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1
Morgant, Georges, Bernard Viossat, Monique Roch-Arveiller, Patrice Prognon, Jean-Paul Giroud, Jean-Charles Lancelot, Max Robba, and Dung Nguyen Huy. "In Vivo Nitric Oxide Synthase Inhibitors Can Be Deprived of This Activity: Unexpected Influence of the Tetrachloroplatinate(II) Counteranion. Crystal Structures of Bis(S-Methyl-Isothiouronium)-N,N′-Bis(3-Guanidinopropyl)Piperazinium and Hexamidinium Tetrachloroplatinates(II) Salts." Metal-Based Drugs 5, no. 3 (January 1, 1998): 127–37. http://dx.doi.org/10.1155/mbd.1998.127.
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The synthesis and crystal structures of bis(S-methylisothiouronium) (MSTUH)+, N,N′-bis((3- guanidinopropyl)piperazinium (PipeC3GuaH4)4+ and hexamidinium (HexaH2)2+ tetrachloro platinate(ll) salts ( called hereafter PtMSTU, PtPipeC3Gua and PtHexa respectively ) were investigated. These compounds contain the “amidine” function (- C(=NH)NH2 ) in which the H atoms supplied by the acid have become attached to the imino group of each terminal amidino function. Moreover, in PtPipeC3Gua, the nitrogen atoms of the chair-piperazine moiety are also protonated. The influence of tetrachloroplatinate(ll) counteranion ( versus sulfate, nitrate and diisethionate ) in the in vivo nitrite inhibition by the (MSTUH)+, (PipeC3GuaH4)4+ and (HexaH2)2+ cations was investigated. The three tetrachloroplatinate(ll) salts, unexpectedly, do not inhibit significantly the in vivo nitrite production in comparison with the other salts (sulfate, nitrate and diisethionate and their corresponding previous countercations) which exhibit NO synthase inhibition, especially bis(S-methylisothiouronium) sulfate, a selective and potent inducible NO synthase (iNOS) inhibitor commonly used as standard.
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Haginoya, Noriyasu, Syozo Kobayashi, Satoshi Komoriya, Toshiharu Yoshino, Tsutomu Nagata, Yumiko Hirokawa, and Takayasu Nagahara. "Design, synthesis, and biological activity of non-amidine factor Xa inhibitors containing pyridine N-oxide and 2-carbamoylthiazole units." Bioorganic & Medicinal Chemistry 12, no. 21 (November 2004): 5579–86. http://dx.doi.org/10.1016/j.bmc.2004.08.001.
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Asahara, Haruyasu, Keita Arikiyo, and Nagatoshi Nishiwaki. "Development of variously functionalized nitrile oxides." Beilstein Journal of Organic Chemistry 11 (July 23, 2015): 1241–45. http://dx.doi.org/10.3762/bjoc.11.138.
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N-Methylated amides (N,4-dimethylbenzamide and N-methylcyclohexanecarboxamide) were systematically subjected to chemical transformations, namely, N-tosylation followed by nucleophilic substitution. The amide function was converted to the corresponding carboxylic acid, esters, amides, aldehyde, and ketone upon treatment with hydroxide, alkoxide, amine, diisobutylaluminium hydride and Grignard reagent, respectively. In these transformations, N-methyl-N-tosylcarboxamides behave like a Weinreb amide. Similarly, N-methyl-5-phenylisoxazole-3-carboxamide was converted into 3-functionalized isoxazole derivatives. Since the amide was prepared by the cycloaddition reaction of ethynylbenzene and N-methylcarbamoylnitrile oxide, the nitrile oxide served as the equivalent of the nitrile oxides bearing a variety of functional groups such as carboxy, alkoxycarbonyl, carbamoyl, acyl and formyl moieties.
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Eckelmann, Jens, Vittorio Saggiomo, Svenja Fischmann, and Ulrich Lüning. "Binding of group 15 and group 16 oxides by a concave host containing an isophthalamide unit." Beilstein Journal of Organic Chemistry 8 (January 3, 2012): 11–17. http://dx.doi.org/10.3762/bjoc.8.2.
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A bi-macrocycle with an incorporated isophthalamide substructure was synthesized by double amide formation between an isophthaloyl dichloride and two equivalents of a bis(alkenyloxy)aniline, followed by ring-closing metathesis and hydrogenation. In contrast to many related isophthalamides, the concave host exhibits a better binding for oxides, such as DMSO or pyridine-N-oxide, than for halide anions. A general method for a quick estimation of the strength of binding derived from only a few data points is presented and gives an estimated K ass of pyridine-N-oxide of ca. 40 M−1, NMR titration confirms 25 M−1.
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Bolla, Geetha, and Ashwini Nangia. "Supramolecular synthon hierarchy in sulfonamide cocrystals with syn-amides and N-oxides." IUCrJ 6, no. 4 (June 21, 2019): 751–60. http://dx.doi.org/10.1107/s2052252519005037.
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Sulfonamide drugs are well known antibacterial and antimicrobial molecules for pharmaceutical development. Building a library of suitable supramolecular synthons for the sulfonamide functional group and understanding their crystal structures with partner coformer molecules continues to be a challenge in crystal engineering. Although a few sulfonamide cocrystals with amides and N-oxides have been reported, the body of work on sulfonamide synthons is limited compared with those that have carboxylic acids and carboxamides. To address this structural gap, the present work is primarily focused on sulfonamide–lactam and sulfonamide–syn-amide synthons with drugs such as celecoxib, hydrochlorothiazide and furosemide. Furthermore, the electrostatic potential of previously reported cocrystals has been recalculated to show that the negative electrostatic potential on the lactam and syn-amide O atom is higher compared with the charge on carboxamide and pyridine N-oxide O atoms. The potential of sulfonamide molecules to form cocrystals with syn-amides and lactams are evaluated in terms of the electrostatic potential energy for the designed supramolecular synthons.
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Syre, Ronny, Nancy Frenzel, Cristian G. Hrib, Edmund P. Burte, Peter G. Jones, and Frank T. Edelmann. "Di-μ-oxido-bis[bis(diisopropylacetamidinato)-κN;κ2N,N′-germanium(IV)]." Acta Crystallographica Section E Structure Reports Online 69, no. 12 (November 30, 2013): m686—m687. http://dx.doi.org/10.1107/s1600536813032133.
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The title compound, [Ge2(C8H17N2)4O2], crystallizes with imposed twofold symmetry, which allows the monodentate amidinate ligands to be arranged in acisoidfashion. The independent Ge—O distances within the central Ge2O2ring, which is essentially planar (r.m.s. deviation = 0.039 Å), are 1.7797 (8) and 1.8568 (8) Å. The germanium centres adopt a distorted trigonal–bipyramidal geometry, being coordinated by the two O atoms and by one bidentate and one monodentate amidinate ligand (three N atoms). OneN-isopropyl group is disordered over two positions; these are mutually exclusive because of `collisions' between symmetry-equivalent methyl groups and thus each has 0.5 occupancy.
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Sandoval, Stefania, Amparo Fuertes, and Gerard Tobias. "Solvent-free functionalisation of graphene oxide with amide and amine groups at room temperature." Chemical Communications 55, no. 81 (2019): 12196–99. http://dx.doi.org/10.1039/c9cc05693a.
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Hajr, Azhar, and Lamjed Marzouki. "A new route to [1,2,4]triazolo[4,3-c][1,3,5,2]triazaphosphinine-5-oxides: reactivity of N-alkyl/aryl-n'-(4h-1,2,4-triazol-3-yl) amidines with N,N-dimethylphosphoramic dichloride." Bulletin of the Chemical Society of Ethiopia 34, no. 1 (April 24, 2020): 157–61. http://dx.doi.org/10.4314/bcse.v34i1.15.
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A series of novel [1,2,4]triazolo[4,3-c][1,3,5,2]triazaphosphinine-5-oxidederivatives 2a-h were synthesized by a reaction of N-alkyl/aryl-N'-(4H-1,2,4-triazol-3-yl) amidines with N,N-dimethylphosphoramic dichloride in the presence of triethylamine (TEA) in refluxing 1,4-dioxane. The structures of all the synthesized compounds have been established by NMR (1H, 13C, 31P) and IR spectroscopy, as well as by elemental analysis and mass spectral analysis.
Bull. Chem. Soc. Ethiop. 2020, 34(1), 157-161.
DOI: https://dx.doi.org/10.4314/bcse.v34i1.15
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Çolak, Senem, Mahmut Durmuş, and Salih Zeki Yıldız. "Investigation of the photophysical and photochemical properties of peripherally tetra-substituted water-soluble zwitterionic and cationic zinc(ii) phthalocyanines." Dalton Transactions 45, no. 25 (2016): 10402–10. http://dx.doi.org/10.1039/c6dt01084a.
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4-{4-[N-((3-Dimethylamino)propyl)amide]phenoxy} substituted zinc(ii) phthalocyanine (2) and its water-soluble sulfobetaine (3), betaine (4) and N-oxide (5) containing zwitterionic and cationic (6) derivatives were synthesized for the first time in this study.
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Panteleieva, Olha S., Vira V. Ponomarova, Alexander V. Shtemenko, and Kostiantyn V. Domasevitch. "Supramolecular networks supported by the anion...π linkage of Keggin-type heteropolyoxotungstates." Acta Crystallographica Section C Structural Chemistry 76, no. 8 (July 21, 2020): 753–62. http://dx.doi.org/10.1107/s205322962000950x.
