bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upper versus lower Colorado River sub‐basin streamflow: characteristics, runoff estimation and model simulation
Authors: Fassnacht S. R. 
Published: June 2006

AbstractStreamflow in the upper Colorado River in the western USA is always snowmelt dominated, whereas the lower river's perennial streamflows are snowmelt dominated only 50% of the time. The magnitude and timing of peak flows is important for water resources management. In the upper basin the annual maximum daily discharge usually occurs in May or June, and in the lower basin this peak is observed to occur in any month except May or June. The timing of one‐half of the specific runoff is used as a second measure of the variability in timing and magnitude of streamflows. For the upper basin, nine watersheds are used to illustrate streamflow trends, with the Yampa River used as a sample sub‐basin. For the lower basin, five watersheds are used, of which Salt River is used as sample sub‐basin. The differences in monthly flow variation over 20‐year time periods (1920–1939, 1940–1959, 1960–1979, and 1980–1999) are substantial for the Salt River but not for the Yampa River.Three model types were used to estimate streamflow characteristics. An autocorrelation model was used to generate winter specific runoffs, which were more reasonable for the Yampa River than the Salt River. A regression between snow water equivalent (SWE) and winter specific runoff showed a good correlation for the two sub‐basins. A weaker relationship exists between SWE and non‐winter flows for the sample lower basin watershed. Streamflow was simulated relatively well using the Precipitation Runoff Modeling System hydrological model. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of glucose:xylose ratio on xylose reductase and xylitol dehydrogenase activities from Candida guilliermondii in sugarcane bagasse hydrolysate
Authors: da Silva Débora Danielle Virgínio , de Almeida Felipe Maria das Graças 
Published: June 2006

AbstractThe influence of glucose on xylose reductase (XR) and xylitol dehydrogenase (XDH) enzyme activity was evaluated from sugarcane bagasse hydrolysate fermentations with different glucose:xylose ratios (1:25, 1:12, 1:5 and 1:2.5) by employing an inoculum of Candida guilliermondii grown in media containing glucose, a mixture of glucose and xylose, or only xylose as carbon sources. According to the results, the glucose:xylose ratio affected positively this bioconversion and a correlation was not observed between the favourable conditions for xylitol production and the XR and XDH activities. Also, the results were influenced not only by the glucose:xylose ratio in the fermentation medium, but also by the carbon source employed in the growth medium of the inoculum. The optimum condition for xylitol production by C. guilliermondii in sugarcane bagasse hemicellulosic hydrolysate should use hydrolysate with a 1:5 glucose:xylose ratio and inoculum grown in medium containing xylose as the only carbon source. Copyright © 2006 Society of Chemical Industry
Chiral separation strategy in polar organic solvent chromatography and performance comparison with normal‐phase liquid and supercritical‐fluid chromatography
Authors: Matthijs Nele , Maftouh Mohamed , Vander Heyden Yvan 
Published: June 2006

AbstractA strategy, including a rapid screening and several optimisation steps, for the separation of chiral molecules of pharmaceutical interest by polar organic solvent chromatography (POSC), using four polysaccharide‐based stationary phases, is proposed and compared with previously reported strategies in normal‐phase (NPLC) and supercritical fluid chromatography (SFC). In a first part of this paper, different examples demonstrate the effectiveness of the POSC strategy for fast method development. Optimisation is based on the use of experimental design to map the experimental domain in an efficient way. In the second part, the best screening results, obtained after performance of earlier defined chromatographic screening strategies in NPLC and SFC, are compared to those obtained in POSC. The three techniques show complementary separation results and allowed baseline separation of 23 of 25 compounds. POSC is found to be a very interesting separation mode compared to NPLC, because of the many fast (< 10 min) baseline separations obtained.
Chiral discrimination of primary amines by HPLC after labeling with a chiral derivatization reagent, trans‐2‐(2,3‐anthracenedicarboximido)‐cyclohexanecarbonyl chloride
Authors: Akasaka Kazuaki , Ohtaki Takashi , Ohrui Hiroshi 
Published: June 2006

