keyword
MENU ▼
Read by QxMD icon Read
search

diacid

keyword
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
#1
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
#2
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
#3
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
#4
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
https://www.readbyqxmd.com/read/28772252/efficient-photodegradation-of-chlorophenols-by-biobr-nabio3-heterojunctioned-composites-under-visible-light
#5
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
https://www.readbyqxmd.com/read/28759140/artificial-metallooxidases-from-cyclodextrin-diacids
#6
Mikael Bols, Bo Wang
Unprecedented simple artificial metalloenzymes were made from cyclodextrin diacids. Six alfa- and beta-cyclodextrin diacids were prepared and their metalbinding and acid properties were investigated. The diacids made fairly stable complexes with copper, zinc and iron with dissociation constants of 0.4-8 x 10-4 M. The iron complexes were found to catalyse a Fenton like oxidation reaction of benzylic alcohols which displayed Michealis-Menten catalysis and rate accelerations up to 2700.
July 31, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28731685/lipophilic-polycation-vehicles-display-high-plasmid-dna-delivery-to-multiple-cell-types
#7
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
https://www.readbyqxmd.com/read/28730822/distributions-of-polycyclic-aromatic-hydrocarbons-aromatic-ketones-carboxylic-acids-and-trace-metals-in-arctic-aerosols-long-range-atmospheric-transport-photochemical-degradation-production-at-polar-sunrise
#8
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 2, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28678292/photocatalytic-decarboxylation-of-diacids-for-the-initiation-of-free-radical-polymerization
#9
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
https://www.readbyqxmd.com/read/28671209/new-bio-based-monomers-tuneable-polyester-properties-using-branched-diols-from-biomass
#10
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
https://www.readbyqxmd.com/read/28657435/enhanced-detection-of-amino-acids-in-hydrophilic-interaction-chromatography-electrospray-tandem-mass-spectrometry-with-carboxylic-acids-as-mobile-phase-additives
#11
Dengyang Yin, Xunxiu Hu, Dantong Liu, Wencheng Du, Haibo Wang, Mengzhe Guo, Daoquan Tang
Liquid chromatography coupled with mass spectrometry technique has been widely used in the analysis of biological targets such as amino acids, peptides, and proteins. In this work, eight common single carboxylic acids or diacids, which contain different pKa have been investigated as the additives to the analysis of amino acids. As the results, carboxylic acid additive can improve the signal intensity of acidity amino acids such as Asp and Glu and the chromatographic separation of basic amino acids such as Arg, His, and Lys...
June 2017: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/28652003/comprehensive-two-dimensional-gas-chromatography-mass-spectrometry-of-complex-mixtures-of-anaerobic-bacterial-metabolites-of-petroleum-hydrocarbons
#12
C M Aitken, I M Head, D M Jones, S J Rowland, A G Scarlett, C E West
Anaerobic biotransformation of petroleum hydrocarbons is an important alteration mechanism, both subsurface in geological reservoirs, in aquifers and in anoxic deep sea environments. Here we report the resolution and identification, by comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS), of complex mixtures of aromatic acid and diacid metabolites of the anaerobic biodegradation of many crude oil hydrocarbons. An extended range of metabolites, including alkylbenzyl, alkylindanyl, alkyltetralinyl, alkylnaphthyl succinic acids and alkyltetralin, alkylnaphthoic and phenanthrene carboxylic acids, is reported in samples from experiments conducted under sulfate-reducing conditions in a microcosm over two years...
June 13, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28636893/controlled-release-from-aspirin-based-linear-biodegradable-poly-anhydride-esters-for-anti-inflammatory-activity
#13
Queeny Dasgupta, Sahitya Movva, Kaushik Chatterjee, Giridhar Madras
This work reports the synthesis of a novel, aspirin-loaded, linear poly (anhydride ester) and provides mechanistic insights into the release of aspirin from this polymer for anti-inflammatory activity. As compared to conventional drug delivery systems that rely on diffusion based release, incorporation of bioactives in the polymer backbone is challenging and high loading is difficult to achieve. In the present study, we exploit the pentafunctional sugar alcohol (xylitol) to provide sites for drug (aspirin) attachment at its non-terminal OH groups...
August 7, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28578576/potential-induced-aggregation-of-anionic-porphyrins-at-liquid-liquid-interfaces
#14
Sho Yamamoto, Hirohisa Nagatani, Hisanori Imura
The adsorption and self-aggregation of anionic porphyrins were studied at the polarized water|1,2-dichloroethane (DCE) interface by polarization-modulation total internal reflection fluorescence (PM-TIRF) spectroscopy. 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphyrin diacid (H4TPPS(2-)) and protoporphyrin IX (H2PP(2-)) exhibited high surface activities at the interface. The selective excitation of interfacial species in PM-TIRF measurements elucidated the potential-induced aggregation mechanism of the porphyrins...
