of HFAN since there may be human exposure, especially in the workplace. The current study was conducted to assess the potential for neurotoxicity in the rat. Adult male Sprague-Dawley rats of approximately 300 grams body weight, in groups of twenty, were exposed by inhalation to HFAN for 90 days at concentrations of 0, 100, 500, and 1500 ppm. During this period the animals were tested monthly for motor activity and in a functional observation battery. After three months of exposure, for 6 hours/day, 5 days/week, 10 animals/group/sex were sacrificed and selected nervous system tissue was examined histopathologically. No signs of neurotoxicity were seen in any of the evaluated parameters, nor was there evidence of pathologic changes in any of the examined tissues.

  10. Bonding properties of acrylonitrile butadiene rubber with polyamide mediated by a functional layer of silane coupling agent

    International Nuclear Information System (INIS)

    Sang, J.; Aisawa, S.; Hirahara, H.; Mori, K.

    2017-01-01

    This study demonstrates that coating layers, expected to be formed as self-assembled monolayers, of silane coupling agents can act as adhesion layers as the hydrogenated acrylonitrile butadiene rubber (HNBR) and polyamide (PA6) plate interfaces. The resulting PA6/HNBR joints showed excellent adhesion properties with cohesive failure and the interfaces were jointed through chemical bonds, which were confirmed by swelling tests. The surfaces and bonding properties of rubber and PA6 were studied by means of peel tests, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and nanoscale infrared microscopy and chemical imaging (AFM-IR). (authors)

  11. Isolation and Quantification of Polyamide Cyclic Oligomers in Kitchen Utensils and Their Migration into Various Food Simulants

    OpenAIRE

    Abe, Yutaka; Mutsuga, Motoh; Ohno, Hiroyuki; Kawamura, Yoko; Akiyama, Hiroshi

    2016-01-01

    Small amounts of cyclic monomers and oligomers are present in polyamide (PA)-based kitchen utensils. In this study, we isolated eight PA-based cyclic monomers and oligomers from kitchen utensils made from PA6 (a polymer of ε-caprolactam) and PA66 (a polymer of 1,6-diaminohexane and adipic acid). Their structures were identified using high-resolution mass spectrometry and 1H- and 13C-nuclear magnetic resonance spectroscopy, and their residual levels in PA-based kitchen utensils and degree of m...

  12. Experiments on different materials (polyamide, stainless & galvanized steel) influencing geothermal CaCO3 scaling formation: Polymorphs & elemental incorporation

    Science.gov (United States)

    Wedenig, Michael; Dietzel, Martin; Boch, Ronny; Hippler, Dorothee

    2016-04-01

    Thermal water is increasingly used for heat and electric power production providing base-load capable renewable and virtually unlimited geothermal energy. Compared to other energy sources geothermal facilities are less harmful to the environment, i.e. chemically and visually. In order to promote the economic viability of these systems compared to other traditional and renewable energy sources, production hindering processes such as corrosion and scaling of components arising from the typically high salinity thermal waters have to be considered as important economic factors. In this context, using proper materials being in contact with the thermal water is crucial and a playground for further improvements. Aim of the study presented, are basic experiments and observations of scaling and corrosive effects from hydrothermal water interacting with different materials and surfaces (stainless steel, polyamide, galvanized steel) and in particular the nucleation and growth effects of these materials regarding the precipitation of solid carbonate phases. The incorporation of Mg, Sr and Ba cations into the carbonate scalings are investigated as environmental proxy. For this purpose, hydrothermal carbonate precipitating experiments were initialized by mixing NaHCO3 and Ca-Mg-Sr-Ba-chloride solutions at temperatures ranging from 40 to 80 °C in glass reactors hosting artificial substrates of the above mentioned materials. The experiments show a strong dependence of the precipitation behaviour of calcium carbonate polymorphs on the particular material being present. Stainless steel and polyamide seem to restrict aragonite formation, whereas galvanized steel supports aragonite nucleation. Vaterite formation is promoted by polyamide surfaces. Importantly, vaterite is more soluble (less stable) compared to the other anhydrous calcium carbonate polymorphs, i.e. vaterite can be more easily re-dissolved. Thus, the use of polyamide components might reduce the amount and durability of

  13. Surface modification of polyamide reverse osmosis membrane with organic-inorganic hybrid material for antifouling

    Science.gov (United States)

    Zhang, Yang; Wan, Ying; Pan, Guoyuan; Yan, Hao; Yao, Xuerong; Shi, Hongwei; Tang, Yujing; Wei, Xiangrong; Liu, Yiqun

    2018-03-01

    A series of thin-film composite reverse osmosis membranes based on polyamide have been modified by coating the polyvinyl alcohol and 3-mercaptopropyltriethoxysilane aqueous solution prepared by a sol-gel process on the membrane surface, followed by thermal crosslinking treatment. In order to improve the hydrophilicity of the modified TFC membranes, the membranes were then immersed into H2O2 aqueous solution to convert -SH into -SO3H. The resulting TFC membranes were characterized by SEM, AFM, ATR-FTIR, streaming potential, XPS as well as static contact angle. After surface modification with the organic-inorganic hybrid material, the TFC membranes show increased NaCl rejection and decreased water flux with increasing 3-mercaptopropyltrimethoxysilane content in coating solution. The optimal modification membrane (PA-SMPTES-0.8) exhibits a NaCl rejection of 99.29%, higher than that (97.20%) of the virgin PA membrane, and a comparable water flux to virgin PA membrane (41.7 L/m2 h vs 47.9 L/m2 h). More importantly, PA-SMPTES-0.8 membrane shows much more improved fouling resistance to BSA than virgin PA and PVA modified PA (PA-PVA-1.0) membranes. PA-SMPTES-0.8 membrane loses about 13% of the initial flux after BSA fouling for 12 h, which is lower than that of virgin PA and PA-PVA-1.0 membranes (42% and 18%). Furthermore, the flux recovery of PA-SMPTES-0.8 membrane reaches 94% after cleaning. Thus the TFC membranes modified by this organic-inorganic hybrid technology show potential applications as antifouling RO membrane for desalination and purification.

  14. Effects of Electron Beam Irradiation on Binary Polyamide-6 Blends with Metallocene Copolymers

    International Nuclear Information System (INIS)

    Rosales, C.

    2006-01-01

    A versatile way to produce new materials with high Izod impact strength and reduced heat deformations is the irradiation of compatibilized blends. The effect of electron beam irradiation and different types of dispersed phase grafted copolymers on thermal and mechanical properties, and SEM morphology of polyamide-6 (PA-6) blends were investigated. Two metallocene copolymers (mEPDM and mPOE) grafted in-situ with maleic anhydride and two commercial maleated copolymers (EPDM-g-MA and mEPR-g-MA) were employed in binary blends with PA6 as matrix. The blends were prepared by extrusion with a composition of 80 wt. % of PA-6. The influence of the radical or functional groups generated in the grafting and the irradiation processes (25, 50, 100 and 200 kGy) was found by ATR-FTIR. The blends exhibited the characteristic thermal behavior of immiscible systems. All compatibilizers employed influenced the melting and crystallization behavior of the blend components without irradiation and an improvement in interface adhesion was clearly observed by SEM micrographs. The sizes of the dispersed phase in the non-irradiated reactive blends were in agreement with the viscosity ratios of the blend components. High toughness materials were obtained with ethylene-polypropylene-diene (mEPDM) grafted copolymers without significant variations in their thermal properties and Izod impact strength at room temperature and -30 degree with the irradiation doses. However, the toughness of the blends with grafted metallocene polyethylenes was affected by the irradiation doses employed. Therefore, the gel content and tensile properties of the samples depended on the chain scission, crosslinking and/or grafting reactions of the blend components

  15. Rheological and mechanical properties of polyamide 6 modified by electron-beam initiated mediation process

    International Nuclear Information System (INIS)

    Shin, Boo Young; Kim, Jae Hong

    2015-01-01

    Polyamide (PA6) has been modified by electron-beam initiated mediator process to improve drawbacks of PA6. Glycidyl methacrylate (GMA) was chosen as a reactive mediator for modification process of PA6. The mixture of the PA6 and GMA was prepared by using a twin-screw extruder, and then the mixture was exposed to electron-beam irradiation at various doses at room temperature. The modified PA6 were characterized by observing rheological and mechanical properties and compared virgin PA6. Thermal properties, water absorption, and gel fraction were also investigated. Tight gel was not found even when PA6 was irradiated at 200 kGy. Complex viscosity and storage modulus of PA6 were remarkably increased by electron-beam irradiation with medium of GMA. Maximum increase in complex viscosity was 75 times higher than virgin PA6 at 0.1 rad/s when it was irradiated at 200 kGy with the GMA. Mechanical properties were also improved without scarifying of processability. The reaction mechanisms for the mediation process with the reactive mediator of GMA were estimated to elucidate the cause of significantly enhanced rheological and mechanical properties without loss of thermoplasticity. - Highlights: • PA6 was modified by the electron-beam initiated mediation process. • Maximum increase in complex viscosity of modified PA6 was 75 times higher than virgin PA6 at 0.1 rad/s. • Mechanical properties were improved without scarifying of processability. • The GMA as a mediator played a key role in the electron-beam initiated mediation process

  16. Electrospinning and characterization of polyamide 66 nanofibers with different molecular weights

    Directory of Open Access Journals (Sweden)

    Lilia Muller Guerrini

    2009-06-01

    Full Text Available Polyamide 66 (PA66 nanofibers of different molecular weights were obtained by electrospinning of formic acid solutions. An ionic salt, NaCl, was also added to the solutions to increase the conductivity. PA66 concentrations between 15-17 wt.(%/v and electrical fields between 2.0 and 2.5 kV/cm were the best conditions to produce the smallest nanofibers; however, the addition of NaCl increased the fibers average diameters.The characterization of the fibers was done by scanning electron microscopy (SEM, differential scanning calorimetry (DSC, wide angle X rays diffraction (WAXD and Fourier Transformed Infrared (FTIR. As the molecular weight decreased, the nanofibers average diameters also decreased; however, critical number average and weight average molecular weights were necessary for electrospinning. As the amounts of carboxyl terminal groups (CTG increased, the nanofibers average diameters decreased; however, above CTG's critical values of 8.7 x 10-5 mol.g-1 no electrospinning was possible. The addition of ionic salt increased the electrical conductivity of the solutions and increased the nanofibers' average diameters. By DSC, residual solvent in all the electrospun mats was found; two melting endotherms, one between 248 and 258 °C and the other one between 258 and 267 °C, depending on the sample were also observed. These endotherms were attributed to the melting, re-crystallization and re-melting of the PA66 α-phase. The nanofibers had low % of crystallinity compared to a textile fiber. By WAXS and FTIR, confirmation of the presence of α-phase crystals, of small dimensions and highly imperfect and of a very small amount of β and γ-phases crystals in the nanofibers structure was obtained.

