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Spectroscopic Analysis (spectroscopic + analysis)
Kinds of Spectroscopic Analysis Selected AbstractsRaman Spectroscopic Analysis of Ancient Egyptian PigmentsARCHAEOMETRY, Issue 4 2001A. Rosalie David The application of FT-Raman spectroscopy and visible Raman microscopy to the non-destructive analysis of pigment specimens excavated from Tell el Amarna by Flinders Petrie in the 1890s has provided information about the chemical composition of the materials used by XVIIIth Dynasty artists in the New Kingdom at the time of King Akhenaten, c. 1340 bc. Comparison of the Raman spectra of the samples labelled ,red and yellow ochre' with documented, archival material from geological collections provided a clear indication of the materials used in the iron(III) oxide/hydroxide system, including ,-hematite, goethite, maghemite, magnetite and lepidocrocite. The yellow,orange specimen labelled ,realgar' proved to be a mixture of realgar and pararealgar; since the specimen had been sheltered from light since its excavation, this could indicate that the ancient Egyptian artists recognized the colour variation and may have used this to effect in their decorations. A specimen of yellow ochre contained goethite, ,-FeO.OH, with particles of crystalline, highly ordered graphite; in contrast, the red ochre specimens contained amorphous carbon particles. [source] Apatite-forming ability (bioactivity) of ProRoot MTAINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2010M. G. Gandolfi Gandolfi MG, Taddei P, Tinti A, Prati C. Apatite-forming ability (bioactivity) of ProRoot MTA. International Endodontic Journal, 43, 917,929, 2010. Abstract Aim, Apatite-forming ability, considered as an index of bioactivity (bond-to-bone ability), was tested on ProRoot MTA cement after immersion in phosphate-containing solution (DPBS). Methodology, Disk samples were prepared and immersed in DPBS for 10 min, 5 h, 1 and 7 days. The cement surface was studied by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, by micro-Raman spectroscopy and by environmental scanning electron microscope with energy dispersive X-ray (ESEM-EDX) analyses. The pH of the storage solution was also investigated. Results, Spectroscopic analyses revealed calcium phosphate bands after 5-h immersion in DPBS. After 1 day, an even coating composed of apatite spherulites (0.1,0.8 micron diameter) was observed by ESEM/EDX. After 7 days, its thickness had increased. Apatite nucleation had already occurred after 5-h immersion. At this time, the presence of portlandite (i.e. Ca(OH)2, calcium hydroxide) on the cement surface was also observed; at longer times, this component was released into the medium, which underwent a remarkable pH increase. Conclusions, The study confirms the ability of ProRoot MTA to form a superficial layer of apatite within hours. The excellent bioactivity of ProRoot MTA might provide a significant clinical advantage over the traditional cements used for root-end or root-perforation repair. [source] Ion-Exchange Plasma Membranes for Fuel Cells on a Micrometer Scale,CHEMICAL VAPOR DEPOSITION, Issue 6-7 2007S. Roualdès Abstract Recent advances in,miniaturization technology make polymer electrolyte membrane fuel cells very attractive as power sources for portable devices. Ion-exchange membranes for microscale fuel cells are synthesized by plasma polymerization (using a precursor containing ion-exchange groups) and intensively characterized. Ion-exchange plasma membranes are thin, amorphous, and dense materials with no defects. Spectroscopic analyses reveal a polymer-type matrix containing a rather high concentration of ion-exchange groups. Under the best synthesis conditions, membranes show a satisfying ionic conduction level and a high compatibility with other active layers of fuel cells, making them suitable for insertion in such power-supply devices. [source] Reagentless Biosensor for Hydrogen Peroxide Based on the Immobilization of Hemoglobin in Platinum Nanoparticles Enhanced Poly(chloromethyl thiirane) Cross-linked Chitosan Hybrid FilmELECTROANALYSIS, Issue 12 2009Shanshan Jia Abstract An unmediated hydrogen peroxide (H2O2) biosensor was prepared by co-immobilizing hemoglobin (Hb) with platinum nanoparticles enhanced poly(chloromethyl thiirane) cross-linked chitosan (CCCS-PNs) hybrid film. CCCS could provide a biocompatible microenvironment for Hb and PNs could accelerate