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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/28816444/mapping-the-intricate-reactivity-of-nanojars-toward-molecules-of-varying-acidity-and-their-conjugate-bases-leading-to-exchange-of-pyrazolate-ligands
#2
Christian K Hartman, Gellert Mezei
A comprehensive reactivity study of nanojars toward 18 different acidic compounds with varying pKa, including 12 different carboxylic acids (both aliphatic and aromatic mono- and dicarboxylic acids), p-toluenesulfonic acid, hydrogen sulfate, hydrogen carbonate, carbonic acid, 1-decanethiol, and methanol, as well as four different conjugate bases (formate, acetate, benzoate, 2-bromoethanesulfonate) is carried out with the aid of electrospray-ionization mass spectrometry. Thus, the effect on nanojar substitution and breakdown pattern of a number of variables, such as concentration of reagent (acid or conjugate base), acidity of reagent (pKa), effect of acid vs conjugate base, steric effects, aromaticity, incarcerated anion and size of the nanojar, is evaluated...
August 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28810179/utility-of-ultrasound-assisted-cloud-point-extraction-and-spectophotometry-as-a-preconcentration-and-determination-tool-for-the-sensitive-quantification-of-mercury-species-in-fish-samples
#3
Nail Altunay
The current study reports, for the first time, the development of a new analytical method employing ultrasound assisted-cloud point extraction (UA-CPE) for the extraction of CH3Hg(+) and Hg(2+) species from fish samples. Detection and quantification of mercury species were performed at 550nm by spectrophotometry. The analytical variables affecting complex formation and extraction efficiency were extensively evaluated and optimized by univariate method. Due to behave 14-fold more sensitive and selective of thiophene 2,5-dicarboxylic acid (H2TDC) to Hg(2+) ions than CH3Hg(+) in presence of mixed surfactant, Tween 20 and SDS at pH5...
August 10, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28801775/plasticizers-and-bisphenol-a-in-packaged-foods-sold-in-the-tunisian-markets-study-of-their-acute-in-vivo-toxicity-and-their-environmental-fate
#4
Asma Beltifa, Anouar Feriani, Monia Machreki, Asma Ghorbel, Lakhdar Ghazouani, Giuseppa Di Bella, Joris Van Loco, Tim Reyns, Hedi Ben Mansour
Today, processed and packaged foods are considered as among the major sources of human exposure to plasticizers and bisphenol which migrate from plastic packing. In the present study, a wide range of food products sold on the Tunisian market such as grain and grain products, milk and dairy products, fats and oil, drink, fish, and sweets have been analyzed firstly in order to identify the presence of phthalates and bisphenol. Then, the identified chemical molecules were studied for their environmental fate and tested in vivo for its toxicity in mice models...
August 12, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28792680/transcriptomic-basis-of-genome-by-genome-variation-in-a-legume-rhizobia-mutualism
#5
Liana T Burghardt, Joseph Guhlin, Chan Lan Chun, Junqi Liu, Michael J Sadowsky, Robert M Stupar, Nevin D Young, Peter Tiffin
In the legume-rhizobia mutualism, the benefit each partner derives from the other depends on the genetic identity of both host and rhizobial symbiont. To gain insight into the extent of genome x genome interactions on hosts at the molecular level and to identify potential mechanisms responsible for the variation, we examined host gene expression within nodules (the plant organ where the symbiosis occurs) of four genotypes of Medicago truncatula grown with either Ensifer meliloti or E. medicae symbionts. These host x symbiont combinations show significant variation in nodule and biomass phenotypes...
August 9, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28781260/-impairments-of-placental-amino-acid-metabolism-in-fetal-growth-restriction
#6
T N Pogorelova, V O Gunko, V V Avrutskaya, L V Kaushanskaya, O A Durnitsyna
The content of the amino acids in the placenta during physiological pregnancy and fetal growth restriction (FGR) has been investigated my means of the method of ion-exchange chromatography. It has been found that in FGR the placental amino acid pool is characterized by a decreased content of arginine, proline, alanine, serine, cysteine, methionine, tryptophan, leucine, threonine, tyrosine, phenylalanine, glutamine and an increased content of dicarboxylic amino acids, lysine, histidine and glycine. These changes are accompanied by altered activity of some enzymes of amino acid metabolism, and the degree of these changes correlates with the level of corresponding amino acids...