  17. Dual-skinned polyamide/poly(vinylidene fluoride)/cellulose acetate membranes with embedded woven

    KAUST Repository

    Duong, Phuoc H.H.

    2016-08-31

    We propose multilayer membranes including (i) a thin selective polyamide (PA) layer prepared via interfacial polymerization, (ii) a poly (vinylidene fluoride) (PVDF) asymmetric porous support with high adhesion to the PA layer and high mechanical strength, (iii) a strong woven fabric, and (iv) fouling resistant porous cellulose acetate (CA) layer. The PA layer rejects solutes of the draw solution. The PVDF/woven fabric/CA (PVDF/CA) integrated layer performs as a mechanical support with unique properties for forward osmosis (FO) applications. It consists of a modified PVDF top layer suitable for the deposition of a PA layer and a highly hydrophilic bottom layer (CA) with a tunable pore size to minimize foulant deposition and intrusion onto and into the support. The experimental results using bovine serum albumin (BSA) as a model foulant show that the presence of the CA layer at the bottom of the FO membrane (PA/PVDF/CA) reduces 75% fouling propensity compared to the simple FO membrane made of PVDF, woven fabric and PA (PA/PVDF). Fouling tests with 2000 ppm oily feed faced the bottom of the FO membranes further indicate the superiority of the PA/PVDF/CA membrane compared to the PA/PVDF membrane. Moreover, the bottom CA layer can be adjusted with a flexible range of pore size, varied from sub-micron to sub-nanometer depending on the feed composition. The newly developed multilayer FO membrane has comparable performance to the state-of-the-art membrane with added tailored fouling resistance for specific wastewater feeds.

  18. Electromechanical properties of polyamide/lycra fabric treated with PEDOT:PSS

    Science.gov (United States)

    Tadesse, M. G.; Mengistie, D. A.; Loghin, C.; Chen, Y.; Wang, L.; Catalin, D.; Müller, C.; Nierstrasz, V.

    2017-10-01

    One of the challenges in smart textiles is to develop suitable multifunctional materials that can address simultaneously several characteristics such as durability, stretchability, lightweight, and conductivity. Conductive polymers which showed success in different technological fields like polymer solar cells and light emitting diodes are promising in many smart textile applications. In this work, we treated a common polyamide/lycra knitted fabric with PEDOT:PSS for stretchable e-textiles. PEDOT:PSS, with DMSO as a conductivity enhancer and different ratios of water-based polyurethane dispersions as a binder, was applied to the fabric with simple immersion and coating applications. The effect of different application methods and binder ratio on the surface resistance of the fabric was monitored with four point probe electrical surface resistance measurement systems. Samples prepared by immersion technique are more uniform and have higher conductivity than those prepared by a coating technique. SEM images showed that PEDOT:PSS is incorporated into the structure in the immersion method while in the coating it is majorly present on the surface of the fabric. The tensile measurement showed that the acidic PEDOT:PSS and polyurethane dispersion coating has no adverse effect on the tensile strength of the fabric. The coated samples can be stretched up to 700% while still reasonably conductive. The resistance increases only by a small amount when samples were stretched cyclically by stretching 100%. Generally, samples prepared by the immersion method maintained better conductivity while stretching than those by a coating method. The washing fastness of the samples was also assessed.

  19. Development of nanocomposites polyamide66/ bentonite clay membranes obtained by solution for water-oil separation

    International Nuclear Information System (INIS)

    Medeiros, Keila Machado de

    2010-01-01

    Microporous membranes were obtained from nanocomposites polyamide66 and regional bentonite clay, through the technique of immersion precipitation. The nanocomposites were obtained by solution with a pre-established reaction time. The clay was treated with quaternary ammonium salt (Cetremide®) in order to make it organophilic. Untreated and treated clay were characterized by X-ray fluorescence (XRF) spectroscopy, Fourier transform infrared (FTIR), X-ray diffraction (XRD) and thermogravimetry (TG), which confirmed the insertion of the Cetremide® salt in the layers of clay and their thermal stability. While the membranes were characterized by XRD, TG, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and flow measurements. The results of XRD, TG and DSC confirmed the thermal stability and morphological structure with intercalated/partially exfoliated lamellae of clay in the polymer matrix. By SEM, it was revealed an asymmetric morphology consisting of a skin layer and a porous sublayer. The higher clay content in the membrane give the lower film thickness. This influencing directly the flow measurements of the membranes produced from the nanocomposites. In general, the initial flow with distilled water through the membranes decrease and stabilise after 60 min, this due to a compression or swelling occurred in the membranes. In tests of water-oil separation it was found that the relationship J/J0 tends to be greater when using emulsions with lower concentration. The water-oil separation tests at concentrations of 300 and 500 ppm for all membranes showed a significant reduction in oil concentration in the permeate, thus showing that these membranes have potential for this application. (author)

  20. Reactive processing of textile-natural fiber reinforced anionic polyamide-6 composites

    International Nuclear Information System (INIS)

    Kan, Ze; Chen, Peng; Liu, Zhengying; Feng, Jianmin; Yang, Mingbo

    2015-01-01

    Nowadays natural fiber, used in reinforced composites, is widely concerned. However, no natural fiber reinforced reactive thermoplastic polymer grades had been prepared so far. Through our studies, it was demonstrated that there was a severe retardation and discoloration occurred in the reactive processing between anionic polyamide-6 (APA-6) and natural fiber, which result in incomplete polymerization when put together. In order to solve the problem, two methods were adopted in this paper, which are fiber pretreatment and usage of a new-style initiator called caprolactam magnesium bromide. The former is to remove sizing agent and impurities on the surface of fiber, and the latter is to weaken the side reactions between APA-6 and natural fiber by the nature of its lower reactivity and weaker alkaline. In cooperation with both methods, the severe retardation and discoloration had been improved significantly, so that the polymerization of APA-6 in natural fiber was occurred smoothly. Following textile-natural fiber reinforced APA-6 composites with an average thickness of 2.5 mm and a fiber volume content of 50% was prepared by vacuum assisted resin transfer molding (VARTM). The soxhlet extraction, dilute solution viscometry and differential scanning calorimeter (DSC) measurements respectively suggested the degree of conversion, viscosity-average molar mass and crystallization of composites was up to 94%, 11.3×104 and 50%. Remarkable improvement of mechanical properties were achieved through dynamic mechanical analysis (DMA), tensile and three-point bending test. Favorable interfacial adhesion and wettability were revealed by scanning electron microscopy (SEM) observation. Therefore, all of the above good performance make this new-style and environmentally friendly composites have broad application prospects

  1. Reactive processing of textile-natural fiber reinforced anionic polyamide-6 composites

    Science.gov (United States)

    Kan, Ze; Chen, Peng; Liu, Zhengying; Feng, Jianmin; Yang, Mingbo

    2015-05-01

    Nowadays natural fiber, used in reinforced composites, is widely concerned. However, no natural fiber reinforced reactive thermoplastic polymer grades had been prepared so far. Through our studies, it was demonstrated that there was a severe retardation and discoloration occurred in the reactive processing between anionic polyamide-6 (APA-6) and natural fiber, which result in incomplete polymerization when put together. In order to solve the problem, two methods were adopted in this paper, which are fiber pretreatment and usage of a new-style initiator called caprolactam magnesium bromide. The former is to remove sizing agent and impurities on the surface of fiber, and the latter is to weaken the side reactions between APA-6 and natural fiber by the nature of its lower reactivity and weaker alkaline. In cooperation with both methods, the severe retardation and discoloration had been improved significantly, so that the polymerization of APA-6 in natural fiber was occurred smoothly. Following textile-natural fiber reinforced APA-6 composites with an average thickness of 2.5 mm and a fiber volume content of 50% was prepared by vacuum assisted resin transfer molding (VARTM). The soxhlet extraction, dilute solution viscometry and differential scanning calorimeter (DSC) measurements respectively suggested the degree of conversion, viscosity-average molar mass and crystallization of composites was up to 94%, 11.3×104 and 50%. Remarkable improvement of mechanical properties were achieved through dynamic mechanical analysis (DMA), tensile and three-point bending test. Favorable interfacial adhesion and wettability were revealed by scanning electron microscopy (SEM) observation. Therefore, all of the above good performance make this new-style and environmentally friendly composites have broad application prospects.

  2. Influence of Nanomaterial Compatibilization Strategies on Polyamide Nanocomposites Properties and Nanomaterial Release during the Use Phase.

    Science.gov (United States)

    Fernández-Rosas, Elisabet; Vilar, Gemma; Janer, Gemma; González-Gálvez, David; Puntes, Victor; Jamier, Vincent; Aubouy, Laurent; Vázquez-Campos, Socorro

    2016-03-01

    The incorporation of small amounts of nanofillers in polymeric matrices has enabled new applications in several industrial sectors. The nanofiller dispersion can be improved by modifying the nanomaterial (NM) surface or predispersing the NMs to enhance compatibility. This study evaluates the effect of these compatibilization strategies on migration/release of the nanofiller and transformation of polyamide-6 (PA6), a thermoplastic polymer widely used in industry during simulated outdoors use. Two nanocomposites (NCs) containing SiO2 nanoparticles (NPs) with different surface properties and two multiwalled carbon nanotube (MWCNT) NCs obtained by different addition methods were produced and characterized, before and after accelerated wet aging conditions. Octyl-modified SiO2 NPs, though initially more aggregated than uncoated SiO2 NPs, reduced PA6 hydrolysis and, consequently, NM release. Although no clear differences in dispersion were observed between the two types of MWCNT NCs (masterbatch vs direct addition) after manufacture, the use of the MWCNT masterbatch reduced PA6 degradation during aging, preventing MWCNT accumulation on the surface and further release or potential exposure by direct contact. The amounts of NM released were lower for MWCNTs (36 and 108 mg/m(2)) than for SiO2 NPs (167 and 730 mg/m(2)), being lower in those samples where the NC was designed to improve the nanofiller-matrix interaction. Hence, this study shows that optimal compatibilization between NM and matrix can improve NC performance, reducing polymer degradation and exposure and/or release of the nanofiller.