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Anion...π interactions are newly recognized weak supramolecular forces which are relevant to many types of electron-deficient aromatic substrates. Being less competitive with respect to conventional hydrogen bonding, anion...π interactions are only rarely considered as a crystal-structure-defining factor. Their significance dramatically increases for polyoxometalate (POM) species, which offer extended oxide surfaces for maintaining dense aromatic/inorganic stacks. The structures of tetrakis(caffeinium) μ12-silicato-tetracosa-μ2-oxido-dodecaoxidododecatungsten trihydrate, (C8H11N4O2)4[SiW12O40]·3H2O, (1), and tris(theobrominium) μ12-phosphato-tetracosa-μ2-oxido-dodecaoxidododecatungsten ethanol sesquisolvate, (C7H9N4O2)3[PW12O40]·1.5C2H5OH, (2), support the utility of anion...π interactions as a special kind of supramolecular synthon controlling the structures of ionic lattices. Both caffeinium [(HCaf)+ in (1)] and theobrominium cations [(HTbr)+ in (2)] reveal double stacking patterns at both axial sides of the aromatic frameworks, leading to the generation of anion...π...anion bridges. The latter provide the rare face-to-face linkage of the anions. In (1), every square face of the metal–oxide cuboctahedra accepts the interaction and the above bridges yield flat square nets, i.e. {(HCaf+)2[SiW12O40]4−} n . Two additional cations afford single stacks only and they terminate the connectivity. Salt (2) retains a two-dimensional (2D) motif of square nets, with anion...π...anion bridges involving two of the three (HTbr)+ cations. The remaining cations complete a fivefold anion...π environment of [PW12O40]3−, acting as terminal groups. This single anion...π interaction is influenced by the specific pairing of (HTbr)+ cations by double amide-to-amide hydrogen bonding. Nevertheless, invariable 2D patterns in (1) and (2) suggest the dominant role of anion...π interactions as the structure-governing factor, which is applicable to the construction of noncovalent linkages involving Keggin-type oxometalates.
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Constantin, Lucian Alexandru, Ionut Cristea, Ines Nitoi, Mirela Alina Constantin, and Gheorghe Nechifor. "Kinetics of Cyclophosphamide and Ifosfamide Degradation from Aqueous System via TiO2 Assisted Photocatalysis." Revista de Chimie 68, no. 8 (September 15, 2017): 1690–94. http://dx.doi.org/10.37358/rc.17.8.5745.
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Cyclophosphamide (CP) - N,N-bis(2-chloroethyl)-1,3,2-oxazaphosphinan-2-amine 2-oxide and ifosfamide (IF) - N,3-bis(2-chloroethyl)-1,3,2-oxazaphosphinan-2-amide 2-oxide degradation under UV-Vis/TiO2 photocatalysis was studied in the following experimental conditions: photocatalyst dose = 100 � 800 mg/L; irradiation time = 30-360 min; initial pollutant concentration = 1 � 50 mg/L. CP and IF degradation via TiO2 photocatalysis was found to obey Langmuir � Hinshelwood model and pollutants degradation rate constants: 5.89 x 10-6 M min-1 (CP); 4.86 x 10-6 M min-1 (IF) and pollutants adsorption � desorption on TiO2 particles equilibrium constants: 5637 M-1 (CP); 4930 M-1 (IF) were calculated.
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Rueda-García, Daniel, María del Rocío Rodríguez-Laguna, Emigdio Chávez-Angel, Deepak P. Dubal, Zahilia Cabán-Huertas, Raúl Benages-Vilau, and Pedro Gómez-Romero. "From Thermal to Electroactive Graphene Nanofluids." Energies 12, no. 23 (November 28, 2019): 4545. http://dx.doi.org/10.3390/en12234545.
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Here, we describe selected work on the development and study of nanofluids based on graphene and reduced graphene oxide both in aqueous and organic electrolytes. A thorough study of thermal properties of graphene in amide organic solvents (N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone) showed a substantial increase of thermal conductivity and specific heat upon graphene integration in those solvents. In addition to these thermal studies, our group has also pioneered a distinct line of work on electroactive nanofluids for energy storage. In this case, reduced graphene oxide (rGO) nanofluids in aqueous electrolytes were studied and characterized by cyclic voltammetry and charge-discharge cycles (i.e., in new flow cells). In addition, hybrid configurations (both hybrid nanofluid materials and hybrid cells combining faradaic and capacitive activities) were studied and are summarized here.
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VanderWeide, Andrew I., Richard J. Staples, and Shannon M. Biros. "Crystal structures of two bis-carbamoylmethylphosphine oxide (CMPO) compounds." Acta Crystallographica Section E Crystallographic Communications 75, no. 7 (June 14, 2019): 991–96. http://dx.doi.org/10.1107/s205698901900820x.
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Two bis-carbamoylmethylphosphine oxide compounds, namely {[(3-{[2-(diphenylphosphinoyl)ethanamido]methyl}benzyl)carbamoyl]methyl}diphenylphosphine oxide, C36H34N2O4P2, (I), and diethyl [({2-[2-(diethoxyphosphinoyl)ethanamido]ethyl}carbamoyl)methyl]phosphonate, C14H30N2O8P2, (II), were synthesized via nucleophilic acyl substitution reactions between an ester and a primary amine. Hydrogen-bonding interactions are present in both crystals, but these interactions are intramolecular in the case of compound (I) and intermolecular in compound (II). Intramolecular π–π stacking interactions are also present in the crystal of compound (I) with a centroid–centroid distance of 3.9479 (12) Å and a dihedral angle of 9.56 (12)°. Intermolecular C—H...π interactions [C...centroid distance of 3.622 (2) Å, C—H...centroid angle of 146°] give rise to supramolecular sheets that lie in the ab plane. Key geometric features for compound (I) involve a nearly planar, trans-amide group with a C—N—C—C torsion angle of 169.12 (17)°, and a torsion angle of −108.39 (15)° between the phosphine oxide phosphorus atom and the amide nitrogen atom. For compound (II), the electron density corresponding to the phosphoryl group was disordered, and was modeled as two parts with a 0.7387 (19):0.2613 (19) occupancy ratio. Compound (II) also boasts a trans-amide group that approaches planarity with a C—N—C—C torsion angle of −176.50 (16)°. The hydrogen bonds in this structure are intermolecular, with a D...A distance of 2.883 (2) Å and a D—H...A angle of 175.0 (18)° between the amide hydrogen atom and the P=O oxygen atom. These non-covalent interactions create ribbons that run along the b-axis direction.
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Makhova, N. N., I. V. Ovchinnikov, A. S. Kulikov, S. I. Molotov, and E. L. Baryshnikova. "Monocyclic and cascade rearrangements of furoxans." Pure and Applied Chemistry 76, no. 9 (September 30, 2004): 1691–703. http://dx.doi.org/10.1351/pac200476091691.
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Monocyclic rearrangements of azoles are extensively studied as alternative methods for the preparation of new heterocyclic systems. The present work is devoted to investigation of monocyclic and cascade rearrangements of 1,2,5-oxadiazole 2-oxide (furoxan) derivatives. It was found during investigations that rearrangements of furoxan ring had some peculiarities in comparison with analogous rearrangements of other azoles. Therefore, three different kinds of rearrangements were found. The first of them occurred through a dinitroso-ethylene intermediate and resulted in the synthesis of 1,2,3-triazole 1-oxides [oximes of 5-acetyl-4-phenyl(methyl)-2-phenyl-2H -1,2,3-triazole 1-oxides and 2-(furoxan-4-yl)-4-nitro-5-R-2H -1,2,3-triazole 1-oxides ]by thermal recyclization accordingly of 3-methyl-4-acetyl(benzoyl)furoxans phenylhydrazones and 3,3'-(R)-disubstituted-4,4'-azofuroxans. The latter reaction was performed in an oxidizing medium. The second kind of rearrangement (classical variant) was the synthesis of new azoles containing the 1-nitroalkyl substituent. These rearrangements were performed using three examples: base-induced interconversion of furoxanyl ketone phenylhydrazones into 5-(1-nitroalkyl)-2H-1,2,3-triazole derivatives and of 1-alkyl(aryl)-3-(furoxan-4-yl)amidines into 1-substituted 3-(1-nitroalkyl)-1,2,4-triazoles as well as a thermally induced rearrangement of 4-thioureido-3-R-furoxans into derivatives of 5-amino-3-(1-nitroalkyl)-1,2,4-thiadiazole including (5-amino-1,2,4-thiadiazol-3-yl)nitro-formaldehyde arylhydrazones (where R =N=N –Ar). Rearrangements of the third kind were those of the cascade type. Three new cascade rearrangements of azofuroxan derivatives [3,3'-azo-4,4'-bis(acetylamino)furoxans, 3-arylazo-4-acetylaminofuroxans, and 3-arylazo-4-(3- ethoxycarbonylureido)furoxans] into 4-amino-5-nitro-2H-1,2,3-triazole derivatives were discovered. These three reactions were assumed to include two consecutive (cascade) rearrangements: a 1,2,4-oxadiazole ring was formed at the first step and then transformed into a 1,2,3-triazole ring with the participation of an azo group.
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Shah, Archana. "Eco-friendly Crosslinking Agent for Acid Functional Acrylic Resin." E-Journal of Chemistry 6, no. 2 (2009): 419–28. http://dx.doi.org/10.1155/2009/673479.
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Oil fromJ. multifidawas extracted and it was first converted intoN,N-bis(2-hydroxyethyl) Jatropha fatty amide (HEJFA). HEJFA has been synthesized by reaction between Jatropha oil and diethanol amine in presence of zinc oxide as a catalyst. The reaction is relatively rapid and proceeded to high yield at 200±5OC. The resulting HEJFA was used to formulate thermosetting coating compositions. Films were cured at ambient (air drying) and elevated (stove drying) temperatures usingN, N-bis(2-hydroxyethyl) Jatropha fatty amide (HEJFA) as eco-friendly crosslinking agent for acrylic resin. The coating performance of the various compositions was tested by measurement of scratch hardness, impact strength and chemical resistance. The results show better performance of the HEJFA based compositions compared to butylated melamine formaldehyde (MF) based compositions.
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Gong, Xue-Di, Lai-Shun Shi, Tian-Yao Wang, and Xiao-Meng Yu. "The Synthesis and Characterization of a Novel Cationic Asphalt Emulsifier." MATEC Web of Conferences 264 (2019): 03006. http://dx.doi.org/10.1051/matecconf/201926403006.
