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https://www.readbyqxmd.com/read/29763441/chemical-composition-of-barks-from-quercus-faginea-trees-and-characterization-of-their-lipophilic-and-polar-extracts
#1
Joana P A Ferreira, Isabel Miranda, Vicelina B Sousa, Helena Pereira
The bark from Quercus faginea mature trees from two sites was chemically characterized for the first time. The barks showed the following composition: ash 14.6%, total extractives 13.2%, suberin 2.9% and lignin 28.2%. The polysaccharides were composed mainly of glucose and xylose (50.3% and 35.1% of all monosaccharides respectively) with 4.8% of uronic acids. The suberin composition was: ω-hydroxyacids 46.3% of total compounds, ɑ,ω-alkanoic diacids 22.3%, alkanoic acids 5.9%, alkanols 6.7% and aromatics 6...
2018: PloS One
https://www.readbyqxmd.com/read/29760333/binary-phase-behavior-of-saturated-unsaturated-mixed-acid-triacylglycerols-a-review
#2
Lu Zhang, Satoru Ueno, Kiyotaka Sato
Most natural lipids contain a complex mixture of individual triacylglycerols (TAGs). An in-depth knowledge of the mixing behavior of TAGs is necessary for the rational design and engineering of food materials. The binary phase diagram of TAGs is a simplified model that can be explored to help foster an understanding of the phase behavior of complex fats and oils. This article reviews recent research on the binary phase behavior of saturated-unsaturated mixed-acid TAGs, with special emphasis on the stearic-unsaturated and palmitic-unsaturated diacid TAGs...
May 15, 2018: Journal of Oleo Science
https://www.readbyqxmd.com/read/29738983/facile-synthesis-of-ph-responsive-polymersomes-based-on-lipidized-peg-for-intracellular-co-delivery-of-curcumin-and-methotrexate
#3
Manuela Curcio, Loredana Mauro, Giuseppina Daniela Naimo, Diana Amantea, Giuseppe Cirillo, Lorena Tavano, Ivan Casaburi, Fiore Pasquale Nicoletta, Carmen Alvarez-Lorenzo, Francesca Iemma
pH-responsive polymersomes were obtained by self-assembling of a carboxyl-terminated PEG amphiphile achieved via esterification of PEG diacid with PEG40stearate. The obtained vesicular systems had spherical shape and a mean diameter of 70 nm. The pH sensitivity was assessed by measuring the variations of particles mean diameter after incubation in media mimicking the physiological (pH 7.4) or tumor (pH 5.0) conditions, recording a significant increase of the vesicles dimensions at acidic pH. The ability of the polymersomes to carry both hydrophobic and hydrophilic drugs was evaluated by loading the vesicles with curcumin and methotrexate, respectively, obtaining high encapsulation efficiencies and pH-dependent release profiles...
April 27, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29704812/%C3%B0-theoretical-study-on-ionization-of-sartans-in-aqueous-media-and-on-interactions-with-surfactant-micelles
#4
Marija R Popović-Nikolić, Gordana V Popović, Maja Grujić, Katarina M Nikolić, Danica D Agbaba
The ionization order of sartans in aqueous media and possible way of interactions between their equilibrium forms and surfactant micelles have been theoretically investigated. The examined sartans are ampholytes (irbesartan and losartan) and a diacid (valsartan) with the close values of ionization constants. In order to get a better insight in the overlapped protolytic equilibria of sartans and to predict an affinity of the equilibrium forms interacting with micelles as biomembrane mimetic systems, the theoretical study was performed...
April 20, 2018: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/29689530/predicted-and-measured-acute-toxicity-and-developmental-abnormalities-in-zebrafish-embryos-produced-by-exposure-to-individual-aromatic-acids
#5
Yuktee Dogra, Alan G Scarlett, Darren Rowe, Tamara S Galloway, Steven J Rowland
Petroleum acids, often called 'Naphthenic Acids' (NA), enter the environment in complex mixtures from numerous sources. These include from Produced and Process-Affected waters discharged from some oil industry activities, and from the environmental weathering of spilled crude oil hydrocarbons. Here, we test the hypothesis that individual NA within the complex mixtures can induce developmental abnormalities in fish, by screening a range of individual acids, with known chemical structures. Sixteen aromatic NA were tested using a Thamnocephalus platyrus (beavertail fairyshrimp) assay, to establish acute toxicity...