  3. Role of the Ah locus in suppression of cytotoxic T lymphocyte activity by halogenated aromatic hydrocarbons (PCBs and TCDD): Structure-activity relationships and effects in C57Bl/6 mice congenic at the Ah locus

    International Nuclear Information System (INIS)

    Kerkvliet, N.I.; Baecher-Steppan, L.; Smith, B.B.; Youngberg, J.A.; Henderson, M.C.; Buhler, D.R.

    1990-01-01

    Previous studies have shown that the generation of cytotoxic T lymphocytes (CTL) following allogeneic tumor challenge is suppressed in Ah-responsive C57Bl/6 mice treated with a single oral dose of the toxic, Ah receptor-binding 3,4,5,3',4',5'-hexachlorobiphenyl (HxCB). The present studies have examined the specific role of the Ah receptor in this immunotoxic response by utilizing HxCB isomers of known, varied affinity for the Ah receptor as well as by comparing effects of high-affinity Ah receptor ligands (3,4,5,3',4',5'-HxCB and 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]) on the CTL response of mice that differ only at the Ah locus, that is, Ah-responsive (Ahbb) and Ah-nonresponsive (Ahdd) congenic C57Bl/6 mice. Correlative changes in thymic weight, serum corticosterone (CS) levels, and spleen cellularity were also measured. The potency of HxCB congeners (3,4,5,3',4',5'-; 2,3,4,5,3',4'-; 2,4,5,2',4',5'-) and 2,3,7,8-TCDD to suppress the CTL response, to reduce spleen cellularity, to cause thymic atrophy, and to elevate serum CS levels was directly correlated with the binding affinity of the congener for the Ah receptor. Furthermore, these parameters of immunotoxicity in Ahdd C57Bl/6 mice were significantly more resistant to alterations induced by either 3,4,5,3',4',5'-HxCB or 2,3,7,8-TCDD as compared to Ahbb C57Bl/6 mice. These results strongly support an Ah receptor-dependent immunotoxic mechanism in suppression of the CTL response following acute exposure to halogenated aromatic hydrocarbons

  4. Theoretical studies of the structures and local aromaticity of conjugated polycyclic hydrocarbons using three aromatic indices

    Science.gov (United States)

    Sakai, Shogo; Kita, Yuki

    2013-07-01

    The structures and local aromaticity of some conjugated polycyclic hydrocarbons (from the butadienoid, acene, and phenylene series) are studied using ab initio MO and density functional methods. The aromaticities of the molecules are estimated using three indices: the nucleus-independent chemical shift (NICS), the harmonic oscillator model of aromaticity (HOMA), and the index of deviation from aromaticity (IDA). Assessment of the relationships between the structures and the aromatic indices shows that the IDA values correspond best to the characteristics of the conjugated polycyclic hydrocarbon structures.

  5. Analysis of damage processes in short glass fibre reinforced polyamide under mechanical loading by X-ray refractometry, fracture mechanics and fractography; Analyse der Schaedigungsprozesse in einem kurzglasfaserverstaerkten Polyamid unter mechanischer Belastung mittels Roentgenrefraktometrie, Bruchmechanik und Fraktografie

    Energy Technology Data Exchange (ETDEWEB)

    Guenzel, Stephan

    2013-04-01

    This thesis presents an analysis of the damage behaviour in a short glass fibre reinforced polyamide. The micro cracking is investigated by X-ray refraction technique under various, mechanical in-service loadings. In this context, potentials and limits of X-ray refraction analysis for short glass fibre reinforced polyamides are compiled. In particular the influence of fibre orientation and the influence of damage mechanisms are examined according to the X-ray refraction analysis and its interpretation. The method offers a quantitative and phenomenological based characterisation of micro crack damage. For the investigated material micro crack damage emerges as fibre matrix debonding and matrix micro cracking. The state of damage correlates with a nonlinear strain portion in a linear manner and depends on the kind of loading. Absorption of moisture in the material may influence significantly the micro crack damage behaviour. Damage of micro cracking appears preferentially under tension. The macro damage due to propagation of a single crack is characterised in an automated test setup, considering the fibre orientation and content of moisture. Based on the findings an empirical assessment approach is developed. The investigations of the micro and macro damage behaviour are accompanied by fractography, in order to support the model assumptions according to damage and fracture mechanisms.

  6. Computer Simulations Reveal Multiple Functions for Aromatic Residues in Cellulase Enzymes (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-07-01

    NREL researchers use high-performance computing to demonstrate fundamental roles of aromatic residues in cellulase enzyme tunnels. National Renewable Energy Laboratory (NREL) computer simulations of a key industrial enzyme, the Trichoderma reesei Family 6 cellulase (Cel6A), predict that aromatic residues near the enzyme's active site and at the entrance and exit tunnel perform different functions in substrate binding and catalysis, depending on their location in the enzyme. These results suggest that nature employs aromatic-carbohydrate interactions with a wide variety of binding affinities for diverse functions. Outcomes also suggest that protein engineering strategies in which mutations are made around the binding sites may require tailoring specific to the enzyme family. Cellulase enzymes ubiquitously exhibit tunnels or clefts lined with aromatic residues for processing carbohydrate polymers to monomers, but the molecular-level role of these aromatic residues remains unknown. In silico mutation of the aromatic residues near the catalytic site of Cel6A has little impact on the binding affinity, but simulation suggests that these residues play a major role in the glucopyranose ring distortion necessary for cleaving glycosidic bonds to produce fermentable sugars. Removal of aromatic residues at the entrance and exit of the cellulase tunnel, however, dramatically impacts the binding affinity. This suggests that these residues play a role in acquiring cellulose chains from the cellulose crystal and stabilizing the reaction product, respectively. These results illustrate that the role of aromatic-carbohydrate interactions varies dramatically depending on the position in the enzyme tunnel. As aromatic-carbohydrate interactions are present in all carbohydrate-active enzymes, the results have implications for understanding protein structure-function relationships in carbohydrate metabolism and recognition, carbon turnover in nature, and protein engineering

  7. Catalytic synthesis of aromatic diisocyanates by means of carbonylation of nitrocompounds with carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Nefedov, B K; Manov-Yuvenskii, V I; Khoshdurdev, Kh O; Novikov, S S [AN SSSR, Moscow. Inst. Organicheskoj Khimii

    1977-02-11

    The development of an active and selective heterogeneous catalyst for synthesis of aromatic diisocyanates has been studied. The catalytic ability of the catalyst PdO-MoO/sub 3/-Fe/sub 2/O/sub 3/ deposited on ..gamma..-Al/sub 2/O/sub 3/ has been investigated in the reactions of carbonylation of aromatic dinitrocompounds with carbon oxide. The effect of the catalyst composition, method of catalyst production, reaction temperature and pressure on the catalytic ability have been studied. It has been established that the catalyst PdO-MoO/sub 3/-Fe/sub 2/O/sub 3/(2-6:1:1) deposited on ..gamma..-Al/sub 2/O/sub 3/ is highly active and selective in the reactions of carbonilation of aromatic dinitrocompounds at 210 deg and 300 atm. It has been used for synthesis of aromatic diisocyanates in yield 32-75%.

  8. The effects of polycyclic aromatic hydrocarbons on the immune system of fish: A review

    International Nuclear Information System (INIS)

    Reynaud, S.; Deschaux, P.

    2006-01-01

    Polycyclic aromatic hydrocarbons are an important class of environmental pollutants that are known to be carcinogenic and immunotoxic. This review summarizes the diverse literature on the effects of these pollutants on innate and acquired immunity in fish and the mechanism of PAH-induced immunotoxicity. Among innate immune parameters, many authors have focused on macrophage activities in fish exposed to polycyclic aromatic hydrocarbons. Macrophage respiratory burst appears especially sensitive to polycyclic aromatic hydrocarbons. Among acquired immune parameters, lymphocyte proliferation appears highly sensitive to polycyclic aromatic hydrocarbon exposure. However, the effects of polycyclic aromatic hydrocarbons on both specific and non-specific immunity are contradictory and depend on the mode of exposure, the dose used or the species studied. In contrast to mammals, fewer studies have been done in fish to determine the mechanism of polycyclic aromatic hydrocarbon-induced toxicity. This phenomenon seems to implicate different intracellular mechanisms such as metabolism by cytochrome P4501A, binding to the Ah-receptor, or increased intracellular calcium. Advances in basic knowledge of fish immunity should lead to improvements in monitoring fish health and predicting the impact of polycyclic aromatic hydrocarbons on fish populations, which is a fundamental ecotoxicological goal

  9. Measurement and prediction of aromatic solute distribution coefficients for aqueous-organic solvent systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.R.; Luthy, R.G.

    1984-06-01

    Experimental and modeling activities were performed to assess techniques for measurement and prediction of distribution coefficients for aromatic solutes between water and immiscible organic solvents. Experiments were performed to measure distribution coefficients in both clean water and wastewater systems, and to assess treatment of a wastewater by solvent extraction. The theoretical portions of this investigation were directed towards development of techniques for prediction of solute-solvent/water distribution coefficients. Experiments were performed to assess treatment of a phenolic-laden coal conversion wastewater by solvent extraction. The results showed that solvent extraction for recovery of phenolic material offered several wastewater processing advantages. Distribution coefficients were measured in clean water and wastewater systems for aromatic solutes of varying functionality with different solvent types. It was found that distribution coefficients for these compounds in clean water systems were not statistically different from distribution coefficients determined in a complex coal conversion process wastewater. These and other aromatic solute distribution coefficient data were employed for evaluation of modeling techniques for prediction of solute-solvent/water distribution coefficients. Eight solvents were selected in order to represent various chemical classes: toluene and benzene (aromatics), hexane and heptane (alkanes), n-octanol (alcohols), n-butyl acetate (esters), diisopropyl ether (ethers), and methylisobutyl ketone (ketones). The aromatic solutes included: nonpolar compounds such as benzene, toluene and naphthalene, phenolic compounds such as phenol, cresol and catechol, nitrogenous aromatics such as aniline, pyridine and aminonaphthalene, and other aromatic solutes such as naphthol, quinolinol and halogenated compounds. 100 references, 20 figures, 34 tables.

