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Elsa Omer, Ronan Cariou, Gérald Remaud, Yann Guitton, Hélène Germon, Paul Hill, Gaud Dervilly-Pinel, Bruno Le Bizec
An untargeted strategy aiming at identifying non-intentionally added substances (NIAS) migrating from coatings was developed. This innovative approach was applied to two polyester-polyurethane lacquers, for which suppliers previously provided the identity of the monomers involved. Lacquers were extracted with acetonitrile and analyzed by liquid chromatography-high resolution mass spectrometry (LC-HRMS). Data, acquired in the full scan mode, were processed using an open-source R-environment (xcms and CAMERA packages) to list the detected features and deconvolute them in groups related to individual compounds...
March 8, 2018: Analytical and Bioanalytical Chemistry
Shawn A Christensen, James Sims, Martha Vaughan, Charles Hunter, Anna Block, Denis Willett, Hans T Alborn, Alisa Huffaker, Eric A Schmelz
Plant defense research is facilitated by the use of genome sequenced inbred lines; however, a foundational knowledge of interactions in commercial hybrids remains relevant to understanding mechanisms present in crops. Using an array of commercial maize hybrids, we quantified the accumulation patterns of defense-related metabolites and phytohormones in tissues challenged with diverse fungal pathogens. Across hybrids, Southern leaf blight (Cochliobolus heterostrophus) strongly elicited specific sesqui- and diterpenoid defenses, namely zealexin A4 (ZA4) and kauralexin diacids, compared to the stalk rotting agents Fusarium graminearum and Colletotrichum graminicola...
January 18, 2018: Journal of Experimental Botany
Kamila Tomoko Yuyama, Clara Chepkirui, Lucile Wendt, Diana Fortkamp, Marc Stadler, Wolf-Rainer Abraham
Treating infections organized in biofilms is a challenge due to the resistance of the pathogens against antibiotics and host immune cells. Many fungi grow in a wet environment, favorable for the growth of bacterial biofilms, and we speculated that fungi possess some strategies to control these bacterial biofilms . A fungus identified as Hypoxylon fragiforme , was collected in the Harz Mountains, Germany, and its mycelial culture was fermented in different culture media for 67 days to test its biological potential against bacterial biofilms...
December 12, 2017: Microorganisms
Thomas H Allen, Anthony R Horner, Steven J Geib, Stephen G Weber, Dennis P Curran
Basic hydrolyses of various ligated α-boryl acetic acid esters provided the first ligated derivatives of the unknown compound boroacetic acid (BH2 CH2 CO2 H). Four monoacids (L-BH2 CH2 CO2 H) and one diacid (L-BH(CH2 CO2 H)2 ) were prepared with N-heterocyclic carbene, amine, and pyridine ligands (L). The stable acids were characterized by X-ray crystallography and acidity constant (pKa ) measurements. They rank among the least acidic of all known carboxylic acids. In turn, their conjugate bases are among the strongest of all carboxylates...
January 19, 2018: Chemistry: a European Journal
Anuj Kumar, Somesh Banerjee, Partha Roy, S M Sondhi, Anuj Sharma
Benzimidazoles and perimidines are subsidiary structures for research and development of new biologically active molecules and have established prominence because of their promising biological activities. Two series of diversified heterocyclic molecules, tetracyclic benzimidazole derivatives, tetracyclic and pentacyclic perimidine derivatives have been synthesized in good yields by condensation of acid anhydrides and diacids with various diamines using microwave irradiation. All synthesized derivatives were fully characterized and evaluated for in vitro antiproliferative activity against five human cancer cell lines...
November 15, 2017: Molecular Diversity
Mohammad Dinari, Elahe Salehi, Amir Abdolmaleki
A new poly(benzimidazole-amide) (PBIA) was fabricated by polycondensation of 1,3-bis(5-amino-1H-benzimidazole-2-yl)benzene with chiral diacid under green media by using tetra-n-butylammonium bromide as a cheap commercially available molten ionic salt at 120°C. The affection of reaction time on the polymer yield and viscosity was tested and optimized for PBIA. Inherent viscosity value of the prepared PBIA under optimized conditions is 0.31dL/g. Then to acquire a uniformly dispersion of graphene oxide (GO) in the PBIA matrix, GO was prepared through strong oxidation procedure...
March 2018: Ultrasonics Sonochemistry
Zhihan Wang, Benjamin Miller, Micah Mabin, Rahul Shahni, Zijun D Wang, Angel Ugrinov, Qianli R Chu
A previously overlooked building block, cyclobutane-1,3-diacid (CBDA), is introduced to materials synthesis due to its great potentials. As an example of CBDA, α-truxillic acid or 2,4-diphenylcyclobutane-1,3-dicarboxylic acid, was readily synthesized from commercially available trans-cinnamic acid. This CBDA showed outstanding stability both in sunlight and upon heating. While its two carboxylic acid groups can be readily utilized in connecting with other molecules to form new materials, the cyclobutane ring was able to tolerate acid and base treatments showing good chemical stability...
