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Structural Determination (structural + determination)
Selected AbstractsStructural Determination of the O-Chain Polysaccharide from the Lipopolysaccharide of the Haloalkaliphilic Halomonas pantelleriensis Bacterium,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2006M. Michela Corsaro Abstract The structural determination of the O-chain repeating unit of the lipopolysaccharide from the haloalkaliphilic Halomonas pantelleriensis bacterium is described. The structure of the repeating unit was suggested on the basis of chemical analysis and NMR and MS data. The 4- O -[(S)-1-carboxyethyl]- D -GlcA residue has been found for the first time in a lipopolysaccharide, being previously only found in capsular polysaccharides. A comparison of the O-chain structures of Halomonas magadiensis and H. pantelleriensis is also reported. The results show that both bacteria present lipopolysaccharides containing a high number of carboxylate groups whose salification might determine a protective buffer effect on bacterium against extreme life conditions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Structural Determination of a Novel O-Chain Polysaccharide of the Lipopolysaccharide from the Bacterium Xanthomonas campestris pv. pruniEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2003Antonio Molinaro Abstract In this paper, we report the structure of the O-specific polysaccharide of the LPS fraction of the strain type NCPPB416 of X. campestris pv. pruni. It is built up of three different monosaccharides , glucose, rhamnose and xylose , in an intricate block-wise polymer. Herein, the primary structure is elucidated by means of chemical degradation and 2D NMR spectroscopy. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Direct Structural Determination of Conformations of Photoswitchable Molecules by Laser Desorption,Electron Diffraction,ANGEWANDTE CHEMIE, Issue 37 2010Andreas Gahlmann Die Beteiligung mannigfacher Strukturen an der komplexen Photochemie photoschaltbaren Nitro-substituierten 1,3,3-Trimethylindolinbenzospiropyrans wird durch Elektronenbeugung offenbart. Die Isomerisierung der Spiropyran- zur Merocyaninform bei der Ringöffnung ergibt vornehmlich die cis-trans-cis -Struktur (siehe Bild; rot O, blau N, gelb C), während konkurrierende strahlungslose Pfade zu anderen Strukturen führen, nämlich den geschlossenen Formen in ihren Triplett- und Singulett-Grundzuständen. [source] ChemInform Abstract: Flexible Synthesis, Structural Determination, and Synthetic Application of a New C1 -Symmetric Chiral Ammonium Betaine.CHEMINFORM, Issue 19 2010Daisuke Uraguchi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Isolation and Structural Determination of Spilacleosides A and B Having a Novel 1,3-Dioxolan-4-one Ring.CHEMINFORM, Issue 27 2003Akiyo Kameyama No abstract is available for this article. [source] Novel ,-1,3-, 1,6-oligoglucan elicitor from Alternaria alternata 102 for defense responses in tobaccoFEBS JOURNAL, Issue 11 2006Tomonori Shinya A novel elicitor that induces chitinases in tobacco BY-2 cells was isolated from Alternaria alternata 102. Six other fungi, including A. alternata IFO 6587, could not induce, or weakly induce chitinase activity. The purified elicitor was soluble in 75% methanol and showed the chitinase-inducing activity when applied at concentrations of as low as 25 ng·mL,1. Structural determination by methylation analysis, reducing-end analysis, MALDI-TOF/MS, and NMR spectroscopy indicated that the elicitor was a mixture of ,-1,3-, 1,6-oligoglucans mostly with a degree of polymerization of between 8 and 17. Periodate oxidation of the elicitor suggested that the 1,6-linked and nonreducing terminal residues are essential for the elicitor activity. Further analysis of the elicitor responses in BY-2 cells indicated that the activity of this ,-1,3-, 1,6-glucan elicitor was about 1000 times more potent than that of laminarin, which is a known elicitor of defense responses in tobacco. Analyzing the expression of defense-related genes indicated that a phenylalanine ammonia-lyase gene and a coumaroyl-CoA O -methyltransferase gene were transiently expressed by this ,-1,3-, 1,6-glucan elicitor. The elicitor induced a weak oxidative burst but did not induce cell death in the BY-2 cells. In the tissue of tobacco plants, this ,-1,3-, 1,6-glucan elicitor induced the expression of basic PR-3 genes, the phenylpropanoid pathway genes, and the sesquiterpenoid pathway genes. In comparison with laminarin and laminarin sulfate, which are reported to be potent elicitors of defense responses in tobacco, the