  10. Catalytic oxidation of o-aminophenols and aromatic amines by mushroom tyrosinase.

    Science.gov (United States)

    Muñoz-Muñoz, Jose Luis; Garcia-Molina, Francisco; Garcia-Ruiz, Pedro Antonio; Varon, Ramon; Tudela, Jose; Rodriguez-Lopez, Jose N; Garcia-Canovas, Francisco

    2011-12-01

    The kinetics of tyrosinase acting on o-aminophenols and aromatic amines as substrates was studied. The catalytic constants of aromatic monoamines and o-diamines were both low, these results are consistent with our previous mechanism in which the slow step is the transfer of a proton by a hydroxyl to the peroxide in oxy-tyrosinase (Fenoll et al., Biochem. J. 380 (2004) 643-650). In the case of o-aminophenols, the hydroxyl group indirectly cooperates in the transfer of the proton and consequently the catalytic constants in the action of tyrosinase on these compounds are higher. In the case of aromatic monoamines, the Michaelis constants are of the same order of magnitude than for monophenols, which suggests that the monophenols bind better (higher binding constant) to the enzyme to facilitate the π-π interactions between the aromatic ring and a possible histidine of the active site. In the case of aromatic o-diamines, both the catalytic and Michaelis constants are low, the values of the catalytic constants being lower than those of the corresponding o-diphenols. The values of the Michaelis constants of the aromatic o-diamines are slightly lower than those of their corresponding o-diphenols, confirming that the aromatic o-diamines bind less well (lower binding constant) to the enzyme. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. The effects of polycyclic aromatic hydrocarbons on the immune system of fish: A review

    Energy Technology Data Exchange (ETDEWEB)

    Reynaud, S. [Laboratoire d' Ecologie Alpine. UMR CNRS 5553. Universite Joseph Fourier. BP 53. 38041 Grenoble cedex 9 (France) and Laboratory of General and Comparative Immunophysiology, Science Teaching and Research Unit, 123, av. Albert Thomas, 87060 Limoges (France)]. E-mail: stephane.reynaud@ujf-grenoble.fr; Deschaux, P. [Laboratory of General and Comparative Immunophysiology, Science Teaching and Research Unit, 123, av. Albert Thomas, 87060 Limoges (France)

    2006-05-01

    Polycyclic aromatic hydrocarbons are an important class of environmental pollutants that are known to be carcinogenic and immunotoxic. This review summarizes the diverse literature on the effects of these pollutants on innate and acquired immunity in fish and the mechanism of PAH-induced immunotoxicity. Among innate immune parameters, many authors have focused on macrophage activities in fish exposed to polycyclic aromatic hydrocarbons. Macrophage respiratory burst appears especially sensitive to polycyclic aromatic hydrocarbons. Among acquired immune parameters, lymphocyte proliferation appears highly sensitive to polycyclic aromatic hydrocarbon exposure. However, the effects of polycyclic aromatic hydrocarbons on both specific and non-specific immunity are contradictory and depend on the mode of exposure, the dose used or the species studied. In contrast to mammals, fewer studies have been done in fish to determine the mechanism of polycyclic aromatic hydrocarbon-induced toxicity. This phenomenon seems to implicate different intracellular mechanisms such as metabolism by cytochrome P4501A, binding to the Ah-receptor, or increased intracellular calcium. Advances in basic knowledge of fish immunity should lead to improvements in monitoring fish health and predicting the impact of polycyclic aromatic hydrocarbons on fish populations, which is a fundamental ecotoxicological goal.

  12. Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

    International Nuclear Information System (INIS)

    Shu, Xikai; Wang, Mei; Liu, Daicheng; Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi

    2013-01-01

    An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-β-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-β-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

  13. Preparative separation of polyphenols from artichoke by polyamide column chromatography and high-speed counter-current chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Xikai; Wang, Mei; Liu, Daicheng [College of Life Science, Shandong Normal University, Jinan, Shandong (China); Wang, Daijie; Lin, Xiaojing; Liu, Jianhua; Wang, Xiao; Huang, Luqi, E-mail: wxjn1998@126.com [Shandong Analysis and Test Center, Shandong Academy of Sciences, Jinan, Shandong (China)

    2013-09-01

    An efficient method for the rapid separation and purification of polyphenols from artichoke by polyamide column chromatography in combination with high-speed counter-current chromatography (HSCCC) was successfully built. The crude ethanol extracts from dry artichoke were first pre-separated by polyamide column chromatography and divided in two parts as sample 1 and sample 2. Then, the samples were further separated by HSCCC and yielded 7.8 mg of chlorogenic acid (compound I), 24.5 mg of luteolin-7-O-{beta}-D-rutinoside (compound II), 18.4 mg of luteolin-7-O-{beta}-D-glucoside (compound III), and 33.4 mg of cynarin (compound IV) with purity levels of 92.0%, 98.2%, 98.5%, and 98.0%, respectively, as determined by high-performance liquid chromatography (HPLC) method. The chemical structures of these compounds were identified by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). (author)

  14. Characterization of Polyamide 66 membranes prepared by phase inversion using formic acid and hydrochloric acid such as solvents

    Directory of Open Access Journals (Sweden)

    Patrícia Poletto

    2011-12-01

    Full Text Available The membranes properties prepared from water/formic acid (FA/ polyamide 66 (PA66 and water/hydrochloric acid (HCl/polyamide 66 (PA 66 systems has been studied. The different solvents interact distinctly with the polymer, affecting the membrane morphology. The asymmetric structure of the membranes showed a dense top layer and a porous sublayer. The membranes M-HCl prepared from HCl/PA 66 system showed a larger dense layer (around 23 μm in compared to those prepared from FA/PA 66 system (M-FA (around 10 μm. The membrane morphology was a determinant factor in results of water absorption, porosity and pure water flux. The lower thickness of dense layer in M-FA membranes resulted in a higher water absorption and, consequently, porosity, approximately 50%, compared with M-HCl membranes, approximately 15%. The same trend was observed to permeate flux, the lower thickness of dense layer higher pure water flux.

  15. Evaluation of Ultimate Pressure Capacity of a Prestressed Concrete Containment Building with Steel or Polyamide Fiber Reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Youngsun; Hahm, Daegi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Fiber reinforced concrete (FRC) includes thousands of small fibers that are distributed randomly in the concrete. Fibers resist the growth of cracks in concrete through their bridging at the cracks. Therefore, FRC fails in tension only when the fibers break or are pulled out of the cement matrix. For this reason, the addition of fibers in concrete mixing increases the tensile toughness of concrete and enhances the post-cracking behavior. A prevention of through-wall cracks and an increase of the post-cracking ductility will improve the ultimate internal pressure capacity of a prestressed concrete containment building (PCCB). In this study, the effects of steel or polyamide fiber reinforcement on the ultimate pressure capacity of a PCCB are evaluated. When R-SFRC contains hooked steel fibers in a volume fraction of 1.0%, the ultimate pressure capacity of a PCCB can be improved by 17%. When R-PFRC contains polyamide fibers in a volume fraction of 1.5%, the ultimate pressure capacity of a PCCB can be enhanced by 10%. Further studies are needed to determine the strain limits acceptable for PCCBs reinforced with fibers.

  16. Evaluation of Ultimate Pressure Capacity of a Prestressed Concrete Containment Building with Steel or Polyamide Fiber Reinforcement

    International Nuclear Information System (INIS)

    Choun, Youngsun; Hahm, Daegi

    2014-01-01

    Fiber reinforced concrete (FRC) includes thousands of small fibers that are distributed randomly in the concrete. Fibers resist the growth of cracks in concrete through their bridging at the cracks. Therefore, FRC fails in tension only when the fibers break or are pulled out of the cement matrix. For this reason, the addition of fibers in concrete mixing increases the tensile toughness of concrete and enhances the post-cracking behavior. A prevention of through-wall cracks and an increase of the post-cracking ductility will improve the ultimate internal pressure capacity of a prestressed concrete containment building (PCCB). In this study, the effects of steel or polyamide fiber reinforcement on the ultimate pressure capacity of a PCCB are evaluated. When R-SFRC contains hooked steel fibers in a volume fraction of 1.0%, the ultimate pressure capacity of a PCCB can be improved by 17%. When R-PFRC contains polyamide fibers in a volume fraction of 1.5%, the ultimate pressure capacity of a PCCB can be enhanced by 10%. Further studies are needed to determine the strain limits acceptable for PCCBs reinforced with fibers

  17. Preparation of epoxy-functionalized methyl methacrylate-butadiene-styrene core-shell particles and investigation of their dispersion in polyamide-6

    NARCIS (Netherlands)

    Aerdts, A.M.; Groeninckx, G.; Zirkzee, H.F.; Aert, van H.A.M.; Geurts, J.M.

    1997-01-01

    Functional core—shell impact modifiers of glycidyl methacrylate (GMA) functionalized methyl methacrylate—butadiene—styrene (MBS) have been prepared via a seeded semi-continuous emulsion polymerization. These functional MBS—GMA particles were blended with polyamide-6. Investigations by transmission

  18. Synthesis and characterization of soluble, blue-fluorescent polyamides and polyimides containing substituted p-terphenyl as well as long aliphatic segments in the main chain

    NARCIS (Netherlands)

    Mikroyannidis, JA; Tsivgoulis, GM

    1999-01-01

    A novel class of semiflexible polyamides and polyimides bearing substituted p-terphenyl as well as long aliphatic segments in the main chain were synthesized through pyrylium salts. Characterization of polymers was accomplished by inherent viscosity, elemental analysis, FT-IR, NMR, UV-vis

  19. Influence of properties and morphology of elastomeric phase on the behavior of ternary reactive blends of polyamide 6/rigid polymer/elastomer

    Czech Academy of Sciences Publication Activity Database

    Kelnar, Ivan; Kotek, Jiří; Munteanu, B. S.; Fortelný, Ivan

    2003-01-01

    Roč. 89, č. 13 (2003), s. 3647-3651 ISSN 0021-8995 R&D Projects: GA ČR GA106/01/0601 Institutional research plan: CEZ:AV0Z4050913 Keywords : polyamides * toughness * elastomers Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.017, year: 2003

  20. Fusing porphyrins with polycyclic aromatic hydrocarbons and heterocycles for optoelectronic applications

    Science.gov (United States)

    Thompson, Mark E.; Diev, Viacheslav; Hanson, Kenneth; Forrest, Stephen R.