October 20, 2017: Scientific Reports
Jing Chen, Yuchao Chen, Yi Cheng, Youheng Gao
Mannose-diester lauric diacid-cholesterol (Man-DLD-Chol), as a liposomal target ligand, was synthesized by lipase catalyzed in a non-aqueous medium. Its chemical structure was confirmed by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Glycyrrhetinic acid (GA) liposomes containing Man-DLD-Chol (Man-DLD-Chol-GA-Lp) were prepared by the film-dispersion method. We evaluated the characterizations of liposomes, drug-release in vitro, the hemolytic test, cellular uptake, pharmacokinetics, and the tissue distributions...
September 24, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Kevin A Kovalchik, Matthew S MacLennan, Kerry M Peru, Chukwuemeka Ajaero, Dena W McMartin, John V Headley, David D Y Chen
RATIONALE: The characterization of naphthenic acid fraction compounds (NAFCs) in oil sands process affected water (OSPW) is of interest for both toxicology studies and regulatory reasons. Previous studies utilizing authentic standards have identified dicarboxylic naphthenic acids using two-dimensional gas chromatography hyphenated to time-of-flight mass spectrometry (GCxGC/TOFMS). The selective derivatization of hydroxyl groups has also recently aided in the characterization of oxy-NAFCs, and indirectly the characterization of dicarboxylic NAFCs...
September 25, 2017: Rapid Communications in Mass Spectrometry: RCM
Michelle C Fairhurst, Michael J Ezell, Barbara J Finlayson-Pitts
While atmospheric particles affect health, visibility and climate, the details governing their formation and growth are poorly understood on a molecular level. A simple model system for understanding the interactions between the gas and particle phases is the reaction of bases with acids, both of which are common constituents of atmospheric particles. In the present study, uptake coefficients for the reactions of gas phase ammonia, methylamine, ethylamine, dimethylamine and trimethylamine with a series of solid dicarboxylic acids (diacids) were measured at 296 ± 1 K using a Knudsen cell interfaced to a quadrupole mass spectrometer...
October 4, 2017: Physical Chemistry Chemical Physics: PCCP
Suresh K R Boreddy, Kimitaka Kawamura, Eri Tachibana
To better understand the impact of East Asian pollutants on the molecular composition of marine organic aerosols, we conducted long-term (2001-2013) observations of water-soluble dicarboxylic acids and related compounds in total suspended particulate samples collected at Chichijima Island in the western North Pacific (WNP). Seasonal variations of all the diacids and related compounds showed maxima in winter and spring and minima in summer, except for azelaic acid (C9), which maximized in summer to autumn. The overall annual concentrations of the total diacids, ω-oxoacids and α-dicarbonyls showed an increase during 2001-2013...
August 17, 2017: Scientific Reports
M M Yuan, M Wang, J Y Liu, Z L Zhang
OBJECTIVE: To optimize and establish the best hydrolysis method of diethyl ester 4-amino-N(5)-formyl-N(8), N(10)-dideazatetrahydrofolate through the optimization of simple compound of diethyl N-(4-aminobenzoyl)-L-glutamate. METHODS: To increase the low yield of hydrolysis reaction of diethyl ester 4-amino-N(5)-formyl-N(8), N(10)-dideazatetrahydrofolate due to the by-products and difficult purification, we studied the effect of NaOH and KOH, two kinds of alkalis, three concentrations between 0...
August 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
David Cruz-Garcia, Nathalie Brouwers, Juan M Duran, Gabriel Mora, Amy J Curwin, Vivek Malhotra
The nutrient starvation-specific unconventional secretion of Acb1 in Saccharomyces cerevisiae requires ESCRT-I, -II, and -III and Grh1. In this study, we report that another signal sequence lacking cytoplasmic protein, superoxide dismutase 1 (SOD1), and its mutant form linked to amyotrophic lateral sclerosis (ALS), is also secreted by yeast upon nutrient starvation in a Grh1- and ESCRT-I-, -II-, and -III-dependent process. Our analyses reveal that a conserved diacidic motif (Asp-Glu) in these proteins is necessary for their export...
