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Results 251 - 300 of 1380
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Wang Li-Juan - - 2012
In this paper, twelve dialkyltartrate-boric acid complexes and two polyols-boric acid complexes were in situ synthesized by the reaction of different dialkyltartrates or polyols with boric acid in methanol containing triethylamine. All of the twelve dialkyltartrate-boric acid complexes were found to have relatively good chiral separation performance in nonaqueous capillary ...
Westfall Corey S - - 2012
Acyl acid amido synthetases of the GH3 family act as critical prereceptor modulators of plant hormone action; however, the molecular basis for their hormone selectivity is unclear. Here, we report the crystal structures of benzoate-specific Arabidopsis thaliana AtGH3.12/PBS3 and jasmonic acid (JA)-specific AtGH3.11/JAR1. These structures, combined with biochemical analysis, define ...
Zhang Yu - - 2012
A novel material, sol-gel derived La(OH)(3) nanorods (La(OH)(3)NRs) with excellent film forming ability was prepared, and it was first designed to incorporate with carbon nanotubes (CNTs) to modify glassy carbon electrode (GCE) to simultaneously voltammetric determine ascorbic acid (AA), dopamine (DA), uric acid (UA), and nitrite (NO(2)(-)). Cyclic voltammetry (CV), ...
Gupta Prasoon - - 2012
Three new bicyclic C(21) terpenoids, clathric acid (1) and two N-acyl taurine derivatives, clathrimides A (2) and B (3), were isolated from the marine sponge Clathria compressa. The structures of these compounds were elucidated by interpretation of spectroscopic data. Clathric acid showed mild antibacterial activity against several Gram-positive bacteria.
Efdi Mai - - 2012
A new ring A-seco triterpenoid, sentulic acid, along with a known oleanane-type triterpenoid, 3-oxoolean-12-en-27-oic acid, were isolated from the Indonesian plant Sandoricum koetjape Merr. Their chemical structures were elucidated by spectroscopic analysis. In addition, the cytotoxic effects of these compounds on human promyelocytic leukemia HL-60 cells were studied. The results ...
Carta Fabrizio - - 2012
Using hydroxy-/dihydroxybenzoic acids as leads, a series of methyl, ethyl and iso-propyl esters of 4-hydroxy-benzoic acid, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-dihydroxybenzoic acids and of coumaric acid, were obtained and investigated for the inhibition of six mammalian carbonic anhydrase (CA, EC 4.2.1.1) isoforms, that is, the cytosolic CA I, II ...
Kenny Shane T - - 2012
Sodium terephthalate (TA) produced from a PET pyrolysis product and waste glycerol (WG) from biodiesel manufacture were supplied to Pseudomonas putida GO16 in a fed-batch bioreactor. Six feeding strategies were employed by altering the sequence of TA and WG feeding. P. putida GO16 reached 8.70 g/l cell dry weight (CDW) and ...
Kim Sang Min - - 2012
Ligularia fischeri (Ledeb.) Turcz, a commercial leafy vegetable, contains caffeoylquinic acid derivatives (CQAs) as major phenolic constituents. The HPLC chromatograms of leaf extracts collected from different areas in Korea showed a significant variation in CQA amount and two tri-O-caffeoylquinic acids (triCQAs) were purified and structurally identified by NMR and MS ...
Igarashi Yasuhiro - - 2012
Jomthonic acid A (1), a new modified amino acid, was isolated from the culture broth of a soil-derived actinomycete of the genus Streptomyces. The structure and absolute configuration of 1 were determined by spectroscopic analyses and chemical conversion. Jomthonic acid A (1) induced differentiation of preadipocytes into mature adipocytes at ...
Loyola-Vargas Victor - - 2012
Methyl jasmonate (MeJA) produces an important reduction in the accumulation of proteins related to energy metabolism. The treatment of hairy roots (HR) with MeJA increased the accumulation of H2O2 during the first 48 h and this H2O2 accumulation was also observed in isolated mitochondria. Peroxidase and catalase activities decreased in ...
