bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermospray liquid chromatography‐mass spectrometry in phytochemical analysis
Authors: Wolfender Jean‐Luc , Maillard Marc , Hostettmann Kurt 
Published: March 2007

AbstractLiquid chromatography‐mass spectrometry (LC‐MS) has become a successful analytical tool and is no longer regarded as a pure research instrument without any routine practical applications. The development of the thermospray interface (TSP) has been of great help in this respect, allowing the direct use of standard HPLC conditions (1 mL/min, aqueous solvents) for the LC‐MS coupling. TSP LC‐MS has been used in phytochemical analysis as a powerful detection technique for on‐line identification and for quantification of plant constituents, even in trace amounts. Applications of this technique to different classes of plant metabolites such as polyphenols, terpenes, sugars, glucosinolates, alkaloids and glycosides are described. The potential of TSP LC‐MS in the analysis of crude plant extracts is discussed.
High performance liquid chromatographic and proton magnetic resonance spectroscopic methods for quality evaluation of Paeonia roots
Authors: Cai Y. , Phillipson J. D. , Harper J. I. , Corne S. J. 
Published: March 2007

AbstractThe root of several Paeonia species is one of the most frequently used plant materials in traditional Chinese medicine, and has been shown to have a variety of pharmacological properties. Owing to the differences in species, cultivation, harvesting and processing, the quality of the roots as commercial medicinal herbs varies to a considerable extent. A quantitative high performance liquid chromatographic method has been developed for the quality evaluation of Paeonia root, and a number of commercial samples have been examined. A quantitative 1H‐nuclear magnetic resonance procedure has also been developed for this purpose, and this may find a wider application in the analysis of other plant materials.
A highly sensitive quantitative determination of glutathione in plant roots by high performance gel filtration chromatography and fluorometric detection after pre‐column derivatization with N‐(7‐dimethylamino‐4‐methyl coumarinyl)‐maleimide
Authors: Obata Hitoshi , Imai Kunio , Inoue Noriyuki , Umebayashi Masanao 
Published: March 2007

AbstractA convenient method was developed for the highly sensitive, quantitative determination of glutathione (GSH) using high performance gel filtration chromatography and fluorescence detection after N‐(7‐dimethylamino‐4‐methyl coumarinyl)‐maleimide modification of the peptides. The fluorescence detection method is highly sensitive and sub pmol GSH contents were detectable. This method is applicable for determining the GSH content of micro samples from higher plant roots.
Characterization of galactose from carrageenans by natural abundance site‐specific isotope parameters
Authors: Zhang Ben Li , Vallet Claude , Blanchard Frédérique , Martin Gérard J. , Combaut Georges 
Published: March 2007

AbstractThe overall 13C or 2H content of the organic matter of marine algae is an interesting source of information on metabolic and environmental effects experienced by aquatic plants. However, in order to appraise the complexity of the phenomena which influence the isotopic distribution, access to more specific isotopic probes is desirable. Thus, determination of the overall and site‐specific natural deuterium fingerprint of the galactose unit of carrageenans is expected to improve the characterization of these molecular species in terms of origin and history of the precursors. A strategy has been developed in order to render the galactose moiety accessible to the study of site‐specific natural isotope fractionation of hydrogen by nuclear magnetic resonance (SNIF‐NMR). Extraction and derivatization procedures have been elaborated and the possible occurrence of fractionation effects in the course of the physical and chemical transformations has been examined. By combining mass spectrometric determination of the overall isotope ratio of the galactose skeleton and analysis of the cluster signals observed in the 2H‐NMR spectra of appropriate galactose derivatives, several groups of site‐specific isotope contents can be obtained. Significant deviations with respect to a statistical distribution of deuterium in the galactose unit have been determined and the isotopic parameters of galactoses from carrageenans have been shown to differ greatly from those of galactose extracted from milk. Moreover, significant variations are observed among the different sources of carrageenans. This behaviour is consistent with the large range of overall isotope contents measured in cellulose from aquatic plants.
A selective photobiological assay to detect and quantify psoralen in Psoralea plants (Leguminosae)
Authors: Bourgaud F. , Grimal J. Y. , Nguyen C. , Bitton G. , Guckert A. 
Published: March 2007

