bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous determination of digoxin and digitoxin by micellar electrokinetic chromatography and application to drug formulations
Authors: Tseng Hsiu‐Hui , Wu Hsin‐Lung , Lin Shun‐Jin , Chen Su‐Hwei 
Published: December 2003

AbstractA simple micellar electrokinetic chromatographic method is described for simultaneous determination of digoxin and digitoxin. The simultaneous analysis of digoxin and digitoxin was performed in Tris buffer (10 mM; pH 9) with 90 mM sodium dodecyl sulfate and 10% isopropyl alcohol as an anionic surfactant and organic modifier. Under these conditions, good separation with high efficiency is achieved in short analysis times. Several parameters affecting the separation of the drugs were studied, including the pH and concentrations of the Tris buffer and sodium dodecyl sulfate. The linear range of the method for the determination of digoxin and digitoxin was over 0.01–0.3 mg/mL; the detection limit (signal to noise ratio = 3; injection 3.5 kPa 3 s) was 4 and 6 μg/mL, respectively. Application of the proposed method to the determination of digoxin in commercial tablets and in injections proved to be feasible.
Increased size‐sorting performance in gravitational SPLITT by using a pinched sample inlet design
Authors: Moon Myeong Hee , Kang Dukjin , Kwon So‐Yeon , Lee Seungho 
Published: December 2003

AbstractSplit‐flow thin fractionation is a continuous, flow‐assisted separation technique for sorting macromolecules and particulate matter on a preparative scale. On reducing the thickness of the sample inlet conduit of a gravitational split‐flow thin fractionation channel, size‐sorting performance is found to increase since particles that are continuously fed into the channel can be more rapidly compressed toward the upper wall of the channel. Experiments are carried out by measuring the number percentage of particles eluted at each outlet as a function of different thickness values of the sample inlet conduit. The effects that the total thickness of the gravitational split‐flow thin fractionation channel and the sample feed concentration have on the size‐fractionation performance are examined with the goal of determining the best pinched sample inlet, gravitational split‐flow thin fractionation channel design.
Determination of moutan tannins by high‐performance liquid chromatography and capillary electrophoresis
Authors: Wu Ya‐Ting , Huang Wen‐Ying , Lin Ta‐Chen , Sheu Shuenn‐Jyi 
Published: December 2003

AbstractCortex Moutan (Radicis Cortex Moutan), the dried root bark of Paeonia moutan and P. spp., contains a series of water‐soluble tannins. With the eight components, 1 4,6‐di‐O‐GG (4,6‐di‐O‐galloyl‐D‐glucose), 2 1,2,3,6‐tetra‐O‐GG, 3 1,2,3,4,6‐penta‐O‐GG, 4 1,3,4,6‐tetra‐O‐GG, 5 3,4,6‐tri‐O‐GG, 6 1,3,6‐tri‐O‐GG, 7 3,6‐di‐O‐GG, and 8 1,2,6‐tri‐O‐GG, as marker substances, a rapid and efficient method of analysis based on HPLC and CE was developed. Using a phosphate eluent, a 5C18‐MS separating column, and a detection wavelength of 280 nm, HPLC was successfully used to analyze the eight constituents within 60 min. The analysis can be completed within 50 min, using the MEKC mode with a buffer composed of borate, SDS, and isopropanol, and a detection wavelength of 210 nm. The detection limit for the marker substances varied from 0.04 to 0.93 μg/mL for the HPLC method and 0.02 to 0.36 μg/mL for the CE method.
Sensitive analyses of agricultural chemicals by capillary electrochromatography
Authors: Starkey Jason A. , Abrantes Shirley , Mechref Yehia , Novotny Milos V. 
Published: December 2003

AbstractCapillary electrochromatography using a monolithic matrix was employed to develop a rapid and highly efficient separation methodology for the analyses of mixtures of agrochemical importance. Using this method, ppm‐ppb detection limits for urea, carbamate, and phenoxy acid herbicides were achieved without a preconcentration technique. The detection limits were further decreased to low‐ppb levels for the same class of compounds using an on‐column preconcentration technique.
Selectivity tuning of cyclodextrin derivatives by specific substitution
Authors: Junge Melanie , König Wilfried A. 
Published: December 2003