AbstractEnantiomeric discrimination of chiral primary amines was performed by both reversed‐phase HPLC and normal‐phase HPLC after labeling with a chiral fluorescent derivatization reagent, (1R,2R)‐ and (1S,2S)‐trans‐2‐(2,3‐anthracenedicarboximido)cyclohexanecarbonyl chloride. Use of HPLC permits separation of diastereomeric derivatives of amines up to C30 which have a primary amino group at the middle of the alkyl chain. The derivatives of primary amines having an anteiso alkyl chain, which has a chiral branched‐methyl at the n‐3 position of the alkyl chain, were also separated by HPLC, and it was also possible to separate niphatesine D by reversed‐phase HPLC after derivatization.
Kinetics of the thermal isomerization of 1,1,2,2‐tetramethylcyclopropane
Authors: Lewis David K. , Gray Timothy , Katsva Vlad , Parcella Kyle , Schlier Jessica , Kalra Bansi L. , Cho Janet , Mish Debra 
Published: June 2006

AbstractReaction rates for the structural isomerization of 1,1,2,2‐tetramethylcyclopropane to 2,4‐dimethyl‐2‐pentene have been measured over a wide temperature range, 672–750 K in a static reactor and 1000–1120 K in a single‐pulse shock tube. The combined data from the two temperature regions give Arrhenius parameters Ea=64.7 (±0.5) kcal/mol and log10(A, s−1) = 15.47 (±0.13). These values lie at the upper end of the ranges of Ea and log A values (62.2–64.7 kcal/mol and 14.82–15.55, respectively) obtained from three previous experimental studies, each of which covered a narrower temperature range. The previously noted trend toward lower Ea values for structural isomerization of methylcyclopropanes as methyl substitution increases extends only through the dimethylcyclopropanes (1,1‐ and 1,2‐); Ea then appears to increase with further methyl substitution. In contrast, the pre‐exponential factors for isomerization of cyclopropane and all of the methylcyclopropanes through tetramethylcyclopropane lie within ±0.3 of log10(A, s−1) = 15.2 and show no particular trend with increasing substitution. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 483–488, 2006
Surfactant effects on the reaction of 2‐(4‐cyanophenoxy)‐quinoxaline with hydroxide ion
Authors: Cuenca Angela 
Published: June 2006

AbstractA reaction of 2‐(4‐cyanophenoxy)quinoxaline 1 with hydroxide ion is accelerated by supramolecular aggregates of cetyltrialkylammonium chlorides (alkyl = Me, n‐Pr, and n‐Bu). In diluted surfactant solutions, with relatively high substrate concentration (7.0 × 10−5 M), rate constants go through double rate maxima with increase in the surfactant concentration. The first rate maximum is ascribed to a reaction occurring in premicellar aggregates and the second to reaction in micelles. At low substrate concentration (7 × 10−6 M), second‐order rate constants in the micellar pseudophase are dependent on the surfactant headgroup size, which is related to charge dispersion in the transition state. Nonmicellizing tri‐n‐octylmethylammonium ions (TOAMs) increase the reaction of 1 with hydroxide ion. The observed rate enhancements may be due to the formation of small, hydrophobic aggregates which bind the substrate and promote the nucleophilic substitution reaction. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 510–515, 2006
Kinetics of the thermal isomerization of 1,1,2‐trimethylcyclopropane
Authors: Lewis David K. , Hughes Steven V. , Miller Justine D. , Schlier Jessica , Wilkinson Kevin A. , Wilkinson Sara R. , Kalra Bansi L. 
Published: June 2006

AbstractThe Arrhenius parameters for the gas phase, unimolecular structural isomerizations of 1,1,2‐trimethylcyclopropane to three isomeric methylpentenes and two dimethylbutenes have been determined over a wide range of temperatures, 688–1124 K, using both static and shock tube reactors. For the overall loss of reactant, Ea = 63.7 (± 0.5) kcal/mol and log10 A = 15.28 (± 0.12). These values are higher by 2.6 kcal/mol and 0.7–0.8 than previously reported from experimental work or predicted from thermochemical calculations. Ea for the formation of trans‐4‐methyl‐2‐pentene is 1.5 kcal/mol higher than Ea for the formation of the cis isomer, which is identical to the Ea difference previously reported for the formation of trans‐ and cis‐2‐butene from methylcyclopropane. Substitution of methyl groups for hydrogen atoms on the cyclopropane ring is expected to weaken the CC ring bonds, and it has been reported previously that activation energies for structural isomerizations of methylcyclopropanes do decrease substantially over the series cyclopropane > methylcyclopropane > 1,1‐ or 1,2‐dimethylcyclopropane. However, the present study shows that the trend does not continue beyond dimethylcyclopropane isomerization. Besides reductions in CC bond energy, steric interactions may be increasingly important in determining the energy surface and conformational restrictions near the transition state in isomerizations of the more highly substituted methylcyclopropanes. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 475–482, 2006
Extrapyramidal symptoms in Wilson's disease are associated with olfactory dysfunction
Authors: Mueller Antje , Reuner Ulrike , Landis Basile , Kitzler Hagen , Reichmann Heinz , Hummel Thomas 
Published: June 2006

