bluuebunny/crossref_metadata_2025_split huggingface dataset:
A polyamine coating for enhanced capillary electrophoresis‐electrospray ionization‐mass spectrometry of proteins and peptides
Authors: Ullsten Sara , Zuberovic Aida , Wetterhall Magnus , Hardenborg Emilia , Markides Karin E. , Bergquist Jonas 
Published: June 2004

AbstractA procedure for enhanced capillary electrophoresis‐electrospray ionization‐mass spectrometry (CE‐ESI‐MS) of proteins is presented. The use of a newly presented capillary coating, PolyE‐323, provided fast separations of typically a few minutes with high efficiency, good deactivation, and no bleeding into the mass spectrometer. Capillaries coated with PolyE‐323 showed high stability over a range of pH 2–10, and tolerance towards methanol and acetonitrile, two modifiers commonly used in CE‐ESI‐MS. Due to the speed and simplicity of the coating procedure, the polymeric surface could, if necessary, easily be regenerated. This capability is especially valuable when working with samples of complex matrix, where a capillary surface cleaning step might be desired in order to eliminate possible memory effects. The potential of PolyE‐323‐coated capillaries in bioanalysis using CE‐ESI‐MS was demonstrated by analyzing peptides and proteins up to 66 kDa using time of flight (TOF)‐MS. Due to the stable, anodal electroosmotic flow generated by the coating, the use of a sheathless ESI interface was enabled, demonstrated in peptide analysis with attomole sensitivity. The fast on‐line CE‐ESI‐TOF system using PolyE‐323‐coated capillaries provided efficient separation and detection of a large number of peaks in a short time, exemplified by the analysis of a tryptic digest of bovine serum albumin (BSA). The capability of the developed capillary surface coating was demonstrated by the separation of human plasma and cerebrospinal fluid (CSF).
Development of capillary zone electrophoresis‐electrospray ionization‐mass spectrometry for the determination of lamotrigine in human plasma
Authors: Zheng Jack , Jann Michael W. , Hon Yuen Yi , Shamsi Shahab A. 
Published: June 2004

AbstractA method of coupling capillary zone electrophoresis (CZE) with electrospray ionization‐mass spectrometry (ESI‐MS) detection has been developed for monitoring an antiepileptic drug, lamotrigine (LTG) in human plasma. The CZE‐MS was developed in three stages: (i) CZE separation and ESI‐MS detection of LTG and tyramine (TRM, internal standard) were simultaneously optimized by studying the influence of CZE background electrolyte (BGE) pH, BGE ionic strength, and nebulizer pressure of the MS sprayer; (ii) sheath liquid parameters, such as pH, ionic strength, organic modifier content, and flow rate of the sheath liquid, were systematically varied under optimum CZE‐MS conditions developed in the first stage; (iii) MS sprayer chamber parameters (drying gas temperature and drying gas flow rate) were varied for the best MS detection of LTG. The developed assay was finally applied for the determination of LTG in plasma samples. The linear range of LTG in plasma sample assay was between 0.1–5.0 μg/mL with a limit of detection as low as 0.05 μg/mL and run time less than 6 min. Finally, the concentration‐time profile of LTG in human plasma sample was found to correlate well when CZE‐ESI‐MS was compared to a more established method of high‐performance liquid chromatography with ultraviolet detection.
Application of capillary electrophoresis‐ electrospray‐mass spectrometry to the separation and characterization of isomeric lipopolysaccharides of Neisseria meningitidis
Authors: Li Jianjun , Cox Andrew D. , Hood Derek , Moxon E. Richard , Richards James C. 
Published: June 2004