AbstractA new, highly enantioselective cyclodextrin derivative combining the properties of heptakis(6‐O‐tert‐butyldimethylsilyl‐2,3‐di‐O‐methyl)‐β‐cyclodextrin and heptakis(2,3‐di‐O‐acetyl‐6‐O‐tert‐butyldimethylsilyl)‐β‐cyclodextrin was prepared by exchanging a methyl group for an acetyl substituent in a single glucose unit of heptakis(6‐O‐tert‐butyldimethylsilyl‐2,3‐di‐O‐methyl)‐β‐cyclodextrin. A comparative evaluation of the separation capabilities showed that the enantioselectivity of both “parent” cyclodextrin derivatives is transferred to the new chiral stationary phase.
Impact of water/PDMS phase ratio, volume of PDMS, and sampling time on Stir Bar Sorptive Extraction (SBSE) recovery of some pesticides with different KO/W
Authors: Bicchi Carlo , Cordero Chiara , Rubiolo Patrizia , Sandra Pat 
Published: December 2003

AbstractIn Stir Bar Sorptive Extraction (SBSE) organic analytes are enriched from aqueous samples by sorption onto a thick film of polydimethylsiloxane (PDMS) coated on a glass‐enveloped magnet. Sampled analytes are recovered by thermodesorption (TDS) and analysed on‐line by cGC‐MS. This study evaluates the SBSE recovery as a function of KO/W, the phase ratio (β), PDMS volume (20, 40, and 110 μL), sample volumes (4, 10, 100, and 1000 mL), and sampling time (0.67, 1, 2, 4, 5, 6, and 24 h) for three pesticides with different KO/W [parathion methyl (KO/W: 7.24×102), β‐endosulfan (KO/W: 6.8×103), and buprofezin (KO/W: 2.0×104)]. Experimental recoveries with SBSE in reasonable sampling times were found to be mainly conditioned by β, which must be as low as possible either by operating on small sample volumes or by using stir bars coated with high PDMS volume when samples of relatively large volume are analysed.
Analysis of intermediates from polycyclic aromatic hydrocarbon biodegradation
Authors: Copper Christine L. 
Published: December 2003

AbstractA major difficulty in assessing bioremediation in hydrocarbon impacted field sites is the determination of the extent and products of contaminant biodegradation. Previously, various analytical techniques, including mass spectrometry and chromatography, have been used to characterize components in mixtures resulting from biodegradation. In this work, the applicability of capillary electrophoresis (CE) to this area of research is demonstrated. CE methods were optimized for analysis of compounds that are known metabolites of polycyclic aromatic hydrocarbon (PAH) biodegradation.
Micellar liquid chromatography of polycyclic aromatic hydrocarbons: Alkylpyridinium chloride as mobile phase modifier and selective fluorescence quencher
Authors: Mao Chunfeng , McGill Kelly E. , Tucker Sheryl A. 
Published: December 2003

AbstractThe dual role of alkylpyridinium chlorides, cetylpyridinium chloride (CPC) and dodecylpyridinium chloride (DDPC), as micellar mobile phase modifiers and selective fluorescence quenching agents of polycyclic aromatic hydrocarbons (PAHs), in micellar liquid chromatographic separation of PAHs is reported. The replacement of 0.037 M cetyltrimethylammonium chloride in the aqueous mobile phase with CPC/DDPC quencher greatly simplifies the observed fluorescence‐detected chromatograms, facilitating PAH identification. The resulting chromatograms are similar to those obtained from the conventional approach – pyridinium chloride quencher in an acetonitrile mobile phase. To quantify the quenching, the (F0 /F – 1) values from the Stern‐Volmer equation are calculated from the chromatograms and compared. The feasibility of using CPC or DDPC as a dual reagent under isocratic and gradient conditions is shown.
Weight approximations in multi‐attribute decision models
Authors: Roberts Ron , Goodwin Paul 
Published: December 2003

AbstractThe use of surrogate weights based on rankings has been proposed as a method for avoiding difficulties associated with the elicitation of weights in multi‐attribute decision analysis. When the simple multiattribute rating technique using swings (SMARTS) method is being employed it has been suggested that rank order centroid (ROC) weights are the best surrogate weights to use. This study shows that ROC weights are appropriate to use as a substitute for original weights that are constrained to sum to a fixed total (usually 1 or 100) as used in the point allocation method. If, however, the original weights are determined without any initial restrictions, as in the direct rating method, and are then normalized, which is the common procedure in SMARTS analysis, then the ROC weights do not provide the best approximations to the original weights. This paper shows how to obtain rank order distribution (ROD) weights that provide a better approximation than the ROC approach to unrestricted original weights. The paper also shows that, as the number of attributes in a decision problem increases, the ROD weights approximate to the more easily calculated rank sum weights. Copyright © 2003 John Wiley & Sons, Ltd.
Towards statistical multicriteria decision modelling: a first approach
Authors: De Smet Yves , Springael Johan , Kunsch Pierre 
Published: December 2003