August 9, 2017: Journal of Cell Biology
Lasith S Kariyawasam, C Scott Hartley
Biochemical systems make extensive use of chemically fueled processes (e.g., using ATP), but analogous abiotic systems remain rare. A key challenge is the identification of transformations that can be adapted to a range of applications and make use of readily available chemical fuels. In this context, the generation of transient covalent bonds is a fundamental tool for nonequilibrium systems chemistry. Here, we show that carbodiimides constitute a simple class of chemical fuels for dissipative assembly, taking advantage of their known reactivity to produce (hydrolytically unstable) anhydrides from carboxylic acids in water...
August 17, 2017: Journal of the American Chemical Society
Aijuan Han, Hongwei Zhang, Di Lu, Jiulong Sun, Gaik Khuan Chuah, Stephan Jaenicke
Forming heterojunctioned composites is an effective way to develop visible-light-driven photocatalysts. A series of BiOBr/NaBiO3 composites were synthesized by surface transformation of NaBiO3 with hydrobromic acid. Commensurate planes of BiOBr and NaBiO3 enabled the formation of a closely bound interface. Composites with <20wt.% BiOBr exhibited excellent photocatalytic activity towards the degradation of chlorophenols under low intensity visible light (λ>400nm). The best photocatalyst was 9% BiOBr/NaBiO3 with a quantum yield of 0...
July 16, 2017: Journal of Hazardous Materials
Bo Wang, Mikael Bols
Unprecedented simple artificial metalloenzymes were made from cyclodextrin diacids. Six α- and β-cyclodextrin diacids were prepared and their metal-binding and acid properties were investigated. The diacids formed fairly stable complexes with copper, zinc, and iron, with dissociation constants of 0.4-8×10(-4)  m. The iron complexes were found to catalyse a Fenton-like oxidation reaction of benzylic alcohols, which displayed Michaelis-Menten catalysis and rate accelerations up to 2700.
July 31, 2017: Chemistry: a European Journal
Yaoying Wu, Adam E Smith, Theresa M Reineke
A class of cationic poly(alkylamidoamine)s (PAAAs) containing lipophilic methylene linkers were designed and examined as in vitro plasmid DNA (pDNA) delivery agents. The PAAAs were synthesized via step-growth polymerization between a diamine monomer and each of four different diacid chloride monomers with varying methylene linker lengths, including glutaryl chloride, adipoyl chloride, pimeloyl chloride, and suberoyl chloride, which served to systematically increase the lipophilicity of the polymers. The synthesized polymers successfully complexed with pDNA in reduced serum medium at N/P ratios of 5 and greater, resulting in polyplexes with hydrodynamic diameters of approximately 1 μm...
August 16, 2017: Bioconjugate Chemistry
Dharmendra Kumar Singh, Kimitaka Kawamura, Ayako Yanase, Leonard A Barrie
The distributions, correlations, and source apportionment of aromatic acids, aromatic ketones, polycyclic aromatic hydrocarbons (PAHs), and trace metals were studied in Canadian high Arctic aerosols. Nineteen PAHs including minor sulfur-containing heterocyclic PAH (dibenzothiophene) and major 6 carcinogenic PAHs were detected with a high proportion of fluoranthene followed by benzo[k]fluoranthene, pyrene, and chrysene. However, in the sunlit period of spring, their concentrations significantly declined likely due to photochemical decomposition...
August 15, 2017: Environmental Science & Technology
Wanfeng Liao, Xiuyuan Ni
Photopolymerization, which is one of the most attractive polymerization methods, has been recently studied for the development of new photoinitiators. Herein, we use a binary mixture of titanium dioxide (TiO2) nanoparticles and carboxylic diacid as a novel photoinitiator to initiate the free radical polymerization of vinyl acetate (VAc). The polymerization of VAc is achieved both in aqueous medium and bulk. The initiation mechanism of TiO2/diacids is studied via nuclear magnetic resonance (NMR) spectroscopy using (13)C labeled diacids as probing molecules...
August 9, 2017: Photochemical & Photobiological Sciences
Sacha Pérocheau Arnaud, Linglin Wu, Maria-Angelica Wong Chang, James W Comerford, Thomas J Farmer, Maximilian Schmid, Fei Chang, Zheng Li, Mark Mascal
A family of monomers, including 2,5-hexandiol, 2,7-octandiol, 2,5-furandicarboxylic acid (FDCA), terephthalic acid (TA), and branched-chain adipic and pimelic acid derivatives, all find a common derivation in the biomass-derived platform molecule 5-(chloromethyl)furfural (CMF). The diol monomers, previously little known to polymer chemistry, have been combined with FDCA and TA derivatives to produce a range of novel polyesters. It is shown that the use of secondary diols leads to polymers with higher glass transition temperatures (Tg) than those prepared from their primary diol equivalents...
September 21, 2017: Faraday Discussions
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