AbstractWilson's disease is a rare autosomal recessive disorder characterized by the accumulation of copper, mainly in the liver and the brain. As copper accumulation in the brain leads to disturbances in basal ganglia function, neurological‐type patients typically present with hypo‐ and hyperkinetic extrapyramidal symptoms, with Parkinsonism being very common. Although there are numerous reports on olfactory deficits in primary neurodegenerative disorders, olfactory function has not been investigated in metabolic disorders presenting with extrapyramidal features. Twenty‐four patients with Wilson's disease participated in the investigation. All patients were treated pharmacologically. They comprised patients with liver disease alone (including mild enzyme elevation in asymptomatic individuals; n = 11) and/or neurological symptoms (n = 13) at the time of testing. Twenty‐one patients underwent both [18F]fluoro‐2‐deoxy‐D‐glucose positron emission tomography ([18F]FDG‐PET) and magnetic resonance imaging (MRI). The severity of extrapyramidal symptoms was judged using a clinical score system ranging from 0 (no symptoms) to 3 (severe symptoms). In all patients, psychophysical testing was performed using the “Sniffin' Sticks,” which involved tests for odor threshold, discrimination, and identification. Results from the present study revealed that Wilson's disease patients with neurological symptoms show a significant olfactory dysfunction compared to hepatic‐type patients. Individuals who are more severely neurologically affected also present with a more pronounced olfactory deficit. Of interest, there was no significant effect of long‐term treatment with penicillamine on olfactory function. Olfactory function did not correlate significantly with the presence of MRI visible lesions in the basal ganglia or with any regional glucose metabolism as measured by [18]F‐FDG‐PET. In conclusion, these findings indicate that the underlying pathological alterations with degeneration in the basal ganglia and neuronal loss in association with a marked increase of the copper content in this brain region play a role in the olfactory deficit. © 2006 Movement Disorder Society
Development of a decision support system for diagnosis and grading of brain tumours using in vivo magnetic resonance single voxel spectra
Authors: Tate Anne R. , Underwood Joshua , Acosta Dionisio M. , Julià‐Sapé Margarida , Majós Carles , Moreno‐Torres Àngel , Howe Franklyn A. , van der Graaf Marinette , Lefournier Virginie , Murphy Mary M. , Loosemore Alison , Ladroue Christophe , Wesseling Pieter , Luc Bosson Jean , Cabañas Miquel E. , Simonetti Arjan W. , Gajewicz Witold , Calvar Jorge , Capdevila Antoni , Wilkins Peter R. , Bell B. Anthony , Rémy Chantal , Heerschap Arend , Watson Des , Griffiths John R. , Arús Carles 
Published: June 2006

AbstractA computer‐based decision support system to assist radiologists in diagnosing and grading brain tumours has been developed by the multi‐centre INTERPRET project. Spectra from a database of 1H single‐voxel spectra of different types of brain tumours, acquired in vivo from 334 patients at four different centres, are clustered according to their pathology, using automated pattern recognition techniques and the results are presented as a two‐dimensional scatterplot using an intuitive graphical user interface (GUI). Formal quality control procedures were performed to standardize the performance of the instruments and check each spectrum, and teams of expert neuroradiologists, neurosurgeons, neurologists and neuropathologists clinically validated each case. The prototype decision support system (DSS) successfully classified 89% of the cases in an independent test set of 91 cases of the most frequent tumour types (meningiomas, low‐grade gliomas and high‐grade malignant tumours—glioblastomas and metastases). It also helps to resolve diagnostic difficulty in borderline cases. When the prototype was tested by radiologists and other clinicians it was favourably received. Results of the preliminary clinical analysis of the added value of using the DSS for brain tumour diagnosis with MRS showed a small but significant improvement over MRI used alone. In the comparison of individual pathologies, PNETs were significantly better diagnosed with the DSS than with MRI alone. Copyright © 2006 John Wiley & Sons, Ltd.
Perfusion, diffusion and spectroscopy values in newly diagnosed cerebral gliomas
Authors: Catalaa Isabelle , Henry Roland , Dillon William P. , Graves Edward E. , McKnight Tracy R. , Lu Ying , Vigneron Daniel B. , Nelson Sarah J. 
Published: June 2006