Esbaugh Andrew J - - 2012
The oceanic carbonate system is changing rapidly due to rising atmospheric CO(2), with current levels expected to rise to between 750 and 1,000 μatm by 2100, and over 1,900 μatm by year 2300. The effects of elevated CO(2) on marine calcifying organisms have been extensively studied; however, effects of imminent CO(2) levels ...
Ritota Mena - - 2012
(1)H High Resolution Magic Angle Spinning-Nuclear Magnetic Resonance (HRMAS-NMR) spectroscopy was used to analyse garlic (Allium sativum L.) belonging to red and white varieties and collected in different Italian regions, in order to address the traceability issue. 1D and 2D NMR spectra, performed directly on untreated small pieces of garlic, ...
Ping Jianfeng - - 2012
A novel carbon composite electrode consisted of ionic liquid n-octylpyridinum hexafluorophosphate (OPFP) and single-walled carbon nanotube (SWCNT) was fabricated and investigated. This electrode combined the advantages of ionic liquid and SWCNT together with the "bulk" composite electrode. Compared with other composite electrodes using graphite or paraffin oil, the ionic liquid-SWCNT ...
Wang Y - - 2012
Bio-inspired chemical approach has been developed for the surface modification and electrophoretic deposition of manganese dioxide and zirconia nanoparticles, prepared by chemical precipitation methods. Caffeic acid, trans-cinnamic acid, p-coumaric acid, and 2,4-dihydroxycinnamic acid were investigated for the surface modification of the nanoparticles. The influence of the structure of the organic ...
Evans Amanda C - - 2012
The primordial appearance of chiral amino acids was an essential component of the asymmetric evolution of life on Earth. In this tutorial review we will explore the original life-generating, symmetry-breaking event and summarise recent thoughts on the origin of enantiomeric excess in the universe. We will then highlight the transfer ...
Zheng Yong-Biao - - 2012
Two new and three known abscisic acid-related metabolites were obtained from the potato dextrose agar culture of Phellinus vaninii YB2005. Their structures were established on the basis of detailed spectroscopic analyses, including 1D NMR, 2D NMR, and HR-Q-TOF-MS techniques. The putative biosynthesis pathway of these secondary metabolites would decipher the ...
Al-Jaber Hala I - - 2012
The novel seco-ursane-type triterpenoid 3β,11α-dihydroxy-17,22-seco-17(28), 12-ursadien-22-oic acid (1) was isolated for the first time from a natural source from two Salvia species growing wild in Jordan, Salvia palaestina Benth. and Salvia syrica L. In addition to compound 1, S. syriaca afforded a new sesquiterpene named syriacine (2). S. palaestina also ...
Peng Xuewei - - 2012
The degradation of three phthalic acid esters (PAEs) (dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-n-butyl phthalate (DBP)) by natural microbial community under aerobic condition and their isotope fractionation were compared by using a laboratory microcosm system with natural marine sediment overlying with natural seawater. The results showed that the ...
Akien Geoffrey R - - 2012
Several intermediates and different reaction paths were identified for the acid catalysed conversion of fructose to 5-(hydroxymethyl)-2-furaldehyde (HMF) in different solvents. The structural information combined with results of isotopic-labelling experiments allowed the determination of the irreversibility of the three steps from the fructofuranosyl oxocarbenium ion to HMF as well as ...
Heckler James E - - 2012
The electrophilic [Ph(3) PAu]NTf(2) quickly diaurates aryl boronic acids providing stable geminally diaurated complexes (see example; yellow, Au; orange, P; blue, C) that have been spectroscopically, and in some cases crystallographically, characterized. Geminally diaurated arenes are putative intermediates in gold(I) catalysis and are analogues of Wheland intermediates of electrophilic aromatic ...
Huo Hua - - 2012
17O-1H double resonance NMR spectroscopy was used to study the local structure of zeolite H-Mordenite. Different contact times were used in cross polarization magic angle spinning (CPMAS) NMR, CP rotational-echo double resonance (CP-REDOR) NMR and heteronuclear correlation (HETCOR) NMR spectroscopy to distinguish between Brønsted acid sites with different O-H distances. ...