the electron transfer between Hb and the electrode. Spectroscopic analysis indicated that the immobilized Hb could maintain its native structure in the CCCS-PNs hybrid film. Entrapped Hb exhibited direct electrochemistry for its heme Fe(III)/Fe(II) redox couples at ,0.396,V in the CCCS-PNs hybrid film, as well as peroxidase-like activity to the reduction of hydrogen peroxide without the aid of an electron mediator. [source] Transitions of serum albumin in patients with glomerulosclerosis ,in vivo' characterization by electrophoretic titration curvesELECTROPHORESIS, Issue 14 2006Maurizio Bruschi Abstract HSA functions as a physiological transporter of solutes and small molecules that induce structural transitions ,in vitro'. Analysis of these transitions requires prior purification of HSA that could introduce bias due to conformational changes. We utilized electrophoretic titration curves to describe a neutral to acid (N,A) transition of HSA directly in sera of seven patients with active focal segmental glomerulosclerosis (FSGS). The divergent electrophoretic profile of HSA was characterized by a shift in the range of pHs between 4.5 and 7.5 with an average variation of free electrophoretic mobility corresponding to loss of 1 positive charge in the pKa protonation range of histidyl residues and should involve domain I of HSA. ,In-gel' determination by maleimide-PEO2-biotin of free SH 34 of domain I showed inaccessibility of the dye at this site in pathological HSA and alkylation with the same complex induced N,A transition in normal HSA. Potential binders of free imidazoles such as Ca++ and/or of SH 34 such as NO were excluded on the basis of direct titration and studies on binding stimulation. This is the first report describing a transition of HSA directly ,in vivo', and the utilization of electrophoretic titration curves was critical to this purpose. This transition appears to be specific to FSGS and is unrelated to the nephrotic syndrome, Ca++ and NO binding. Spectroscopic analysis will elucidate the structural implication. [source] The oxidation process of Antarctic fish hemoglobinsFEBS JOURNAL, Issue 9 2004Luigi Vitagliano Analysis of the molecular properties of proteins extracted from organisms living under extreme conditions often highlights peculiar features. We investigated by UV-visible spectroscopy and X-ray crystallography the oxidation process, promoted by air or ferricyanide, of five hemoglobins extracted from Antarctic fishes (Notothenioidei). Spectroscopic analysis revealed that these hemoglobins share a common oxidation pathway, which shows striking differences from the oxidation processes of hemoglobins from other vertebrates. Indeed, simple exposure of these hemoglobins to air leads to the formation of a significant amount of the low-spin hexacoordinated form, denoted hemichrome. This hemichrome form, which is detected under a variety of experimental conditions, can be reversibly transformed to either carbomonoxy or deoxygenated forms with reducing agents. Interestingly, the spectra of the fully oxidized species, obtained by treating the protein with ferricyanide, show the simultaneous presence of peaks corresponding to different hexacoordinated states, the aquomet and the hemichrome. In order to assign the heme region state of the , and , chains, the air-oxidized and ferricyanide-oxidized forms of Trematomus bernacchii hemoglobin were crystallized. Crystallographic analysis revealed that these forms correspond to an ,(aquomet)-,(bishistidyl-hemichrome) state. This demonstrates that the , and , chains of Antarctic fish hemoglobins follow very different oxidation pathways. As found for Trematomus newnesi hemoglobin in a partial hemichrome state [Riccio, A., Vitagliano, L., di Prisco, G., Zagari, A. & Mazzarella, L. (2002) Proc. Natl Acad. Sci. USA99, 9801,9806], the quaternary structures of these ,(aquomet)-,(bishistidyl-hemichrome) forms are intermediate between the physiological R and T hemoglobin states. Together, these structures provide information on the general features of this intermediate state. [source] Vibrational spectroscopic studies to acquire a quality control method of Eucalyptus essential oils,BIOPOLYMERS, Issue 5 2005M. Baranska Abstract This article presents a novel and original approach to analyze in situ the main components of Eucalyptus oil by means of Raman spectroscopy. The obtained two-dimensional Raman maps demonstrate a unique possibility