bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of acetochlor degradation in the unsaturated zone using two novel in situ field techniques: comparisons with laboratory‐generated data and implications for groundwater risk assessments
Authors: Mills Margaret S , Hill Ian R , Newcombe Andrew C , Simmons Nick D , Vaughan Phil C , Verity Alison A 
Published: August 2002

AbstractDegradation of the herbicide acetochlor in the unsaturated zone was quantified using two unique in situ field techniques. The DT50 values generated at two different sites on surface soil and two subsoil depths using these techniques were compared with values generated under aerobic laboratory‐incubation conditions (typically 20 °C, 40% maximum water holding capacity). Additionally, laboratory‐degradation data were generated on surface and subsoils from four other sites. All subsoils were treated with acetochlor at 5% of the surface soil application rate. Acetochlor degradation in both field‐ and laboratory‐incubated subsoils was rapid and often exceeded surface soil rates. Field and laboratory DT50 values from all sites ranged from 2 to 88 days in subsoil, compared with a range of 1 to 18 days in surface soils. The DT50 results from in situ field techniques were comparable with those generated from laboratory incubations in the same soils, confirming the validity of performing laboratory‐based degradation studies to determine pesticide DT50 values in subsoils. Microbiological characterisation of selected soils revealed that subsoils had a viable and active population, although direct counts of bacteria were consistently lower in subsoil (108–109 g−1 dry soil) compared with surface soils (1010 g−1 dry soil). The leaching models used to perform groundwater risk assessments (eg PELMO, PESTLA, MACRO‐DB, PRZM and the FOCUS EU leaching scenarios) have provision for inclusion of subsoil degradation rates. However, conservative default estimates are typically used, as no other alternative is available. Results presented here show that these default values may significantly underestimate true subsoil degradation contributions, and therefore not accurately predict pesticide concentrations in groundwater. The degradation data generated for acetochlor were applied to the mathematical model PELMO to demonstrate the importance of the inclusion of subsoil degradation data in groundwater risk assessment models and thereby in the registration of pesticides in Europe.© 2001 Society of Chemical Industry
Negative cross‐resistance between dihydropyrazole insecticides and pyrethroids in houseflies, Musca domestica
Authors: Khambay Bhupinder P S , Denholm Ian , Carlson Glenn R , Jacobson Richard M , Dhadialla Tarlochan S 
Published: August 2002

AbstractA series of insecticidal dihydropyrazoles and related compounds have been shown to exhibit negative cross‐resistance to a resistant (super‐kdr) strain of houseflies with site‐insensitivity to pyrethroids. The level of cross‐resistance is similar to that observed previously for a range of N‐alkylamides against the same strain.© 2001 Society of Chemical Industry
Catechol as a nucleophilic catalyst of peptide bond formation
Authors: Ivanova Gabriela , Bratovanova Emilia , Petkov Dimiter 
Published: August 2002

AbstractThe aminolysis of a mildly activated aminoacid ester, benzyloxycarbonyl‐L‐phenylalanine cyanomethyl ester, by glycine esters in the presence of catechol has been studied as a model of catalysis by RNA cis‐vicinal‐diol systems in protein biosynthesis. Catechol accelerated the aminolysis, especially in the presence of bases, probably by nucleophilic catalysis. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Rehabilitation of existing structures in seismic zones
Authors: Bob Corneliu 
Published: August 2002

AbstractExisting structures built before the 1970s are gravity load designed with inadequate lateral load resistance because earlier codes specified lower levels of seismic loads and many of these structures are still in service beyond their design life. On the other hand, some deterioration of component parts of buildings are encountered in old structures due to the actions of different hazard factors. This paper discusses the characteristics of existing structures under seismic motions, general and specific solutions for rehabilitation with three examples.Characteristics of existing structures and specific solutions for rehabilitation are detailed for reinforced concrete, steel and masonry structures. Rehabilitation of three different types of existing structures are described: a reinforced concrete framed structure with local damage caused by the action of chloride ions and reinforcement weakness; an old masonry structure which is at risk in the event of a future earthquake; a huge building at significant seismic risk, but without dangerous situation of structure elements.
Effect of ganhuangenin obtained from Scutellaria radix on the chemical mediator production of peritoneal exudate cells and immunoglobulin E level of mesenteric lymph node lymphocytes in Sprague‐Dawley rats
Authors: Lim Beong Ou 
Published: August 2002