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A new cationic asphalt emulsifier of N,N-dimethyl-N-(3-(N',N'-dimethyl amido)-2-hydroxy propyl)- coconut oil amide propyl-1-ammonium chloride was synthesized by two steps reaction of coconut oil acyl propyl dimethyl tertiary amine (PKO), epoxy chloropropane and dimethylamine. The chemical structure of the key intermediate of N,N-dimethyl-N-(ethylene oxide-2-methylene)-coconut oil amide propyl-1-ammonium chloride was confirmed by FTIR, 1H NMR and elemental analysis. The optimum reaction condition of first step was obtained by single factor analysis: reaction time 5 h, reaction temperature 50 °C, feedstock mole ratio of epoxy chloropropane to PKO 1.05. The reaction yield is 82.15% and the epoxy value is 40.39% at the optimum conditions. The critical micelle concentration (CMC) of the asphalt emulsifier is 7.80×10-2 mol/L. The surface tension at CMC is 24.57 mN/m. The emulsifier showed excellent emulsification effect for the asphalt. The prepared bituminous emulsion had higher storage stability. The emulsifier belongs to medium-set asphalt emulsifier.
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Nasir, Muhamad, and Dita Apriani. "Synthesis of Catechin-Gelatin Nanofiber by Electrospinning." Materials Science Forum 887 (March 2017): 96–99. http://dx.doi.org/10.4028/www.scientific.net/msf.887.96.
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Catechin and gelatin are important natural products for food, medical, pharmaceutical and cosmetic industry. We have successfully synthesized catechin-gelatin nanofiber by electrospinning process. Catechin-gelatin nanofiber was synthesized by using gelatin from yellow fin skin tuna fish as biopolymer, polyethylene oxide (PEO) as spinnability improver polymer, acetic acid as solvent and catechin as bioactive component, respectively. Morphology and structure of bioactive catechin-gelatin nanofiber were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR), respectively. SEM analysis showed that morphology of nanofiber was very smooth without bead on nanofiber string. The average of catechin-gelatin nanofiber diameter was 389 nm. FTIR analysis results were used to confirm structure of catechin-gelatin nanofiber. Catechin-gelatin nanofiber has vibration band peak of amide A (N-H) at 3289,043 cm-1 and amide B (N-H) 3062,310 cm-1, amide I (C=O) at 1643,812 cm-1, amide II (N-H and CN) at 1538,949 cm-1, amide III (C-N) at 1237,11 cm-1 from gelatin, C-O-C from PEO at 1143,583 cm-1, and vibration band peak OH at 3200-3600 cm-1, and at C-O ether around 1300-1100 from catechin, respectively. FTIR spectra showed us that there is no change in chemical structure of gelatin and catechin in nanofiber which was produced by electrospinning process. Catechin-gelatin nanofiber can inhibit S. Aureus bacteria around 43.38%
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Khaldoun, Khadidja, Abdelmounaim Safer, Salima Saidi-Besbes, Bertrand Carboni, Rémy Le Guével, and François Carreaux. "An Efficient Solvent-Free Microwave-Assisted Synthesis of Cinnamamides by Amidation Reaction Using Phenylboronic Acid/Lewis Base Co-catalytic System." Synthesis 51, no. 20 (July 29, 2019): 3891–900. http://dx.doi.org/10.1055/s-0039-1690132.
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A microwave-assisted dehydrative amide condensation reaction is reported as an efficient access to cinnamamide derivatives under solvent-free conditions. This protocol between conjugated carboxylic acids and amines is based on the use of a co-catalytic system, including the presence of the commercially available phenylboronic acid and 4-(N,N-dimethylamino)pyridine N-oxide (DMAPO), with a complete chemoselectivity in favor of the corresponding α,β-unsaturated amides. The implementation of the reaction needs no special precaution, and less reactive amines, such as substituted anilines, are also efficient under these conditions. A series of novel conjugated amides have been evaluated for their cytotoxic activities against several human cancer cell lines.
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Ban, Kiwon, Kyoung-Han Kim, Chan-Kyung Cho, Meghan Sauvé, Eleftherios P. Diamandis, Peter H. Backx, Daniel J. Drucker, and Mansoor Husain. "Glucagon-Like Peptide (GLP)-1(9-36)Amide-Mediated Cytoprotection Is Blocked by Exendin(9-39) Yet Does Not Require the Known GLP-1 Receptor." Endocrinology 151, no. 4 (February 19, 2010): 1520–31. http://dx.doi.org/10.1210/en.2009-1197.
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The widely expressed dipeptidyl peptidase-4 enzyme rapidly cleaves the gut hormone glucagon-like peptide-1 [GLP-1(7-36)amide] at the N terminus to generate GLP-1(9-36)amide. Both intact GLP-1(7-36)amide and GLP-1(9-36)amide exert cardioprotective actions in rodent hearts; however, the mechanisms underlying the actions of GLP-1(9-36)amide remain poorly understood. We used mass spectrometry of coronary effluents to demonstrate that isolated mouse hearts rapidly convert infused GLP-1(7-36)amide to GLP-1(9-36)amide. After ischemia-reperfusion (I/R) injury of isolated mouse hearts, administration of GLP-1(9-36)amide or exendin-4 improved functional recovery and reduced infarct size. The direct actions of these peptides were studied in cultured neonatal mouse cardiomyocytes. Both GLP-1(9-36)amide and exendin-4 increased levels of cAMP and phosphorylation of ERK1/2 and the phosphoinositide 3-kinase target protein kinase B/Akt. In I/R injury models in vitro, both peptides improved mouse cardiomyocyte viability and reduced lactate dehydrogenase release and caspase-3 activation. These effects were attenuated by inhibitors of ERK1/2 and phosphoinositide 3-kinase. Unexpectedly, the cardioprotective actions of GLP-1(9-36)amide were blocked by exendin(9-39) yet preserved in Glp1r−/− cardiomyocytes. Furthermore, GLP-1(9-36)amide, but not exendin-4, improved the survival of human aortic endothelial cells undergoing I/R injury, actions sensitive to the nitric oxide synthase inhibitor, N(G)-nitro-l-arginine methyl ester (L-NAME). In summary, our findings demonstrate separate actions for GLP-1(9-36)amide vs. the GLP-1R agonist exendin-4 and reveal the existence of a GLP-1(9-36)amide-responsive, exendin(9-39)-sensitive, cardioprotective signaling pathway distinct from that associated with the classical GLP-1 receptor.
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Bencková, Mária, and Alžbeta Krutošíková. "5-Aminofuro[3,2-c]pyridinium Tosylates and Substituted Furo[3,2-c]pyridine N-Oxides: Synthesis and Reactions." Collection of Czechoslovak Chemical Communications 64, no. 3 (1999): 539–47. http://dx.doi.org/10.1135/cccc19990539.
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5-Aminofuro[3,2-c]pyridinium tosylates 2a-2c were synthesized by direct N-amination of furo[3,2-c]pyridines 1a-1c with O-(4-methylbenzenesulfonyl)hydroxylamine in dichloromethane. Zwitterionic furo[3,2-c]pyridinium N-imides 3a-3c generated from 2a-2c and anhydrous potassium carbonate in N,N-dimethylformamide afforded by 1,3-dipolar cycloaddition reactions with dimethyl butynedioate or ethyl propiolate the corresponding furo[3,2-c]pyrazolo[1,5-a]pyridinecarboxylic esters 4a-4c and 5a-5c. Furo[3,2-c]pyridine N-oxides 6a-6c and their benzo derivative 6d were synthesized by reaction of 1 with 3-chloroperbenzoic acid in dichloromethane. Treatment of N-oxides 6 with benzoyl chloride and cyanide anion (Reissert-Henze reaction) was shown to produce the corresponding furo[3,2-c]pyridine-4-carbonitriles 7. In further transformations (acid and alkaline hydrolysis), the cyano group was converted successively to amide and carboxylic acid.
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O'Sullivan, Saoirse E., David A. Kendall, and Michael D. Randall. "Time-Dependent Vascular Effects of Endocannabinoids Mediated by Peroxisome Proliferator-Activated Receptor Gamma (PPAR)." PPAR Research 2009 (2009): 1–9. http://dx.doi.org/10.1155/2009/425289.
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The aim of the present study was to examine whether endocannabinoids cause PPAR-mediated vascular actions. Functional vascular studies were carried out in rat aortae. Anandamide and N-arachidonoyl-dopamine (NADA), but not palmitoylethanolamide, caused significant vasorelaxation over time (2 hours). Vasorelaxation to NADA, but not anandamide, was inhibited by C receptor antagonism (AM251, 1 M), and vasorelaxation to both anandamide and NADA was inhibited by PPAR antagonism (GW9662, 1 M). Pharmacological inhibition ofde novoprotein synthesis, nitric oxide synthase, and super oxide dismutase abolished the responses to anandamide and NADA. Removal of the endothelium partly inhibited the vasorelaxant responses to anandamide and NADA. Inhibition of fatty acid amide hydrolase (URB597, 1 M) inhibited the vasorelaxant response to NADA, but not anandamide. These data indicate that endocannabinoids cause time-dependent, PPAR-mediated vasorelaxation. Activation of PPAR in the vasculature may represent a novel mechanism by which endocannabinoids are involved in vascular regulation.
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Takahashi, Kenji, Hiroshi Funakubo, Shiro Hino, Makoto Nakayama, Naoki Ohashi, Takanori Kiguchi, and Eisuke Tokumitsu. "Effect of deposition temperature on the characteristics of hafnium oxide films deposited by metalorganic chemical vapor deposition using amide precursor." Journal of Materials Research 19, no. 2 (February 2004): 584–89. http://dx.doi.org/10.1557/jmr.2004.19.2.584.
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Hafnium oxide films were deposited on silicon substrates at deposition temperatures ranging from 190 to 500 °C by metalorganic chemical vapor deposition using an amide precursor, Hf[N(C2H5)2]4, and O2 as source materials. The effect of deposition temperature on the deposition characteristics and electrical properties of the resultant films were investigated. Reaction-limited deposition of hafnium oxide films occurred at deposition temperatures under 380 °C. Concentration of residues, such as carbon, nitrogen, and hydrogen, monotonously decreased with increasing deposition temperature, with nitrogen being the most thermally susceptible. However, surface roughness reached a minimum value at 400 °C. Amorphous films were obtained for deposition temperatures up to 450 °C, but obviously became crystallized at 500 °C. Accumulation capacitance increased with increasing deposition temperature but saturated above 400 °C. Moreover, postdeposition annealing at 800 °C caused no obvious degradation in the electrical properties of the film deposited at 400 °C.