to study the essential oil distribution in the intact plant tissue. Additionally, Fourier Transform (FT)-Raman and attenuated total reflection (ATR)-IR spectra of essential oils isolated from several Eucalyptus species by hydrodistillation are presented. Density Functional Theory (DFT) calculations were performed in order to interpret the spectra of the essential oils of the Eucalyptus species. It is shown that the main components of the essential oils can be recognized by both vibrational spectroscopic techniques using the spectral information of the pure terpenoids. Spectroscopic analysis is based on the key bands of the individual volatile substances and therefore allows one to discriminate different essential oil profiles of several Eucalyptus species. It has been found that the presented spectroscopic data correlate very well with those obtained by gas chromatography (GC) analysis. All these investigations are helpful tools to generate a fast and easy method to control the quality of the essential oils with vibrational spectroscopic techniques in combination with DFT calculations. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 237,248, 2005 [source] Secondary Metabolites of Phomopsis sp.EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2009XZ-2, an Endophytic Fungus from Camptothecaacuminate Abstract Eleven new metabolites, including nine lovastatin analogues [oblongolides N,V (1,2 and 5,11), which were defined as naphthalene-type fungal polyketides], one linear furanopolyketide (13) and a monoterpene named dihydroxysabinane (14), together with four known compounds including oblongolides B (3) and C (4), one linear furanopolyketide (12) and the sesterterpene terpestacin (15), were isolated from the endophytic fungal strain Phomopsis sp. XZ-26 of Camptotheca acuminate. Their structures were elucidated by spectroscopic analyses including HR-ESI-MS, 1H and 13C NMR, 2D NMR (HMQC, HMBC, 1H- 1H COSY and NOESY), and X-ray single-crystal analysis. The antimicrobial activities of 1,5, 8, 10 and 13,15 were evaluated, but none showed a substantial effect. Additionally, a hypothetical biosynthetic pathway for oblongolides was proposed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Study on the Constituents of Roots of Aceriphyllum rossiiHELVETICA CHIMICA ACTA, Issue 9 2010Le Thi Kim Van Abstract A new stereoisomer of a tetrahydrofuranoid lignan, acerifuranoid A (1), and two new oleanane-type triterpenoids, aceriphyllic acids J and K (2 and 3), were isolated from the roots of Aceriphyllum rossii. Their structures were elucidated on the basis of spectroscopic analyses and chemical evidence. These isolated compounds exhibited weak cytotoxic activity against various cancer cell lines with IC50>150,,M. [source] New Epoxy-Substituted Nitrogenous Bisabolene-Type Sesquiterpenes from a Hainan Sponge Axinyssa sp.HELVETICA CHIMICA ACTA, Issue 3 2010Ji-Zheng Sun Abstract Two new uncommon epoxy-substituted nitrogenous bisabolene-type sesquiterpenes, 3-formamido-7,8-epoxy- , -bisabolane (4), 3-isocyano-7,8-epoxy- , -bisabolane (5), together with three known related sesquiterpenes, 1,3, were isolated from the Hainan sponge Axinyssa sp. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison of their NMR data with those of structurally related compounds. [source] Three New ent -Trachylobane Diterpenoids from Co-cultures of the Calli of Trewia nudiflora and Fusarium sp.HELVETICA CHIMICA ACTA, Issue 12 2009Abstract Five diterpenoids, including three new ent -trachylobane diterpenoids, i.e., (3,)-3-hydroxy- ent -trachylobane-17,19-dioic acid 19-methyl ester (1), ent -trachylobane-17,19-dioic acid 19-methyl ester (2), ent -trachylobane-17,19-dioic acid (3), and two known atisane-type ones, i.e., (16,)-16,17-dihydroxy- ent -atisan-19-oic acid methyl ester (4), and 17-hydroxy- ent -atisan-19-oic acid methyl ester (5), were isolated from the co-culture extract of the calli of Trewia nudiflora and its endophytic fungus Fusarium sp. WXE. Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR experiments, and HR-Q-TOF mass spectrometry. The antitumor and antibacterial properties of the new compounds were evaluated. [source] Two New Kaempferol Glycosides from Androsace umbellataHELVETICA CHIMICA ACTA, Issue 7 2009Jun Lei Abstract Two new kaempferol glycosides, 5-hydroxy-2-(4-hydroxyphenyl)-4-oxo-7-(, - L -rhamnopyranosyloxy)-4H -chromen-3-yl 2- O -acetyl-3- O - , - D -glucopyranosyl- , - L -rhamnopyranoside (1) and 5-hydroxy-2-(4-hydroxyphenyl)-4-oxo-7-(, - L -rhamnopyranosyloxy)-4H -chromen-3-yl , - D -glucopyranosyl-(1,2)-6- O -[(2E)-3-(4-hydroxyphenyl)prop-2-enoyl]- , - D -glucopyranosyl-(1,2)- , - D -glucopyranoside (2), along with ten known compounds, were isolated from the 95% EtOH extract of the whole plant of Androsace umbellata. The structures of the new glycosides were determined on the basis of detailed spectroscopic analyses, including 1D- and 2D-NMR, MS, and chemical methods. [source] Ecdysteroids from Silene viridifloraHELVETICA CHIMICA ACTA, Issue 4 2009András Simon Abstract Two new ecdysteroid acetonide derivatives, 5, -2-deoxy-20-hydroxyecdysone 20,22-acetonide (6) and makisterone C 2,3;20,22-diacetonide (8), were isolated from the dried herb of Silene viridiflora. The already known 5, -2-deoxy-20-hydroxyecdysone 20,22-acetonide (7) is additionally reported here as a new constituent of S. viridiflora. Five earlier described S. viridiflora ecdysteroids, integristerone A (1), 5,20,26-trihydroxyecdysone (26-hydroxypolipodine B; 2), 20,26-dihydroxyecdysone (3), 2-deoxy-20-hydroxyecdysone (4), 2-deoxyintegristerone A (5), are also included because of their improved characterization. The structures were established via spectroscopic analyses, including one- and two-dimensional NMR and mass spectrometry. [source] New Verticillane-Type Diterpenoids from the Taiwanese Soft Coral Cespitularia hypotentaculataHELVETICA CHIMICA ACTA, Issue 12 2008Yuan-Bin Cheng Abstract Investigation of the MeOH/CH2Cl2 extract of the soft coral Cespitularia hypotentaculata collected in Taiwan has resulted in the isolation of four new verticillane-type diterpenoids, cespihypotins M,P (1,4). Compounds 2 and 3 are C(20)-epimers. Compound 4 with a CO group at C(10) and a methoxycarbonyl group at C(12) may be an important precursor of cespitularins and cespihypotins. The structures of these compounds were determined on the basis of spectroscopic analyses. [source] Highly Oxygenated Triterpenoids from the Marine Red Alga Laurencia mariannensis (Rhodomelaceae)HELVETICA CHIMICA ACTA, Issue 10 2008Nai-Yun Ji Abstract Two new and one known squalenoid-derived triterpenoids, namely, laurenmariannol (1) and (21,)-21-hydroxythyrsiferol (2), and the known thyrsiferol (3) were isolated and identified from the marine red alga Laurencia mariannensis, which was collected off the coast of Hainan and Weizhou Islands of China. The structures of these compounds were established by means of spectroscopic analyses, as well as by comparison with literature data. Compounds 1 and 2 displayed significant cytotoxic activity against P-388 tumor cells with IC50 values of 0.6 and 6.6,,g/ml, respectively. [source] Daphnoldines A and B, Two New Yuzurine Alkaloids with a Four-Ring System, from the Fruits of Daphniphyllum oldhamiHELVETICA CHIMICA ACTA, Issue 5 2008Qiang Zhang Abstract Two new yuzurine alkaloids, daphnoldines A (1) and B (2), possessing a rare four-ring system, were isolated from the fruits of Daphniphyllum oldhami. Their structures were established on the basis of extensive spectroscopic analyses. Daphnoldine A (1) is the first example of Daphniphyllum alkaloids bearing a hydroxymethyl group at C(14). [source] Novel Polyketides Isolated from Streptomyces sp.HELVETICA CHIMICA ACTA, Issue 4 2008Jian Li Abstract From the endophytic strain Streptomyces sp. CS of Maytenus hookeri, five novel type III polyketides, compounds 1,5, were isolated. Their structures were elucidated by spectroscopic analyses including 1D- and 2D-NMR experiments, and by HR-ESI-MS. [source] Novel Bibenzyl Derivatives from the Tubers of Bletilla striataHELVETICA CHIMICA ACTA, Issue 3 2008Jia-Quan Feng Abstract Three novel bibenzyl derivatives, blestritins A,C (1,3), along with 18 known constituents, were isolated from the tubers of Bletilla striata (Orchidaceae), a traditional Chinese medicine used for the treatment of tuberculosis and haemorrhage of the stomach and lungs. Their structures were identified on the basis of spectroscopic analyses. [source] Diarylheptanoids from the Rhizomes of Alpinia officinarumHELVETICA CHIMICA ACTA, Issue 1 2008Yi Sun Abstract A novel dimeric diarylheptanoid, (5R,5,R)-7,7,-(6,6,-dihydroxy-5,5,-dimethoxy[1,1,-biphenyl]-3,3,-diyl)bis[5-methoxy-1-phenylheptan-3-one] (1), and two new diarylheptanoids, (4E,6R)-6-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-1-phenylhept-4-en-3-one (2) and (4E,6R)-6-hydroxy-1,7-diphenylhept-4-en-3-one (3), together with seven known diarylheptanoids, were isolated from the rhizomes of Alpinia officinarum. Their structures were elucidated by application of extensive spectroscopic analyses and the modified Mosher method. [source] Phenylpropanoid-Substituted Catechins and Epicatechins from Smilax chinaHELVETICA CHIMICA ACTA, Issue 9 2007Hui-Lian Huang Abstract The four new phenylpropanoid-substituted catechins 1, 3, and 4 and 3-epicatechin (2), together with seven analogues, were isolated from the AcOEt extract of Smilax china L. (catechin=(2R,3S)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H -2-benzopyran-3,5,7-triol). Their structures were determined by means of spectroscopic analyses, including HR-MS, IR, 1H- and 13C-NMR, and 2D experiments (COSY, HSQC, and HMBC), and comparison with known related compounds. [source] A Novel Atisane Diterpenoid from Spiraea japonica var. acutaHELVETICA CHIMICA ACTA, Issue 7 2007Hai-Yang Liu Abstract A novel ent -atisane lactone, spiramilactone E (1), was isolated from Spiraea japonica var. acutaYu. Its structure was elucidated by extensive spectroscopic analyses, and unequivocally confirmed by single-crystal X-ray diffraction (Fig.,2). Compound 1 contains a , -lactone moiety between the 6-OH function and C(20), and ,- configuration for the 7-OH group, in contrast to known related diterpenes previously isolated from the S. japonica complex. [source] Lewis Acid Catalyzed, Selective Cyclopropane-Ring Opening in Ingol Diterpene DerivativesHELVETICA CHIMICA ACTA, Issue 9 2005Masuna Srinivasulu Lewis acid mediated skeletal rearrangement of the ingol diterpenoids 1 and 4via regio- and stereospecific cyclopropane-ring opening afforded the four new compounds 2, 3, 5, and 6, named nivulianol A,D (Scheme,1). Their structures were established by means of IR, MS, and in-depth NMR spectroscopic analyses. The rearranged congeners were tested for lipopolysaccharide (LPS)-induced prostaglandin (PG) E2 (cyclooxygenase-2) inhibition. Thereby, nivulianol B (=(1S*,2E,4R*,5S*,7Z,9S*,11R,13S*,14S*)-14-acetoxy-5-methoxy-3,9,13-trimethyl-6-(1-methylethenyl)-10-oxo-15-oxatricyclo[9.3.1.01,11]pentadeca-2,7-dien-4-yl (2Z)-2-methylbut-2-enoate; 3) was found to be significantly active, with an IC50 value of 36.3,,g/ml. [source] Cuparene-Derived Sesquiterpenes from the Chinese Red Alga Laurencia okamurai YamadaHELVETICA CHIMICA ACTA, Issue 5 2005Shui-Chun Mao Four new cuparene-derived sesquiterpenes, laureperoxide (1), 10-bromoisoaplysin (2), isodebromolaurinterol (3), and 10-hydroxyisolaurene (4), together with seven known, related sesquiterpenes, 5,11, have been isolated from the red alga Laurencia okamurai. Their structures were determined on the basis of detailed spectroscopic analyses and comparison with known compounds. Compounds 8,11 were shown for the first time to represent true natural products, and the full 1H- and 13C-NMR assignments of 5 are reported for the first time. [source] New Long-Chain Esters and Adenine Analogs from the Leaves of Formosan Bridelia balansaeHELVETICA CHIMICA ACTA, Issue 7 2003Yeh-Hsin Tsai Six new compounds, including the two long-chain esters balansenate I (=6,8,11-trimethyldodecanoic acid (2E)-3-methylhexadec-2-enyl ester; 1) and balansenate II (=10,12,15-trimethylhexadedecanoic acid (2E)-3-methylhexadec-2-enyl ester; 2), the eburicane-like triterpenoid bridelone (=hexadecahydro-4,4,10,13,14-pentamethyl-17-(5-methyl-1,4-dimethylenehexyl)-3H -cyclopenta[a]phenanthren-3-one; 3), the ,deimino-xanthine', bridelonine (=5-(3-methylbut-2-enyl)pyrrolo[3,4- d]imidazole-4,6(1H,5H)-dione; 6), and the two adenine analogs 9-(3-methylbut-2-enyl)adenine (7) and 1-(3-methylbut-2-enyl)adenine (8), besides three known compounds, i.e., N6 -(3-methylbut-2-enyl)adenine (4), 3-(3-methylbut-2-enyl)adenine (5), and adenine (9), were isolated from the leaves of Formosan Bridelia balansae. The novel skeleton of 6 consists of a fused pyrrolidine-2,5-dione and imidazole moiety. The already known adenines 7 and 8 were isolated for the first time from a plant. The structures of the isolated compounds were elucidated by spectroscopic analyses. [source] Substitution- and Elimination-Free Phosphorylation of Functionalized Alcohols Catalyzed by Oxidomolybdenum TetrachlorideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Cheng-Yuan Liu Abstract Among 14 oxidometallic species examined for catalytic phosphorylation of the