AbstractPurposeTo evaluate perfusion, diffusion, and spectroscopy values in enhancing and non‐enhancing lesions for patients with newly diagnosed gliomas of different grades.Materials and MethodsSixty‐seven patients with newly diagnosed glioma were entered into the study 20 grade II, 26 grade III and 21 grade IV. MR data were acquired at 1.5T and included diffusion weighted images (59/67 patients), dynamic perfusion weighted images (30/67 patients) and 3D H‐1 MR spectroscopy (64/67 patients). Enhancing and non‐enhancing lesions were delineated by a neuroradiologist and applied to maps of relative cerebral blood volume (rCBV), apparent diffusion coefficient (ADC), relative anisotropy (RA) and metabolite intensities.ResultsThe median rCBV within enhancing regions of grade IV gliomas was significantly elevated relative to enhancing regions in grade III gliomas and normal brain. ADC was elevated relative to normal brain, but was not significantly different between grades or between enhancing and non‐enhancing regions. The RA was higher in the non‐enhancing region of grade IV gliomas relative to grade II and grade III. Levels of lactate plus lipid were significantly elevated in grade IV relative to grade II and grade III gliomas. Both enhancing and non‐enhancing regions in grade IV gliomas showed significant correlations between CBV, ADC and choline levels.ConclusionThe data were consistent with grade IV gliomas having higher membrane turnover, increased cell density and increased vascularity within enhancing lesions. Analysis of the correlations among parameters within grade IV gliomas suggested that high vascularity (high rCBV) was correlated with increased cellularity (low ADC) and increased membrane turnover (high choline) in these lesions. The non‐enhancing region of grades II and III gliomas had MR parameters consistent with increased cellularity and/or membrane turnover. Copyright © 2006 John Wiley & Sons, Ltd.
Current Awareness in NMR in Biomedicine
Authors:   John Wiley & Sons, Ltd.
Published: June 2006

AbstractIn order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 11 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Contrast Agents; 5 Brain and Nerves; 6 Neuropathology; 7 Cancer; 8 Cardiac, Vascular and Respiratory Systems; 9 Liver, Kidney and Other Organs; 10 Muscle and Orthopaedic; 11 Plants, Micro‐organisms and Parasites; 12 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
Adaptive reduction‐based AMG
Authors: MacLachlan Scott , Manteuffel Tom , McCormick Steve 
Published: June 2006

AbstractWith the ubiquity of large‐scale computing resources has come significant attention to practical details of fast algorithms for the numerical solution of partial differential equations. Included in this group are the class of multigrid and algebraic multigrid algorithms that are effective solvers for many of the large matrix problems arising from the discretization of elliptic operators. Algebraic multigrid (AMG) is especially effective for many problems with discontinuous coefficients, discretized on unstructured grids, or over complex geometries. While much effort has been invested in improving the practical performance of AMG, little theoretical understanding of this performance has emerged. This paper presents a two‐level convergence theory for a reduction‐based variant of AMG, called AMGr, which is particularly appropriate for linear systems that have M‐matrix‐like properties. For situations where less is known about the problem matrix, an adaptive version of AMGr that automatically determines the form of the reduction needed by the AMGr process is proposed. The adaptive cycle is shown, in both theory and practice, to yield an effective AMGr algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of a slow‐release and superabsorbent nitrogen fertilizer and its properties
Authors: Liu Mingzhu , Liang Rui , Zhan Falu , Liu Zhen , Niu Aizhen 
Published: June 2006