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Piegeler, Tobias, E. Gina Votta-Velis, Farnaz R. Bakhshi, Mao Mao, Graeme Carnegie, Marcelo G. Bonini, David E. Schwartz, Alain Borgeat, Beatrice Beck-Schimmer, and Richard D. Minshall. "Endothelial Barrier Protection by Local Anesthetics." Anesthesiology 120, no. 6 (June 1, 2014): 1414–28. http://dx.doi.org/10.1097/aln.0000000000000174.
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Abstract Background: Pulmonary endothelial barrier dysfunction mediated in part by Src-kinase activation plays a crucial role in acute inflammatory disease. Proinflammatory cytokines, such as tumor necrosis factor-α (TNFα), activate Src via phosphatidylinositide 3-kinase/Akt-dependent nitric oxide generation, a process initiated by recruitment of phosphatidylinositide 3-kinase regulatory subunit p85 to TNF-receptor-1. Because amide-linked local anesthetics have well-established anti-inflammatory effects, the authors hypothesized that ropivacaine and lidocaine attenuate inflammatory Src signaling by disrupting the phosphatidylinositide 3-kinase–Akt–nitric oxide pathway, thus blocking Src-dependent neutrophil adhesion and endothelial hyperpermeability. Methods: Human lung microvascular endothelial cells, incubated with TNFα in the absence or presence of clinically relevant concentrations of ropivacaine and lidocaine, were analyzed by Western blot, probing for phosphorylated/activated Src, endothelial nitric oxide synthase, Akt, intercellular adhesion molecule-1, and caveolin-1. The effect of ropivacaine on TNFα-induced nitric oxide generation, co-immunoprecipitation of TNF-receptor-1 with p85, neutrophil adhesion, and endothelial barrier disruption were assessed. Results: Ropivacaine and lidocaine attenuated TNFα-induced Src activation (half-maximal inhibitory concentration [IC50] = 8.611 × 10−10 M for ropivacaine; IC50 = 5.864 × 10−10 M for lidocaine) and endothelial nitric oxide synthase phosphorylation (IC50 = 7.572 × 10−10 M for ropivacaine; IC50 = 6.377 × 10−10 M for lidocaine). Akt activation (n = 7; P = 0.006) and stimulus-dependent binding of TNF-receptor-1 and p85 (n = 6; P = 0.043) were blocked by 1 nM of ropivacaine. TNFα-induced neutrophil adhesion and disruption of endothelial monolayers via Src-dependent intercellular adhesion molecule-1- and caveolin-1-phosphorylation, respectively, were also attenuated. Conclusions: Ropivacaine and lidocaine effectively blocked inflammatory TNFα signaling in endothelial cells by attenuating p85 recruitment to TNF-receptor-1. The resultant decrease in Akt, endothelial nitric oxide synthase, and Src phosphorylation reduced neutrophil adhesion and endothelial hyperpermeability. This novel anti-inflammatory “side-effect” of ropivacaine and lidocaine may provide therapeutic benefit in acute inflammatory disease.
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Marinović, Marina, Ivana Perković, Diana Fontinha, Miguel Prudêncio, Jana Held, Lais Pessanha de Carvalho, Tana Tandarić, Robert Vianello, Branka Zorc, and Zrinka Rajić. "Novel Harmicines with Improved Potency against Plasmodium." Molecules 25, no. 19 (September 23, 2020): 4376. http://dx.doi.org/10.3390/molecules25194376.
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Harmicines represent hybrid compounds composed of β-carboline alkaloid harmine and cinnamic acid derivatives (CADs). In this paper we report the synthesis of amide-type harmicines and the evaluation of their biological activity. N-harmicines 5a–f and O-harmicines 6a–h were prepared by a straightforward synthetic procedure, from harmine-based amines and CADs using standard coupling conditions, 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo [4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU) and N,N-diisopropylethylamine (DIEA). Amide-type harmicines exerted remarkable activity against the erythrocytic stage of P. falciparum, in low submicromolar concentrations, which was significantly more pronounced compared to their antiplasmodial activity against the hepatic stages of P. berghei. Furthermore, a cytotoxicity assay against the human liver hepatocellular carcinoma cell line (HepG2) revealed favorable selectivity indices of the most active harmicines. Molecular dynamics simulations demonstrated the binding of ligands within the ATP binding site of PfHsp90, while the calculated binding free energies confirmed higher activity of N-harmicines 5 over their O-substituted analogues 6. Amino acids predominantly affecting the binding were identified, which provided guidelines for the further derivatization of the harmine framework towards more efficient agents.
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JEYAKUMAR, P., S. S. SARAVANAKUMAR, K. KULATHURAAN, V. RAMADAS, and B. NATARAJAN. "FUNCTIONALIZATION OF BIOMOLECULES WITH NANOSTRUCTURED POROUS SILICON FOR BIOMEDICAL APPLICATION." Surface Review and Letters 22, no. 02 (April 2015): 1550022. http://dx.doi.org/10.1142/s0218625x15500225.
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Porous silicon (PS) fabrication, changes in the optical properties and surface modification in the oxidized PS (dipped into the Glucose oxide) due to the infiltration of biomolecules using Luminescence Spectrophotometer [Photoluminescence (PL)], Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM) were studied. The surface morphology of oxidized PS (OPS) and treated with Glucose have been studied by SEM. Spontaneous imbibition weight was calculated theoretically using imbibition equation for the porous medium using glucose solution as the wetting liquid. FTIR analysis revealed that, the strong Si–H, Si–O–Si bonds which covered most of the OPS surface. In the glucose treated PS layer, the amide I (C=O) stretch and amide II (C=N) stretch (1690 cm−1 and 1551 cm−1) groups were appeared in the spectrum which confirmed the coupling reaction. Efficient visible Photoluminescence was obtained at around 624 nm from glucose treated porous silicon. The functionalization of glucose with nano structured PS, changes light emission over the surface of OPS. It can be applied in optical biosensor and which can be used in biomedical applications.
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Haake, Paul, and Donald A. Tyssee. "Estimation of Charge Density on Nitrogen in Amides by Measurement of One-Bond Carbon-Hydrogen Nuclear Coupling Constants in N-CH3 Group." Zeitschrift für Naturforschung A 48, no. 1-2 (February 1, 1993): 58–62. http://dx.doi.org/10.1515/zna-1993-1-216.
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Abstract One-bond, 13C-1H coupling constants, J1(C-H), 'in amines, ammonium ions, and carboxylic amides correlate with structure and support the concept that the value of J1(C-H) is related to the charge density on the nitrogen atom; for example, amine oxides have nearly the same charge density at nitrogen as does the tetramethylammonium ion. The J1(C-H) values for methyls bonded to nitrogen in various amides then give an experimental estimate of the charge density at the nitrogen atom that enables an estimate of the bond order in the C-N amide-bond; the data suggest that carboxylic amides have a C-N bond order of about 1.35, that sulfonamides have an S-N bond order of about 1.45, and that phosphinamides, R2 P(O)N(CH3)2 , have a P-N bond order of about 1.3. In contrast, aminephosphines have a P-N single bond. The value for carboxylic amides is in reasonable agreement with bond distances in amides.
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M¨ohrle, Hans, and Petra Arndt. "Hydroxylamin-Funktion als Nachbargruppe bei Dehydrierungen / Hydroxylamine Function as Neighboring Group with Dehydrogenations." Zeitschrift für Naturforschung B 60, no. 6 (June 1, 2005): 688–700. http://dx.doi.org/10.1515/znb-2005-0614.
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The β -amino-hydroxylamines 5a - d are prepared of the α-amino-oximes 1a - d with boranedimethylsulfide. With mercury-EDTA, 5a - d react to (E/Z)-oxime-lactams 3a - d and benzaldoxime 7. Additionally 5b,c give the bicyclic amidine-N-oxides 8b,c, which slowly hydrolyze to the hydroxylamine-lactams 9b,c. These are easily oxidized to (E/Z)-3b,c. Postulated as intermediates in the mercury-assisted reduction of 5, the cyclic hydroxylamines 10a - d are available from the nitrones 4a - d with LiAlH4. From 10a - d with mercury-EDTA the same products are obtained as from 5a - d but without 7. Only the pyrrolidine 10a forms besides (E/Z)-3a the nitrone 4a. Thinlayer chromatography shows that the pure isomers of 3a - d in solution isomerize, contrary to the amine-oximes 1a - d. The configuration of the oxime-lactams depends on the manner of preparation. With mercury-EDTA, 1b,c yield 3b,c with retention of the configuration, while the oximation of phenacyl-lactams 13b,c give rise to (E/Z)-mixtures of 3b,c. The condensed imidazoles 12 result from the nitrones 4a - d and the dihydrooxadiazines 2a,d on treatment with hydrogen chloride.
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Takafuji, Makoto, Maino Kajiwara, Nanami Hano, Yutaka Kuwahara, and Hirotaka Ihara. "Preparation of High Refractive Index Composite Films Based on Titanium Oxide Nanoparticles Hybridized Hydrophilic Polymers." Nanomaterials 9, no. 4 (April 2, 2019): 514. http://dx.doi.org/10.3390/nano9040514.
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Optical materials with high refractive index (n) have been rapidly improved because of urgent demands imposed by the development of advanced photonic and electronic devices such as solar cells, light emitting diodes (LED and Organic LED), optical lenses and filters, anti-reflection films, and optical adhesives. One successful method to obtain high refractive index materials is the blending of metal oxide nanoparticles such as TiO2 and ZrO2 with high n values of 2.1–2.7 into conventional polymers. However, these nanoparticles have a tendency to agglomerate by themselves in a conventional polymer matrix, due to the strong attractive forces between them. Therefore, there is a limitation in the blending amount of inorganic nanoparticles. In this paper, various hydrophilic polymers such as poly(N-hydroxyl acrylamide) (pHEAAm), poly(vinyl alcohol), poly(ethylene glycol), and poly(acrylic acid) were examined for preparation of high refractive index film based on titanium oxide nanoparticle (TiNP) dispersed polymer composite. The hydrogen bonding sites in these hydrophilic polymers would improve the dispersibility of inorganic nanoparticles in the polymer matrix. As a result, pHEAAm exhibited higher compatibility with titanium oxide nanoparticles (TiNPs) than other water-soluble polymers. Transparent hybrid films were prepared by mixing pHEAAm with TiNPs and drop casting the mixture onto a glass plate. The refractive indices of the films were in good agreement with calculated values. The compatibility of TiNPs with pHEAAm was dependent on the surface characteristics of TiNPs. TiNPs with the highest observed compatibility could be hybridized with pHEAAm at concentrations of up to 90 wt%, and the refractive index of the corresponding film reached 1.90. The high compatibility of TiNPs with pHEAAm may be related to the hydrophilicity and amide and hydroxyl moieties of pHEAAm, which cause hydrogen bond formation on the TiO2 surface. The obtained thin film was slightly yellow due to the color of the original TiNP dispersion; however, the transmittance of the film was higher than 80% in the wavelength range from 480 to 900 nm.