Rama Gustavo - - 2012
Playing into our hands: The achiral bipyridine amino acid fluorenylmethyoxlcarbonyl 5-amino-3-oxapentanoic acid (Fmoc-O1PenBpy-OH) has been used for the solid-phase synthesis of metallopeptides. Circular dichroism, molecular modeling, and NMR spectroscopic studies show that the chirality of the resulting metal complexes in aqueous solution is determined, and can thus be controlled, by ...
de Clippel Filip - - 2012
A novel catalyst design for the conversion of mono- and disaccharides to lactic acid and its alkyl esters was developed. The design uses a mesoporous silica, here represented by MCM-41, which is filled with a polyaromatic to graphite-like carbon network. The particular structure of the silica-carbon composite allows the accommodation ...
Shashkov A S - - 2012
The cell wall of Actinoplanes utahensis VKM Ac-674(T) contains two anionic polymers: teichoic acid 1,3-poly(glycerol phosphate) that is widespread in cell walls of Gram-positive bacteria; and a unique teichulosonic acid belonging to a new class of bioglycans described only in microorganisms of the Actinomycetales order. The latter polymer contains residues of ...
Sirisoontorn Irin - - 2012
The effect of zoledronic acid, a potent and novel bisphosphonate, on tooth movement and orthodontically induced root resorption in osteoporotic animals systemically treated with zoledronic acid as similarly used in postmenopausal patients has not been elucidated. Therefore, this study was undertaken. Fifteen 10-week-old female Wistar rats were divided into 3 ...
Sanjai Karpagaselvi - - 2012
In routine histopathology, decalcification of bone and teeth is often an essential and important step during tissue processing. Various decalcifying agents have been used in the past. The rate of decalcification and the effect of decalcifying agents on the tissue and its staining characteristics are two important parameters which influence ...
Papagianni Maria - - 2012
ABSTRACT: This paper gives an overview of the recent advances in engineering the central carbon metabolism of the industrially important bacteria Escherichia coli, Bacillus subtilis, Corynobacterium glutamicum, Streptomyces spp., Lactococcus lactis and other lactic acid bacteria. All of them are established producers of important classes of products, e.g. proteins, amino ...
Polavarapu Prasad L - - 2012
Chiroptical spectroscopy is being widely used for determining the three-dimensional molecular structures (i.e., absolute configurations and conformations) of chiral molecules. The general procedure used with any of the chiroptical spectroscopic methods is to analyze the experimental data using corresponding quantum chemical predictions. Such analysis involves multiple steps, including consideration of ...
Liu Li L Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, - - 2012
Four metabolites of okadaic acid were generated by incubation with human recombinant cytochrome P450 3A4. The structures of two of the four metabolites have been determined by MS/MS experiments and 1D and 2D NMR methods using 94 and 133 μg of each metabolite. The structure of a third metabolite was ...
Wang Yu - - 2012
A filtration-aided acid cleaning method was used to collect biosilica structures from a diatom culture medium, natural seawater, or water bloom. Cell extraction, acid cleaning, and acid removal were all performed on a polytetrafluoroethylene (PTFE) filter cloth, significantly improving the treatment capacity and efficiency of the traditional acid wash method. ...
Li Yaya - - 2012
Single-walled carbon nanotubes (SWCNTs) fabricated by sodium dodecyl sulfate (SDS) (f-SWCNTs) modified glassy carbon electrodes (f-SWCNTs/GCE) for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The f-SWCNTs/GCE displayed very good electrochemical catalytic activities with respect to GCE. The oxidation over-potentials of DA and UA decreased ...
Sukumaran Pradeesh - - 2012
Bidens biternata, belonging to the family Asteraceae, is an erect annual herb, up to 1 cm in height, and a widespread weed of cultivated areas. This plant is common, particularly in the Western Ghats regions of Kerala state in India. It is used as a leafy vegetable by the Paniya and ...