AbstractWe previously showed that ganhuangenin (GHG) has beneficial antioxidative properties against lipid peroxidation in tissues of Sprague‐Dawley (SD) rats. In this study, the effect of GHG on immunoglobulin E (IgE), histamine and leukotriene B4 (LTB4) levels of cells isolated from SD rats was examined with regard to the manifestation of the type I allergic reaction. We showed that GHG inhibited the IgE production of mesenteric lymph node (MLN) lymphocytes. In the presence or absence of concanavalin A (ConA), the concentration used did not exert a toxic effect against MLN lymphocytes. Interestingly, the increase in the IgE content and lipid peroxidation induced by ConA was alleviated in the presence of GHG. Moreover, GHG also inhibited histamine release from the peritoneal exudate cells stimulated with a calcium ionophore, A23187, or with the histamine releaser, compound 48/80. In the case of LTB4, GHG markedly inhibited its release at a concentration of 100 μM. Thus, it is concluded that GHG may block the common pathway for the release of histamine and LTB4, and that the IgE level is responsible for the lipid peroxidation induced by ConA. Copyright © 2002 John Wiley & Sons, Ltd.
Study of alkaloids from Adhatoda vasica Nees on their antiinflammatory activity
Authors: Chakraborty A. , Brantner A. H. 
Published: August 2002

AbstractAdhatoda vasica Nees is a shrub widespread throughout the tropical regions of southeast Asia. It possesses a wide spectrum of medicinal properties including positive effects on inflammatory diseases. The antiinflammatory activity of the methanol extract, the non‐alkaloid fraction, the saponins and the alkaloids was evaluated by the modified hen's egg chorioallantoic membrane test. The alkaloid fraction showed potent activity at a dose of 50 µg/pellet equivalent to that of hydrocortisone while the MeOH extract and the other fractions showed less activity. Copyright © 2001 John Wiley & Sons, Ltd.
A reporter gene assay for the detection of phytoestrogens in traditional Chinese medicine
Authors: Miller‐Martini D. M. , Chan R. Y. K. , Ip N. Y. , Sheu S. J. , Wong Y. H. 
Published: August 2002

AbstractBupleurum & Peony Formula (Jia Wei Xiao Yao San) is a herbal formula which possesses a clinical history for the treatment of menopausal syndrome and menstrual irregularity. The present investigation reports the ability to monitor the formula's phytoestrogen content that will allow for the implementation of a standardization protocol that is based on a quantifiable biological response. Utilizing an oestrogen‐sensitive chimeric receptor/reporter gene element which has been stably transfected into HeLa cells, the botanical formula was shown to induce the expression of the reporter gene, luciferase, in a dose dependent manner. Pretreatment of the HeLa cells with the botanical formula produced a 5‐fold increase in bioluminescence compared with the control. Additionally, our studies showed that the response of the cells, when challenged by the botanical formula, was oestrogen specific. Pretreatment of the cells with tamoxifen effectively blocked the activation of the chimeric oestrogen receptor by the botanical formula. The cell line provides a sensitive assay that can easily detect the presence of phytoestrogens in complex botanical formulas. Copyright © 2001 John Wiley & Sons, Ltd.
On the distribution of the estimated process yield index Spk
Authors: Lee J. C. , Hung H. N. , Pearn W. L. , Kueng T. L. 
Published: August 2002