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Guo, Haitao, Xiaoming Xue, Chenghui Nan, Xi Liu, Zehui Wang, and Bin Dao. "Comparison of the Composition of Three Mahonia Plants Based on GC-MS Analysis." E3S Web of Conferences 131 (2019): 01125. http://dx.doi.org/10.1051/e3sconf/201913101125.
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Plant material evidence inspection is Mahonia bealei (Fort.) Carr., Mahonia fortunei (Lindl.) and Mahonia bodinieri Gagnep. are three common medicinal plants commonly found in Mahonia. In this study, gas chromatography-mass spectrometry (GC-MS) was used to compare the chemical constituents of stems and leaves of these three plants. The results showed that 6 of the volatile oils of the three plant species contained the same chemical composition, which was neophytadiene, palmitic acid, n-dodecane, octacosane, erucamide, and vitamin E oil, but the percentage content was difference. The main components of the volatile oils of the three plant stems were different. Erucamide was only detected in Mahonia fortunei (Lindl.) Fedde, oleic acid amide only detected in Mahonia bealei (Fort.) Carr. , and oxidized cyclooctene , and four compounds such as triphenylphosphine oxide was detected in Mahonia bodinieri Gagnep. ..
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Jin, Wenhui, Longhe Yang, Zhiwei Yi, Hua Fang, Weizhu Chen, Zhuan Hong, Yiping Zhang, Guangya Zhang, and Long Li. "Anti-Inflammatory Effects of Fucoxanthinol in LPS-Induced RAW264.7 Cells through the NAAA-PEA Pathway." Marine Drugs 18, no. 4 (April 21, 2020): 222. http://dx.doi.org/10.3390/md18040222.
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Palmitoylethanolamide (PEA) is an endogenous lipid mediator with powerful anti-inflammatory and analgesic functions. PEA can be hydrolyzed by a lysosomal enzyme N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages and other immune cells. The pharmacological inhibition of NAAA activity is a potential therapeutic strategy for inflammation-related diseases. Fucoxanthinol (FXOH) is a marine carotenoid from brown seaweeds with various beneficial effects. However, the anti-inflammatory effects and mechanism of action of FXOH in lipopolysaccharide (LPS)-stimulated macrophages remain unclear. This study aimed to explore the role of FXOH in the NAAA–PEA pathway and the anti-inflammatory effects based on this mechanism. In vitro results showed that FXOH can directly bind to the active site of NAAA protein and specifically inhibit the activity of NAAA enzyme. In an LPS-induced inflammatory model in macrophages, FXOH pretreatment significantly reversed the LPS-induced downregulation of PEA levels. FXOH also substantially attenuated the mRNA expression of inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), and markedly reduced the production of TNF-α, IL-6, IL-1β, and nitric oxide (NO). Moreover, the inhibitory effect of FXOH on NO induction was significantly abolished by the peroxisome proliferator-activated receptor α (PPAR-α) inhibitor GW6471. All these findings demonstrated that FXOH can prevent LPS-induced inflammation in macrophages, and its mechanisms may be associated with the regulation of the NAAA-PEA-PPAR-α pathway.
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Stoscup, Julie A., Richard J. Staples, and Shannon M. Biros. "Crystal structure of a samarium(III) nitrate chain cross-linked by a bis-carbamoylmethylphosphine oxide ligand." Acta Crystallographica Section E Structure Reports Online 70, no. 10 (September 13, 2014): 188–91. http://dx.doi.org/10.1107/s1600536814020078.
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In the title compound poly[aquabis(μ-nitrato-κ4O,O′:O,O′′)tetrakis(nitrato-κ2O,O′){μ4-tetraethyl [(ethane-1,2-diyl)bis(azanediyl)bis(2-oxoethane-2,1-diyl)]diphosphonate-κ2O,O′}disamarium(III)], [Sm2(NO3)6(C14H30N2O8P2)(H2O)]n, a 12-coordinate SmIIIand a nine-coordinate SmIIIcation are alternately linkedviashared bis-bidentate nitrate anions into a corrugated chain extending parallel to theaaxis. The nine-coordinate SmIIIatom of this chain is also chelated by a bidentate, yet flexible, carbamoylmethylphoshine oxide (CMPO) ligand and bears one water molecule. This water molecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate SmIIIcation. The CMPO ligand, which lies about an inversion center, links neighboring chains along thecaxis, forming sheets parallel to theacplane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along thebaxis through only van der Waals interactions.
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Zanatta, Josiléia Acordi, Cimélio Bayer, Frederico C. B. Vieira, Juliana Gomes, and Michely Tomazi. "Nitrous oxide and methane fluxes in south Brazilian gleysol as affected by nitrogen fertilizers." Revista Brasileira de Ciência do Solo 34, no. 5 (October 2010): 1653–65. http://dx.doi.org/10.1590/s0100-06832010000500018.
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Nitrogen fertilizers increase the nitrous oxide (N2O) emission and can reduce the methane (CH4) oxidation from agricultural soils. However, the magnitude of this effect is unknown in Southern Brazilian edaphoclimatic conditions, as well as the potential of different sources of mineral N fertilizers in such an effect. The aim of this study was to investigate the effects of different mineral N sources (urea, ammonium sulphate, calcium nitrate, ammonium nitrate, Uran, controlled- release N fertilizer, and urea with urease inhibitor) on N2O and CH4 fluxes from Gleysol in the South of Brazil (Porto Alegre, RS), in comparison to a control treatment without a N application. The experiment was arranged in a randomized block with three replications, and the N fertilizer was applied to corn at the V5 growth stage. Air samples were collected from a static chambers for 15 days after the N application and the N2O and CH4 concentration were determined by gas chromatography. The topmost emissions occurred three days after the N fertilizer application and ranged from 187.8 to 8587.4 µg m-2 h-1 N. The greatest emissions were observed for N-nitric based fertilizers, while N sources with a urease inhibitor and controlled release N presented the smallest values and the N-ammonium and amidic were intermediate. This peak of N2O emissions was related to soil NO3--N (R² = 0.56, p < 0.08) when the soil water-filled pore space was up to 70 % and it indicated that N2O was predominantly produced by a denitrification process in the soil. Soil CH4 fluxes ranged from -30.1 µg m-2 h-1 C (absorption) to +32.5 µg m-2 h-1 C (emission), and the accumulated emission in the period was related to the soil NH4+-N concentration (R² = 0.82, p < 0.001), probably due to enzymatic competition between nitrification and metanotrophy processes. Despite both of the gas fluxes being affected by N fertilizers, in the average of the treatments, the impact on CH4 emission (0.2 kg ha-1 equivalent CO2-C ) was a hundredfold minor than for N2O (132.8 kg ha-1 equivalent CO2-C). Accounting for the N2O and CH4 emissions plus energetic costs of N fertilizers of 1.3 kg CO2-C kg-1 N regarding the manufacture, transport and application, we estimated an environmental impact of N sources ranging from 220.4 to 664.5 kg ha-1 CO2 -C , which can only be partially offset by C sequestration in the soil, as no study in South Brazil reported an annual net soil C accumulation rate larger than 160 kg ha-1 C due to N fertilization. The N2O mitigation can be obtained by the replacement of N-nitric sources by ammonium and amidic fertilizers. Controlled release N fertilizers and urea with urease inhibitor are also potential alternatives to N2O emission mitigation to atmospheric and systematic studies are necessary to quantify their potential in Brazilian agroecosystems.
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Glover, Stephen A., and Adam A. Rosser. "The role of substituents in the HERON reaction of anomeric amides." Canadian Journal of Chemistry 94, no. 12 (December 2016): 1169–80. http://dx.doi.org/10.1139/cjc-2016-0300.
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Anomeric amides, RCON(X)(Y), have two electronegative atoms at the amide nitrogen, a configuration that results in greatly reduced amide resonance and strongly pyramidal nitrogen atoms. This, combined with facilitation of anomeric interactions, can result in the HERON reaction, an intramolecular migration of the more electronegative atom, X, from nitrogen to the carbonyl with production of a Y-stabilised nitrene. We have modelled, at the B3LYP/6-31G(d) level, a variety of anomeric amides that undergo the HERON reaction to determine factors that underpin the process. The overriding driving force is anomeric destabilisation of the bond to the migrating group. Rotated transition states show loss of residual resonance and this is a component of the overall activation energies. However, the reduced resonance in these systems plays only a minor role. We have determined the resonance energies (RE) and HERON activation barriers (EA) of five anomeric systems. REs for the amides have been calculated isodesmically using our calibrated trans amidation method and COSNAR calculations. Reduction of their overall EAs by the corresponding RE gives rearrangement energies (Erearr.), a measure of relative impact on rearrangement of substituents on nitrogen. In CH3CON(OMe)(Y) systems producing (CH3CO2Me + NY), a loosely bound electron pair on the donor atom, Y, in nY–σ*NOMe anomeric interactions drives the reaction. Erearr. increases in the sequence Y = N(nitrene) < O−(oxide) ≪ NMe2 < SMe ≪ OMe. For the same systems, RE increases in the order Y = N < O− ≪ OMe ≪ NMe2 ∼ SMe. Other effects such as molecular conformation, nature of the migrating group, X, and acyl substituents at the carbonyl carbon are discussed.
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Melford, Sarah E., Anthony H. Taylor, and Justin C. Konje. "Nitric oxide positively affects endometrial receptivity via FAAH and NAPE-PLD in vitro." Reproduction and Fertility 2, no. 2 (April 21, 2021): 107–16. http://dx.doi.org/10.1530/raf-20-0035.
