排序方式: 共有55条查询结果,搜索用时 375 毫秒
41.
Yin J Aviles P Lee W Ly C Floriano P Ignacio M Faircloth G 《Rapid communications in mass spectrometry : RCM》2003,17(16):1909-1914
A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay was developed and validated to quantify a novel marine-derived depsipeptide, Aplidin, in human plasma. The method was validated to demonstrate the specificity, recovery, limit of quantitation (LOQ), accuracy, and precision of measurements. The calibration range for Aplidin was established using Aplidin standards from 0.05-50 ng/mL in blank human plasma. The multiple reaction monitoring, based on the transition m/z 1110.7 --> 295.3, was specific for Aplidin, and that based on the transition m/z 1112.6 --> 297.3 was specific for didemnin B (the internal standard); no endogenous materials interfered with the analysis of Aplidin and didemnin B from blank human plasma. The assay was linear over the concentration range 0.05-50.0 ng/mL. The correlation coefficients for the calibration curves ranged from 0.9979 to 0.9999. The mean intra- and interday accuracies for all calibration standards (n = 12) ranged from 97 to 106% (=6% bias), and the mean interday precision for all calibration standards was less than 8.3%. The mean intra- and interday assay accuracy for all quality control replicates (n = 12), determined at each QC level throughout the validated runs, remained below 12 and 7%, respectively. The mean intra- and interday assay precision was less than 13.1 and 10.7% for all QC levels, respectively. The assay is currently used to measure Aplidin plasma concentrations to support clinical trials. 相似文献
42.
Jose Miguel Oliva Felicia Sáez Ignacio Ballesteros Alberto González Maria José Negro Paloma Manzanares Mercedes Ballesteros 《Applied biochemistry and biotechnology》2003,105(1-3):141-153
The filtrate from steam-pretreated poplar was analyzed to identify degradation compounds. The effect of selected compounds
on growth and ethanolic fermentation of the thermotolerant yeast strain Kluyveromyces marxianus CECT 10875 was tested. Several fermentations on glucose medium, containing individual inhibitory compounds found in the hydrolysate,
were carried out. The degree of inhibition on yeast strain growth and ethanolic fermentation was determined. At concentrations
found in the prehy-drolysate, none of the individual compounds significantly affected the fermentation. For all tested compounds,
growth was inhibited to a lesser extent than ethanol production. Lower concentrations of catechol (0.96 g/L) and 4-hydroxybenzaldehyde
(1.02 g/L) were required to produce the 50% reduction in cell mass in comparison to other tested compounds. 相似文献
43.
Carlos Manzanares I. Jingping Peng Nairmen Mina-Camilde Ansgar Brock 《Chemical physics》1995,190(2-3):247-259
The spectra of the fundamental and overtones of the C---H stretches of (CH3)3CH have been measured in liquid argon solutions at 90 K and for the pure liquid sample at 135 K. Absorptions in the visible were obtained with a low temperature cell and a resonant continuous wave laser technique with acoustic detection. Absorptions in the IR and near-IR were observed with a Fourier transform spectrophotometer. Comparison is made between the absorption bands in gas phase, liquid argon solution, and liquid phase isobutane. The spectra of isobutane in solution show improved resolution of the vibrational bands with respect to the room temperature gas phase bands and the pure liquid bands at 135 K. To interpret the experimental results, overtone transitions are described in terms of the local mode model. A harmonically coupled anharmonic oscillator (HCAO) model was used to determine the overtone energy levels and assign the absorption bands to vibrational transitions. Ab initio molecular orbital calculations of geometries and vibrational frequencies were also performed. 相似文献
44.
García-Aparicio MP Ballesteros M Manzanares P Ballesteros I González A Negro MJ 《Applied biochemistry and biotechnology》2007,137(1-12):353-365
In this study, different enzyme preparations available from Novozymes were assessed for their efficiency to hydrolyze lignocellulosic materials. The enzyme mixture was evaluated on a pretreated cellulose-rich material, and steam-exploded barley straw pretreated under different temperatures (190, 200, and 210 degrees C, respectively) in order to produce fermentable sugars. Results show that xylanase supplementation improves initial cellulose hydrolysis effectiveness of water-insoluble solid fraction from all steam-exploded barley straw samples, regardless of the xylan content of substrate. The mixture constituted by cellulase: beta-glucosidase: endoxylanase of the new kit for lignocellulose conversion at a ratio 10:1:5% ([v/w], enzyme [E]/substrate [S]) provides the highest increment of cellulose conversion in barley straw pretreated at 210 degrees C, for 10 min. 相似文献
45.