AbstractMany real life situations result from decisions taken by a very large number of decision makers. Among them, we may cite road traffic congestion, crowding during shopping, equity market behaviour, distribution of holiday destinations, etc. Furthermore, these decisions often depend on the optimisation of several conflicting criteria. In this paper, we introduce a new multicriteria tool based on Markov chains to model and manage these macroscopic phenomena. Finally, the road traffic congestion problem will be considered to illustrate the applicability of our approach. Copyright © 2003 John Wiley & Sons, Ltd.
Attribute‐based differentiation of alternatives
Authors: Keisler Jeffrey M. 
Published: December 2003

AbstractAn intermediate step is introduced to the dialogue decision process for decision analysis. Alternatives are refined after they have been generated within a strategy table but before they are subject to more detailed evaluation. Two or more judges create a subjective mapping from alternatives to attributes that will later be mapped to criteria. In strategy tables, each of the alternative strategies consists of a coherent set of choices made across several decisions that are to be coordinated. These strategic alternatives are modified so as to increase their differentiation in the attribute space, rather than in the decision space alone. When criteria weights are unknown, the best alternative from the modified set may be superior to the best alternative from the original set. Furthermore, analysis of the resulting alternatives may yield a better mapping of the value response surface for the action space, in the sense that this mapping leads to eventual construction of a higher value alternative. Results are reported for a consulting engagement incorporating the proposed step. Copyright © 2003 John Wiley & Sons, Ltd.
Neuronal glial interaction in different neurological diseases studied by ex vivo13C NMR spectroscopy
Authors: Sonnewald Ursula , Kondziella Daniel 
Published: December 2003

AbstractNuclear magnetic resonance spectroscopy (NMRS) has been used extensively for several decades to elucidate metabolic pathways in biological systems and has led to new insights into cerebral metabolism. Many of these insights have been gained by NMRS using in vitro models, such as tissue extracts, cell cultures or brain slices. Extracts of cells or tissue provide an excellent basis for metabolic studies and facilitate the interpretation of in vivo spectra. 13C NMRS is at present mostly used for in vitro or animal studies. Conclusions from the epilepsy models presented in this review are that turnover of metabolites is time‐dependant in kainate‐injected rats with limbic seizures. Early and only temporarily enhanced astrocytic activity is followed by altered metabolism in neurons with an increased turnover of important amino acids such as GABA and glutamate. However, pentylenetetrazole (PTZ) kindling affects astrocytes in younger and glutamatergic neurons in older animals. In the presence of PTZ, phenobarbital decreases labeling of most metabolites in all cell types, except GABAergic neurons, from both labeled precursors in the younger animals. However, in older animals only GABAergic neurons are affected by phenobarbital, as indicated by an increase in GABA labeling. In kaolin‐induced hydrocephalus it was shown that astrocyte metabolism is disturbed in the early phase, particularly in the cerebrum. These alterations continue into the chronic period. Only then do the first signs of neuronal metabolic impairment appear, which might explain why dementia is a prominent clinical feature in patients with chronic hydrocephalus. Copyright © 2003 John Wiley & Sons, Ltd.
Toward dynamic isotopomer analysis in the rat brain in vivo: automatic quantitation of 13C NMR spectra using LCModel
Authors: Henry Pierre‐Gilles , Öz Gülin , Provencher Stephen , Gruetter Rolf 
Published: December 2003

AbstractThe LCModel method was adapted to analyze localized in vivo 13C NMR spectra obtained from the rat brain in vivo at 9.4 T. Prior knowledge of chemical‐shifts, J‐coupling constants and J‐evolution was included in the analysis. Up to 50 different isotopomer signals corresponding to 10 metabolites were quantified simultaneously in 400 μl volumes in the rat brain in vivo during infusion of [1,6‐13C2]glucose. The analysis remained accurate even at low signal‐to‐noise ratio of the order of 3:1. The relative distribution of isotopomers in glutamate, glutamine and aspartate determined in vivo in 22 min was in excellent agreement with that measured in brain extracts. Quantitation of time series of 13C spectra yielded time courses of total 13C label incorporation into up to 16 carbon positions, as well as time courses of individual isotopomer signals, with a temporal resolution as low as 5 min (dynamic isotopomer analysis). The possibility of measuring in vivo a wealth of information that was hitherto accessible only in extracts is likely to expand the scope of metabolic studies in the intact brain. Copyright © 2003 John Wiley & Sons, Ltd.
Reflections on the application of 13C‐MRS to research on brain metabolism
Authors: Morris Peter , Bachelard Herman 
Published: December 2003

