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dicarboxylic acid

E-Jen Teh, Yee-Kwong Leong, Vincent S J Craig
The surface forces and yield stress of titanium dioxide were measured in the presence of dicarboxylic acids in order to understand the molecular basis for the observed rheological response. The yield stress was measured using the static vane technique whilst the surface forces were characterised using an Atomic Force Microscope. The trans and cis isomers of butenedioic acid (fumaric and maleic acids respectively) were chosen as the relative orientation of the carboxylic groups differs substantially. This enables us to test the hypothesis that an increase in adhesion leads to an increase in yield stress as a consequence of the dicarboxylic acids participating in highly directed bridging...
January 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Sergiu Coseri
Oxidation of the primary OH groups in cellulose is a pivotal reaction both at lab and industrial scale, leading to the value-added products, i.e. oxidized cellulose which have tremendous applications in medicine, pharmacy and hi-tech industry. Moreover, the introduction of carboxyl moieties creates prerequisites for further cellulose functionalization through covalent attachment or electrostatic interactions, being an essential achievement designed to boost the area of cellulose-based nanomaterials fabrication...
January 14, 2017: Biotechnology Advances
Xun Feng, Yuquan Feng, Nan Guo, Yiling Sun, Tian Zhang, Lufang Ma, Liya Wang
A series of five unique d-f heteronuclear luminescent metal-organic frameworks (MOFs) in an entangled polyrotaxane array and the light-harvesting block homonuclear zinc compound have been isolated successfully and characterized. The series of isostructural polymers feature 3,4-connected (4.8(2))(4.8(3).9(2))(6.8.9)2(6.9(2))(8(3)) topology and high stability, exhibiting diverse void spaces. By taking advantage of the isostructural MOFs 2 and 3, the intensities of red and green emissions can be modulated by adjusting the ratios of Eu(III) and Tb(III) ions correspondingly, and white-light emission can be generated by a combination of different doped Tb(III) and Eu(III) concentrations...
January 17, 2017: Inorganic Chemistry
Alessandro Sinopoli, Fiona A Black, Christopher J Wood, Elizabeth A Gibson, Paul I P Elliott
A novel anchoring ligand for dye-sensitised solar cell chromophoric complexes, 1-(2,2'-bipyrid-4-yl)-1,2,3-triazole-4,5-dicarboxylic acid (dctzbpy), is described. The new dye complexes [Ru(bpy)2(dctzbpy)][PF6]2 (AS16), [Ir(ppy)2(dctzbpy)][PF6] (AS17) and [Re(dctzbpy)(CO)3Cl] (AS18) were prepared in a two stage procedure with intermediate isolation of their diester analogues, AS16-Et2, AS17-Et2 and AS18-Et2 respectively. Electrochemical analysis of AS16-Et2, AS17-Et2 and AS18-Et2 reveal reduction potentials in the range -1...
January 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Zhongkai Lu, Yan Gao, Hu Chen, Zhao Liu, Licheng Sun
A new charge-neutral Ru(iii) complex RuL(pic)3 (1) (H3L = 3,6-di-tert-butyl-9H-carbazole-1,8-dicarboxylic acid, pic = 4-picoline) was synthesized and fully characterized. This complex promoted chemical and photochemical water oxidation efficiently with turnover frequencies of 0.28 s(-1) and 5 min(-1), respectively. In particular, for photochemical water oxidation, complex 1 showed excellent stability and good activity. The X-ray crystal structure, electrochemical results, and the detection of the Ru(IV)-OH intermediate by high-resolution mass spectrometry revealed that complex 1 exchanged its 4-picoline ligand with water at the Ru(III) state to form the authentic water oxidation catalyst...