expression pattern of genes induced by the purified ,-1,3-, 1,6-glucan elicitor was more similar to that induced by laminarin than to that induced by laminarin sulfate. [source] Structural determination of the O-chain polysaccharide from Agrobacterium tumefaciens, strain DSM 30205FEBS JOURNAL, Issue 12 2002Cristina De Castro Agrobacterium tumefaciens is a Gram-negative, phytopathogenic bacterium and is characterized by an unique mode of action on dicotyledonous plants: it is able to genetically modify the host, and because of this feature, it is used as a tool for transgenic plants. Many experiments have demonstrated that lipopolysaccharides (LPSs) play an important role for the disease development, as they are involved in the adhesion process of the bacterium on the plant cell wall. Despite the wealth of information on the role of LPS on phytopathogenesis, the present paper appears as the first report on the molecular primary structure of the O-chain produced from Agrobacterium. Its repeating unit was determined by means of chemical and spectroscopical analysis, and has the following structure: (3)-,- d -Araf -(1,3)-,- l -Fucp -(1,. [source] Reduction of cis - and trans -1,2-epithio- p -menth-8-ene: preparation of new fragrant terpenoid thiolsFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2003Karine Candela Abstract The synthesis of 2-mercapto- p -menth-8-ene (3) and 1-mercapto- p -menth-8-ene (4) are described, starting, respectively, from thioepoxydation of (+)- trans -limonene 1,2-epoxide (1a) and (+)- cis -limonene 1,2-epoxide (1b) via hydride reduction of episulphides 2a and 2b. Structural determination of these sulphur-containing terpenoids was achieved by one- and two-dimensional NMR spectroscopy. The odours of these two new monoterpene thiols were described, respectively, as reminescent of grapefruit juice and as being typically alliaceous. Copyright © 2002 John Wiley & Sons, Ltd. [source] Structural determination of ethylene-propylene-diene rubber (EPDM) containing high degree of controlled long-chain branchingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2009Susanta Mitra Abstract This work highlights an attempt to characterize the degree and nature of long-chain branching (LCB) in an unknown sample of ethylene-propylene-diene rubber (EPDM). Two EPDM rubbers selected for this study were comparable in comonomer compositions but significantly different with respect to molar mass and the presence of LCB. Both rubbers contained 5-ethylidene-2-norbornene (ENB) as diene. Solution cast films of pure EPDM samples were used for different characterization techniques. 1H-NMR, and 13C-NMR were used for assessing the comonomer ratios and LCB. Size exclusion chromatography (SEC) equipped with triple detector system was used to determine the molar mass (both absolute and relative) and polydispersity index (PDI). Presence of branching was also detected using sec-viscometry. Rheological analysis has also been used for characterizing LCB. Finally, on the basis of the experimental findings and the available theories, an attempt was made to identify the chemical nature and degree of LCB. This study reveals the possibility of detailed characterization of molecular architecture of EPDM containing LCB by comparing with an essentially linear EPDM in light of an existing theory. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Structural determination of the stable and meta-stable forms of atomoxetine HCl using single crystal and powder X-ray diffraction methodsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2006Gregory A. Stephenson Abstract StratteraÔ is the first FDA-approved nonstimulant medication for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children, adolescents, and adults. Two polymorphic forms and an amorphous form of the active pharmaceutical ingredient, atomoxetine HCl, were discovered during drug development. The thermodynamically stable polymorphic form was selected for the commercial product. The stable form readily grows as crystals suitable for single crystal diffraction. The meta-stable crystal form is isolated by rapid crystallization, providing crystals that are too small for routine single crystal methods; consequently its structure was determined by X-ray powder diffraction. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95: 1677,1683, 2006 [source] Structural determination of two new triterpenoids biotransformed from glycyrrhetinic acid by Mucor polymorphosporusMAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2010Xiu Lan Xin Abstract Five hydroxylated derivatives of glycyrrhetinic acid by Mucor polymorphosporus were isolated. Among them, 6,, 7,-dihydroxyglycyrrhentic acid (2) and 27-hydroxyglycyrrhentic acid (3) are new compounds. Their chemical structures were identified by spectral methods including 2D-NMR. Copyright © 2009 John Wiley & Sons, Ltd. [source] Structural determination of ,-lactams by 1H and 13C NMRMAGNETIC RESONANCE IN CHEMISTRY, Issue 12 2009Rubén Montalvo-González Abstract The thermodynamic products (,-lactams) of the degradation of ten different spirocyclic oxaziridines were analyzed by 1H and 13C NMR spectroscopy. The preferred conformations were determined by examining the homonuclear spin,spin coupling constant and the chemical shift effects of the N -substituent and the alkyl group of the aliphatic ring on 1H and 13C NMR spectra. Copyright © 2009 John Wiley & Sons, Ltd. [source] Structural determination of two new sesquiterpenes biotransformed from germacrone by Mucor alternataMAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2008Niu Jia Abstract Eight transformed sesquiterpenes of germacrone by Mucor alternata were obtained. Their structures were characterized on the basis of spectral methods including 2D NMR. Among them, (1S, 4S, 5S, 10R)-isozedoarondiol (2) and (1R, 4S, 5S, 10R)-diepoxy-12-hydroxygermacrone (3) are new compounds. Copyright © 2007 John Wiley & Sons, Ltd. [source] Structural determination of kochiosides A,C, new steroidal glucosides from Kochia prostrata, by 1D and 2D NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2007Muhammad Imran Abstract Kochiosides A,C, three new steroidal glucosides, have been isolated from the ethyl acetate fraction of Kochia prostrata and their structures assigned from its 1H and 13C NMR spectra, DEPT and by 2D COSY, NOESY, HMQC and HMBC experiments. Copyright © 2007 John Wiley & Sons, Ltd. [source] Structural determination of seven new triterpenoids from Kadsura heteroclita by NMR techniquesMAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2007Wei Wang Abstract Seven new triterpenoids, namely heteroclitalactones G,M (1,7), were isolated from the ethanol extract of the stems of Kadsura heteroclita. Structures of these compounds were characterized by extensive 1D and 2D NMR spectroscopic analyses. Copyright © 2007 John Wiley & Sons, Ltd. [source] Structural determination of a new 2(3 , 20)abeotaxane with an unusual 13,-substitution pattern and a new 6/8/6-ring taxane from Taxus cuspidataMAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2007Changhong Huo Abstract A new 2(3 , 20)abeotaxane with an unusual 13,-substitution pattern and a new 6/8/6-ring taxane were isolated from the methanol extract of the needles of Taxus cuspidata. The structures were established as 2,,7,-diacetoxy-5,,10,,13,-trihydroxy-2(3 , 20)abeotaxa-4(20), 11-dien-9-one (1) and 2,,5,,7,,9,,13,-pentahydroxy-10,-acetoxytaxa-4(20),11-diene (2) on the basis of 1D and 2D NMR spectral data and high-resolution FAB-MS analyses. Copyright © 2007 John Wiley & Sons, Ltd. [source] Structural determination of silymins A and B, new pentacyclic triterpenes from Silybum marianum, by 1D and 2D NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2007Ejaz Ahmed Abstract Silymins A (1) and B (2), the new pentacyclic triterpenes, have been isolated from ethyl acetate fraction of Silybum marianum and their structures assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, NOE and HMBC experiments. Copyright © 2007 John Wiley & Sons, Ltd. [source] Structural determination of diterpenes from Daphne genkwa by NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2006Kalsoom Akhtar Abstract Five daphnane type diterpenes have been isolated from the chloroform soluble fraction of Daphne genkwa. The structure of the new compound (1) was assigned as 5,-hydroxyresiniferonol-6,,7,-epoxy-12,-acetoxy-9,13,14- ortho -2E -decenoate by extensive NMR studies. Copyright © 2006 John Wiley & Sons, Ltd. [source] Structural determination and complete NMR spectral assignments of a new diterpenoid obtained from triptonide by biotransformationMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2003Lili Ning Abstract A new diterpenoid, 12,,13,-dihydroxytriptonide, was obtained from the transformed culture of triptonide by Catharanthus roseus cell suspension cultures. The complete 1H and 13C NMR assignments of the compound were carried out by using DEPT, COSY, HSQC, g-HMBC and NOESY techniques. Copyright © 2003 John Wiley & Sons, Ltd. [source] Structural determination of hexadecanoic lysophosphatidylcholine regioisomers by fast atom bombardment tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2002Jongki Hong The structural determination of sn -1 and sn -2 