tested alcohols, oxidomolybdenum tetrachloride (MoOCl4) was found to be the most efficient with a negligible background reaction mediated by triethylamine (Et3N). The new catalytic protocol can be applied to the chemoselective phosphorylations of primary, secondary and tertiary alcohols as well as the substitution-free phosphorylations of allylic, propargylic, and benzylic alcohols. Functionalized alcohols bearing acetonide, tetrahydropyranyl ether, tert -butyldimethylsilyl ether, or ester group are also amenable to the new catalytic protocol. The most difficult scenarios involve substitution-free phosphorylations of 1-phenylethanol and 1-(2-naphthyl)ethanol which can be effected in 95 and 90% yields, respectively. ESI-MS, IR, 1H, and 31P,NMR spectroscopic analyses of the reaction progress suggest the intermediacy of an alkoxyoxidomolybdenum trichloride-triethylamine adduct such as [(RO)Mo(O)Cl3 -Et3N] to be responsible for the catalytic turnover. [source] Antioxidant polyphenols from the mycelial culture of the medicinal fungi Inonotus xeranticus and Phellinus linteusJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008J.-Y. Jung Abstract Aims:, The medicinal fungi Inonotus xeranticus and Phellinus linteus in the family Hymenochaetaceae have been used as traditional medicines for the treatment of various diseases. However, the compound responsible for the antioxidant activity is still unknown. Therefore, this study was conducted to characterize the antioxidant substances present in cultured broths made from these fungi. Methods and Results:, Antioxidant fractions of the cultured broths obtained from I. xeranticus and P. linteus were analysed using reversed-phase HPLC, which revealed several peaks that exhibited a potent free radical scavenging activity. To identify these antioxidant peaks, an I. xeranticus strain was mass-cultured, and the cultured broth was separated using antioxidant activity-guided fractionation. Four major active substances were purified and identified as hispidin and its dimers, 3,14,-bihispidinyl, hypholomine B, and 1,1-distyrylpyrylethan based on spectroscopic analyses. All compounds exhibited a significant scavenging activity against these radical species in a concentration-dependent manner. Conclusions:, Antioxidant substances found in the cultured broths of the medicinal fungi I. xeranticus and P. linteus were identified as hispidin and its dimers, 3,14,-bihispidinyl, hypholomine B, and 1,1-distyrylpyrylethan. Significance and Impact of the Study:, Polyphenol antioxidants were isolated from the cultured broth of the medicinal fungi I. xeranticus and P. linteus and identified based on extensive spectroscopic analyses. These compounds exhibited a strong antioxidant activity. [source] Generalization of multivariate optical computations as a method for improving the speed and precision of spectroscopic analysesJOURNAL OF CHEMOMETRICS, Issue 6 2008Marc K. Boysworth Abstract Multivariate optical computations (MOCs) offer improved analytical precision and increased speed of analysis via synchronous data collection and numerical computation with scanning spectroscopic systems. The improved precision originates in the redistribution of integration time from spurious channels to informative channels in an optimal manner for increasing the signal-to-noise ratio with multivariate analysis under the constraint of constant total analysis time. In this work, MOCs perform the multiplication and addition steps of spectral processing by adjusting the integration parameters of the optical detector or adjusting the scanning profile of the tunable optical filter. Improvement in the precision of analysis is achieved via the implicit optimization of the analytically useful signal-to-noise ratio. The speed improvements are realized through simpler data post-processing, which reduces the computation time required after data collection. Alternatively, the analysis time may be significantly truncated while still seeing an improvement in the precision of analysis, relative to competing methods. Surface plasmon resonance (SPR) spectroscopic sensors and visible reflectance spectroscopic imaging were used as test beds for assessing the performance of MOCs. MOCs were shown to reduce the standard deviation of prediction by 15% compared to digital data collection and analysis with the SPR and up to 45% for the imaging applications. Similarly, a 30% decrease in the total analysis time