Liu Wei - - 2012
A portion of hemicelluloses and acetic acid can be pre-extracted with dilute sulfuric acid prior to aspen chemi-thermomechanical pulp (CTMP) process. The streams collected from the second press-impregnation stage after acid pre-extraction contain significant amount of acid pre-extracted hemicelluloses. Most of total sugars obtained from the pressate were xylan, in ...
Li Heng - - 2012
The carbonylation of a 1-lithio-1,3-butadiene derivative with CO gave rise to a butadienyl acyllithio intermediate, which underwent an immediate intramolecular acyllithiation of the C=C double bond affording a lithio cyclopentadienyl enolate. The X-ray structural analysis of the enolate revealed a dimer connected with a "Li2O2" four-membered ring. Subsequent intermolecular acylation ...
Esche Rebecca - - 2012
An approach based on solid-phase extraction for the effective separation of free phytosterols/-stanols and phytosteryl/stanyl fatty acid and phenolic acid esters from cereal lipids was developed. The ester conjugates were analyzed in their intact form by means of capillary gas chromatography. Besides free sterols and stanols, up to 33 different ...
Smith Graham - - 2012
The racemic title compound, C(9)H(11)NO(4)·H(2)O, a tricyclic rearranged amino-norbornane dicarb-oxy-lic acid, is a conformationally rigid analogue of glutamic acid and exists as an ammonium-carboxyl-ate zwitterion, with the bridghead carb-oxy-lic acid group anti-related. In the crystal, N-H⋯O and O-H⋯O hydrogen bonds involving the ammonium, carb-oxy-lic acid and water donor groups with ...
Hu Fan - - 2012
Pseudo-lignin, which can be broadly defined as aromatic material that yields a positive Klason lignin value and is not derived from native lignin, has been recently reported to form during the dilute acid pretreatment of poplar holocellulose. To investigate the chemistry of pseudo-lignin formation, GPC, FT-IR and (13)C NMR were ...
Wang Kun - - 2012
In order to understand the behaviors of hemicelluloses and lignin under the given acidic conditions with increasing severity, the structural characteristics were elucidated in detail by both wet chemistry methods and spectroscopic analyses in this study. Although acidic pretreatment significantly hydrolyzed the glycosidic linkages in xylan backbone and then reduced ...
Cabanillas Billy Joel - - 2012
Two new dihydrochalcones (1, 2), as well as eight known compounds, piperaduncin C (3), 2',6'-dihydroxy-4'-methoxydihydrochalcone (4), 4,2',6'-trihydroxy-4'-methoxydihydrochalcone (5), 4-hydroxy-3,5-bis(3-methyl-2-butenyl)-benzoic acid (6), 3,5-bis(3-methyl-2-butenyl)-4-methoxybenzoic acid (7), 4-hydroxy-3-(3-methyl-2-butenoyl)-5-(3-methyl-2-butenyl)-benzoic acid (8), 2,2-dimethyl-8-(3-methyl-2-butenyl)-2H-1-chromene-6-carboxylic acid (9), and 3-(3',7'-dimethyl-2',6'-octadienyl)-4-methoxybenzoic acid (10) were isolated from the leaves of Piper dennisii Trelease (Piperaceae), using a bioassay-guided fractionation to determine ...
Chaudhuri Prabir K PK Central Institute of Medicinal and Aromatic Plants, Medicinal Plants Chemistry Section, PO CIMAP, Lucknow 226015, Uttar Pradesh, India. - - 2013
A new triterpenoid, 2α,24-diacetoxy-3β-hydroxyolean-12-en-28-oic acid (1), was characterised from the rhizomes of Nelumbo nucifera Gaertn by spectroscopic and chemical methods along with four known compounds, hyptatic acid-A (2α,3β,24-trihydroxyolean-12-en-28-oic acid) (2), maslinic acid (2α,3β-dihydroxyoleane-12-ene-28-oic acid), betulin and lupeol.
Cruz Andre F - - 2012
Fusarium diseases cause major economic losses in wheat-based crop rotations. Volatile organic compounds (VOC) in wheat and rotation crops, such as chickpea, may negatively impact pathogenic Fusarium. Using the headspace GC-MS method, 16 VOC were found in greenhouse-grown wheat leaves: dimethylamine, 2-methyl-1-propanol, octanoic acid-ethyl ester, acetic acid, 2-ethyl-1-hexanol, nonanoic acid-ethyl ...