AbstractA simple and rapid bioassay involving the gram‐positive bacterium Bacillus brevis was developed to detect and quantify furocoumarins (psoralen and angelicin) in Psoralea plants (Leguminosae). Small paper discs, soaked with furocoumarin standards or the corresponding plant samples, are placed on B. brevis lawns in Petri dishes and irradiated for 24 h with UVA. The diameter of the growth inhibition zone around the discs is very well‐correlated with the quantity of furocoumarin standard in the disc. Because psoralen is more phototoxic than angelicin, its detection limit (5 × 10−8 g/disc) was lower than angelicin (5 × 10−7 g/disc). Consequently, it is possible to dilute a crude plant extract in order to reach a detectable psoralen concentration whilst maintaining the angelicin concentration below its lower detection limit. In this condition, angelicin does not interfer with psoralen detection, and the growth inhibition is entirely due to psoralen. The bioassay was validated using a classical high pressure liquid chromatographic method and the correlation between the two techniques was satisfactory with plant samples. Therefore, the bioassay can be considered as a sensitive, simple, rapid and selective method to quantify psoralen in Psoralea plants.
A method for the determination of conifer foliage protein extracted using sodium dodecyl sulphate and mercaptoethanol
Authors: Ekramoddoullah K. M. , Davidson Joanne J. 
Published: March 2007

AbstractSodium dodecyl sulphate and mercaptoethanol are commonly used for extraction and solubilization of proteins, but these substances interfere with previously reported methods for the quantitation of small amounts of protein. In order to overcome this difficulty, a method has been developed for assaying small quantities of protein by (i) spotting the protein solution on a polyvinylidene difluoride membrane, (ii) staining the membrane bound protein with Coomassie Blue, (iii) destaining, and (iv) determining the optical density of the stained membrane by laser‐based scanning. The determination of proteins in conifer foliage by this method is described.
Analysis of crude extracts and fractions of brazilian polypodiaceae by high‐resolution gas chromatography‐mass spectrometry. I. triterpenes
Authors: Patitucci Maria Lucia , Pinto Angelo C. , Cardoso Jari N. 
Published: March 2007

AbstractCharacterization of individual components in plant extracts through classical phytochemical methods is a multi‐step procedure which is both costly and time‐consuming. Also significant amounts of extract are required and detection of minor compounds is frequently not possible. The method described in this work involves direct analysis of crude or prefractioned apolar or medium‐polar extracts by high‐resolution gas chromatography and computerized high resolution gas chromatography‐mass spectrometry, followed by co‐injections of the crude extract with certified standards on capillary columns of different polarities. The effectiveness of the method is illustrated for several species of Polypodiaceae (spores and rhizomes). allowing easy monitoring of compound‐type distributions (e.g. triterpenes) and detection of structures present at trace levels (for example, 22,29,30‐trisnorhopane).
π‐conjugated polymers having diaza[12]annulene rings and aminopenta‐2,4‐dienylidene groups generated by the ring opening of pyridinium rings
Authors: Yamaguchi Isao , Gobara Yoshiaki , Sato Moriyuki 
Published: March 2007