AbstractThis paper considers an asymptotic distribution for an estimate $\hat{S}_{pk}$ of the process yield index $S_{pk}$ proposed by Boyles (1994). The asymptotic distribution of $\hat{S}_{pk}$ is useful in statistical inferences for $S_{pk}$. An illustrative example is given for hypothesis testing and for interval estimation on the yield index $S_{pk}$. Copyright © 2002 John Wiley & Sons, Ltd.
Electronic structure of adamantane
Authors: Korolkov Dimitry V. , Sizova Olga V. 
Published: August 2002

AbstractThe geometry and electronic structure of adamantane and related molecular cations is studied with the emphasis on the electron density distribution on the face planes and in the carbon cage. The results are compared with the corresponding data for the boron hydrides and carbocations. The bonding in these compounds is discussed in terms of the theory of trishomoaromacity. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Common‐sense reasoning cast over D–U model in simulation of chemical reactions
Authors: Nowak Grażyna 
Published: August 2002

AbstractThe Ugi–Dugundji model of chemistry has been commonly applied as a mathematical tool aimed at the unrestricted prediction of the behavior of chemical objects. In the computer simulation of chemical reactions, it enables us to generate, for a given set of reagents, a mathematically complete product space, and therefore it can predict new unprecedented reactions. However, the principal drawback of this model is connected to the enormous solution space, which comprises all mathematically conceivable chemistry featuring very low reliability. For this reason, in the CSB system, the course of the chemical reaction generation is controlled through the examination and evaluation of reaction centers (i.e., reactive atoms and bonds) in reacting molecules. The resulting products space is determined by a set of recognized reaction centers and a set of schemes transforming these reaction centers in substrate/product molecules. In this article, the progress in the developed strategy is discussed, concerning the application of different methods for acquiring rules required to infer reaction sites. As a working example, the search for structure–reactivity correlations and the resulting product space are presented for a set of test structures. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 282–289, 2001
Evaluation of several solid phase extraction liquid chromatography/tandem mass spectrometry on‐line configurations for high‐throughput analysis of acidic and basic drugs in rat plasma
Authors: Mallet Claude R. , Mazzeo Jeff R. , Neue Uwe 
Published: August 2002

AbstractSeveral configurations using 6‐ and 10‐port switching valves were studied for high flow, on‐line extraction of rat plasma coupled to an electrospray triple quadrupole mass spectrometer. Each plasma sample was diluted 1:1 with an aqueous internal standard solution. The sample was injected into a 2.1 × 20 mm cartridge column packed with 25 µm divinylbenzene/N‐vinylpyrrolidone packing using 100% aqueous mobile phase at 4 mL/min. After sample loading and sample cleanup, the analytes were eluted from the extraction column with a 1.0‐min gradient at 0.4 mL/min. The samples were either analyzed directly after elution from the extraction column or after additional separation using a short high performance liquid chromatography (HPLC) column. The different configurations were tested using an acidic drug (diflunisal) and a basic drug (clemastine) in rat plasma. On‐line analysis was performed by injecting 200 µL of diluted plasma. The mass spectrometer was operated in the multiple reaction monitoring (MRM) mode. All calibration standards gave relative standard deviations (RSDs) below 5%. The total time per sample was 3 min. Copyright © 2001 John Wiley & Sons, Ltd.
A high pressure matrix‐assisted laser desorption/ionization Fourier transform mass spectrometry ion source for thermal stabilization of labile biomolecules
Authors: O'Connor Peter B. , Costello Catherine E. 
Published: August 2002