was realized while still seeing precision improvements. Copyright © 2008 John Wiley & Sons, Ltd. [source] Characterization of site I of human serum albumin using spectroscopic analyses: Locational relations between regions Ib and Ic of site IJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2004Keishi Yamasaki Abstract Site I of human serum albumin is an important and complex region for high-affinity binding of drugs. Equilibrium dialysis showed independent binding of dansyl- L -asparagine (DNSA) and n -alkyl p -aminobenzoates (p -ABEs) to regions Ib and Ic, respectively, in the pH range 6.0,9.0. However, individual binding of DNSA increased with pH in the same range. Binding of the four n -alkyl p -ABEs strongly perturbed the circular dichroism spectrum of bound DNSA, and the effect increased with concentration and the number of carbon atoms in the alkyl moiety. A similar effect was observed by increasing pH from 6.0 to 9.0, a pH range in which human serum albumin is known to undergo the neutral-to-base transition. The spectral changes propose spatial orientation changes of DNSA at region Ib. This proposal was supported by increased fluorescence anisotropy values: n -alkyl p -ABEs binding and the pH-dependent conformational change each restricted the mobility of the naphthalene ring of bound DNSA. Despite the similar effects on the spatial orientation of DNSA, clear differences were observed between the effects of n -alkyl p -ABEs and neutral-to-base transition. The former hardly changed the affinity and maximum fluorescence emission wavelength of bound DNSA; in contrast, the latter significantly affected them. The results give new information about site I and, according to our knowledge, represent a new type of ligand interaction, because the binding site of DNSA could be changed by simultaneous binding of the n -alkyl p -ABEs without affecting the binding constant. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:3004,3012, 2004 [source] Anionic alternating copolymerization of 3,4-dihydrocoumarin and glycidyl ethers: A new approach to polyester synthesisJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2008Kazuya Uenishi Abstract Anionic copolymerizations of 3,4-dihydrocoumarin (DHCM) and a series of glycidyl ethers (n -butyl glycidyl ether, tert -butyl glycidyl ether, and allyl glycidyl ether) with 2-ethyl-4-methylimidazole as an initiator proceeded in a 1:1 alternating manner to give the corresponding polyesters, whose structures were confirmed by spectroscopic analyses and reductive scission of the ester bonds in the main chain with lithium aluminum hydride, followed by detailed analyses of the resulting fragments. The polyester obtained by the copolymerization of DHCM and allyl glycidyl ether inherited the allyl groups in the side chain, whose applicability to chemical modifications of the polyester was successfully demonstrated by a platinum-catalyzed hydrosilylation reaction. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4092,4102, 2008 [source] Effect of pH on the Carbonate Incorporation into the Hydroxyapatite Prepared by an Oxidative Decomposition of Calcium,EDTA ChelateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2008Yusuf Yusufoglu In this study, the carbonate incorporation into the hydroxyapatite (HAp) lattice under various pH conditions was investigated. Crystalline-sodium and carbonate-containing calcium HAp (NaCO3HAp) powders were prepared using an oxidative decomposition of calcium,EDTA chelates in a sodium phosphate solution with hydrogen peroxide. The powders obtained were characterized by X-ray diffraction, infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and elemental analysis. Depending on pH, spherical particles approximately 3.5 ,m in diameter or hexagonal prismatic particles measuring 3,9 ,m in length were obtained. Various characterization techniques showed that the precipitates were a single-phase NaCO3HAp. The carbonate content and the lattice parameters of the HAp were a function of solution pH. Maximum carbonate incorporated into the HAp lattice was at pH=10, corresponding to lattice parameters of a=0.93880 nm and c=0.69070 nm. Furthermore, spectroscopic analyses indicate that the as-prepared samples are B-type carbonated HAp, in which carbonate ions occupy the phosphate sites. After heat treatment at 965°C, most of the carbonate is removed from the HAp lattice. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||