AbstractReactions of N‐(2,4‐dinitrophenyl)pyridinium chloride with 2,5‐dimethyl‐1,4‐phenylenediamine in 1:2, 1:1.5, 1:1, and 2:1 molar ratios caused the ring opening of the pyridinium ring and thereby yielded polymers (P1–P4) consisting of 5‐(2,5‐dimethyl‐1,4‐phenylene)penta‐2,4‐dienylideneammonium chloride (unit A) and N‐2,5‐dimethyl‐1,4‐phenylene diaza[12]annulenium dichloride (unit B). The 1H NMR spectra suggested that the composition ratios of unit A to unit B in P1–P4 were 0.98:0.02, 0.94:0.06, 0.81:0.19, and 0.79:0.21, respectively. P1–P4 showed an absorption maximum (λmax) at a longer wavelength than the monomers because of the expansion of the π‐conjugation system. Films of P3 and P4 showed λmax at a considerably longer wavelength than those in solution, and this was attributable to the ordered structures of the polymers in the solid state. Powder X‐ray diffraction analysis supported the ordered structures of P3 and P4. Pellets molded from P3 and P4 exhibited a metallic luster, whereas those from P1 and P2 did not show such a luster. Cyclic voltammetry measurements indicated that P1–P4 were electrochemically active in films. The thermal stability of the polymers depended on the composition ratios of unit A to unit B. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1507–1514, 2007
2‐D DIGE and MALDI‐TOF‐MS analysis of the serum proteome in human osteosarcoma
Authors: Jin Song , Shen Jing‐Nan , Guo Qian‐Chen , Zhou Jia‐Guo , Wang Jin , Huang Gang , Zou Chang‐ye , Yin Jun‐qiang , Liu Shao‐Jun , Liu Wei , Li Ming‐Tao , Wang Li‐Na 
Published: March 2007

AbstractWe performed 2‐D DIGE on proteins prepared from serum obtained from patients with osteosarcoma (OS) and controls, to identify differentially expressed proteins that might serve as serum biomarkers for OS prognosis. Proteins found to be differentially expressed were identified by MALDI‐TOF mass spectrometric analysis, coupled with database interrogation. We compared serum samples from four individuals with OS to four age‐ and sex‐matched healthy controls. We identified 24 protein spot‐features that were significantly increased, and 34 that were significantly decreased in serum from patients with OS relative to the controls. The MS analysis revealed 18 unique proteins that were increased, and 25 unique proteins that were decreased in OS serum samples. Western blot and ELISA analysis confirmed increased levels of amyloid‐related serum protein (SAA) in the OS serum samples. The increased expression levels of SAA were decreased after using MTX and cisplatin combination chemotherapy, and were further decreased after operation. Moreover, increased expression levels of sera SAA were seen in the relapsed patients. Our results suggested that the determination of serum SAA in OS patients might be utilized as a marker for relapse and in evaluation of the efficacy of therapy.
Specific peptides identified by mass spectrometry in placental tissue from pregnancies complicated by early onset preeclampsia attained by laser capture dissection
Authors: de Groot Christianne J. M. , Güzel Coşkun , Steegers‐Theunissen Régine P. M. , de Maat M. , Derkx Pieter , Roes Eva‐Maria , Heeren Ron M. A. , Luider Theo M. , Steegers Eric A. P. 
Published: March 2007

AbstractPreeclampsia is a common pregnancy‐specific syndrome that is diagnosed by the appearance of both increased blood pressure and proteinuria. Preeclampsia is associated with significant fetal and maternal morbidity and mortality. Although the etiology of preeclampsia is unknown, it is evident that abnormal placentation and trophoblast metabolism plays an important role. We therefore analyzed, identified, and verified specific proteins of villous trophoblast and villous stroma in small numbers of microdissected cells (approximately 125 cells) from seven placentas of women with pregnancies complicated by preeclampsia (cases) and seven uncomplicated pregnancies (controls). Tryptic peptide profiling by MALDI‐TOF MS was used for comparison and identification of significantly expressed peptides. The data were analyzed by ClinProTools (Bruker Daltonics) and by principal component analysis. Subsequently, a subset of placental tissues were homogenized and separated on a NanoLC system to obtain sequencing information (MS/MS spectra).We identified specific peptide patterns in the different cell types: villous stroma and trophoblast cells and differences in these cells of placentas from women with pregnancies complicated by early compared to late onset preeclampsia (<34 and >34 wk gestation, respectively) and controls. Principal component analysis revealed significant differences between the groups. The comparison with placental tissue after preterm delivery with unknown cause revealed that placental peptide patterns in early onset preeclampsia could not be explained by preterm delivery per se. Subsequently, specific, discriminating proteins for early onset preeclampsia compared to controls were identified including calcyclin, surfeit locus protein, and choriomammotropin A precursor. The expression of calcyclin was verified in early onset preeclamptic placental sections by immunohistochemistry. These data suggest that in early onset preeclampsia trophoblastic choriomammotropin regulation is abnormal, possibly through abnormal calcyclin expression and regulation.
Photochemical reactions of small mixed alkali‐metal particles in KCl
Authors: Okada T. 
Published: March 2007