hexadecanoic lysophosphatidylcholine (LPC) regioisomers was carried out using fast atom bombardment tandem mass spectrometry (FAB-MS/MS). The collision-induced dissociation (CID) of protonated and sodiated molecules produced diverse product ions due mainly to charge remote fragmentations. Based on the information obtained from the CID spectra of protonated and sodiated molecules, sn-1 and sn-2 hexadecanoic LPC isomers could be discriminated. Especially, the abundance ratio of the diagnostic ion pair [m/z 224/226] in the CID spectra of [M,+,H]+ ions was shown to be greatly different. Moreover, the CID-MS/MS spectra of sodium-adducted molecules for hexadecanoic LPC isomers showed characteristic product ions such as [M,+,Na,,,103]+, [M,+,Na,,,85]+, and [M,+,Na,,,59]+, by which their regio-specificity can be differentiated. Copyright © 2002 John Wiley & Sons, Ltd. [source] Expression, purification, crystallization and preliminary crystallographic study of the carboxyl-terminal domain of the human voltage-gated proton channel Hv1ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2009Shu Jie Li The voltage-gated proton channel Hv1 is essential to proton permeation and contains a voltage-sensor domain without a pore domain. It contains three predicted domains: an N-terminal acid and proline-rich domain, a transmembrane voltage-sensor domain and a C-terminal domain that is responsible for the dimeric architecture of Hv1. Here, the C-terminal domain of the human voltage-gated proton channel Hv1 (C-Hv1) was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystals have a tetragonal form and diffraction data were collected to 2.5,Å resolution in-house. The crystal belongs to space group P41212, with unit-cell parameters a = b = 37.76, c = 137.52,Å. Structural determination of C-Hv1 is in progress. [source] Crystallization and preliminary X-ray crystallographic analysis of a highly stable mutant V107A of glutathione transferase from Anopheles dirus in complex with glutathioneACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2006Jantana Wongsantichon An engineered mutant V107A of the dimeric glutathione transferase enzyme from Anopheles dirus (adgstD4-4) was cocrystallized with glutathione substrate using the hanging-drop vapour-diffusion method. The crystal diffracted to 2.47,Å resolution in space group P3221 (unit-cell parameters a = b = 49.4, c = 272.4,Å). Although the crystal morphology differed from that previously obtained for the wild-type enzyme, the crystal packing was the same. At 318,K, the engineered mutant showed an enzyme stability that was increased by about 32-fold, while possessing a similar catalytic function to the wild type. Structural determination will provide valuable understanding of the role of Val107. This residue is in the dimeric interface and appears to contribute towards enhancing the physical properties of the entire protein. [source] Structural determinations by circular dichroism spectra analysis using coupled oscillator methods: An update of the applications of the DeVoe polarizability model,CHIRALITY, Issue 7 2004Stefano Superchi Abstract The exciton (coupled oscillator) model for optical activity is a very useful and powerful method which allows to analyze a circular dichroism (CD) spectrum in a nonempirical way, arriving at a safe assignment of the absolute configuration of organic and inorganic compounds. Usually in this model only the exciton coupling of two electrically allowed transitions (oscillators) is taken into account. This approach has the important advantage of an easy application but, sometimes, it may lead to wrong results. Thus, in this review article a more general treatment, which allows considering the simultaneous coupling of several oscillators, i.e., the DeVoe model, is presented and critically analyzed, discussing in detail the latest applications reported in the literature. In the authors opinion, since the DeVoe model joins generality and reliability requiring an almost negligible computational effort, it represents the method of choice for stereochemical assignments, even by nonspecialists. Chirality 16:422,451, 2004. © 2004 Wiley-Liss, Inc. [source] A Single-Source-Precursor Approach to Late Transition Metal Molybdate Materials: The Structural Role of Chelating Ligands in the Formation of Heterometallic Heteroleptic Alkoxide ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2006Pia Werndrup Abstract The synthesis and structural determination of three new heterometallic molybdenum complexes, one with cobalt and two with nickel and two of these with ,-diketonate ligands and one with amino alcohol