AbstractA capillary electrophoresis‐electrospray‐mass spectrometry technique for the characterization of lipopolysaccharides (LPSs) was developed, permitting the separation of trace‐level O‐deacylated LPS isoforms for subsequent structural characterization using tandem mass spectrometry (MS/MS). The separation buffer and electrospray interface were optimized first using O‐deacylated LPS samples from large‐scale preparations. It was found that with microelectrospray or sheath‐solution interface, we could separate LPS in anionic forms and detect them using either negative or positive ion mode MS. For negative ion detection mode MS, 30 mM morpholine with addition of 5% v/v methanol was employed as separation buffer. When positive ion detection mode MS was required, 10 mM ammonium acetate with addition of 5% methanol was used as separation buffer. The structural assignments obtained from MS/MS and capillary zone electrophoresis‐electrospray‐MS (CZE‐ESMS) analyses enabled the identification of isomeric glycoforms. Application of this technique to the analysis of LPS from the galE mutants of Neisseria meningitidis strain BZ157 B5+ revealed the presence of isomeric glycoforms, in which the location of a functional group phosphoethanolamine was found to be in either inner core or lipid A‐OH regions. The described technique was also applied to the analysis of LPS samples from the galE mutant of N. meningitidis strains F1576 A4+ and A4−. The occurrence of isomeric LPS glycoforms differing by the location or presence of neutral sugar residues, such as hexoses, can also be characterized using MS/MS.
A beveled tip sheath liquid interface for capillary electrophoresis‐electrospray ionization‐mass spectrometry
Authors: Tseng Mei‐Chun , Chen Yet‐Ran , Her Guor‐Rong 
Published: June 2004

AbstractA simple and durable sheath liquid interface for capillary zone electrophoresis‐electrospray ionization‐mass spectrometry (CZE‐ESI‐MS) has been developed. This interface utilized a beveled tip emitter and was found to be more sensitive than the conventional sheath liquid interface. The use of a beveled tip reduces the optimal flow rate and therefore decreases sample dilution. The interface utilized a 380 μm inner diameter and 400 μm outer diameter beveled tapered tip. Because of the large inner diameter and outer diameter of the tip, the interface is robust and can be easily implemented. The performance of this interface for CZE‐ESI‐MS and micelle electrokinetic capillary electrophoresis‐electrospray‐mass spectrometry, as demonstrated by the analysis of synthetic drugs and triazine mixtures, was significantly better than results obtained using a conventional sheath liquid interface.
Capillary electrophoresis‐mass spectrometry for glycoscreening in biomedical research
Authors: Zamfir Alina , Peter‐Katalinić Jasna 
Published: June 2004

AbstractApplication of capillary electrophoresis (CE) in combination with mass spectrometry (MS) and tandem MS to glycoscreening in biomedical projects is highlighted. In the first part recent CE‐MS experiments by sheath liquid CE and multiple stage MS are reported. Neutral and negatively charged N‐glycan mixtures from ribonuclease B and fetuin, high‐mannose type N‐glycoforms, oligosaccharides from lipopolysaccharides (LPS) of Haemophilus influenzae, polysaccharides of Pseudomonas aeruginosa and Staphylococcus aureus were analyzed. A particular emphasis is devoted to the applicability of novel off‐ and on‐line CE‐MS and tandem MS methods for screening of proteoglycan‐derived oligosaccharides, glycosaminoglycans (GAGs), such as hyaluronates from Streptococcus agalactiae, chondroitin/dermatan sulfates (CS/DS) from bovine aorta and human skin fibroblast decorin, and heparin/heparan sulfate (HS) from porcine and bovine mucosa. The performance of CE‐MS/MS for identification of glycoforms in glycopeptides and glycoproteins is illustrated by experiments performed on complex mixtures from urine of patients suffering from a hereditary N‐acetylhexosaminidase deficiency (Schindler's disease) and urine of patients suffering from cancer cachexia. For determination of glycosylation patterns in glycoproteins like enzymes and antibodies by CE/MS, both CE‐matrix assisted laser desorption/ionization (MALDI) and CE‐electrospray ionization (ESI)‐MS were functional. Finally, the potential of CE‐ESI‐MS strategy in glycolipid analysis is demonstrated for gangliosides from bovine brain for which particular CE buffer conditions are required.
On‐line sheathless capillary electrophoresis/nanoelectrospray ionization‐tandem mass spectrometry for the analysis of glycosaminoglycan oligosaccharides
Authors: Zamfir Alina , Seidler Daniela G. , Schönherr Elke , Kresse Hans , Peter‐Katalinic´ Jasna 
Published: June 2004