AbstractWhen the additively colored KCl crystals containing small amounts of Na+ ions are annealed at 370 K, there appears the absorption band attributable to the mixed small colloidal‐particles consisting of K°‐ and Na°‐atoms. We have also found that the thermal annealing of KCl crystals including these mixed K°‐ and Na°‐colloidal particles results in the production of both the K° metal particles and the F centres situating at the normal sites. The optical bleaching of the F centres in the crystals including the colloidal particles is found to be led to produce the isolated FA and M centres. The consideration is also given on the destruction process of the mixed colloidal particles. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescence of YAB:Er single crystal
Authors: Földvári I. , Beregi E. , Solarz P. , Dominiak‐Dzik G. , Ryba‐Romanowski W. , Watterich A. 
Published: March 2007

AbstractLuminescence spectra of YAB:Er crystals were studied in the ultraviolet‐visible region and in the 10–300 K temperature range. The dominant Er3+‐emission belonged to the 4S3/2 → 4I15/2 transition (18000–18500 cm–1). Its Stark components were assigned and found to be consistent with those derived from the absorption spectra. The lifetime of the luminescence was determined as a function of temperature and Er‐concentration, and the decay kinetics was analyzed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computer modelling of intrinsic and substitutional defects in LiNbO3
Authors: Araujo R. M. , Lengyel K. , Jackson R. A. , Valerio M. E. G. , Kovács L. 
Published: March 2007

AbstractLithium niobate is a material with many important technological applications due to its diverse physical properties. Using a recently derived interatomic potential, intrinsic defect energies have been calculated leading to conclusions about the defect properties of the material that are compared with experimental conclusions. The incorporation of dopant ions into the structure is also considered, and solution energies are calculated, which enable predictions to be made about which ions are most easily added, and which solution energy schemes are favoured energetically. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescent spectroscopy of lead tungstate crystals doped with europium ions
Authors: Chukova O. , Nedilko S. , Scherbatskyi V. 
Published: March 2007

AbstractSpectral‐luminescent properties of the lead tungstate crystals doped with the Eu3+ ions were investigated in a wide temperature range at different excitation and registration wave lengths. The spectra consist of both weak wide nonstructural bands of the matrix emission and narrow spectral lines caused by inner f‐f electron transitions in the impurity Eu3+ ions. The analysis and interpretation of spectral lines observed in excitation and luminescence spectra have shown formation of at least two different types of luminescent centers on the basis of the Eu3+ ions in the PbWO4 crystals. These two types of centers are considered as caused by arrangement of the impurity Eu3+ ions in Pb sites as well as in W sites of the host matrix. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison between models of insulator and semiconductor thin films islanding
Authors: Lallet François , Dauger Alain , Olivi‐Tran Nathalie 
Published: March 2007

AbstractThe synthesis of self‐organized quantum dots (QD's) can be achieved through bottom up layer by layer deposition processes as chemical vapor deposition (CVD) or physical vapor deposition (PVD). However, QD's may also be synthesized via sol‐gel route, which involves a spontaneous evolution from thin films to discrete QD's without further deposition. The aim of the paper is to discuss and compare the physical phenomena involved in QD's formation which initiate from thin film surface roughening between PVDCVD and sol‐gel synthesis approaches. We propose two simple physical models which are relevant to explain the fundamental differences between those methods. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge evolution of F2 centers being in different spin states
Authors: Lisitsyna L. 
Published: March 2007

AbstractTime‐resolved pulse spectrometry methods have been used to study the processes of formation and destruction of F2, F2+, F2– color centers in the time range from 10 ns to 0.1s after irradiation by the electron nanosecond pulse in LiF crystals. It has been found that the direction charge evolution of F2 center under radiation depends on the spin state it is in. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanism of radiation‐induced defects in SiO2: The role of hydrogen
Authors: Salh Roushdey , Fitting H.‐J. 
Published: March 2007