AbstractA slow‐release and superabsorbent nitrogen fertilizer (SSNF) was synthesized by aqueous solution copolymerization of acrylic acid and maleic anhydride using N,N′‐methylene bisacrylamide as a crosslinker, ammonium persulfate and sodium sulfite as an initiator in the presence of urea. The effects on water absorbency such as amount of crosslinker, initiator, urea and maleic acid, degree of neutralization, etc. were investigated. To improve slow release and water retention properties, the product was surface‐crosslinked with trihydroxymethyl propane glycidol ether (6360). The nitrogen content of the SSNF synthesized under optimal conditions was 28.5%, and the water absorbencies were about 900 (g/g) in distilled water and 180 (g/g) in tap water. The nitrogen slow release behavior of the SSNF in water and water retention capacity of the soil with SSNF were also investigated. The results showed that the surface‐crosslinked product not only had good slow release property but also excellent soil moisture preservation capacity, which could effectively improve the utilization of fertilizer and water resources simultaneously. The results of the present work indicated that the SSNF could be found an application in agriculture and horticulture, especially in drought‐prone areas where the availability of water is insufficient. Copyright © 2006 John Wiley & Sons, Ltd.
The comparative safety of rosuvastatin: a retrospective matched cohort study in over 48 000 initiators of statin therapy
Authors: McAfee Andrew T. , Ming Eileen E. , Seeger John D. , Quinn Sherry G. , Ng Eva W. , Danielson Jared D. , Cutone Jennifer A. , Fox Jonathan C. , Walker Alexander M. 
Published: June 2006

AbstractPurposeThe purpose of this study was to compare incidence rates of hospitalization associated with rhabdomyolysis, myopathy, renal, or hepatic dysfunction, and of in‐hospital death, between initiators of rosuvastatin and other statins.MethodsThis was a matched cohort study of statin initiators from the administrative database of a large health insurer in the US, during the first 6 months of rosuvastatin availability with up to 18 months of follow‐up. All outcome events were verified by medical record review. Incidence rates, risk ratios, and associated 95% confidence intervals were estimated.ResultsFrom an initial pool of 12 217, 11 249 eligible rosuvastatin initiators were matched to 37 282 initiators of other statins. The incidence rate (IR) per 1000 person‐years for rhabdomyolysis was 0.10 [0.00, 0.55] for rosuvastatin initiators (n = 1) and 0.06 [0.01, 0.22] for other statin initiators (n = 2), for a hazard ratio (HR) of 1.98 [0.18, 21.90]. The IR for myopathy was 0.20 [0.02, 0.71] for rosuvastatin initiators (n = 2) and 0.00 [0.00, 0.09] for other statin initiators (n = 0). The IR for renal dysfunction was 1.18 [0.61, 2.06] for rosuvastatin initiators (n = 12) and 1.26 [0.91, 1.71] for other statin initiators (n = 42), for a HR of 0.90 [0.47, 1.73]. The IR for hepatic dysfunction was 0.20 (0.02, 0.71) for rosuvastatin initiators (n = 2) and 0.24 (0.10, 0.47) for other statin initiators (n = 8), for a HR of 0.87 (0.18, 4.14).ConclusionsThis study found no difference between rosuvastatin and the other statins in the incidence of hospitalizations associated with renal or hepatic events, or death. The absolute incidence rates of rhabdomyolysis and myopathy were reassuringly low among all statin initiators but remain too small for firm conclusions to be drawn on any difference between the statins. Copyright © 2006 John Wiley & Sons, Ltd.
Characteristic overpressure–impulse–distance curves for vessel burst
Authors: Ferradás Enrique González , Alonso Fernando Díaz , Sánchez Pérez Juan Francisco , Aznar Agustín Miñana , Gimeno José Ruiz , Alonso Jesús Martínez 
Published: June 2006

AbstractIn industrial explosions, various models have been proposed to calculate overpressure and impulse at specified distances. When the explosion is attributed to vessel burst, the Baker method is widely used. From the curves given by this model, data are fitted to obtain equations showing the relationship between overpressure and impulse. These curves, referred to as characteristic curves, can be fitted by potential equations, which depend on explosion energy and geometry of the tank. If several characteristic curves (corresponding to different explosion energies) are represented in the same overpressure–impulse diagram, including distances to the explosion center, determination of overpressure and impulse at each distance is simple and fast. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2006