ligands, are presented. The reaction of cobalt acetylacetonate with [MoO(OMe)4] provides [Co2Mo2O2(acac)2(OMe)10] (1) and [MoO(acac)(OMe)3] (4),and the reaction of nickel acetylacetonate with [MoO(OMe)4]provides [Ni2Mo2O2(acac)2(OMe)10] (2) and 4. The reaction of [Ni(ORN)2] (RN = CHMeCH2NMe2) with [MoO(OMe)4] yields [Ni2Mo2O2(ORN)2(OMe)10] (3). The two new oxomolybdenum complexes undergo ether elimination upon storage to give the corresponding dioxo complexes [MoO2(acac)(OMe)]2 (5) and [MoO2(ORN)(OMe)]2 (6). Compounds 3 and 4 could also be obtained from the reaction of stoichiometric amounts of Hacac with [MoO(OMe)4] and [MoO2(OMe)2], respectively. The local structure around the nickel atom in compound 2 in solution and compound 3 in the solid state and in toluene/hexane solution has been determined by means of EXAFS spectroscopy. The complexes are intended to be used as single-source precursors, which are attractive in coatings and for the preparation of mesoporous materials; its application for the synthesis of nickel molybdate by sol,gel processing is therefore reported. The oxide material obtained from 3 displays a uniform grain size and a large surface area. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Synthesis of Isoxazolopyridobicyclooxacalix[4]arenes: A New Family of Heteracalixarene SystemsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2008Serena Ferrini Abstract A new family of isoxazolopyridobicyclooxacalix[4]arenes was obtained by reaction of dichloroisoxazolopyridines with phloroglucinol. X-ray crystallography and density functional calculations were used for their structural determination and evaluation of their chemical properties. Their role as metal chelators was studied by mass spectrometry. This new family of heteracalixarenes is of potential interest for host,guest interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] For Bourdieu, Against Alexander: Reality and ReductionJOURNAL FOR THE THEORY OF SOCIAL BEHAVIOUR, Issue 2 2000Garry Potter Jeffrey Alexander argues that despite Bourdieu's considerable achievements ultimately his work is reductionist and determinist. He further argues that though Bourdieu is a middle range theorist he is implicitly realist in his meta-theoretical assumptions. This article accepts these conclusions but argues that Bourdieu's meta-theoretical realism is a virtue rather than a vice and that the manner in which he is a reductionist and determinist necessitate a re-thinking of what is meant by these notions. Alexander uses Bourdieu's concept of habitus to demon-strate a fundamental contradiction in Bourdieu's theorising. According to him habitus presents us with the oxymoron of unconscious strategisation. This article uses a discussion of habitus in order to demonstrate that in its relationship with the concept of field it instead produces a practical resolution of long standing theoretical problems concerning structural determination and human agency. It is also argued that these problems are resolved at the meta-theoretical level in the form of critical realist ontology and that it is Alexander's misunderstandings on this level which cause him to fail to appreciate the significance of Bourdieu's achievements. [source] Critical contact residues that mediate polymerization of nematode major sperm proteinJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2008Antonio del Castillo-Olivares Abstract The polymerization of protein filaments provides the motive force in a variety of cellular processes involving cell motility and intracellular transport. Regulated assembly and disassembly of the major sperm protein (MSP) underlies amoeboid movement in nematode sperm, and offers an attractive model system for characterizing the biomechanical properties of filament formation and force generation. To that end, structure-function studies of MSP from the nematode Caenorhabditis elegans have been performed. Recombinant MSP was purified from Escherichia coli using a novel affinity chromatography technique, and filament assembly was assessed by in vitro polymerization in the presence of polyethylene glycol. Prior molecular studies and structure from X-ray crystallography have implicated specific residues in protein,protein interactions necessary for filament assembly. Purified MSP containing substitutions in these residues fails to form filaments in vitro. Short peptides based on predicted sites of interaction also effectively disrupt MSP polymerization. These results confirm the structural determination of intermolecular contacts and demonstrate the importance of these residues in MSP assembly. J. Cell. Biochem. 