    2015-08-18

    A compound that can be used as a donor material in organic photovoltaic devices comprising a non-activated porphyrin fused with one or more non-activated polycyclic aromatic rings or one or more non-activated heterocyclic rings can be obtained by a thermal fusion process. The compounds can include structures of Formula I: ##STR00001## By heating the reaction mixture of non-activated porphyrins with non-activated polycyclic aromatic rings or heterocyclic rings to a fusion temperature and holding for a predetermined time, fusion of one or more polycyclic rings or heterocyclic rings to the non-activated porphyrin core in meso,.beta. fashion is achieved resulting in hybrid structures containing a distorted porphyrin ring with annulated aromatic rings. The porphyrin core can be olygoporphyrins.

  1. Aromatic claw: A new fold with high aromatic content that evades structural prediction: Aromatic Claw

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, Joseph R. [Biomolecular NMR Core Facility, University of Chicago, Chicago Illinois; Adhikari, Aashish N. [Department of Chemistry, University of Chicago, Chicago Illinois; Gawlak, Grzegorz [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Hoey, Robert J. [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Liu, Gaohua [Northeast Structural Genomics Consortium (NESG), Department of Molecular Biology and Biochemistry, School of Arts and Sciences, and Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, and Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey; Joachimiak, Andrzej [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Biological Sciences Division, Argonne National Laboratory, Argonne Illinois; Montelione, Gaetano T. [Northeast Structural Genomics Consortium (NESG), Department of Molecular Biology and Biochemistry, School of Arts and Sciences, and Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, and Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey; Sosnick, Tobin R. [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Koide, Shohei [Department of Biochemistry and Molecular Biology, University of Chicago, Chicago Illinois; Department of Biochemistry and Molecular Pharmacology and the Perlmutter Cancer Center, New York University School of Medicine, New York New York

    2016-11-10

    We determined the NMR structure of a highly aromatic (13%) protein of unknown function, Aq1974 from Aquifex aeolicus (PDB ID: 5SYQ). The unusual sequence of this protein has a tryptophan content five times the normal (six tryptophan residues of 114 or 5.2% while the average tryptophan content is 1.0%) with the tryptophans occurring in a WXW motif. It has no detectable sequence homology with known protein structures. Although its NMR spectrum suggested that the protein was rich in β-sheet, upon resonance assignment and solution structure determination, the protein was found to be primarily α-helical with a small two-stranded β-sheet with a novel fold that we have termed an Aromatic Claw. As this fold was previously unknown and the sequence unique, we submitted the sequence to CASP10 as a target for blind structural prediction. At the end of the competition, the sequence was classified a hard template based model; the structural relationship between the template and the experimental structure was small and the predictions all failed to predict the structure. CSRosetta was found to predict the secondary structure and its packing; however, it was found that there was little correlation between CSRosetta score and the RMSD between the CSRosetta structure and the NMR determined one. This work demonstrates that even in relatively small proteins, we do not yet have the capacity to accurately predict the fold for all primary sequences. The experimental discovery of new folds helps guide the improvement of structural prediction methods.

  2. Hexacoordinate bonding and aromaticity in silicon phthalocyanine.

    Science.gov (United States)

    Yang, Yang

    2010-12-23

    Si-E bondings in hexacoordinate silicon phthalocyanine were analyzed using bond order (BO), energy partition, atoms in molecules (AIM), electron localization function (ELF), and localized orbital locator (LOL). Bond models were proposed to explain differences between hexacoordinate and tetracoordinate Si-E bondings. Aromaticity of silicon phthalocyanine was investigated using nucleus-independent chemical shift (NICS), harmonic oscillator model of aromaticity (HOMA), conceptual density functional theory (DFT), ring critical point (RCP) descriptors, and delocalization index (DI). Structure, energy, bonding, and aromaticity of tetracoordinate silicon phthalocyanine were studied and compared with hexacoordinate one.

  3. Pulse shape discrimination in non-aromatic plastics

    Energy Technology Data Exchange (ETDEWEB)

    Paul Martinez, H.; Pawelczak, Iwona; Glenn, Andrew M.; Leslie Carman, M.; Zaitseva, Natalia; Payne, Stephen

    2015-01-21

    Recently it has been demonstrated that plastic scintillators have the ability to distinguish neutrons from gamma rays by way of pulse shape discrimination (PSD). This discovery has lead to new materials and new capabilities. Here we report our work with the effects of aromatic, non-aromatic, and mixed aromatic/non-aromatic matrices have on the performance of PSD plastic scintillators.

  4. Microbial transformation of chlorinated aromatics in sediments

    NARCIS (Netherlands)

    Beurskens, J.E.M.

    1995-01-01

    Numerous contaminants like heavy metals, polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes (CBs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo- p -dioxins (PCDDs) and polychlorinated furans (PCDFs) are detected in the major rivers in the

  5. Volatilisation of aromatic hydrocarbons from soil

    DEFF Research Database (Denmark)

    Lindhardt, B.; Christensen, T.H.

    1996-01-01

    The non-steady-state fluxes of aromatic hydrocarbons were measured in the laboratory from the surface of soils contaminated with coal tar Four soil samples from a former gasworks site were used for the experiments. The fluxes were quantified for 11 selected compounds, 4 mono- and 7 polycyclic...... aromatic hydrocarbons, for a period of up to 8 or 16 days. The concentrations of the selected compounds in the soils were between 0.2 and 3,100 mu g/g. The study included the experimental determination of the distribution coefficient of the aromatic hydrocarbons between the sorbed phase and the water under...... saturated conditions. The determined distribution coefficients showed that the aromatic hydrocarbons were more strongly sorbed to the total organic carbon including the coal tar pitch - by a factor of 8 to 25 - than expected for natural organic matter. The fluxes were also estimated using an analytical...

  6. International congress on aromatic and medicinal plants

    International Nuclear Information System (INIS)

    2009-01-01

    Full Text : In Morocco, medicinal and aromatic plants occupy an important place in the traditional care system of a large number of local people. They are also economically strong potential, but unfortunately they are not valued enough. Indeed, Morocco by its privileged geographical position in the Mediterranean basin and its floristic diversity (with a total of over 4,200 species and subspecies of which over 500 are recognized as medicinal and aromatic plants), is a leading provider of traditional global market. In this context and given the back label of the natural global, group research and studies on Aromatic and Medicinal Plants (GREPAM), the Faculty of Semlalia and University Cadi Ayyad, organize: the International Congress on Medicinal and Aromatic Plants CIPAM 2009. The organization of this conference is part of scientific research developed by the GREPAM. [fr

  7. Sodium Perborate Oxidation of an Aromatic Amine

    Science.gov (United States)

    Juestis, Laurence

    1977-01-01

    Describes an experiment involving the oxidation of aromatic primary amines to the corresponding azo compound; suggests procedures for studying factors that influence the yield of such a reaction, including the choice of solvent and the oxidant-amine ratio. (MLH)

  8. Polycyclic aromatic hydrocarbons (PAHs) degradation by laccase ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... Full Length Research Paper. Polycyclic aromatic ... production of paper, feeds, chemicals and fuels there is ... microbes with the production of lignin-modifying enzymes ... enable white rot fungi to degrade a variety of toxic.

  9. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J.

    2011-01-01

    We reconsider the contribution that singly protonated polycyclic aromatic hydrocarbons (PAHs; HPAH + s) might make to the Class A component of the 6.2 μm interstellar emission feature in light of the recent experimental measurements of protonated naphthalene and coronene. Our calculations on the small HPAH + s have a band near 6.2 μm, as found in experiment. While the larger HPAH + s still have emission near 6.2 μm, the much larger intensity of the band near 6.3 μm overwhelms the weaker band at 6.2 μm, so that the 6.2 μm band is barely visible. Since the large PAHs are more representative of those in the interstellar medium, our work suggests that large HPAH + s cannot be major contributors to the observed emission at 6.2 μm (i.e., Class A species). Saturating large PAH cations with hydrogen atoms retains the 6.2 μm Class A band position, but the rest of the spectrum is inconsistent with observed spectra.

  10. AN AROMATIC INVENTORY OF THE LOCAL VOLUME

    International Nuclear Information System (INIS)

    Marble, A. R.; Engelbracht, C. W.; Block, M.; Van Zee, L.; Dale, D. A.; Cohen, S. A.; Schuster, M. D.; Smith, J. D. T.; Gordon, K. D.; Wu, Y.; Lee, J. C.; Kennicutt, R. C.; Skillman, E. D.; Johnson, L. C.; Calzetti, D.; Lee, H.

    2010-01-01

    Using infrared photometry from the Spitzer Space Telescope, we perform the first inventory of aromatic feature emission (also commonly referred to as polycyclic aromatic hydrocarbon emission) for a statistically complete sample of star-forming galaxies in the local volume. The photometric methodology involved is calibrated and demonstrated to recover the aromatic fraction of the Infrared Array Camera 8 μm flux with a standard deviation of 6% for a training set of 40 SINGS galaxies (ranging from stellar to dust dominated) with both suitable mid-infrared Spitzer Infrared Spectrograph spectra and equivalent photometry. A potential factor of 2 improvement could be realized with suitable 5.5 μm and 10 μm photometry, such as what may be provided in the future by the James Webb Space Telescope. The resulting technique is then applied to mid-infrared photometry for the 258 galaxies from the Local Volume Legacy (LVL) survey, a large sample dominated in number by low-luminosity dwarf galaxies for which obtaining comparable mid-infrared spectroscopy is not feasible. We find the total LVL luminosity due to five strong aromatic features in the 8 μm complex to be 2.47 x 10 10 L sun with a mean volume density of 8.8 x 10 6 L sun Mpc -3 . Twenty-four of the LVL galaxies, corresponding to a luminosity cut at M B = -18.22, account for 90% of the aromatic luminosity. Using oxygen abundances compiled from the literature for 129 of the 258 LVL galaxies, we find a correlation between metallicity and the aromatic-to-total infrared emission ratio but not the aromatic-to-total 8 μm dust emission ratio. A possible explanation is that metallicity plays a role in the abundance of aromatic molecules relative to the total dust content, but other factors, such as star formation and/or the local radiation field, affect the excitation of those molecules.