May 2017: Biomedit︠s︡inskai︠a︡ Khimii︠a︡
https://www.readbyqxmd.com/read/28766935/poly-ester-amide-s-from-poly-ethylene-terephthalate-waste-for-enhancing-bone-regeneration-and-controlled-release
#7
Janeni Natarajan, Giridhar Madras, Kaushik Chatterjee
The present study elucidates the facile synthesis and exceptional properties of a family of novel poly(ester amide)s (PEAs) based on bis(2-hydroxy ethylene) terephthalamide that was obtained from the poly(ethylene terephthalate) waste. Fourier transform infrared and (1)H NMR were used to verify the presence of ester and amide in the polymer backbone. Differential scanning calorimetry data showed that the glass transition temperature decreased with as the chain length of dicarboxylic acids increased. Dynamic mechanical analysis and contact angle studies proved that the modulus values and hydrophobicity increased with as the chain lengths of dicarboxylic acids increased...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28766656/amide-rotation-trajectories-probed-by-symmetry
#8
Vladimir Kubyshkin, Nediljko Budisa
Amide rotation of peptidyl-prolyl fragments is an important factor in backbone structure organization of proteins. Computational studies have indicated that this rotation preferentially proceeds through a defined transition-state structure (syn/exo). Here, we complement the computational findings by determining the amide bond rotation barriers for derivatives of the two symmetric proline analogues, meso and racemic pyrrolidine-2,5-dicarboxylic acids. The rotations around these residues represent syn/exo-syn/exo and anti/endo-syn/exo hybrid transition states for the meso and racemic diastereomer, respectively...
August 16, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28764333/trimethylation-enhancement-using-13-c-diazomethane-gas-phase-charge-inversion-of-modified-phospholipid-cations-for-enhanced-structural-characterization
#9
Stella K Betancourt, Carlos R Canez, Samuel W J Shields, Jeffrey M Manthorpe, Jeffrey C Smith, Scott A McLuckey
Methylation of phospholipids (PL) leads to increased uniformity in positive electrospray ionization (ESI) efficiencies across the various PL subclasses. This effect is realized in the approach referred to as "trimethylation enhancement using (13)C-diazomethane" ((13)C-TrEnDi), which results in the methyl esterification of all acidic sites and the conversion of amines to quaternary ammonium sites. Collision-induced dissociation (CID) of these cationic modified lipids enables class identification by forming distinctive headgroup fragments based on the number of (13)C atoms incorporated during derivatization...
August 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28762981/crystal-structure-and-luminescent-properties-of-novel-coordination-polymers-constructed-with-bifurandicarboxylic-acid
#10
Xianyu Huang, Daoliang Chen, Mingrui He, Jianfeng Li, Jiawei Huang, Baolin Li
Four novel coordination polymers (CPs) assembled with [2,2'-bifuran]-5,5'-dicarboxylic acid (H2L) and metal ions Zn(II), Cd(II) or Co(II) have been successfully synthesized. Their molecular structures have been determined to be Zn(L)(H2O)2 (1), [Zn(L)(DMF)]2 (2), [Cd(L)(EtOH)(DMF)2]2 (3) and Co(L)(H2O)4·(H2O)2 (4) by crystallographic analysis. It is found that (2) exhibits a two-dimensional infinite framework, whereas the others exhibit a one-dimensional framework. Both (2) and (3) exhibit ligand-based emission which is blue-shifted compared with the emission from the H2L ligand...
August 1, 2017: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
https://www.readbyqxmd.com/read/28762640/exploring-bacterial-carboxylate-reductases-for-the-reduction-of-bifunctional-carboxylic-acids
#11
Anna N Khusnutdinova, Robert Flick, Ana Popovic, Greg Brown, Anatoli Tchigvintsev, Boguslaw Nocek, Kevin Correia, Jeong Chan Joo, Radhakrishnan Mahadevan, Alexander F Yakunin
Carboxylic acid reductases (CARs) selectively reduce carboxylic acids to aldehydes using ATP and NADPH as cofactors under mild conditions. Although CARs have attracted significant interest, only a few enzymes have been characterized to date, whereas the vast majority of CARs have yet to be examined. Herein we report that 12 bacterial CARs reduced a broad range of bifunctional carboxylic acids containing oxo-, hydroxy-, amino-, or second carboxyl groups with several enzymes showing activity toward 4-hydroxybutanoic (4-HB) and adipic acids...