January 9, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Arnaud Germain, David Ruppert, Susan M Levine, Maureen R Hanson
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) remains a continuum spectrum disease without biomarkers or simple objective tests, and therefore relies on a diagnosis from a set of symptoms to link the assortment of brain and body disorders to ME/CFS. Although recent studies show various affected pathways, the underlying basis of ME/CFS has yet to be established. In this pilot study, we compare plasma metabolic signatures in a discovery cohort, 17 patients and 15 matched controls, and explore potential metabolic perturbations as the aftermath of the complex interactions between genes, transcripts and proteins...
January 6, 2017: Molecular BioSystems
Paul G Crichton, Yang Lee, Edmund R S Kunji
Uncoupling protein 1 (UCP1) is an integral membrane protein found in the mitochondrial inner membrane of brown adipose tissue, and facilitates the process of non-shivering thermogenesis in mammals. Its activation by fatty acids, which overcomes its inhibition by purine nucleotides, leads to an increase in the proton conductance of the inner mitochondrial membrane, short-circuiting the mitochondrion to produce heat rather than ATP. Despite 40 years of intense research, the underlying molecular mechanism of UCP1 is still under debate...
January 3, 2017: Biochimie
Junyoung Kim, Hyung-Min Seo, Shashi Kant Bhatia, Hun-Seok Song, Jung-Ho Kim, Jong-Min Jeon, Kwon-Young Choi, Wooseong Kim, Jeong-Jun Yoon, Yun-Gon Kim, Yung-Hun Yang
Itaconate, a C5 unsaturated dicarboxylic acid, is an important chemical building block that is used in manufacturing high-value products, such as latex and superabsorbent polymers. Itaconate is produced by fermentation of sugars by the filamentous fungus Aspergillus terreus. However, fermentation by A. terreus involves a long fermentation period and the formation of various byproducts, resulting in high production costs. E. coli has been developed as an alternative for producing itaconate. However, fermentation of glucose gives low conversion yields and low productivity...
January 4, 2017: Scientific Reports
Edson Borges, Daniela P A F Braga, Amanda Souza Setti, Daniela A Montanni, Elaine Cristina Cabral, Marcos N Eberlin, Edson G Lo Turco, Assumpto Iaconelli
OBJECTIVE: To identify lipid markers of blastocyst implantation and ongoing pregnancy by day three culture medium mass spectrometry (MS) fingerprinting. METHODS: For this study, 33 culture media samples were harvested on day three, from 22 patients undergoing day five embryo transfers. All embryos achieved the blastocyst stage and were split into groups based on their implantation (Negative Implantation, n= 14 and Positive Implantation, n= 19). The positive implantation cycles resulted in successful ongoing pregnancies...
December 1, 2016: JBRA Assisted Reproduction
J Wu, K K Qi, Z W Xu
This study aimed to investigate the effects of porcine [gly2] glucagon-like peptide-2 (p[gly2]GLP-2) microspheres on lipopolysaccharide-challenged piglets and to evaluate efficacy of microspheres for administration compared with more conventional administration. Eighteen 21-d-old Duroc female piglets were randomly assigned into 3 groups: the control group (intraperitoneal injection with 3 mL saline solution daily), the glucagon-like peptide-2 (GLP-2) group (intraperitoneal injection with 3 mL p[gly2]GLP-2 at 20 nmol/kg BW daily), and the microsphere (MS) group (intraperitoneal injection with 100 mg p[gly2]GLP-2 microsphere suspension at Day 1)...
December 2016: Journal of Animal Science
Wei Wei Chen, Wei Fan, He Qiang Lou, Jian Li Yang, Shao Jian Zheng
Oxalic acid is the simplest of the dicarboxylic acids. In addition to its role in biological and metabolic processes, oxalate has been implicated in biotic and abiotic stresses. Being a strong chelator of Al, oxalate also has pivotal role in Al resistance mechanisms. However, we demonstrated that cytoplasmic oxalate accumulation is a critical event leading to root growth inhibition under Al stress. Transcriptome analysis from three crop plants identified Acyl Activating Enzyme3 (AAE3) genes to be up-regulated by Al stress...