AbstractThe power of 13C‐MRS lies in its unique chemical specificity, enabling detection and quantification of metabolic intermediates which would not be so readily monitored using conventional radiochemical techniques. Examples from animal studies, by examination of tissue extracts from the whole brain, brain slices and cultured cells, include observation of intermediates such as citrate and triose phosphates which have yielded novel information on neuronal/glial relationships. The use of 13C‐labelled acetate as a specific precursor for glial metabolism provided evidence in support of the view that some of the GABA produced in the brain is derived from glial glutamine. Such studies have also provided direct evidence on the contribution of anaplerotic pathways to intermediary metabolism. Analogous studies are now being performed on the human brain, where 13C‐acetate is used to quantitate the overall contribution of glial cells to intermediary metabolism, and use of 13C‐glucose enables direct calculation of rates of flux through the TCA (FTCA) and of the glutamate–glutamine cycle (FCYC), leading to the conclusion that the rate of glial recycling of glutamate accounts for some 50% of FTCA. The rate of 0.74 μmol min−1 g−1 for FTCA is compatible with PET rates of CMRglc of 0.3–0.4 μmol min−1 g−1 (since each glucose molecule yields two molecules of pyruvate entering the TCA). Our brain activation studies showed a 60% increase in FTCA, which is very similar to the increases in CBF and in CMRglc observed in PET activation studies. Copyright © 2003 John Wiley & Sons, Ltd.
Clinical experience with 13C MRS in vivo
Authors: Ross Brian , Lin Alexander , Harris Kent , Bhattacharya Pratip , Schweinsburg Brian 
Published: December 2003

Abstract13C MRS was installed on a clinical scanner at 1.5 T in order to facilitate integrated MR examinations of human brain disorders. Using a simplified protocol, (1‐13C) glucose and/or (1‐13C) acetate were administered orally or by intravenous infusion. 13C spectra of diagnostic quality were acquired in more than 100 consecutive studies. Novel 13C neurochemical data contributed to the understanding of Alzheimer's, Canavan's, mitochondrial and hepatic encephalopathy, epilepsy and normal brain development. 13C MRS uncovered hitherto unknown disorders of NAA‐synthesis, glutamate neurotransmission, TCA‐cycle and glycolysis. Despite low inherent signal‐to‐noise, natural abundance 13C MRS showed diagnostic promise. 13C MRS is feasible in a clinical setting, at reasonable cost in neonates, children, adults and elderly patients. Copyright © 2003 John Wiley & Sons, Ltd.
An improvement of the EDI method in linear elastic fracture mechanics by means of an a posteriori error estimator in G
Authors: Giner E. , Fuenmayor F. J. , Tarancón J. E. 
Published: December 2003

AbstractIn this paper, an error estimator that quantifies the effect of the finite element discretization error on the computation of the stress intensity factor in linear elastic fracture mechanics is presented. In order to obtain the proposed estimator, a shape design sensitivity analysis (SDSA) is applied to the fracture mechanics problem. Following this approach, one of the most efficient post‐processing techniques for computing the strain energy release rate G, the well‐known EDI method, may be interpreted as a continuum method of the SDSA. The proposed error estimator is based on the recovery of the gradient fields and its reliability has been checked by means of numerical problems, yielding very good estimations of the true error. The new estimator remarkably improves the results given by a previous error estimator, which is based on a discrete analytical approach of SDSA. As a consequence, the combination of the new error estimator and the result given by the EDI method provides a much more accurate estimation of G. Copyright © 2003 John Wiley & Sons, Ltd.
Differential protein expressions induced by adenovirus‐mediated p16 gene transfer into Balb/c nude mouse
Authors: Park Misun , Kang Hoil , Lim Sinae , Lee Choon‐Taek , Kim Okhee 
Published: December 2003