August 1, 2017: Biotechnology Journal
https://www.readbyqxmd.com/read/28761944/topochemical-polymerization-of-dumbbell-shaped-diacetylene-monomers-relationship-between-chemical-structure-molecular-packing-structure-and-gelation-property
#12
Dae-Yoon Kim, Sang-A Lee, Daseal Jung, Jahyeon Koo, Jin Soo Kim, Yeon-Tae Yu, Cheul-Ro Lee, Kwang-Un Jeong
Herein, we have synthesized novel photopolymerizable dumbbell-shaped diacetylene liquid crystal (LC) monomers by locating a diacetylene dicarboxylic acid group at the center and chemically connecting swallow-tails, such as hydrophobic alkyl chains (abbreviated as AT3DI) and amphiphilic biphenyl mesogens (abbreviated as BP3DI), with bisamide groups. Major phase transitions of dumbbell-shaped diacetylene monomers were identified using differential scanning calorimetry (DSC), polarized optical microscopy (POM), and Fourier transform infrared spectroscopy (FT IR)...
August 1, 2017: Soft Matter
https://www.readbyqxmd.com/read/28756564/production-of-dodecanedioic-acid-via-biotransformation-of-low-cost-plant-oil-derivatives-using-candida-tropicalis
#13
Irina Funk, Nina Rimmel, Christoph Schorsch, Volker Sieber, Jochen Schmid
Dodecanedioic acid (DDA) is highly useful to the chemical industry as a versatile precursor for producing the polyamide nylon-6,12, which is used for many technical applications, such as heat and chemical-resistant sheaths. However, DDA synthesis has several drawbacks, such as high energy input and cost-intensive removal of by-products. Therefore, alternative bio-based production routes are required due to increasing industrial demand for green chemicals and renewable products. Candida tropicalis converts petrochemical-based n-dodecanes to the corresponding dicarboxylic acids by targeted functionalization...
July 29, 2017: Journal of Industrial Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28756153/hybrid-pharmacophore-approach-for-bio-relevant-di-imines-based-homobimetallic-complexes-incorporating-functionalized-dicarboxylates-as-co-ligands-synthesis-spectral-and-structural-activity-dependent-biological-insights-in-vitro-dna-and-hsa-binding-antioxidant
#14
Mohammad Shakir, Summaiya Hanif, Md Fazle Alam, Mohd Farhan, Hina Younus
Synthesis of bio-efficient homobimetallic complexes, [Cu2(L(1))2(dipic)](NO3)2.3H2O (1), [Zn2(L(1))2(dipic)](NO3)2.4H2O (2), [Cu2(L(2))2(oxa)](NO3)2.4H2O (3) and [Zn2(L(2))2(oxa)] (NO3)2.5H2O (4) was carried out using Schiff bases [(N(1)E,N(2)E)-N(1),N(2)-bis(5-chlorothiophen-2-ylmethylene)-4-chlorobenzene-1,2-diamine; L(1)] and [(N(1)E,N(2)E)-N(1),N(2)-bis(5-chlorofuran-2-ylmethylene)-4-chlorobenzene-1,2-diamine; L(2)] as main ligands and dicarboxylate moieties of 2,6-pyridine dicarboxylic acid (H2-dipic) and oxalic acid (H2-oxa) as co-ligands, respectively in order to apprehend their structure activity relationships on the basis of pharmacophore hybrid approach...
July 24, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28753002/efficient-formation-of-light-absorbing-polymeric-nanoparticles-from-the-reaction-of-soluble-fe-iii-with-c4-and-c6-dicarboxylic-acids
#15
Ashley Tran, Geoffrey Williams, Shagufta Younus, Nujhat Ali, Sandra Blair, Sergey A Nizkorodov, Hind A Al-Abadleh
The role of transition metals in the formation and aging of secondary organic aerosol (SOA) from aliphatic and aromatic precursors in heterogeneous/multiphase reactions is not well understood. The reactivity of soluble Fe(III) towards known benzene photooxidation products that include fumaric (trans-butenedioic) and muconic (trans, trans-2,4-hexadienedioic) acids was investigated. Efficient formation of brightly-colored nanoparticles was observed that are mostly rod- or irregularly-shaped depending on the structure of the organic precursor...