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Objective To determine if models of human 'receptive' and 'non-receptive endometrium' differ in their responses to nitric oxide (NO) supplementation by measuring the levels of the enzymes of the endocannabinoid system (ECS) (fatty acid amide hydrolase (FAAH) and N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD)), which control the 'anandamide tone' essential for successful pregnancy. Design A study of FAAH and NAPE-PLD expression (using human endometrium) through the menstrual cycle and an in vitro using a model of 'receptive' (Ishikawa) and 'non-receptive' (HEC-1A) human endometrial cell lines treated with the NO-donating compound S-nitroso-N-acetylpenicillamine (SNAP). Results Immunoreactivity measured by optimised H-score for both FAAH and NAPE-PLD was reduced in secretory (receptive) endometrium compared to proliferative (non-receptive) endometrium (P = 0.0009 and <0.0001, respectively). FAAH and NAPE transcript levels were significantly higher in untreated Ishikawa cells than in HEC-1A cells (P = 0.0228 and 0.0001, respectively). Treatment of cultures with SNAP resulted in an increase in the amount of FAAH mRNA produced by Ishikawa cells and a decrease in NAPE-PLD mRNA. No effect of SNAP was observed in HEC-1A cells. Similarly, FAAH protein was significantly decreased in endometria representative of the receptive endometrium. Conclusion These data suggest that NO most likely affects the expression of ECS enzymes in the implantation site of a receptive endometrium; a phenomenon not seen in a non-receptive endometrium. These effects are most marked with FAAH expression, suggesting that FAAH may play the more critical role in ensuring the correct 'anandamide tone' for successful embryo implantation than NAPE-PLD. Lay summary Embryo implantation into the wall of the uterus is only successful when the inner wall of the uterus (the endometrium) is ‘receptive’, because if it is ‘non-receptive’, implantation will fail. Previous work showed that enzymes of the 'endocannabinoid system' are critical for implantation by maintaining the correct level of a fat called anandamide. This is by balancing its synthesis (by N-acylphosphatidylethanolamine specific phospholipase D, NAPE-PLD) and degradation (by fatty acid amide hydrolase, FAAH). Using immortalised cell lines as models of ‘receptive’ and ‘non-receptive’ human endometrium, we demonstrate a key stimulator of implantation, nitric oxide, has a positive effect on implantation by both increasing the mRNA levels of the degrading enzyme (FAAH) and decreasing the expression of the synthesising enzyme (NAPE-PLD). These effects are most marked with the degrading enzyme, suggesting that FAAH plays a more critical role than NAPE-PLD in ensuring the correct 'anandamide tone' for successful embryo implantation.
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Zhang, Manli, Meiying Chen, Yong Hou, Congzhao Fan, Hongyan Wei, Leiling Shi, Guoxu Ma, and Jing Zhang. "Inflammatory and Cytotoxic Activities of Abietane Terpenoids from Nepeta bracteata Benth." Molecules 26, no. 18 (September 15, 2021): 5603. http://dx.doi.org/10.3390/molecules26185603.
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Nepeta bracteata Benth. is used clinically to treat tracheal inflammation, coughs, asthma, colds, fevers, adverse urination, and other symptoms, along with functions in clearing heat and removing dampness. However, there have been few studies characterizing the material basis of its efficacy. Therefore, the aim of this study was to screen for compounds with anti-inflammatory activities in N. bracteata Benth. Using silica gel, ODS C18, and Sephadex LH-20 column chromatography, as well as semipreparative HPLC, 10 compounds were separated from N. bracteata Benth. extract, including four new diterpenoids (1–4), one amide alkaloid (5), and five known diterpenoids (6–10). The structures of all the isolates were elucidated by HR-ESI-MS, NMR, and CD analyses. Using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, we investigated the anti-inflammatory activities of compounds 1–10. It is worth noting that all were able to inhibit nitric oxide (NO) production with IC50 values < 50 μM and little effect on RAW 264.7 macrophage viability. Compounds 2 and 4 displayed remarkable inhibition with IC50 values of 19.2 and 18.8 μM, respectively. Meanwhile, screening on HCT-8 cells demonstrated that compounds 2 and 4 also had moderate cytotoxic activities with IC50 values of 36.3 and 41.4 μM, respectively, which is related to their anti-inflammatory effects.
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Bharucha, Adil E., Nisha Charkoudian, Christopher N. Andrews, Michael Camilleri, David Sletten, Alan R. Zinsmeister, and Phillip A. Low. "Effects of glucagon-like peptide-1, yohimbine, and nitrergic modulation on sympathetic and parasympathetic activity in humans." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 295, no. 3 (September 2008): R874—R880. http://dx.doi.org/10.1152/ajpregu.00153.2008.
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Glucagon-like peptide-1 (GLP-1), an incretin, which is used to treat diabetes mellitus in humans, inhibited vagal activity and activated nitrergic pathways. In rats, GLP-1 also increased sympathetic activity, heart rate, and blood pressure (BP). However, the effects of GLP-1 on sympathetic activity in humans are unknown. Our aims were to assess the effects of a GLP-1 agonist with or without α2-adrenergic or -nitrergic blockade on autonomic nervous functions in humans. In this double-blind study, 48 healthy volunteers were randomized to GLP-1-(7-36) amide, the nitric oxide synthase (NOS) inhibitor N G-monomethyl-l-arginine acetate (l-NMMA), the α2-adrenergic antagonist yohimbine, or placebo (i.e., saline), alone or in combination. Hemodynamic parameters, plasma catecholamines, and cardiac sympathetic and parasympathetic modulation were measured by spectral analysis of heart rate. Thereafter, the effects of GLP-1-(7-36) amide on muscle sympathetic nerve activity (MSNA) were assessed by microneurography in seven subjects. GLP-1 increased ( P = 0.02) MSNA but did not affect cardiac sympathetic or parasympathetic indices, as assessed by spectral analysis. Yohimbine increased plasma catecholamines and the low-frequency (LF) component of heart rate power spectrum, suggesting increased cardiac sympathetic activity. l-NMMA increased the BP and reduced the heart rate but did not affect the balance between sympathetic and parasympathetic activity. GLP-1 increases skeletal muscle sympathetic nerve activity but does not appear to affect cardiac sympathetic or parasympathetic activity in humans.
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Kurdanova, Zhanna I., Kamila T. Shakhmurzova, Azamat A. Zhansitov, Arthur E. Baykaziev, Karina Kh Teunova, and Svetlana Yu Khashirova. "METHODS FOR SYNTHESIS OF POLYETHERIMIDES." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 6 (July 8, 2019): 4–14. http://dx.doi.org/10.6060/ivkkt.20196206.5892.
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The review summarizes and systematizes the currently known data on the synthesis of polyetherimides. Polyetherimides are a promising class of high-quality polymeric materials with a valua-ble set of properties that can be directed to the appropriate design of the polymer chain. Thus, to obtain polyetherimide with a lower glass transition temperature, as much as possible of ether bonds are introduced into the macromolecule, as well as m-phenylene fragments that increase the flexibility of the polymer chain. Polyetherimides of this structure are amorphous and soluble in a number of amide solvents and chlorinated hydrocarbons. Three main methods for the preparation of polyetherimide are discussed in detail: high-temperature polycondensation by nucleophilic substitution in solution, polycondensation in a melt, and production of polyetherimide directly during extrusion. The most promising method for today is the method of high-temperature polycondensation in solution by the reaction of nucleophilic aromatic substitution. As a halogen-containing monomer, chlorine or fluorophthalic anhydrides are used in the synthesis. The reaction of diamines with chlorophthalic anhydride proceeds at lower rates in comparison with the fluorine-containing analog. However, the use of fluorophthalic anhydride proved to be inexpedient from the economic point of view. The economic availability of the corresponding nitrosubstituted phthalic derivatives and high rates of displacement of nitro groups with the help of aryl oxide ions allow to product the commercially avail-able polymers. As solvents, aprotic dipolar (dimethylsulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.), nonpolar organic (o-dichlorobenzene, methylene chloride, etc.) and phenolic solvents can be used. However, the increasing attention of researchers is attracted to the synthesis in the environment of o-dichlorobenzene.
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Giorno, Thais Biondino Sardella, Fernanda Alves Lima, Ana Laura Macedo Brand, Camila Martins de Oliveira, Claudia Moraes Rezende, and Patricia Dias Fernandes. "Characterization of βN-Octadecanoyl-5-hydroxytryptamide Anti-Inflammatory Effect." Molecules 26, no. 12 (June 18, 2021): 3709. http://dx.doi.org/10.3390/molecules26123709.
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Background: N-octadecanoyl-5-hydroxytryptamide (C18-5HT) is an amide that can be obtained by the coupling of serotonin and octadecanoic acid. This study aims to characterize the in vivo and in vitro anti-inflammatory activity of C18-5HT. Methods: A subcutaneous air pouch model (SAP) was used. The exudates were collected from SAP after carrageenan injection to assess cell migration and inflammatory mediators production. RAW 264.7 cells were used for in vitro assays. Results: C18-5HT significantly inhibited leukocyte migration into the SAP as well as nitric oxide (NO) and cytokines production and protein extravasation. We also observed an reduction in some cytokines and an increase in IL-10 production. Assays conducted with RAW 264.7 cells indicated that C18-5HT inhibited NO and cytokine produced. Conclusions: Taken together, our data suggest that C18-5HT presents a significant effect in different cell types (leukocytes collected from exudate, mainly polumorphonuclear leukocytes and cell culture macrophages) and is a promising compound for further studies for the development of a new anti-inflammatory drug.
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Fiori, Anna, Monica Bari, Filippo Granata, Valeria Gasperi, M. De Stefano, Alessandro Finazzi-Agrò, Roberto Strom, and Mauro Maccarrone. "Regulation by cannabinoid receptors of anandamide transport across the blood-brain barrier and through other endothelial cells." Thrombosis and Haemostasis 95, no. 01 (2006): 117–27. http://dx.doi.org/10.1160/th05-06-0413.