AbstractA novel approach in glycosaminoglycomics, based on sheathless on‐line capillary electrophoresis/nanoelectrospray ionization‐quadrupole time of flight‐mass spectrometry (CE/nanoESI‐QTOF‐MS) and tandem MS of extended chondroitin sulfate/dermatan (CS/DS) oligosaccharide chains is described. The methodology required the construction of a new sheathless CE/nanoESI‐QTOF‐MS configuration, its implementation and optimization for the high sensitivity analysis of CS/DS oligosaccharide mixtures from conditioned culture medium of decorin transfected human embryonic kidney (HEK) 293 cells. Under newly established sheathless on‐line CE/(‐)nanoESI conditions for glycosaminoglycan (GAG) ionization and MS detection, single CS/DS oligosaccharide components of extended chain length and increased sulfation degree were identified. Molecular ions corresponding to species carrying 5 and 6 negative charges could be generated for large GAG oligosaccharide species in the negative ion nanoESI‐MS. The optimized on‐line conditions enabled the detection of molecular ions assigned to oversulfated tetradeca‐, octadeca‐, and eicosasaccharide CS/DS molecules, which represent the category of largest sulfated GAG‐derived oligosaccharides evidenced by CE/ESI‐MS. By on‐line CE/ESI tandem MS in data‐dependent acquisition mode the oversulfated eicosasaccharide species could be sequenced and the localization of the additional sulfate group along the chain could be determined.
The realized volatility of FTSE‐100 futures prices
Authors: Areal Nelson M. P. C. , Taylor Stephen J. 
Published: June 2004

AbstractFive‐minute returns from FTSE‐100 index futures contracts are used to obtain accurate estimates
of daily index volatility from January 1986 to December 1998. These realized volatility measures are used to
obtain inferences about the distributional and autocorrelation properties of FTSE‐100 volatility. The
distribution of volatility measured daily is similar to lognormal while the volatility time series has
persistent positive autocorrelation that displays long‐memory effects. The distribution of daily returns
standardized using the measures of realized volatility is shown to be close to normal, unlike the unconditional
distribution. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:627–648, 2002
Index futures leadership, basis behavior, and trader selectivity
Authors: Chatrath Arjun , Christie‐David Rohan , Dhanda Kanwalroop K. , Koch Timothy W. 
Published: June 2004

AbstractEmploying intraday data for futures and cash values for the S&P 500 over the 1993–1996 period, we
attempt to characterize the lead–lag relationship between these two markets and their basis behavior. Our
findings show evidence of pronounced futures leadership when markets are rising, with no feedback from the cash
market. However, when markets are falling, futures leadership is less evident and significant feedback from the
cash market is noted. We also provide evidence of a positive relationship between the basis and return volatility.
We offer an explanation, based on trader selectivity, for the leadership‐asymmetry and the
basis–volatility relationship. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:649–677, 2002
Characterizing the spatial variability of groundwater quality using the entropy theory: I. Synthetic data
Authors: Mogheir Y. , de Lima J. L. M. P. , Singh V. P. 
Published: June 2004

AbstractThis paper, the first in a series of two, applies the entropy (or information) theory to describe the spatial variability of synthetic data that can represent spatially correlated groundwater quality data. The application involves calculating information measures such as transinformation, the information transfer index and the correlation coefficient. These measures are calculated using discrete and analytical approaches. The discrete approach uses the contingency table and the analytical approach uses the normal probability density function. The discrete and analytical approaches are found to be in reasonable agreement. The analysis shows that transinformation is useful and comparable with correlation to characterize the spatial variability of the synthetic data set, which is correlated with distance. Copyright © 2004 John Wiley & Sons, Ltd.
Hydrological sensitivity of a large Himalayan basin to climate change
Authors: Singh Pratap , Bengtsson Lars 
Published: June 2004