July 28, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28748224/utility-of-genetic-testing-for-confirmation-of-abnormal-newborn-screening-in-disorders-of-long-chain-fatty-acids-a-missed-case-of-carnitine-palmitoyltransferase-1a-cpt1a-deficiency
#16
Leah Dowsett, Lauren Lulis, Can Ficicioglu, Sanmati Cuddapah
An 18-month-old male was evaluated after presenting with disproportionately elevated liver transaminases in the setting of acute gastroenteritis. He had marked hepatomegaly on physical exam that was later confirmed with an abdominal ultrasound. Given this clinical picture, suspicion for a fatty acid oxidation disorder was raised. Further investigation revealed that his initial newborn screen was positive for carnitine palmitoyltransferase 1A (CPT1A) deficiency-a rare autosomal recessive disorder of long-chain fatty acid oxidation...
June 2017: International Journal of Neonatal Screening
https://www.readbyqxmd.com/read/28745343/a-comparative-study-of-the-influence-of-n-n-dialkyl-vs-n-n-diaryl-based-electron-donor-ancillary-ligands-on-photocurrent-and-photovoltage-in-dye-sensitized-solar-cells-dsscs
#17
Saba Ashraf, Erol Yildirim, Javeed Akhtar, Humaira M Siddiqi, Ahmed El-Shafei
In this study, we report the synthesis of a novel heteroleptic Ru(ii)-sensitizer, (Ru(2,2'-bipyridine-4,4'-dicarboxylic acid)-4,4'-bis(4-piperidin-1-yl)phenyl ethenyl)-(2,2'-bipyridine) (NCS)2, denoted as SD-1; moreover, its photophysical, electrochemical, and photovoltaic performances were compared with those of N719 and K77-7 (N,N'-diaryl Ru-sensitizer, namely Ru(2,2'-bipyridine-4,4'-dicarboxylic-acid)-4,4'-bis(2-(4-N,N'-diphenylaminophenyl)ethenyl)-2,2'-bipyridine (NCS)2). The photovoltaic performance of SD-1 outperformed those of N-719 and K77-7, particularly in the red region, and the overall efficiency of SD-1 was 8...
August 9, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28744007/molecular-recognition-by-multiple-metal-coordination-inside-wavy-stacked-macrocycles
#18
Takashi Nakamura, Yuya Kaneko, Eiji Nishibori, Tatsuya Nabeshima
Most biological and synthetic receptors for small organic molecules employ a combination of relatively weak intermolecular interactions such as hydrogen bonds. A host compound that utilizes stronger yet reversible bonding in a synergistic manner could realize precise recognition, but the regulation and spatial arrangement of such reactive interaction moieties have been a challenge. Here, we show a multinuclear zinc complex synthesized from a macrocyclic ligand hexapap, which inwardly arranges labile metal coordination sites for external molecules...
July 25, 2017: Nature Communications
https://www.readbyqxmd.com/read/28740978/synthesis-and-photo-electro-catalytic-properties-of-a-3d-pomof-material-based-on-an-interpenetrated-copper-coordination-polymer-linked-by-in-situ-dual-ligands-and-dawson-type-phosphotungstates
#19
Ling-Yu Fan, Kai Yu, Jing-Hua Lv, He Zhang, Zhan-Hua Su, Lu Wang, Chun-Mei Wang, Bai-Bin Zhou
A novel 3D polyoxometalate metal organic framework (POMOF), [{CuCu (H2O)5(pzc)10(pz)6}{P2W18O62}2]·4H2O (1) (Hpzc = pyrazine-2-carboxylic acid, pz = pyrazine) has been hydrothermally synthesized and characterized by IR, TG, XRD, UV-vis and elemental analyses. In compound 1, the pzc and pz ligands are generated through in situ transformation from pyrazine-2,3-dicarboxylic acid (pzdc) to remove one or two CO2 molecules. The ligands with four coordination modes connect nine crystallographically independent Cu atoms to form a super-big circle unit...
July 25, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28732338/toxic-organic-substances-and-marker-compounds-in-size-segregated-urban-particulate-matter-implications-for-involvement-in-the-in%C3%A2-vitro-bioactivity-of-the-extractable-organic-matter
#20
Athanasios Besis, Alexandra Tsolakidou, Dimitra Balla, Constantini Samara, Dimitra Voutsa, Anastasia Pantazaki, Theodora Choli-Papadopoulou, Theodore S Lialiaris
Toxic organic substances and polar organic marker compounds, i.e. polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs) and their nitro-derivatives (N-PAHs), as well as dicarboxylic acids (DCAs) and sugars/sugar anhydrites (S/SAs) were analyzed in size-segregated PM samples (<0.49, 0.49-0.97, 0.97-3 and >3 μm) collected at two urban sites (urban traffic and urban background) during the cold and the warm season...
July 18, 2017: Environmental Pollution
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