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SummaryThe endocannabinoid anandamide (AEA) has many neurovascular activities. However, it is not yet clear how AEA can be metabolized at the neurovascular interface, and how it can move through the vascular and the cerebral compartments. The results reported in this article show that isolated bovine brain microvessels, an ex vivo model of the blood-brain barrier, have detectable levels of endogenous AEA and possess the biochemical machinery to bind and metabolize it, i. e. type-1 and type-2 cannabinoid receptors (CB1R and CB2R), a selective AEA membrane transporter (AMT), an AEA-degrading fatty acid amide hydrolase, and the AEA-synthesizing enzymes N-acyltransferase and N-acyl-phosphatidylethanolamines-specific phospholipase D. We also show that activation of CB1R enhances AMT activity through increased nitric oxide synthase (NOS) activity and subsequent increase of NO production. AMT activity is instead reduced by activation of CB2R, which inhibits NOS and NO release. In addition, binding experiments and immunoelectronmicroscopy demonstrate that different endothelial cells vary in the expression of CB1R and CB2R on the luminal and/or abluminal sides. The different localization of CBRs can lead to a diverse effect on AMT activity on the luminal and abluminal membranes, suggesting that the distribution of these receptors may drive AEA directional transport through the blood-brain barrier and other endothelial cells.
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Shaik, Mohammed Rafi, Manawwer Alam, and Naser M. Alandis. "Development of sustainable resource based poly(urethane-etheramide)/Fe2O3 nanocomposite as anticorrosive coating materials." Journal of Polymer Engineering 35, no. 9 (November 1, 2015): 905–16. http://dx.doi.org/10.1515/polyeng-2015-0009.
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Abstract Linseed polyetheramide (LPEtA) resin was synthesized by the condensation polymerization of N-N-bis (2-hydroxyethyl) linseed oil fatty amide (HELA) with pyrogallol. The residual hydroxyl groups of LPEtA resin were further modified with isophorone diisocyanate (IPDI) to obtain linseed poly(urethane-etheramide) (ULPEtA) via addition polymerization. ULPEtA was modified with iron oxide nanoparticles in different weight percent (0.1 wt%, 0.2 wt%, 0.3 wt% and 0.4 wt%) producing ULPEtA/Fe2O3 nanocomposite. Spectroscopic characterization of HELA, LPEtA and ULPEtA was carried out by using Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR) and carbon nuclear magnetic resonance (13C-NMR) techniques. Physicochemical and physico-mechanical properties of LPEtA and ULPEtA were carried out by using standard methods. Thermal stability and anticorrosion performance were assessed by thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and potentiodynamic polarization. The corrosion behavior of ULPEtA/Fe2O3 nanocomposite coatings on mild steel was investigated in different corrosive environments (3.5 wt% HCl, 5.0 wt% NaCl, 3.5 wt% NaOH, and tap water) at room temperature. Surface morphology study was performed through scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Coating properties such as gloss, scratch hardness, flexibility and impact resistance were evaluated using standard methods. The results of this study showed that ULPEtA/Fe2O3 nanocomposite coatings exhibit good physico-mechanical, anticorrosive properties and can be safely used up to 220°C.
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Noriega-Navarro, Roxana, Jésica Castro-Medina, Martha V. Escárcega-Bobadilla, and Gustavo A. Zelada-Guillén. "Control of pH-Responsiveness in Graphene Oxide Grafted with Poly-DEAEMA via Tailored Functionalization." Nanomaterials 10, no. 4 (March 27, 2020): 614. http://dx.doi.org/10.3390/nano10040614.
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Polymer-grafted nanomaterials based on carbon allotropes and their derivatives (graphene oxide (GO), etc.) are typically prepared by successive reaction stages that depend upon the initial functionalities in the nanostructure and the polymerization type needed for grafting. However, due to the multiple variables involved in the functionalization steps, it is commonly difficult to predict the properties in the final product and to correlate the material history with its final performance. In this work, we explored the steps needed to graft the carboxylic acid moieties in GO (COOH@GO) with a pH-sensitive polymer, poly[2-(diethylamino)ethyl methacrylate] (poly[DEAEMA]), varying the reactant ratios at each stage prior to polymerization. We studied the combinatorial relationship between these variables and the behavior of the novel grafted material GO-g-poly[DEAEMA], in terms of swelling ratio vs. pH (%Q) in solid specimens and potentiometric response vs. Log[H+] in a solid-state sensor format. We first introduced N-hydroxysuccinimide (NHS)-ester moieties at the –COOH groups (GO-g-NHS) by a classical activation with N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide (EDC). Then, we substituted the NHS-ester groups by polymerizable amide-linked acrylic moieties using 2-aminoethyl methacrylate (AEMA) at different ratios to finally introduce the polymer chains via radical polymerization in an excess of DEAEMA monomer. We found correlated trends in swelling pH range, interval of maximum and minimum swelling values, response in potentiometry and potentiometric linear range vs. Log[H+] and could establish their relationship with the combinatorial stoichiometries in synthetic stages.
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Liu, Min-Tsai, and Annette L. Kirchgessner. "Guinea pig pancreatic neurons: morphology, neurochemistry, electrical properties, and response to 5-HT." American Journal of Physiology-Gastrointestinal and Liver Physiology 273, no. 6 (December 1, 1997): G1273—G1289. http://dx.doi.org/10.1152/ajpgi.1997.273.6.g1273.
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The morphology, neurochemistry, and electrical properties of guinea pig pancreatic neurons were determined. The majority of neurons expressed choline acetyltransferase (ChAT) immunoreactivity; however, ChAT-negative neurons were also found. Both cholinergic and noncholinergic neurons expressed nitric oxide synthase (NOS) immunoreactivity. Three types of pancreatic neurons were distinguished. Phasic neurons fired action potentials (APs) at the onset of depolarizing current pulse, tonic neurons spiked throughout the duration of a suprathreshold depolarizing pulse, and APs could not be generated in nonspiking neurons, even though they did receive synaptic input. APs were tetrodotoxin sensitive, and all types of neurons received fast and slow excitatory postsynaptic potentials (EPSPs). Fast EPSPs had cholinergic and noncholinergic components. The majority of pancreatic neurons appeared to innervate the acini. NOS- and/or neuropeptide Y-immunoreactive phasic and tonic neurons were found. Microejection of 5-hydroxytryptamine (5-HT) caused a slow depolarization that was inhibited by the 5-HT1P antagonist N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide and mimicked by the 5-HT1Pagonist 6-hydroxyindalpine. A pancreatic 5-HT transporter was located, and inhibition of 5-HT uptake by fluoxetine blocked slow EPSPs in 5-HT-responsive neurons by receptor desensitization.
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Lee, Jonghyuk, Geun-Bae Yi, Douglas R. Powell, Masood A. Khan, and George B. Richter-Addo. "Synthesis, characterization, and protonation of octaethylporphyrin osmium nitrosyl complexes containing axial thiolate ligands - X-ray structures of an alkyl thionitrite (RSNO) and its (OEP)Os(NO)(SR) addition product." Canadian Journal of Chemistry 79, no. 5-6 (May 1, 2001): 830–40. http://dx.doi.org/10.1139/v00-168.
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The (OEP)Os(NO)(SR) compounds (R = Me, Et, i-Pr, t-Bu) have been prepared in 33-48% isolated yields by the formal trans-addition of the precursor alkyl thionitrites (RSNO) across the metal center in (OEP)Os(CO). The nitrosyl thiolate compounds have been characterized by IR, 1H NMR, and UV-vis spectroscopy, and by FAB mass spectrometry. Their IR spectra display bands in the 1751-1755 cm-1 (KBr) range, which is indicative of terminal N-bound NO ligands in this class of compounds. The thiolate-thiol (OEP)Os(NO)(SCH2CH2SH) complex has been prepared in 70% isolated yield from the reaction of (OEP)Os(NO)(O-i-C5H11) with ethane-1,2-dithiol. Nitrosation of the free -SH group in (OEP)Os(NO)(SCH2CH2SH) with t-BuONO, followed by reaction with (TTP)Ru(CO) gave [(OEP)Os(NO)](µ-SCH2CH2S-S,S')[Ru(NO)(TTP)] in 70% yield by 1H NMR spectroscopy. The (OEP)Os(NO)(SCR'2CH2NHC(O)Me) compounds have also been prepared either by an alkoxide-thiolate exchange reaction (for R' = H) or by RSNO addition to (OEP)Os(CO) (for R' = Me). The solid-state molecular structures of the precursor RSNO thionitrite (for R' = Me) and the metalloderivative have been determined by single-crystal X-ray crystallography. Protonation of these (OEP)Os(NO)(SCR'2CH2NHC(O)Me) complexes gave the amide-bound [(OEP)Os(NO)(O=C(Me)NHCH2CR'2SH)]BF4 derivatives. The latter cationic compounds were also obtained by the sequential reaction of (OEP)Os(CO) with nitrosonium tetrafluoroborate, followed by addition of the amide-thiol reagent. Key words: thionitrite, nitrosothiol, porphyrin, X-ray structure, nitric oxide, osmium.
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Henderson, William, Allen G. Oliver, and Brian K. Nicholson. "Isolation and X-ray structure of the platinum(II)–amidate complex cis-[PtCl{N(CO2Et)C(O)CH2CN}(PPh3)2], an intermediate in the silver(I) oxide-mediated synthesis of a platinalactam complex." Inorganica Chimica Acta 298, no. 1 (January 2000): 84–89. http://dx.doi.org/10.1016/s0020-1693(99)00395-3.
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Casili, Giovanna, Marika Lanza, Michela Campolo, Rosalba Siracusa, Irene Paterniti, Alessio Ardizzone, Sarah Adriana Scuderi, Salvatore Cuzzocrea, and Emanuela Esposito. "Synergic Therapeutic Potential of PEA-Um Treatment and NAAA Enzyme Silencing In the Management of Neuroinflammation." International Journal of Molecular Sciences 21, no. 20 (October 11, 2020): 7486. http://dx.doi.org/10.3390/ijms21207486.