AbstractThe present study sets out to investigate the sensitivity of water availability to climate change for a large western Himalayan river (the Satluj River basin with an area of 22 275 km2 and elevation range of 500 to 7000 m), which receives contributions from rain, snow and glacier melt runoff. About 65% of the basin area is covered with snow during winter, which reduces to about 11% after the ablation period. After having calibrated a conceptual hydrological model to provide accurate simulations of observed stream flow, the hydrological response of the basin was simulated using different climatic scenarios over a period of 9 years. Adopted plausible climate scenarios included three temperature scenarios (T + 1, T + 2, T + 3 °C) and four rainfall scenarios (P − 10, P − 5, P + 5 and P + 10%). The effect of climate change was studied on snowmelt and rainfall contribution runoff, and total stream flow. Under warmer climate, a typical feature of the study basin was found to be reduction in melt from the lower part of the basin owing to a reduction in snow covered area and shortening of the summer melting season, and, in contrast, an increase in the melt from the glacierized part owing to larger melt and an extended ablation period. Thus, on the basin scale, reduction in melt from the lower part was counteracted by the increase from melt from upper part of the basin, resulting in a decrease in the magnitude of change in annual melt runoff. The impact of climate change was found to be more prominent on seasonal rather than annual water availability. Reduction of water availability during the summer period, which contributes about 60% to the annual flow, may have severe implications on the water resources of the region, because demand of water for irrigation, hydropower and other usage is at its peak at this time. Copyright © 2004 John Wiley & Sons, Ltd.
Predicting catchment flow in a semi‐arid region via an artificial neural network technique
Authors: Riad S. , Mania J. , Bouchaou L. , Najjar Y. 
Published: June 2004

AbstractA model of rainfall–runoff relationships is an essential tool in the process of evaluation of water resources projects. In this paper, we applied an artificial neural network (ANN) based model for flow prediction using the data for a catchment in a semi‐arid region in Morocco. Use of this method for non‐linear modelling has been demonstrated in several scientific fields such as biology, geology, chemistry and physics.The performance of the developed neural network‐based model was compared against multiple linear regression‐based model using the same observed data. It was found that the neural network model consistently gives superior predictions. Based on the results of this study, artificial neural network modelling appears to be a promising technique for the prediction of flow for catchments in semi‐arid regions. Accordingly, the neural network method can be applied to various hydrological systems where other models may be inappropriate. Copyright © 2004 John Wiley & Sons, Ltd.
Hydrochemical variations during flood pulses in the south‐west China peak cluster karst: impacts of CaCO3–H2O–CO2interactions
Authors: Liu Zaihua , Groves Chris , Yuan Daoxian , Meiman Joe , Jiang Guanghui , He Shiyi , Li Qiang 
Published: June 2004

AbstractHigh‐resolution measurements of rainfall, water level, pH, conductivity, temperature and carbonate chemistry parameters of groundwater at two adjacent locations within the peak cluster karst of the Guilin Karst Experimental Site in Guangxi Province, China, were made with different types of multiparameter sonde. The data were stored using data loggers recording with 2 min or 15 min resolution. Waters from a large, perennial spring represent the exit for the aquifer's conduit flow, and a nearby well measures water in the conduit‐adjacent, fractured media. During flood pulses, the pH of the conduit flow water rises as the conductivity falls. In contrast, and at the same time, the pH of groundwater in the fractures drops, as conductivity rises. As Ca2+and HCO3−were the dominant (>90%) ions, we developed linear relationships (bothr2> 0·91) between conductivity and those ions, respectively, and in turn calculated variations in the calcite saturation index (SIC) and CO2partial pressure (P) of water during flood pulses. Results indicate that thePof fracture water during flood periods is higher than that at lower flows, and itsSICis lower. Simultaneously,Pof conduit water during the flood period is lower than that at lower flows, and itsSICalso is lower. From these results we conclude that at least two key processes are controlling hydrochemical variations during flood periods: (i) dilution by precipitation and (ii) water–rock–gas interactions. To explain hydrochemical variations in the fracture water, the water–rock–gas interactions may be more important. For example, during flood periods, soil gas with high CO2concentrations dissolves in water and enters the fracture system, the water, which in turn has become more highly undersaturated, dissolves more limestone, and the conductivity increases. Dilution of rainfall is more important in controlling hydrochemical variations of conduit water, because rainfall with higher pH (in this area apparently owing to interaction with limestone dust in the lower atmosphere) and low conductivity travels through the conduit system rapidly. These results illustrate that to understand the hydrochemical variations in karst systems, considering only water–rock interactions is not sufficient, and the variable effects of CO2on the system should be evaluated. Consideration of water–rock–gas interactions is thus a must in understanding variations in karst hydrochemistry. Copyright © 2004 John Wiley & Sons, Ltd.
Artificial neural networks and fuzzy logic based control of spillway gates of dams
Authors: Bagis Aytekin , Karaboga Dervis 
Published: June 2004