January 3, 2017: Plant Signaling & Behavior
Jann Lippke, Birte Brosent, Tobias von Zons, Erika Virmani, Sebastian Lilienthal, Thomas Preuße, Miriam Hülsmann, Andreas M Schneider, Stefan Wuttke, Peter Behrens, Adelheid Godt
A Zr-based MOF of the PIZOF type, which consists of two independent and mutually interpenetrating UiO-type frameworks with [Zr6O4(OH)4(O2C)12] nodes, does not only form with a PEPEP dicarboxylic acid (P = phenylene, E = ethynylene). Also dicarboxylic acids with the shorter PPPP and PEPP spacers were found to give PIZOFs, denoted PPPP-PIZOF and PEPP-PIZOF, respectively. Reducing the spacer length even further to a PEEP segment caused a switchover to the formation of a UiO framework. The hysteresis in the Ar sorption curve of PEPP-PIZOF-1 and the slightly too large amount of combustion residue from PPPP-PIZOF-1 suggest structural defects...
December 29, 2016: Inorganic Chemistry
Moazur Rahman, Fouzia Ismat, Li Jiao, Jocelyn M Baldwin, David J Sharples, Stephen A Baldwin, Simon G Patching
Escherichia coli glutamate/aspartate-proton symporter GltP is a member of the Dicarboxylate/Amino Acid:Cation Symporter family of secondary active transport proteins. A range of computational, chemical, biochemical and biophysical methods characterised evolutionary relationships, structural features, substrate binding affinities and transport kinetics of wild-type and mutant forms of GltP. Sequence alignments and phylogenetic analysis revealed close homologies of GltP with human glutamate transporters involved in neurotransmission, neutral amino acid transporters and with the archaeal aspartate transporter GltPh...
December 26, 2016: Journal of Membrane Biology
Rosa M Ortuno, Bernat Pi-Boleda, Marta Sans, Maria Campos, Pau Nolis, Ona Illa, Juan Carlos Estévez, Vicenc Branchadell
Enantiomerically pure C16-alkyl amides derived from cis and trans cycloalkane-1,2-dicarboxylic acids, respectively, have been synthesized and their behaviour as organogelators has been investigated. These compounds include cis/trans diastereomeric cyclobutane and cyclohexane derivatives with the aim to explore the influence of the ring size as well as the relative configuration in their hierarchical self-assembly to form gels. High resolution 1H NMR spectroscopy studies allowed the determination of the dynamics of the gelation process in [D8]-toluene and the sol-gel transition temperature...
December 22, 2016: Chemistry: a European Journal
Mark D Chappell, Renhua Li, Stephon C Smith, Bruce A Dressman, Eric G Tromiczak, Allie E Tripp, Maria-Jesus Blanco, Tatiana Vetman, Steven J Quimby, James Matt, Thomas C Britton, Adam M Fivush, Jeffrey M Schkeryantz, Daniel Mayhugh, Jon A Erickson, Mark G Bures, Carlos Jaramillo, Mercedes Carpintero, José Eugenio de Diego, Mario Barberis, Susana Garcia-Cerrada, José F Soriano, Stephen Antonysamy, Shane Atwell, Iain MacEwan, Bradley Condon, Christine Sougias, Jing Wang, Aiping Zhang, Kris Conners, Chris Groshong, Stephen R Wasserman, John W Koss, Jeffrey M Witkin, Xia Li, Carl Overshiner, Keith A Wafford, Wesley Seidel, Xu-Shan Wang, Beverly A Heinz, Steven Swanson, John T Catlow, David W Bedwell, James A Monn, Charles H Mitch, Paul L Ornstein
As part of our ongoing efforts to identify novel ligands for the metabotropic glutamate 2 and 3 (mGlu2/3) receptors, we have incorporated substitution at the C3 and C4 positions of the (1S,2R,5R,6R)-2-amino-bicyclo[3.1.0]hexane-2,6-dicarboxylic acid scaffold to generate mGlu2/3 antagonists. Exploration of this structure-activity relationship (SAR) led to the identification of (1S,2R,3S,4S,5R,6R)-2-amino-3-[(3,4-difluorophenyl)sulfanylmethyl]-4-hydroxy-bicyclo[3.1.0]hexane-2,6-dicarboxylic acid hydrochloride (LY3020371·HCl, 19f), a potent, selective, and maximally efficacious mGlu2/3 antagonist...