April 14, 2018: Chemosphere
https://www.readbyqxmd.com/read/29589916/designing-helical-molecular-capsules-based-on-folded-aromatic-amide-oligomers
#6
Yann Ferrand, Ivan Huc
The ab initio rational structure-based design of a synthetic molecular receptor for a given complex biomolecular guest remains an elusive objective, yet remarkable progress has been achieved in recent years. This Account deals with the use of folded artificial aromatic amide oligomers, also termed aromatic foldamers, inspired from biopolymer structures, for the design of helical molecular capsules that can recognize guest molecules, completely surround them, and isolate them from the solvent, thus giving rise to a sort of guest encapsulation associated with slow binding and release kinetics...
March 28, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29516137/elucidation-of-non-intentionally-added-substances-migrating-from-polyester-polyurethane-lacquers-using-automated-lc-hrms-data-processing
#7
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
https://www.readbyqxmd.com/read/29361044/commercial-hybrids-and-mutant-genotypes-reveal-complex-protective-roles-for-inducible-terpenoid-defenses-in-maize
#8
Shawn A Christensen, James Sims, Martha M 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 with the stalk-rotting agents Fusarium graminearum and Colletotrichum graminicola...
March 24, 2018: Journal of Experimental Botany
https://www.readbyqxmd.com/read/29231891/bioactive-compounds-produced-by-hypoxylon-fragiforme-against-staphylococcus-aureus-biofilms
#9
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
https://www.readbyqxmd.com/read/29207202/synthesis-structure-and-acidity-constants-of-ligated-%C3%AE-boryl-acetic-acids
#10
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
https://www.readbyqxmd.com/read/29143160/solvent-free-synthesis-and-anticancer-activity-evaluation-of-benzimidazole-and-perimidine-derivatives
#11
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...
February 2018: Molecular Diversity
https://www.readbyqxmd.com/read/29137790/thermal-and-morphological-properties-of-nanocomposite-materials-based-on-graphene-oxide-and-l-leucine-containing-poly-benzimidazole-amide-prepared-by-ultrasonic-irradiation
#12
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
https://www.readbyqxmd.com/read/29057941/cyclobutane-1-3-diacid-cbda-a-semi-rigid-building-block-prepared-by-2-2-photocyclization-for-polymeric-materials
#13
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
https://www.readbyqxmd.com/read/28946644/glycyrrhetinic-acid-liposomes-containing-mannose-diester-lauric-diacid-cholesterol-conjugate-synthesized-by-lipase-catalytic-acylation-for-liver-specific-delivery
#14
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
https://www.readbyqxmd.com/read/28944977/characterization-of-dicarboxylic-naphthenic-acid-fraction-compounds-utilizing-amide-derivatization-proof-of-concept
#15
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 (GC × GC/TOFMS). The selective derivatization of hydroxyl groups has also recently aided in the characterization of oxy-NAFCs, and indirectly the characterization of dicarboxylic NAFCs...
December 30, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28936531/knudsen-cell-studies-of-the-uptake-of-gaseous-ammonia-and-amines-onto-c3-c7-solid-dicarboxylic-acids
#16
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
https://www.readbyqxmd.com/read/28819124/long-term-2001-2013-observations-of-water-soluble-dicarboxylic-acids-and-related-compounds-over-the-western-north-pacific-trends-seasonality-and-source-apportionment
#17
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
https://www.readbyqxmd.com/read/28816294/-optimization-of-alkaline-hydrolysis-based-on-the-side-chain-of-diethyl-ester-4-amino-n-5-formyl-n-8-n-10-dideazatetrahydrofolic-acid
#18
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
https://www.readbyqxmd.com/read/28794127/a-diacidic-motif-determines-unconventional-secretion-of-wild-type-and-als-linked-mutant-sod1
#19
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
https://www.readbyqxmd.com/read/28777554/dissipative-assembly-of-aqueous-carboxylic-acid-anhydrides-fueled-by-carbodiimides
#20
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
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