AbstractA high pressure matrix‐assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry (FTMS) ion source was designed and tested. With this design, pressure is pulsed to an estimated 1–10 mbar in the region of the MALDI sample during desorption with the result of significantly decreased fragmentation compared to similar systems operating with pressures of <0.1 mbar. The thermal stabilization of vibrationally excited ions under these conditions is shown with small peptides desorbed from the ‘hot’ matrix α‐cyano‐4‐hydroxycinnamic acid, and with the highly labile oxidized β‐chain of insulin. Fragile gangliosides with several sialic acid residues are desorbed under high pressure and remain intact without the typical losses of sialic acid, and a protein standard, ubiquitin (8565.64 Da), is desorbed with minimal dehydration. Under high pressure collisional cooling conditions, non‐covalent matrix adduction to the molecular ions becomes prominent, but with the trapped ions in an FT mass spectrometer, the ions can be mildly activated to detach the matrix adducts. The new source, additionally, generates significant levels of the multiply charged ions which are commonly seen in MALDI‐TOFMS, but are rarely observed in MALDI‐FTMS. This effect is more likely due to the elimination of a mass filtering effect in the previous FTMS ion source than to collisional cooling of the ions. Copyright © 2001 John Wiley & Sons, Ltd.
Mass‐directed fractionation and isolation of pharmaceutical compounds by packed‐column supercritical fluid chromatography/mass spectrometry
Authors: Wang Tao , Barber Michael , Hardt Ingo , Kassel Daniel B. 
Published: August 2002

AbstractAn automated packed‐column semi‐preparative supercritical fluid chromatography/mass spectrometry (SFC/MS) system incorporating mass‐directed fraction collection has been designed and implemented as an alternative to preparative HPLC and preparative HPLC/MS (PrepLC/MS) for the purification of pharmaceutical compounds. The system incorporates a single quadrupole mass spectrometer and a supercritical fluid chromatograph. Separations were achieved using a binary solvent system consisting of carbon dioxide and methanol. Purification of SFC‐separated compounds was achieved incorporating mass‐directed fraction collection, enabling selective isolation of the target molecular weight compound and eliminating the collection of undesired compounds (e.g., by‐products, excess starting materials, etc.). Cross contamination between fractions and recoveries of the system were investigated. Mass spectrometer ionization with basic mobile additives is discussed, and examples of preparative SFC/MS chiral separations are presented. Early experiences suggest SFC will be a powerful and complementary technique to HPLC for the purification of pharmaceutical compounds. Copyright © 2001 John Wiley & Sons, Ltd.
Hydroxyl radical probe of the surface of lysozyme by synchrotron radiolysis and mass spectrometry
Authors: Maleknia Simin D. , Kiselar Janna G. , Downard Kevin M. 
Published: August 2002

AbstractA new approach is reported that combines synchrotron radiolysis and mass spectrometry to probe the surface of proteins. Hydroxyl radicals produced upon the radiolysis of protein solutions with synchrotron light for several milliseconds result in the reaction of amino acid side chains. This results in the formation of stable oxidation products where the level of oxidation at the reactive residues is influenced by the accessibility of their side chains to the bulk solvent. The aromatic and sulfur‐containing residues have been found to react preferentially in accord with previous peptide studies. The sites of oxidation have been determined by tandem mass spectrometry. The rate of oxidation at these reactive markers has been measured for each of the proteolytic peptides as a function of exposure time based on the relative proportion of modified and unmodified peptide ions detected by mass spectrometry. Oxidation rates have been found to correlate closely with a theoretical measure of the accessibility of residue side chains to the bulk solvent in the native protein structure. The synchrotron‐based approach is able to distinguish the relative accessibility of the tryptophan residue side chains of lysozyme at positions 62 and 123 from each other and all other tryptophan residues based on their rates of oxidation. Copyright © 2001 John Wiley & Sons, Ltd.
Influence of chain end groups on the matrix‐assisted laser desorption/ionization spectra of polymer blends
Authors: Alicata R. , Montaudo G. , Puglisi C. , Samperi F. 
Published: August 2002