AbstractIn this paper a new and efficient control method based on fuzzy logic is proposed for real‐time operation of spillway gates of a reservoir during any flood of any magnitude up to the probable maximum flood. Artificial neural networks are used to model the non‐linear relationship among the main variables of the reservoir under consideration. In order to demonstrate the performance of the proposed method, we simulate the control system using different probable overflow hydrographs. The results of the proposed control method are compared with the results of the conventional control methods. The results obtained from the simulations indicate that the proposed method exhibits superior performance over the conventional reservoir flood operation, with much more flexible results. Copyright © 2004 John Wiley & Sons, Ltd.
Identifying storm flow pathways in a rainforest catchment using hydrological and geochemical modelling
Authors: Kinner David A. , Stallard Robert F. 
Published: June 2004

AbstractThe hydrological model TOPMODEL is used to assess the water balance and describe flow paths for the 9·73 ha Lutz Creek Catchment in Central Panama. Monte Carlo results are evaluated based on their fit to the observed hydrograph, catchment‐averaged soil moisture and stream chemistry. TOPMODEL, with a direct‐flow mechanism that is intended to route water through rapid shallow‐soil flow, matched observed chemistry and discharge better than the basic version of TOPMODEL and provided a reasonable fit to observed soil moisture and wet‐season discharge at both 15‐min and daily time‐steps. The improvement of simulations with the implementation of a direct‐flow component indicates that a storm flow path not represented in the original version of TOPMODEL plays a primary role in the response of Lutz Creek Catchment. This flow path may be consistent with the active and abundant pipeflow that is observed or delayed saturation overland flow. The ‘best‐accepted’ simulations from 1991 to 1997 indicate that around 41% of precipitation becomes direct flow and around 10% is saturation overland flow. Other field observations are needed to constrain evaporative and groundwater losses in the model and to characterize chemical end‐members posited in this paper. Published in 2004 by John Wiley & Sons, Ltd.
Suppression of growth of H‐69 small cell lung carcinoma by antagonists of growth hormone releasing hormone and bombesin is associated with an inhibition of protein kinase C signaling
Authors: Kanashiro Celia A. , Schally Andrew V. , Zarandi Marta , Hammann Brian D. , Varga Jozsef L. 
Published: June 2004

AbstractWe investigated the effects of antagonists of growth hormone‐releasing hormone (GHRH) alone and in combination with bombesin/gastrin‐releasing peptide (BN/GRP) antagonist RC‐3940‐II on the growth of H‐69 human small cell lung carcinoma (SCLC) xenografted into nude mice. Since the activation of the signaling pathways involving protein kinase C (PKC) and the subsequent steps involving mitogen‐activated protein kinase (MAPK) and c‐fos and c‐jun oncogenes are known to be important mechanisms implicated in cellular growth, we investigated how the blockade of tumoral GHRH receptor splice variants and BN/GRP receptors by these antagonists could interfere with these intracellular signaling pathways. Treatment with GHRH antagonists JV‐1‐65 or MZ‐J‐7‐110 for 4 weeks significantly (p<0.05) decreased the tumor volume by 22.7±3.0% and 36.7 ± 3.6%, respectively, as compared to controls. A larger decrease in tumor volume of 73.0 ± 9.5% (p<0.01) was produced by BN/GRP antagonist RC‐3940‐II and its combination with JV‐I‐65 caused the greatest tumor reduction of 91.0 ± 9.8% (p<0.01) vs. controls. H‐69 SCLC tumors expressed α‐, βII‐, δ‐ and η‐PKC isoforms. Antagonists of GHRH and BN/GRP decreased significantly (p<0.05) the expression of βII‐ and δ‐, but not of α‐ and η‐PKC isoforms. They also inhibited MAPK levels, the effects being significant (p<0.05) in the groups that received BN/GRP antagonist. In addition, expression of c‐fos and c‐jun mRNA was reduced after combined treatment with JV‐1‐65 and RC‐3940‐II. The proliferation of H‐69 SCLC cells “in vitro” was also significantly inhibited after incubation of cells with GHRH antagonist, PKC inhibitors or MAPK inhibitor. These findings suggest that the anti‐proliferative effects of antagonists of GHRH and BN/GRP on H69‐SCLC involve an inhibition of the signaling pathways of specific PKC isoforms, MAPK and c‐fos and c‐jun oncogenes. © 2004 Wiley‐Liss, Inc.