AbstractHydrogen related defects in anhydrous “dry”, hydrated “wet” and hydrogen implanted amorphous silicon dioxide (a ‐SiO2) layers are investigated using cathodoluminescence (CL) technique in a wave length range 200–800 nm at specimen temperatures between room and liquid nitrogen temperature. Particular defect centers have been identified including the non‐bridging oxygen hole center (NBOHC) associated with the red luminescence at 650 nm (1.9 eV) and the oxygen deficient centers (ODCs) with the blue (460 nm; 2.7 eV) and UV band (290 nm; 4.3 eV). An additional luminescence band Y in the green‐yellow region has been clearly detected in hydrogen‐implanted as well as in oxygen‐deficient samples. The red luminescence shows quite different CL dose behavior in wet and hydrogen‐treated samples due to dissociation and re‐association of mobile hydrogen and oxygen from and to the NBOHC. The yellow luminescence at 580 nm (2.1 eV) is discussed in terms of radiolytic water dissociation as well as of ODC's in form of small silicon aggregates in the silica matrix. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cathodoluminescence from mixed KTaO3‐KNbO3 crystals
Authors: Kibar R. , Nunn P. J. T. , Townsend P. D. , Wang Y. , Boatner L. A. 
Published: March 2007

AbstractCathodoluminescence spectra are shown for a sequence of mixed crystals of KTaO3:KNbO3. The luminescence emission bands are broadly similar across the spectrum from 250 to 850 nm, although their relative strengths are sensitive to composition and temperature. A UV band near 330 nm is only well resolved in some compositions and a broad line near 700 nm may arise from Cr ions. The presence of low temperature phase transitions within the crystals is evidenced by intensity steps and spectral changes of the cathodoluminescence. Hysteresis is seen, as are domain effects and electric field shifts of the transition temperatures. The cathodoluminescence of the surface material reveals more transitions than are reported from earlier bulk studies. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Orientation dependence of the ion beam and cathodoluminescence of albite
Authors: Garcia‐Guinea J. , Finch A. , Can N. , Hole D. , Townsend P. 
Published: March 2007

AbstractIon beam induced luminescence and cathodoluminescence of albite produce unexpected differences between (010) and (001) aligned samples. The emission spectra are modified by temperature and different components change in their relative intensity as a result of excitation by different ion beams of H+, H2+ and He+. A consideration of processes which can induce the orientation dependence and the role of excitation density that influences the component features are both discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defects induced in bioglass by gamma radiation for dosimetric purposes
Authors: Da Costa Z. M. , Melo Adeilson P. , Giehl J. M. , Ludwig V. , Pontuschka W. M. , Caldas Linda V. E. 
Published: March 2007

AbstractSome dosimetric properties of the glass system 50P2O5·30‐40CaO·20‐10Na2O mol% were studied applying the thermoluminescence technique. The glass samples were powdered, and were pressed with Teflon™ in the proportion 1:2 to produce pellets. The glow curves of the pellets presented three peaks at 130 °C, 215 °C and 270 °C, respectively. The TL response reproducibility presented a maximum coefficient of variation lower than 10%. The calibration curve is linear between 1.0 Gy and 1 kGy. Minimum detection limits were also determined. The gamma radiation dose response and the thermal stability of the materials were studied with the purpose to establish the best conditions of the present bioglass system for use in gamma ray TL dosimetry. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical spectra of Tm3+‐doped YAl3(BO3)4 single crystals
Authors: Cavalli E. , Jaque D. , Leonyuk N. I. , Speghini A. , Bettinelli M. 
Published: March 2007

AbstractFlux grown YAl3(BO3)4 (YAB) crystals doped with Tm3+ have been characterised by optical spectroscopy techniques. The absorption and emission spectra in the UV‐VIS‐NIR region have been measured at 10 and 298 K. The visible emission decay profiles have been measured at room temperature. The low temperature spectra have been used to obtain the energy level scheme of the optically active ion in YAB. The Judd‐Ofelt parametrization scheme has been applied to the analysis of the room temperature absorption spectra in order to evaluate the intensity parameters, the branching ratios and the radiative lifetimes of the emitting states. These have been compared with the experimental values. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)