T. Rivera H. R. Vega J. Azorin E. Manzanares P. R. Gonzalez C. Furetta 《辐射效应与固体损伤》2013,168(4):224-231
This paper reports the experimental results concerning the thermoluminescent measurements of thermal neutron using nanostructured zirconium oxide (ZrO2) powder prepared by the sol–gel method. Transmission electron microscopy and X-ray diffraction techniques were used for morphological and structural characterization of the compound. Thermal annealing processes for the precipitates were studied. It was observed that the crystalline structure and the crystallinity of the powders depend on the annealing temperature. For temperatures higher than 1100 °C, the material presents the monoclinic phase with average nanocrystallite sizes ranging from 8–10 nm up to ~40 nm. These zirconium oxide materials developed in our laboratory were used in this investigation. Within the experimental uncertainties, these measurements were compared with those obtained using the well-known gamma rays sensitive lithium fluoride (LiF:Mg,Cu,P), also developed in our laboratory. 相似文献
46.
47.
[reaction: see text] A total solid-phase synthesis of lamellarins U and L has been achieved. The conversion of an aldehyde group into a formate by a Baeyer-Villiger reaction and a intramolecular [3 + 2] cycloaddition of a 3,4-dihydroisoquinolinium salt over a triple bond comprise the key steps of the process. Each transformation has been controlled with the proper spectroscopic and analytical methods. 相似文献
48.
Cuevas C Pérez M Martín MJ Chicharro JL Fernández-Rivas C Flores M Francesch A Gallego P Zarzuelo M de La Calle F García J Polanco C Rodríguez I Manzanares I 《Organic letters》2000,2(16):2545-2548
An efficient new process is described for the synthesis of ecteinascidin ET-743 (1) and phthalascidin (2), starting from readily available cyanosafracin B (3). 相似文献
49.
Maria José Negro Paloma Manzanares Ignacio Ballesteros Jose Miguel Oliva Araceli Cabañas Mercedes Ballesteros 《Applied biochemistry and biotechnology》2003,105(1-3):87-100
Pretreatment has been recognized as a key step in enzyme-based conversion processes of lignocellulose biomass to ethanol. The aim of this study is to evaluate two hydrothermal pretreatments (steam explosion and liquid hot water) to enhance ethanol production from poplar (Populus nigra) biomass by a simultaneous saccharification and fermentation (SSF) process. The composition of liquid and solid fractions obtained after pretreatment, enzymatic digestibility, and ethanol production of poplar biomass pretreated at different experimental conditions was analyzed. The best results were obtained in steam explosion pretreatment at 210°C and 4 min, taking into account cellulose recovery above 95%, enzymatic hydrolysis yield of about 60%, SSF yield of 60% of theoretical, and 41% xylose recovery in the liquid fraction. Large particles can be used for poplar biomass in both pretreatments, since no significant effect of particle size on enzymatic hydrolysis and SSF was obtained. 相似文献
50.
Ethanol production from pretreated olive tree wood and sunflower stalks by an SSF process 总被引:2,自引:0,他引:2
Encarnación Ruiz Cristóbal Cara Mercedes Ballesteros Paloma Manzanares Ignacio Ballesteros Eulogio Castro 《Applied biochemistry and biotechnology》2006,130(1-3):631-643
Olive tree wood and sunflower stalks are agricultural residues largely available at low cost in Mediterranean countries. As
renewable lignocellulosic materials, their bioconversion may allow both obtaining a value-added product, for fuel ethanol,
and facilitating their elimination. In this work, the ethanol production from olive tree wood and sunflower stalks by a simultaneous
saccharification and fermentation (SSF) process is studied. As a pretreatment, steam explosion at different temperatures was
applied. The water insoluble fractions of steam-pretreated sunflower stalks and steamed, delignified olive tree wood were
used as substrates at 10% w/v concentration for an SSF process by a cellulolytic commercial complex and Saccharomyces cerevisiae. After 72-h fermentation, ethanol concentrations up to 30 g/L were obtained in delignified steam-pretreated olive tree wood
at 230°C and 5 min. Sunflower stalks pretretated at 220°C and 5 min gave maximum ethanol concentrations of 21 g/L in SSF experiments. 相似文献