June 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28522412/athero-inflammatory-nanotherapeutics-ferulic-acid-based-poly-anhydride-ester-nanoparticles-attenuate-foam-cell-formation-by-regulating-macrophage-lipogenesis-and-reactive-oxygen-species-generation
#15
Rebecca A Chmielowski, Dalia S Abdelhamid, Jonathan J Faig, Latrisha K Petersen, Carol R Gardner, Kathryn E Uhrich, Laurie B Joseph, Prabhas V Moghe
Enhanced bioactive anti-oxidant formulations are critical for treatment of inflammatory diseases, such as atherosclerosis. A hallmark of early atherosclerosis is the uptake of oxidized low density lipoprotein (oxLDL) by macrophages, which results in foam cell and plaque formation in the arterial wall. The hypolipidemic, anti-inflammatory, and antioxidative properties of polyphenol compounds make them attractive targets for treatment of atherosclerosis. However, high concentrations of antioxidants can reverse their anti-atheroprotective properties and cause oxidative stress within the artery...
July 15, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28499946/lipid-drug-conjugate-nanoparticle-as-a-potential-nanocarrier-for-the-oral-delivery-of-pemetrexed-diacid-formulation-design-characterization-ex-vivo-and-in-vivo-assessment
#16
Kriti Soni, Ali Mujtaba, Kanchan Kohli
The present work was to develop lipid drug conjugated (LDC) nanoparticles for the potential oral delivery of pemetrexed diacid (PTX) and evaluation of its in vitro, ex vivo and in vivo potentials. The LDC was prepared by salt formation of PTX with stearic acid and followed by cold homogenization technique to produce the LDC nanoparticles. FTIR analysis of LDC proved the presence of amide bond in LDC powder indicating the conjugation between drug and lipid. LDC nanoparticles was found to have particle size 121...
October 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28471081/metal-coordination-assisted-folding-and-guest-binding-in-helical-aromatic-oligoamide-molecular-capsules
#17
Maxime Horeau, Guillaume Lautrette, Barbara Wicher, Virginie Blot, Jacques Lebreton, Muriel Pipelier, Didier Dubreuil, Yann Ferrand, Ivan Huc
The development of foldamer-based receptors is driven by the design of monomers with specific properties. Herein, we introduce a pyridazine-pyridine-pyridazine diacid monomer and its incorporation into helical aromatic oligoamide foldamer containers. This monomer codes for a wide helix diameter and can sequester metal ions on the inner wall of the helix cavity. Crystallographic studies and NMR titrations show that part of the metal coordination sphere remains available and may then promote the binding of a guest within the cavity...
May 4, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28420232/gas-phase-carboxylic-acids-in-a-university-classroom-abundance-variability-and-sources
#18
Shang Liu, Samantha L Thompson, Harald Stark, Paul J Ziemann, Jose L Jimenez
Gas-phase carboxylic acids are ubiquitous in ambient air, yet their indoor occurrence and abundance are poorly characterized. To fill this gap, we measured gas-phase carboxylic acids in real-time inside and outside of a university classroom using a high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) equipped with an acetate ion source. A wide variety of carboxylic acids were identified indoors and outdoors, including monoacids, diacids, hydroxy acids, carbonyl acids, and aromatic acids...
May 2, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28353675/nmr-and-ir-investigations-of-strong-intramolecular-hydrogen-bonds
#19
REVIEW
Poul Erik Hansen, Jens Spanget-Larsen
For the purpose of this review, strong hydrogen bonds have been defined on the basis of experimental data, such as OH stretching wavenumbers, νOH, and OH chemical shifts, δOH (in the latter case, after correction for ring current effects). Limits for O-H···Y systems are taken as 2800 > νOH > 1800 cm(-1), and 19 ppm > δOH > 15 ppm. Recent results as well as an account of theoretical advances are presented for a series of important classes of compounds such as β-diketone enols, β-thioxoketone enols, Mannich bases, proton sponges, quinoline N-oxides and diacid anions...
March 29, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28322864/water-soluble-derivatives-of-25-och3-ppd-and-their-anti-proliferative-activities
#20
Wu-Xi Zhou, Yuan-Yuan Sun, Wei-Hui Yuan, Yu-Qing Zhao
(20R)-25-Methoxyl-dammarane-3β,12β,20-triol (25-OCH3-PPD, AD-1) is a dammarane-type sapogenin showing anti-tumor potential. In the search for new anti-tumor agents with higher potency than our previously identified compound 25-OCH3-PPD, 11 novel sulfamic acid and diacid derivatives that could improve water solubility and contribute to good drug potency and pharmacokinetic profiles were designed and synthesized. Their in vitro anti-tumor activities in MCF-7, A-549, HCT-116, and BGC-823 cell lines and one normal cell line were tested by standard MTT assay...
May 2017: Steroids
keyword
keyword
56026
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"