  11. Reduction of Aromatic and Heterocyclic Aromatic N-Hydroxylamines by Human Cytochrome P450 2S1

    Science.gov (United States)

    Wang, Kai; Guengerich, F. Peter

    2013-01-01

    Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals and there is also strong evidence for some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anti-cancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions (Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740–1751). In the present study, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs. PMID:23682735

  12. Antioxidant effect of aromatic volatiles emitted by Lavandula dentata, Mentha spicata, and M. piperita on mouse subjected to low oxygen condition.

    Science.gov (United States)

    Hu, Zenghui; Wang, Chunling; Shen, Hong; Zhang, Kezhong; Leng, Pingsheng

    2017-12-01

    This study aims to investigate the antioxidant effect of aromatic volatiles of three common aromatic plants, Lavandula dentata, Mentha spicata, and M. piperita. In this study, kunming mice subjected to low oxygen condition were treated with the volatiles emitted from these aromatic plants through inhalation administration. Then the blood cell counts, and the activities and gene expressions of antioxidant enzymes in different tissues were tested. The results showed that low oxygen increased the counts of red blood cells, white blood cells, and blood platelets of mice, and aromatic volatiles decreased their counts. Exposure to aromatic volatiles resulted in decreases in the malonaldehyde contents, and increases in the activities and gene expressions of superoxide dismutase, glutathione peroxidase, and catalase in different tissues under low oxygen. In addition, as the main component of aromatic volatiles, eucalyptol was the potential source that imparted positive antioxidant effect.

  13. Photoacoustic spectroscopic studies of polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Zaidi, Zahid H.; Kumar, Pardeep; Garg, R. K.

    1999-02-01

    Because of their involvement in environmental pollutants, in carcinogenic activity, plastics, pharmaceuticals, synthesis of some laser dyes and presence in interstellar space etc., Polycyclic aromatic hydrocarbons (PAHs) are important. As their structure and properties can be varied systematically, they form a beautiful class of molecules for experimental and quantum chemical investigations. These molecules are being studied for last several years by using conventional spectroscopy. In recent years, Photoacoustic (PA) spectroscopy has emerged as a new non-destructive technique with unique capability and sensitivity. The PA effect is the process of generation of acoustic waves in a sample resulting from the absorption of photons. This technique not only reveals non- radiative transitions but also provides information about forbidden singlet-triplet transitions which are not observed normally by the conventional spectroscopy. The present paper deals with the spectroscopic studies of some PAH molecules by PA spectroscopy in the region 250 - 400 nm. The CNDO/S-CI method is used to calculate the electronic transitions with the optimized geometries. A good agreement is found between the experimental and calculated results.

  14. Aromatic Hydrocarbons: Degrading Bacteria in the Desert Soil of Kuwait

    International Nuclear Information System (INIS)

    Al-Gounaim, M.; Diab, A.; Al-Hilali, A.; Abu-Shady, A. Sattar

    2005-01-01

    Soil samples of different levels of oil pollutants were collected from Kuwait's Burgan Oil Field, near an oil lake. The samples represented, highly polluted (8.0% w/w), moderately polluted (2.1%-3.4%) and slightly polluted (2.1%-3.4%) and slightly polluted (0.5- 0.8%). The aromatic fractions of the collected samples were in the range of (0.21-2.57g/100g) soil. (GC) analysis of the aromatic fractions of the resolution of the different individual (PAHs) revealed the presence of (16) different (PAHs) resolved from the aromatic fraction of the highly polluted sample (S3). (15), (14) and (13) individual (PAHs) were identified soil samples (S5), (S2) and (S1, S4, S6) respectively. The most frequent (PAH) was indeno (1, 2, 3-c, d) pyrene (22.5%-45.11%) followed chrysene (13.6%-19.48%). Eight carcinogenic (PAHs) were resolved from the aromatic fractions of the polluted samples. Total carcinogenic (PAHs) recorded in this study were in this study were in the range of (11.53) (forS4) - (510.98) (for S3) ppm. The counts of (CFU) of aromatic degraders (AD) were in the range of (3x10) - (110x 10) (CFU/g) soil (with a percent of (2.2%-69.6%)). The results show that, higher counts of (AD) were recorded from a highly polluted sample (S3), followed by the moderately polluted samples; total of (51) bacteria, that gave presumptive positive biodegradation activities, were isolated and identified (45.1%) of them were isolated and identified. (45.1%) of them were isolated from the highly polluted sample (S3). Total of (13) different species were identified of which Micrococcus luteus was more frequent (23.5) followed by Bacillus licheniformis (19.6%) and Bacillus subtilis (11.8%). The three Pseudomonas species collectively were presented by (11.8%). Five different species proved to be of good activities, they are: Bacillus brevis, Bacillus lichenoformis, Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas flourescens. The ability of five species and their mixture was

  15. Influence of the clay content and drying of successive no solvents change in the morphology of polyamide 6 / clay membranes

    International Nuclear Information System (INIS)

    Pereira, C.H.; Ferreira, R.S.B.; Bezerra, E.B.; Leite, A.M.D.; Araujo, E.D.; Lira, H.L.

    2014-01-01

    Membranes of polyamide 6/clay nanocomposites with different contents (1 and 3%) of Brazilian bentonite clay using the technique of phase inversion was obtained. The nanocomposites were obtained in a co-rotating twin screw extruder, by the melt intercalation method and were characterized by x-ray diffraction (XRD), which showed possibly an exfoliated and / or partially exfoliated structure was obtained. The membranes were dried at room temperature and also by successive exchange of non-solvents, to prevent collapse the pores using ethanol and n-hexane as a non-solvent. From the photomicrographs of top surface by scanning electron microscopy (SEM) showed to morphology change in the membranes from the presence of different clay contents as well as drying the same by successive exchange of non-solvents, obtaining membranes with larger amount of pores uniformly distributed. (author)

  16. Photo and Thermal Behavior of New Reinforced Polyamide-nanocomposite Montmorillonite on 2,3-Pyrazin Dicarboxylic Acid

    Science.gov (United States)

    Faghihi, Khalil; Samiei, Mojtaba; Hajibeygi, Mohsen

    2012-06-01

    Two new samples of reinforce polyamidemontmorillonite nanocomposites were synthesized by a convenient solution intercalation technique. Polyamide (PA) 3 as a source of polymer matrix was synthesized by the direct polycondensation reaction of pyrazine 2,3-dicarboxylic acid 1 with 4,4'-diamino diphenyl ether 2 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PA matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

  17. Direct assembly of in situ templated CdSe quantum dots via crystalline lamellae structure of polyamide 66

    Energy Technology Data Exchange (ETDEWEB)

    Cheval, Nicolas; Brooks, Richard [University of Nottingham, Division of Materials, Mechanics and Structures, Faculty of Engineering (United Kingdom); Fahmi, Amir, E-mail: Amir.Fahmi@hochschule-Rhein-waal.de [Rhein-Waal University of Applied Sciences, Faculty of Technology and Bionics (Germany)

    2012-03-15

    A simple concept is proposed for templating in situ synthesised CdSe quantum dots (QDs) into an organised nano-pattern using the crystalline lamellae structure of polyamide 66 (PA66). The morphology obtained for PA66 and the hybrid material on Si/SiO{sub x} solid substrate was characterised by means of atomic force microscope. Controlling the PA66 concentration in solution and the organic-inorganic interactions are found to be the keys factors to direct the assembly of CdSe QDs along the PA66 linear crystalline structure. This simple approach could be opened a new avenue for a large spectrum of innovative high-tech applications.

  18. Direct investigations of deformation and yield induced structure transitions in polyamide 6 below glass transition temperature with WAXS and SAXS

    DEFF Research Database (Denmark)

    Guo, Huilong; Wang, Jiayi; Zhou, Chengbo

    2015-01-01

    Deformation and yield induced structure transitions of polyamide 6 (PA6) were detected with the combination of the wide- and small-angle X-ray scattering (WAXS and SAXS) at 30 degrees C below glass transition temperature (T-g) of PA6. During deformation, gamma-alpha phase transition was found...... at elastic stage. The concentrated stress in crystals at elastic stage provided adequate energy for the direct gamma-alpha phase transition under T-g. The force to promote the gamma-phase into a phase directly is insufficient at the yield stage and a transient phase as a compromise was formed. The transient...... phase was confirmed by DSC measurements and assisted the gamma-alpha phase transition indirectly. The gamma-phase slips into incomplete fragments at yield point, and the parts along tensile direction are responsible for the formation of transient phase. The gamma-fragments after yield is oriented...

  19. Recognition by nonaromatic and stereochemical subunit-containing polyamides of the four Watson-Crick base pairs in the DNA minor groove.

    Science.gov (United States)

    Zhang, Hong-Fei; Wu, Yan-Ling; Jiang, Shi-Kun; Wang, Pu; Sugiyama, Hiroshi; Chen, Xing-Lai; Zhang, Wen; Ji, Yan-Juan; Guo, Chuan-Xin

    2012-06-18

    In order to develop an optimal subunit as a T-recognition element in hairpin polyamides, 15 novel chirality-modified polyamides containing (R)-α,β-diaminopropionic acid ((R) β α-NH 2), (S)-α,β-diaminopropionic acid ((S) β α-NH 2), (1R,3S)-3-aminocyclopentanecarboxylic acid ((RS) Cp), (1S,3R)-3-amino-cyclopentanecarboxylic acid ((RS) Cp), (1R,3R)-3-aminocyclopentanecarboxylic acid ((RR) Cp) and (1S,3S)-3-amino-cyclopentanecarboxylic acid ((SS) Cp) residues were synthesized. Their binding characteristics to DNA sequences 5'-TGCNCAT-3'/3'-ACGN'GTA-5' (N⋅N'=A⋅T, T⋅A, G⋅C and C⋅G) were systemically studied by surface plasmon resonance (SPR) and molecular simulation (MSim) techniques. SPR showed that polyamide 4, AcIm-(S) β α-NH 2-ImPy-γ-ImPy-β-Py-βDp (β/(S) β α-NH 2 pair), bound to a DNA sequence containing a core binding site of 5'-TGCACAT-3' with a dissociation equilibrium constant (K(D) ) of 4.5×10(-8)  m. This was a tenfold improvement in specificity over 5'-TGCTCAT-3' (K(D) =4.5×10(-7)  M). MSim studies supported the SPR results. More importantly, for the first time, we found that chiral 3-aminocyclopentanecarboxylic acids in polyamides can be employed as base readers with only a small decrease in binding affinity to DNA. In particular, SPR showed that polyamide 9 ((RR) Cp/β pair) had a 15-fold binding preference for 5'-TGCTCAT-3' over 5'-TGCACAT-3'. A large difference in standard free energy change for A⋅T over T⋅A was determined (ΔΔG(o) =5.9 kJ mol(-1) ), as was a twofold decrease in interaction energy by MSim. Moreover, a 1:1 stoichiometry (9 to 5'-TGCTCAT-3'/3'-ACGAGTA-5') was shown by MSim to be optimal for the chiral five-membered cycle to fit the minor groove. Collectively, the study suggests that the (S)-α-amino-β-aminopropionic acid and (1R,3R)-3-aminocyclopentanecarboxylic acid can serve as a T-recognition element, and the stereochemistry and the nature of these subunits significantly influence