AbstractTo evaluate the safety of adenovirus‐mediated gene transfer, we investigated differential protein expression after transducing adenoviral vector containing the p16INK4a tumor suppressor gene (Ad5CMV‐p16) into Balb/c nude mice. We found that adenovirus‐mediated p16INK4a gene transfer inhibited experimental lung metastasis, and that the intratumoral injection of Ad5CMV‐p16 resulted in regression of A549 cell xenografted tumors in Balb/c nude mice. We investigated changes in protein expression after intratumoral injection of Ad5CMV‐p16 or Ad5CMV (1010 plaque‐forming units) into A549 cell xenografted Balb/c nude mice by two‐dimensional gel electrophoresis /matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry. Compared with the control (serum‐free medium treated tumor cells) Ad5CMV‐p16 gene transfer changed the expression of 29 proteins including heterogeneous nuclear ribonucleoprotein, protein phosphatase 2, 14‐3‐3 zeta protein, alpha‐tubulin, and glutathione‐S‐transferase P1. Moreover, both Ad5CMV‐p16 and Ad5CMV up‐regulated the expression of glutathione‐S‐transferase P1. In addition, Ad5CMV‐p16 gene transfer did not seem to increase the expression of tumorigenicity‐related protein in Balb/c nude mice. Further studies will be needed to investigate the effect of Ad5CMV‐p16 on normal human cells and tissues for safety evaluation. These results suggest that the p16 gene seems to have an important role in apoptosis as well as in cell cycle arrest in non‐small cell lung cancer.
Proteome analysis of rat pancreatic acinar cells: Implication for cerulein‐induced acute pancreatitis
Authors: Yu Ji Hoon , Yun Shin Young , Lim Joo Weon , Kim Hyeyoung , Kim Kyung Hwan 
Published: December 2003

AbstractCerulein pancreatitis was shown to be one of the best characterized models for acute pancreatitis. High doses of cerulein induce a dysregulation of the digestive enzyme production and cytoplasmic vacuolization and the death of acinar cells, edema formation, and an infiltration of inflammatory cells into the pancreas, which are similar symptoms shown in human acute pancreatitis. The present study aims to determine the differentially expressed proteins in cerulein‐treated pancreatic acinar cells as an in vitro model for acute pancreatitis. Pancreatic acinar AR42J cells were treated with 10−8 M cerulein for 24 h. The changed protein patterns separated by two‐dimensional electrophoresis using pH gradients of 5–8 were conclusively identified by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry analysis of the peptide digests. Five differentially expressed proteins (heat shock protein 90, mitochondrial ATP synthase beta chain precursor, tubulin beta chain, 3‐mercaptopyruvate sulfurtransferase, mitochondrial ATP synthase subunit D) were identified in cerulein‐treated AR42J cells. These proteins are related to cellular stress such as reactive oxygen species, cytoskeletal function, and cell signaling. In conclusion, the differentially expressed proteins will provide valuable information to understand the pathophysiologic mechanism of acute pancreatitis and may be useful for prognostic indices of acute pancreatitis.
Mass spectrometry and tandem mass spectrometry analysis of rat mitochondrial ATP synthase: Up‐regulation in pancreatic acinar cells treated with cerulein
Authors: Yu Ji Hoon , Yun Shin Young , Lim Joo Weon , Kim Hyeyoung , Kim Kyung Hwan 
Published: December 2003

AbstractMitochondrion is a vulnerable intracellular target to reactive oxygen species (ROS). ROS have been considered to be important regulators of the pathogenesis of pancreatitis. This study aims to determine whether ROS induces mitochondrial damage by monitoring the expression level of mitochondrial ATP synthase as the key molecular component in mitochondria associated with cellular damage. Pancreatic acinar AR42J cells were treated with cerulein which induces symptoms similar to that associated with human acute pancreatitis. Proteins were separated by two‐dimensional electrophoresis using pH gradients of 5–8 and identified using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer (MS), quadrupole time‐of‐flight MS and MS/MS with nano‐electrospray. Following cerulein treatment, mitochondrial ATP synthase beta chain was highly expressed compared to nontreated cell. The protein was identified by its pI of 5.2 and molecular weight (56 354 Da) with 27 matched peptides. Among the MS spectrum, precursor ions m/z 488.28, 544.81, 631.82, 693.34, 718.38, 729.41, 801.40, 809.39, 825.94, and 994.52 were further identified using MS/MS and confirmed the isolated protein to be mitochondrial ATP synthase beta chain. In conclusion, cerulein‐induced oxidative injury may result in the induction of mitochondrial ATP synthase, which may act as an adaptive pathophysiological process in the pancreas.