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Inflammation is a key element in the pathobiology of neurodegenerative diseases and sees the involvement of different neuronal and non-neuronal cells as players able to respond to inflammatory signals of immune origin. Palmitoylethanolamide (PEA) is an endogenous potent anti-inflammatory agent, in which activity is regulated by N-acylethanolamine acid amidase (NAAA), that hydrolyzes saturated or monounsaturated fatty acid ethanolamides, such as PEA. In this research, an in vitro study was performed on different neuronal (SH-SY5Y) and non-neuronal cell lines (C6, BV-2, and Mo3.13) subjected to NAAA enzyme silencing and treated with PEA ultra-micronized (PEA-um) (1, 3, and 10 μM) to increase the amount of endogenous PEA available for counteract neuroinflammation provoked by stimulation with lipopolysaccharide (LPS) (1 μg/mL) and interferon gamma (INF-γ )(100 U/mL). Cell viability was performed by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) staining, suggesting a protective effect of PEA-um (3 and 10 μM) on all cell lines studied. Western Blot analysis for inflammatory markers (Inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2)) was carried out in control and NAAA-silenced cells, highlighting how the concomitant treatment of the neuronal and non-neuronal cells with PEA-um after NAAA genic downregulation is satisfactory to counteract neuroinflammation. These in vitro findings support the protective role of endogenous PEA availability in the neuronal field, bringing interesting information for a translational point of view.
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Santos, Jephesson, Monalisa Brito, Rafael Ferreira, Ana Moura, Tatyanna Sousa, Tatianne Batista, Vivianne Mangueira, et al. "Th1-Biased Immunomodulation and In Vivo Antitumor Effect of a Novel Piperine Analogue." International Journal of Molecular Sciences 19, no. 9 (September 1, 2018): 2594. http://dx.doi.org/10.3390/ijms19092594.
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Natural products have an important role as prototypes in the synthesis of new anticancer drugs. Piperine is an alkaloid amide with antitumor activity and significant toxicity. Then, the N-(p-nitrophenyl)acetamide piperinoate (HE-02) was synthesized, and tested for toxicological and antitumor effects. The toxicity was evaluated in vitro (on RAW 264.7 cells and mice erythrocytes) and in vivo (acute toxicity in mice). The Ehrlich ascites carcinoma model was used to evaluate the antitumor activity of HE-02 (6.25, 12.5 or 25 mg/kg, intraperitoneally, i.p.), as well as toxicity. HE-02 induced only 5.01% of hemolysis, and reduced the viability of RAW 264.7 cells by 49.75% at 1000 µg/mL. LD50 (lethal dose 50%) was estimated at around 2000 mg/kg (i.p.). HE-02 reduced Ehrlich tumor cell viability and peritumoral microvessels density. There was an increase of Th1 helper T lymphocytes cytokine profile levels (IL-1β, TNF-α, IL-12) and a decrease of Th2 cytokine profile (IL-4, IL-10). Moreover, an increase was observed on reactive oxygen species and nitric oxide production. Weak in vivo toxicological effects were recorded. Our data provide evidence that the piperine analogue HE-02 present low toxicity, and its antitumor effect involves modulation of immune system to a cytotoxic Th1 profile.
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Atkinson, Ian M., Davar M. Boghai, Leonard F. Lindoy, Bahram Ghanbari, George V. Meehan, and Vinod Saini. "New Macrocyclic Ligands. VIII Di- and Tri-linked Macrocyclic Systems Incorporating N2O2-Donor Atoms." Australian Journal of Chemistry 52, no. 5 (1999): 351. http://dx.doi.org/10.1071/ch99054.
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The synthesis and characterization of new lipophilic di- and tri-linked O2N2-donor macrocycles is reported. The synthesis of the dilinked species involved the initial alkylation of one secondary nitrogen of the parent 15-membered, O2N2-donor macrocycle (1) with 2-bromoethanol or with ethylene oxide to yield (2), followed by protection of the appended alcohol group by reaction with t-butyldiphenylsilyl chloride to give (3). Two such moieties were then bridged via a diacylation reaction with ClCO(CH2)8COCl to yield the corresponding diamide product (4). Deprotection of the alcohol functions followed by reduction of the both amide linkages resulted in formation of theN,N′-alkyl-linked species (5) incorporating two pendant hydroxyethyl groups. This product was then converted [via the corresponding dichloro derivative (6)] into the diether (7) by condensation with 4-t-butylphenol. By use of analogous chemistry, the trilinked trismacrocycle species (12), based on a phloroglucinol core, has also been synthesized. An aim of the present study was thus the preparation of new ‘linked’ macrocyclic systems that might be expected to show higher lipophilicity than their corresponding single-ring systems. These were designed for future use as ionophores in metal ion membrane transport (and solvent extraction) experiments.
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Olayemi, R. F., I. O. Jawonisi, and J. A. Samuel. "Characterization and physico-chemical analysis of essential oil of Cymbopogon citratus leaves." Bayero Journal of Pure and Applied Sciences 11, no. 1 (October 11, 2018): 74–81. http://dx.doi.org/10.4314/bajopas.v11i1.14.
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The genus Cymbopogon is important from the point of view of their essential oils. Essential oils from these species are widely used in flavours, fragrances, cosmetics, soaps, detergents and perfumery owing to their typical lemon-like aroma. Essential oil of Cymbopogon citratus was extracted by hydrodistillation and characterized using Gas chromatography/mass spectrometry (GC-MS) and Fourier Transform Infrared (FTIR).The oil was also subjected to physico-chemical analysis, the physical and chemical properties evaluated were Boiling point (74oC), Specific gravity (0.8960), Refractive index (1.4838) and pH (6.00) at 25oC. Saponification value(109.76) and Acid value (0.55) mg KOH/g oil. Iodine value (100g of I2/g oil) 105, Ester value (189.21), Residue on evaporation (10%) at 100oC.The chemical composition of the essential oil analyzed by GC-MS showed citral (31.1%), β-Myrcene (14.2%), citronellal (9.8%), limonene oxide (7.7%), eraniol (7.3%) and linalool (6.2%) as the major compounds. The FTIR spectra revealed the presence of n-alkane, conjugated alkene, primary amide, amine, aldehyde, primary and secondary alcohols. The results obtained from the physico-chemical parameters, and functional groups identified by FTIR as well as the compounds identified by GC-MS revealed that the oil has medicinal and nutritive values as well as industrial applications in the pharmaceutical, perfumery and cosmetic industries .Keywords: Characterization, Citral, Cymbopogon citratus, Essential oil, FTIR, GC-MS
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Vokhmyanin, M. A., R. L. Vesnin, V. V. Pyatina, and V. A. Sedykh. "The use of terephthalic acid diamide in rubbers based on NBR-40." Proceedings of the Voronezh State University of Engineering Technologies 82, no. 2 (September 18, 2020): 161–68. http://dx.doi.org/10.20914/2310-1202-2020-2-161-168.
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In the present work, the kinetics of aminolytic degradation of polyethylene terephthalate with a mixture of amino alcohols (monoethanolamine and triethanolamine) was studied to obtain terephthalic acid diamide (N, N'-bis (2-hydroxyethyl) terephthalamide).The degradation reaction was carried out at atmospheric pressure and periodically stirring the reaction mass, followed by purification of the product by recrystallization.The dependence of the yield of the target product (N, N'-bis (2-hydroxyethyl) terephthalamide) on the reaction time and temperature, as well as on the ratio of the components, was revealed. The possibility of using diamide as one of the components of rubbers to expand the ingredient base in the rubber industry is considered. The effect of the obtained diamide on the kinetics of vulcanization of rubbers based on nitrile butadiene rubber (NBR-40) was studied, and the physicochemical and physicomechanical properties of the obtained vulcanizates were examined. In a similar way, the effect of an oligomer obtained by polycondensation of this terephthalic acid diamide was studied. The choice of SKN-40 rubber as the basis is due to the high polarity of the rubber and its good compatibility with the obtained terephthalic acid diamide and its oligomer.The accelerating effect of terephthalic acid diamide in combination with 2-mercaptobenzothiazole (MBT) on sulfur vulcanization of rubbers based on NBR-40 was revealed. The time to reach the optimum vulcanization is reduced by 4 min. In the case of using only terephthalic acid diamide, without the use of common accelerators, the optimum point of vulcanization shifts toward a longer time.In the case of using only terephthalic acid diamide, without the use of common accelerators, the optimum point of vulcanization shifts toward a longer time. Introduction diamide of terephthalic acid or its oligomer results in a change of physical and mechanical properties of the rubber - strength at break and elongation at break. The kinetics of the swelling of the resulting rubbers in toluene and gasoline was studied for four hundred hours. A decrease in the degree of swelling of vulcanizates in gasoline was observed with the introduction of terephthalic acid diamide instead of the zinc oxide vulcanization activator. Possible options for further application and use of the obtained terephthalic acid amide and its oligomer are considered.
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Adamo, Arianna, Emanuele Calabrò, and Salvatore Magazù. "Thermostabilization of BSA in TMAO Water Mixtures by Infrared Spectroscopy." Current Chemical Biology 13, no. 1 (February 8, 2019): 49–59. http://dx.doi.org/10.2174/2212796812666180613082040.
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Background: Trimethylamine-N-Oxide (TMAO) is a small organic molecule derived from the metabolism of L-carnitine and choline after ingestion of animal food. TMAO has many functions such as electron acceptor, an osmolyte, stabilizer of macromolecules folding. It seems that TMAO plays an important role in nature but, in humans, it is a remnant of the evolution of the osmolyte system. Objective: The present paper is addressed on the study of thermal stability of hydrated Bovine Serum Albumins (BSA) in the presence of water and TMAO water solution by means of InfraRed spectroscopy. In particular, this work has investigated the protein amide I spectral regions, which is sensitive to protein secondary structure, and the intramolecular OH stretching region. Methods: The analysis has been performed by different approaches, namely by evaluating the Thermal Spectral Distance (SDT), the spectral shift (Δω), the spectral Fractal Dimension (FD) and the Wavelet Cross Correlation temperature variation (ΔTCXWT). Results: The obtained results revealed for BSA in TMAO, in respect to BSA, smaller values of SDT, Δω, FD and ΔTCXWT. Furthermore, the SDT, Δω and ΔTCXWT temperature trends to follow sigmoid trends that have been modeled by means of logistic functions; in all the above three cases BSA in TMAO shows a higher value of the inflection point temperature. Conclusion: These results can be interpreted by hypothesizing that TMAO influences the hydrogen bond network of water. In particular, the strengthening of the network intermolecular O-H interactions reduces the protein dynamic fluctuations and in turn leads to the stabilization of the protein tertiary structure.