  20. Toxicity of Aromatic Ketone to Yeast Cell and Improvement of the Asymmetric Reduction of Aromatic Ketone Catalyzed by Yeast Cell with the Introduction of Resin Adsorption

    Directory of Open Access Journals (Sweden)

    Zhong-Hua Yang

    2008-01-01

    Full Text Available Asymmetric reduction of the prochiral aromatic ketone catalyzed by yeast cells is one of the most promising routes to produce its corresponding enantiopure aromatic alcohol, but the space-time yield does not meet people’s expectations. Therefore, the toxicity of aromatic ketone and aromatic alcohol to the yeast cell is investigated in this work. It has been found that the aromatic compounds are poisonous to the yeast cell. The activity of yeast cell decreases steeply when the concentration of acetophenone (ACP is higher than 30.0 mmol/L. Asymmetric reduction of acetophenone to chiral S-α-phenylethyl alcohol (PEA catalyzed by the yeast cell was chosen as the model reaction to study in detail the promotion effect of the introduction of the resin adsorption on the asymmetric reduction reaction. The resin acts as the substrate reservoir and product extraction agent in situ. It has been shown that this reaction could be remarkably improved with this technique when the appropriate kind of resin is applied. The enantioselectivity and yield are acceptable even though the initial ACP concentration reaches 72.2 mmol/L.

  1. 1 - Aromatization of n-hexane and natural gasoline over ZSM-5 zeolite, 2- Wet catalytic oxidation of phenol on fixed bed of active carbon; 1 - Aromatisation de n-hexane et d'essence sur zeolithe ZSM-5, 2 - Oxydation catalytique en voie humide du phenol sur charbon actif

    Energy Technology Data Exchange (ETDEWEB)

    Suwanprasop, S.

    2005-04-15

    I - The production of aromatic hydrocarbons from n-hexane and natural gasoline over Pd loaded ZSM-5 zeolite in a tubular reactor was achieved under the suitable conditions at 400 deg. C, and 0.4 ml/min reactant feeding rate, employing ZSM-5 (0.5% Pd content) as a catalyst. Under these conditions, n-hexane and natural gasoline conversions were found to be 99.7% and 94.3%, respectively (with respective aromatic selectivity of 92.3% and 92.6%). II - Wet catalytic air oxidation of phenol over a commercial active carbon was studied in a three phase fixed bed reactor under mild temperature and oxygen partial pressure. Exit phenol concentration, COD, and intermediates were analysed. Oxidation of phenol was significantly improved when increasing operating temperature, oxygen partial pressure, and liquid space time, while up or down flow modes had only marginal effect. A complete model involving intrinsic kinetics and all mass transfer limitations gave convenient reactor simulation. (author)

  2. Optical and Thermal Behaviors of Polyamide-Layered Silicate Nanocomposites Based on 4,4'-Azodibenzoic Acid by Solution Intercalation Technique

    Science.gov (United States)

    Faghihi, Khalil; Shabanian, Meisam

    2011-04-01

    Two new samples of polyamide-montmorillonite reinforced nanocomposites based on 4,4'-azodibenzoic acid were prepared by a convenient solution intercalation technique. Polyamide (PA) 4 as a source of polymer matrix was synthesized by the direct polycondensation reaction of 4,4'-azodibenzoic acid 2 with 4,4'-diamino diphenyl sulfone 3 in the presence of triphenyl phosphate (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PA-nanocomposite films 4a and 4b with 10 and 20% silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposite films were investigated by using Uv-vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements.

  3. Isolation and identification of arctiin and arctigenin in leaves of burdock (Arctium lappa L.) by polyamide column chromatography in combination with HPLC-ESI/MS.

    Science.gov (United States)

    Liu, Shiming; Chen, Kaoshan; Schliemann, Willibald; Strack, Dieter

    2005-01-01

    A simple method involving polyamide column chromatography in combination with HPLC-PAD and HPLC-ESI/MS for isolating and identifying two kinds of lignans, arctiin and arctigenin, in the leaves of burdock (Arctium lappa L.) has been established. After extraction of burdock leaves with 80% methanol, the aqueous phase of crude extracts was partitioned between water and chloroform and the aqueous phase was fractionated on a polyamide glass column. The fraction, eluting with 100% methanol, was concentrated and gave a white precipitate at 4 degrees C from which two main compounds were purified by semi-preparative HPLC. In comparison with the UV and ESI-MS spectra and the HPLC retention time of authentic standards, the compounds were determined to be arctiin and arctigenin. The extraction/separation technique was validated using an internal standard method.

  4. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites; Avaliacao da resistencia mecanica sob impacto de nanocompositos de poliamida 6/argila bentonitica

    Energy Technology Data Exchange (ETDEWEB)

    Paz, Rene A.; Leite, Amanda M.D.; Medeirosa, Vanessa da N., E-mail: rene@cct.ufcg.edu.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Curso de Pos-Graduacao em Ciencia e Engenharia de Materiais; Araujo, Edcleide M.; Melo, Tomas J.A. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Pessan, Luiz A. [Universidade Federal de Sao Carlos (DEMa/UFSCAR), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that they affect the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a regional bentonite modified with a quaternary ammonium salt in an amount of 3% by weight. XRD results showed that incorporation of salt among the layers of clay, making it organophilic and obtaining exfoliated and/or partially exfoliated structures. The impact properties of the nanocomposites showed inferior in relation to pure polyamide, in other words, lost of toughness. (author)

  5. Study of the radiation effect on the mechanical properties of flammability and the glow wire of polyamide 6.6 with and without fiber glass reinforcement

    International Nuclear Information System (INIS)

    Ferro, Waldir Pedro; Silva, Leonardo Gondim de Andrade e

    2002-01-01

    The Automotive, Electric and Electronic Component Industry, more and more employ the Engineering Plastic as a viable alternative for the reduction of costs and increase of productivity without loss of quality. Polyamide 6.6 is an Engineering Plastic with distinguished role on this category of polymers due to its high thermal and chemical resistances and strength. The aim of this work is to present the results of Tensile Strength, Flexural Strength and Izod Notched Impact Strength as well as thermal experiments of Flammability (Automotive and Electronic Components Industry) and of Glow Wire (Electric Components Industry) of Polyamide 6.6 with or without Fiber Glass reinforcement, irradiated by Electron Beams in different doses. (author)

  6. Metabolic activation of volatile organic compounds and polycyclic aromatic hydrocarbons coated onto airborne PM{sub 2.5} in isolated human alveolar macrophages; Etude de l'activation metabolique des composes organiques volatils et des hydrocarbures aromatiques polycycliques d'un aerosol anthropogenique par des macrophages alveolaires humains en culture primaire

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Georges, F.; Mulliez, P. [Hopital Saint Philibert - GHICL-FLM, Service de Pneumologie, 59 - Lomme (France); Saint-Georges, F.; Abbas, I.; Garcon, G.; Billet, S.; Verdin, A.; Shirali, P. [LCE-EA2598, Lab. de Recherche en toxicologie Industrielle et Environnementale - ULCO-MREI, 59 - Dunkerque (France); Gosset, P. [Hopital Saint Vincent, Laboratoire d' Anatomie et de Cytologie Pathologiques - GHICL-FLM, 59 - Lille (France); Courcot, D. [LCE-EA2598, Lab. de Catalyse et Environnement - ULCO-MREI, 59 - Dunkerque (France)

    2009-01-15

    To contribute to improve the knowledge of the underlying mechanisms of action involved in air pollution Particulate Matter (PM)-induced cytotoxicity, we were interested in the metabolic activation of Volatile Organic Compounds (VOC) and/or Polycyclic Aromatic Hydrocarbons (PAH)-coated onto Dunkerque City's PM{sub 2.5} in human Alveolar Macrophages (AM) isolated from Bronchoalveolar Lavage Fluid (BALF). This in vitro cell lung model is very close to the normal in vivo situation, notably in the characteristics that AM display in terms of gene expression of phase I and phase II-metabolizing enzymes. The bronchoscopic examinations and BAL procedures were carried out without any complications. The exposure of AM, during 24, 48 or 72 h, to increasing concentrations of the collected aerosol induced significant variations of the activities of the extracellular lactate dehydrogenase and the mitochondrial dehydrogenase. The lethal concentrations at 10% and 50% were 14.93 and 74.63 {mu}g/mL for AM, respectively, and indicated the relatively higher sensibility of such target lung cells. VOC and/or PAH-coated at low levels onto the surface of the particulate fraction significantly induced gene expression of cytochrome P450 (GYP) 1A1, CYP2E1, NADPH Quinone oxido-reductase (NQO)-1) and Glutathione S-Transferase (GST)P1 and M3, versus controls, suggesting thereby the formation of biologically reactive metabolites. Moreover, these results suggested the role of physical vector of carbonaceous core of PM, which can, therefore, increase both the penetration and the retention of attached-VOC into the cells, thereby enabling them to exert a more durable induction. Hence, we concluded that the metabolic activation of the very low doses of VOC and/or PAH-coated onto Dunkerque City's PM{sub 2.5} is one of the underlying mechanisms of action closely involved in its cytotoxicity in isolated human AM in culture. (author)

  7. Ion beam irradiation effects on aromatic polymers

    International Nuclear Information System (INIS)

    Shukushima, Satoshi; Ueno, Keiji

    1995-01-01

    We studied the optical and thermal properties of aromatic polymer films which had been irradiated with 1 MeV H + , H 2 + and He + ions. The examined aromatic polymers were polyetherether ketone(PEEK), polyetherimide(PEI), polyether sulfon(PES), polysulfon(PSF), and polyphenylene sulfide(PPS). The optical densities at 300nm of PES and PSF greatly increased after the irradiation. The optical densities at 400nm of all the examined polymer lineally increased with the irradiation dose. The PEEK film which had been irradiated with 1 MeV H + was not deformed above melting point. This demonstrates that cross-linking occurs in PEEK films by ion beam irradiation. As for the effects, depending on the mass of the irradiated ions, it was found that the ions with a high mass induced larger effects on the aromatic polymers for the same absorption energy. (author)

  8. A New Flame-Retardant Polyamide Containing Phosphine Oxide and N,N-(4,4-diphenylether) Moieties in the Main Chain: Synthesis and Characterization

    OpenAIRE

    FAGHIHI, Khalil

    2014-01-01

    A new flame-retardant polyamide containing phosphine oxide moieties in the main chain was synthesized from the solution polycondensation reaction of bis(3-aminophenyl) phenyl phosphine oxide with N,N-(4,4-diphenylether) bis trimellitimide, using thionyl chloride, N-methyl-2-pyrolidone, and pyridine as condensing agents. This new polymer was obtained in high yield (92%), has high inherent viscosity (0.73 dL/g), and was characterized by elemental analysis, FT-IR spectroscopy, thermal gr...