December 22, 2016: Journal of Medicinal Chemistry
Adrian Mehlitz, Eva Eylert, Claudia Huber, Buko Lindner, Nadine Vollmuth, Karthika Karunakaran, Werner Goebel, Wolfgang Eisenreich, Thomas Rudel
Metabolic adaptation is a key feature for the virulence of pathogenic intracellular bacteria. Nevertheless, little is known about the pathways in adapting the bacterial metabolism to multiple carbon sources available from the host cell. To analyze the metabolic adaptation of the obligate intracellular human pathogen Chlamydia trachomatis, we labeled infected HeLa or Caco-2 cells with (13) C-marked glucose, glutamine, malate or a mix of amino acids as tracers. Comparative GC-MS-based isotopologue analysis of protein-derived amino acids from the host cell and the bacterial fraction showed that C...
December 20, 2016: Molecular Microbiology
Purna Chandra Rao, Sonu Pratap Chaudhary, Denis Kuznetsov, Sukhendu Mandal
We have isolated two copper-based coordination polymers through solvent diffusion and solvothermal methods using copper salt, furan dicarboxylic acid (FDC), 4,4'-bipyridine (bpy) in MeOH/ethylene glycol, and water solvents. Compound 1 is adopting P21/c space group and adopts a one-dimensional wirelike structure with a free carboxylate anion. Compound 2 crystallizes in chiral space group P65. This is a three-dimensional structure with helical chains. This helicity might be the reason for chiral generation and symmetry breaking...
December 19, 2016: Inorganic Chemistry
Yan Liu, Zijian Li, Guozan Yuan, Qingchun Xia, Chen Yuan, Yong Cui
A homochiral 3D porous metal-organic framework was assembled from a chiral dicarboxylic acid-functionalized Cu(salen)-based catalyst and could serve as an efficient heterogeneous catalyst for aziridination and allylic amination of olefins. Besides easy separation and reuse of the catalyst, the chiral framework confinement could impart substrate size selectivity, enhance catalyst activity, and induce product enantioselectivity.
December 19, 2016: Inorganic Chemistry
Donald W Rogers, Andreas A Zavitsas
Despite their abundance in nature and their importance in biology, medicine, nutrition, and in industry, gas phase enthalpies of formation of many long chain saturated and unsaturated fatty acids and of dicarboxylic acids are either unavailable or have been estimated with large uncertainties. Available experimental values for stearic acid show a spread of 68 kJ mol(-1). This work fills the knowledge gap by obtaining reliable values by quantum theoretical calculations using G4 model chemistry. Compounds with up to 20 carbon atoms are treated...
December 28, 2016: Journal of Organic Chemistry
Xue Li, Dhrubajyoti Gupta, Jisoo Lee, Geonhee Park, Chul-Un Ro
Recently, ambient sea spray aerosols (SSAs) have been reported to undergo reactions with dicarboxylic acids (DCAs). Several studies have examined the hygroscopic behavior and chemical reactivity of aerosols generated from NaCl-DCA mixture solutions, but the results have varied, especially for the NaCl-malonic acid (NaCl-MA) mixture system. In this work, in situ Raman microspectrometry (RMS) was used to simultaneously monitor the change in chemical composition, size, and phase as a function of the relative humidity, for individual aerosols generated from NaCl-MA solutions, during two hygroscopic measurement cycles, which were performed first through the dehydration process, followed by a humidification process, in each cycle...
January 3, 2017: Environmental Science & Technology
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