104: 477,487, 2008. © 2007 Wiley-Liss, Inc. [source] Differential fragmentation patterns of pectin oligogalacturonides observed by nanoelectrospray quadrupole ion-trap mass spectrometry using automated spectra interpretationJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 4 2007Kudzai E. Mutenda Abstract Oligogalacturonides of different degrees of polymerization (DP) and methyl esterification (DE) were structurally analyzed by nanoESI quadrupole ion-trap mass spectrometry. The fragmentation patterns of the oligogalacturonides were compared using the program ,Virtual Expert Mass Spectrometrist' (VEMS) for structural annotation. In the analyzed oligogalacturonides of lower DP, the generation of C/Y ions, i.e. ions retaining the glycosidic oxygen, was higher than that of B/Z ions. In general, with oligogalacturonides of higher DP, the B/Z ions were generated more abundantly. Oligogalacturonides with free carboxylic acid groups underwent higher water loss compared to fully methyl-esterified oligogalacturonides under the same fragmentation conditions. Cross-ring cleavage, in which fragmentation occurs across the ring system of the galacturonate residue and signified by unique mass losses, was observed to be higher in fully methyl-esterified oligogalacturonides than in non-methyl-esterified ones. This study demonstrates the different fragmentation patterns of oligogalacturonides as influenced by the presence or absence of methyl ester groups. For a detailed analysis of unknown oligogalacturonides, cross-ring fragmentation gives more structural information than glycosidic bond cleavage. One implication of this is that more structural information is obtained when analyzing methyl-esterified oligogalacturonides than non-methyl-esterified ones in an ion-trap instrument. This is of particular importance in pectin chemistry, where mass spectrometry has become the technique of choice for structural determination. Although this study was not designed to explain the mechanisms of oligogalacturonide fragmentation, possible explanations for why non-methyl-esterified oligogalacturonides undergo more water loss than methyl-esterified ones will be postulated. In addition, the VEMS program was extended to automatically interpret and assign the fragment ions peaks generated in this study. Copyright © 2007 John Wiley & Sons, Ltd. [source] Chip-mass spectrometry for glycomic studiesMASS SPECTROMETRY REVIEWS, Issue 2 2009Laura Bindila Abstract The introduction of micro- and nanochip front end technologies for electrospray mass spectrometry addressed a major challenge in carbohydrate analysis: high sensitivity structural determination and heterogeneity assessment in high dynamic range mixtures of biological origin. Chip-enhanced electrospray ionization was demonstrated to provide reproducible performance irrespective of the type of carbohydrate, while the amenability of chip systems for coupling with different mass spectrometers greatly advance the chip/MS technique as a versatile key tool in glycomic studies. A more accurate representation of the glycan repertoire to include novel biologically-relevant information was achieved in different biological sources, asserting this technique as a valuable tool in glycan biomarker discovery and monitoring. Additionally, the integration of various analytical functions onto chip devices and direct hyphenation to MS proved its potential for glycan analysis during the recent years, whereby a new analytical tool is on the verge of maturation: lab-on-chip MS glycomics. The achievements until early beginning of 2007 on the implementation of chip- and functional integrated chip/MS in systems glycobiology studies are reviewed here. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:223,253, 2009 [source] Core-level shifts in complex metallic systems from first principlePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2006Weine Olovsson Abstract We show that core-level binding energy shifts (CLS) can be reliably calculated within density functional theory. The scheme includes both the initial (electron energy eigenvalue) as well as final state (relaxation due to core-hole screening) effects in the same framework. The results include CLS as a function of composition in substitutional random bulk and surface alloys. Sensitivity of the CLS to the local chemical environment in the bulk and at the surface is demonstrated. A possibility to use the CLS for structural determination is discussed. Finally, an extension of the model is made for Auger kinetic energy shift calculations. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||||||||||||||||||||