  9. Potential antisecretory antidiarrheals. 1. Alpha 2-adrenergic aromatic aminoguanidine hydrazones.

    Science.gov (United States)

    Pitzele, B S; Moormann, A E; Gullikson, G W; Albin, D; Bianchi, R G; Palicharla, P; Sanguinetti, E L; Walters, D E

    1988-01-01

    Guanabenz, a centrally acting antihypertensive agent, has been shown to have intestinal antisecretory properties. A series of aromatic aminoguanidine hydrazones was made in an effort to separate the antisecretory and cardiovascular activities. Benzaldehyde, naphthaldehyde, and tetralone derivatives were synthesized. The compounds were evaluated in the cholera toxin treated ligated jejunum of the rat and in the Ussing chamber using a rabbit ileum preparation. A number of compounds, including members of each structural class, were active upon subcutaneous administration in the rat. Active compounds were determined to be alpha 2-adrenergic agonists by yohimbine reversals of their Ussing chamber activities. The compound displaying the best separation of activities was the aminoguanidine hydrazone of 2,6-dimethyl-4-hydroxybenzaldehyde (20).

  10. Polycyclic Aromatic Compounds as Anticancer Agents: Synthesis and Biological Evaluation of Methoxy Dibenzofluorene Derivatives

    Directory of Open Access Journals (Sweden)

    Bimal Krishna Banik

    2014-08-01

    Full Text Available Synthesis of a new methoxy dibenzofluorene through alkylation, cyclodehydration and aromatization in a one-pot operation is achieved for the first time. Using this hydrocarbon, a few derivatives are prepared through aromatic nitration, catalytic hydrogenation, coupling reaction with a side chain and reduction. The benzylic position of this hydrocarbon with the side chain is oxidized and reduced. Some of these derivatives have demonstrated excellent antitumor activities in vitro. This study confirms antitumor activity depends on the structures of the molecules.

  11. Missing facial parts computed by a morphable model and transferred directly to a polyamide laser-sintered prosthesis: an innovation study.

    Science.gov (United States)

    Mueller, A A; Paysan, P; Schumacher, R; Zeilhofer, H-F; Berg-Boerner, B-I; Maurer, J; Vetter, T; Schkommodau, E; Juergens, P; Schwenzer-Zimmerer, K

    2011-12-01

    Mirroring of missing facial parts and rapid prototyping of templates have become widely used in the manufacture of prostheses. However, mirroring is not applicable for central facial defects, and the manufacture of a template still requires labour-intensive transformation into the final facial prosthesis. We have explored innovative techniques to meet these remaining challenges. We used a morphable model of a face for the reconstruction of missing facial parts that did not have mirror images, and skin-coloured polyamide laser sintering for direct manufacture of the prosthesis. From the knowledge gleaned from a data set of 200 coloured, three-dimensional scans, we generated a missing nose that was statistically compatible with the remaining parts of the patient's face. The planned prosthesis was manufactured directly from biocompatible skin-coloured polyamide powder by selective laser sintering, and the prosthesis planning system produced a normal-looking reconstruction. The polyamide will need adjustable colouring, and we must be able to combine it with a self-curing resin to fulfil the requirements of realistic permanent use. Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Global aromatics supply. Today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Aromatics are the essential building blocks for some of the largest petrochemical products in today's use. To the vast majority they are consumed to produce intermediates for polymer products and, hence, contribute to our modern lifestyle. Their growth rates are expected to be in line with GDP growth in future. This contrasts the significantly lower growth rates of the primary sources for aromatics - fuel processing and steam cracking of naphtha fractions. A supply gap can be expected to open up in future for which creative solutions will be required. (orig.)

  13. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2017-07-04

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  14. Transformations of Aromatic Compounds by Nitrosomonas europaea

    OpenAIRE

    Keener, William K.; Arp, Daniel J.

    1994-01-01

    Benzene and a variety of substituted benzenes inhibited ammonia oxidation by intact cells of Nitrosomonas europaea. In most cases, the inhibition was accompanied by transformation of the aromatic compound to a more oxidized product or products. All products detected were aromatic, and substituents were often oxidized but were not separated from the benzene ring. Most transformations were enhanced by (NH4)2SO4 (12.5 mM) and were prevented by C2H2, a mechanism-based inactivator of ammonia monoo...

  15. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated, as well as the excitation energy from the collision between electron carriers...... and benzene rings in PDMS-PPMS copolymer was measured by UV-vis spectroscopy. The developed elastomers were inherently soft with enhanced electrical breakdown strength due to delocalized pi-electrons of aromatic rings attached to the silicone backbone. The dielectric relative permittivity of PDMS...

  16. Engineering Aromatic-Aromatic Interactions To Nucleate Folding in Intrinsically Disordered Regions of Proteins.

    Science.gov (United States)

    Balakrishnan, Swati; Sarma, Siddhartha P

    2017-08-22

    Aromatic interactions are an important force in protein folding as they combine the stability of a hydrophobic interaction with the selectivity of a hydrogen bond. Much of our understanding of aromatic interactions comes from "bioinformatics" based analyses of protein structures and from the contribution of these interactions to stabilizing secondary structure motifs in model peptides. In this study, the structural consequences of aromatic interactions on protein folding have been explored in engineered mutants of the molten globule protein apo-cytochrome b 5 . Structural changes from disorder to order due to aromatic interactions in two variants of the protein, viz., WF-cytb5 and FF-cytb5, result in significant long-range secondary and tertiary structure. The results show that 54 and 52% of the residues in WF-cytb5 and FF-cytb5, respectively, occupy ordered regions versus 26% in apo-cytochrome b 5 . The interactions between the aromatic groups are offset-stacked and edge-to-face for the Trp-Phe and Phe-Phe mutants, respectively. Urea denaturation studies indicate that both mutants have a C m higher than that of apo-cytochrome b 5 and are more stable to chaotropic agents than apo-cytochrome b 5 . The introduction of these aromatic residues also results in "trimer" interactions with existing aromatic groups, reaffirming the selectivity of the aromatic interactions. These studies provide insights into the aromatic interactions that drive disorder-to-order transitions in intrinsically disordered regions of proteins and will aid in de novo protein design beyond small peptide scaffolds.

  17. Condensation reactions of glucose and aromatic ring; Glucose to hokokan tono shukugo hanno

    Energy Technology Data Exchange (ETDEWEB)

    Komano, T.; Mashimo, K.; Wainai, T.; Tanaka, C.; Yoshioka, T. [Nihon University, Tokyo (Japan). College of Science and Technology; Sugimoto, Y.; Miki, Y. [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1996-10-28

    For artificial coalification, condensation reactions of aromatic ring and activated compounds produced by dehydrating reaction of glucose were studied experimentally. In heat treatment experiment in water, three reaction specimens such as glucose, glucose and phenol, and glucose and benzaldehyde were fed into an autoclave together with distilled water, and subjected to reaction at 180{degree}C under spontaneous pressure for 50 hours. In hydrogenation experiment, the specimens were fed into an autoclave together with tetradecane and sulfurization catalyst, and subjected to reaction at 350{degree}C under initial pressure of 9.8MPa for 2 hours for gas chromatography (GC) analysis of products. As the experimental result, the reaction between glucose and aromatic ring in heat treatment in water occurred between aromatic ring and active fragment with a mean carbon number of 4-5 produced by decomposition of glucose. The reactivity was higher in benzaldehyde addition than phenol addition. 3 refs., 4 figs., 1 tab.

  18. Recent advances in the ruthenium-catalyzed hydroarylation of alkynes with aromatics: synthesis of trisubstituted alkenes.

    Science.gov (United States)

    Manikandan, Rajendran; Jeganmohan, Masilamani

    2015-11-14

    The hydroarylation of alkynes with substituted aromatics in the presence of a metal catalyst via chelation-assisted C-H bond activation is a powerful method to synthesize trisubstituted alkenes. Chelation-assisted C-H bond activation can be done by two ways: (a) an oxidative addition pathway and (b) a deprotonation pathway. Generally, a mixture of cis and trans stereoisomeric as well as regioisomeric trisubstituted alkenes was observed in an oxidative addition pathway. In the deprotonation pathway, the hydroarylation reaction can be done in a highly regio- and stereoselective manner, and enables preparation of the expected trisubstituted alkenes in a highly selective manner. Generally, ruthenium, rhodium and cobalt complexes are used as catalysts in the reaction. In this review, a ruthenium-catalyzed hydroarylation of alkynes with substituted aromatics is covered completely. The hydroarylation reaction of alkynes with amide, azole, carbamate, phosphine oxide, amine, acetyl, sulfoxide and sulphur directed aromatics is discussed.

  19. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  20. SEDIMENT-ASSOCIATED REACTIONS OF AROMATIC AMINES. 2. QSAR DEVELOPMENT

    Science.gov (United States)

    The fate of aromatic amines in soils and sediments is dominated by irreversible binding through nucleophilic addition and oxidative radical coupling. Despite the common occurrence of the aromatic amine functional group in organic chemicals, the molecular properties useful for pr...