Liu Jingyi - - 2012
Caffeoylquinic acids and lignans in the crude extracts of both roots and seeds from different burdock ( Arctium lappa L.) genotypes were simultaneously characterized and systematically compared by LC-MS and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS), and their antioxidant activities were also investigated. A total ...
Szakiel Anna - - 2012
ABSTRACT: Triterpenoid compounds extracted from fruits and leaves of lingonberry (Vaccinium vitis-idaea L.) collected in Finland and Poland were identified and quantitated by GC-MS/FID. The main lingonberry triterpenoid profile consisted of α-amyrin, β-amyrin, betulin, campesterol, cycloartanol, erythrodiol, fern-7-en-3β-ol, friedelin, lupeol, sitosterol, stigmasterol, stigmasta-3,5-dien-7-one, swert-9(11)-en-3β-ol, taraxasterol, urs-12-en-29-al, uvaol, oleanolic acid and ...
Momo Itbert Joseph - - 2012
A new pentacyclic triterpenoid and three new derivatives based on the taraxer-14-ene skeleton with a C-28 attached a carboxylic acid group have been isolated from the stem bark of Hypodaphnis zenkeri, together with six known compounds. The new product was identified as 2α,3α-dihydroxytaraxer-14-en-28-oic acid (1). Its derivatives, 2α,3α-diacetyltaraxer-14-en-28-oic acid (2), ...
Massaad Julie - - 2012
The present study quantitatively analyses the gated photochromism and the acidity photomodulation properties of a diacid dithienylethene compound. Photoisomerisation between the open and closed isomers was investigated by UV/visible and (1) H NMR spectroscopy. It was found that the photocyclisation quantum yield of the diacid form was remarkably high (around 90 %). ...
Lakshmi Prasuna M - - 2012
A phototrophic bacterium (Rubrivivax benzoatilyticus JA2) grows at the expense of l-phenylalanine as sole source of nitrogen but not as carbon source. Near stoichiometric yields of l-phenylpyruvic acid (0.4mM) and l-phenyllactate (0.4mM) were observed from l-phenylalanine (0.9mM consumed). Aminotransfarase and dehydrogenase activities involved in the formation of l-phenylpyruvic acid and ...
Fang Ping - - 2012
Catalytic α-allylation of unprotected amino acid esters to produce α-quaternary α-allyl amino acid esters is reported. Catalytic loadings of picolinaldehyde and Ni(II) salts induce preferential reactivity at the enolizable α-carbon of amino acid esters over the free nitrogen with electrophilic palladium π-allyl complexes. Fourteen examples are given. Additionally, the use ...
Ali Abuzer - - 2012
Two lupeol-type pentacyclic triterpenoids characterised as lup-20(29)-en-3β-ol-27-oic acid (moruslupenoic acid A) and lup-12, 20(29)-dien-3β-ol-26-oic acid (moruslupenoic acid B) and lanst-5, 24-dien-3β-yl acetate (moruslanosteryl acetate) along with the known triterpenoidal phytoconstituents α-amyrin acetate, β-amyrin-β-D-glucopyranoside and betulinic acid have been isolated from the stem bark of Morus alba L. (Moraceae). The structures ...
Mai Thi Thoa - - 2012
Frozen: The spontaneous crystallization of an achiral compound in a chiral conformation is used as unique source of chirality in an absolute asymmetric synthesis of tertiary amino acids. The dynamic axial chirality of tertiary aromatic amides is frozen in a crystal and is responsible for the stereoselectivity of the deprotonation/alkylation. ...
Shah Heena J - - 2012
Dioscorea alata var. purpurae (Indian purple yam) is an important source of diosgenin, a triterpenoid that is used as a raw material in the synthesis of corticosteroid hormones. These drugs are used for the treatment of pharmacological conditions such as arthritis. This paper reports in vitro propagation of explants of ...
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