AbstractThe positive ion matrix‐assisted laser desorption/ionization (MALDI) spectrum of an equimolar blend of Nylon 6 (Ny6) and hydroxyl‐terminated polybutyleneterephthalate (PBT) shows a surprisingly strong imbalance between the two components. Since the average molar masses and the polydispersions of the two polymers are comparable, it follows that the efficiency of MALDI is quite different for the two components of the blend. This finding prompted us to a more detailed study, and to synthesize Ny6 and PBT samples terminated with different end groups, in order to analyze their blends by MALDI. The negative ion MALDI spectra of the mixtures investigated show that PBT samples do not yield signals, so that only Ny6 peaks appear in these spectra. By comparing positive and negative ion MALDI spectra of mixtures of Ny6 terminated with various end groups, it was found that the peak intensity depends on the nature of the end groups. The results reported in the present study may help to clarify some fundamental aspects of the mechanisms of ion formation, when MALDI mass spectrometry is applied to macromolecules. End group ionization efficiency appears to be the most important parameter in determining the relative intensity of peaks in the MALDI spectra of the polymer blends investigated. End‐group‐dependent ionization is the key to the rationalization of the relative peak intensities in MALDI spectra of polymer mixtures. Copyright © 2002 John Wiley & Sons, Ltd.
Oxygen isotope corrections for online δ34S analysis
Authors: Fry Brian , Silva Steven R. , Kendall Carol , Anderson Richard K. 
Published: August 2002

AbstractElemental analyzers have been successfully coupled to stable‐isotope‐ratio mass spectrometers for online measurements of the δ34S isotopic composition of plants, animals and soils. We found that the online technology for automated δ34S isotopic determinations did not yield reproducible oxygen isotopic compositions in the SO2 produced, and as a result calculated δ34S values were often 1–3‰ too high versus their correct values, particularly for plant and animal samples with high C/S ratio. Here we provide empirical and analytical methods for correcting the S isotope values for oxygen isotope variations, and further detail a new SO2‐SiO2 buffering method that minimizes detrimental oxygen isotope variations in SO2. Published in 2002 by John Wiley & Sons, Ltd.
Hype or Hope: The Potential of Phytoremediation as an Emerging Green Technology
Authors: Schwitzguébel Jean‐Paul 
Published: August 2002

AbstractPhytoremediation is defined as the use of green plants and their associated microorganisms, soil amendments,
and agronomic techniques to remove, contain, or render harmless environmental pollutants. At the present time,
phytoremediation is an emerging technology and there is still a significant need to pursue both fundamental and
applied research to fully exploit the metabolic and growth habits of higher plants. It is precisely the purpose
of the European COST Action 837 to stimulate the development and evaluate the potential of plant biotechnology
for the removal of organic pollutants and toxic metals from wastewater and contaminated sites. However, green
plants grow under nonsterile conditions and thus strongly interact with many microorganisms, like bacteria and
mycorrhizal fungi. In this context, an Inter‐COST Workshop on bioremediation was recently organized to
address the significance of soil microorganisms for plants, and the importance of their interactions, with
regard to their potential for phytoremediation. Based on the outcomes of this workshop, the potential use of
phytoremediation is presented in this article. © 2001 John Wiley & Sons, Inc.
Contrasting temperatures, waterflows, and light: seasonal habitat selection by young Atlantic salmon and brown trout in a boreonemoral river
Authors: Heggenes Jan , Gunnar Dokk John 
Published: August 2002

AbstractHabitat use and habitat selection by young Atlantic salmon and brown trout were investigated by direct underwater observation. We sampled during winter and summer water temperatures (low: 3–7°C; high: 9–12°C) coinciding with low and high waterflows (12–20 and 60–80 m3s−1), and during day and night in winter, and on six selected stations in the river. Observations of 396 salmon and 120 trout indicated a distinct seasonal pattern in behaviours and habitat selection. Feeding was the dominant behaviour at high water temperatures during summer. In winter, there was a diurnal pattern in behaviour; both species sheltered in interstitial spaces in the substrate during daylight, but during night held positions on or close to the substrate in slower flowing stream areas. Coarse substrate providing cover was therefore an important habitat factor during daylight at low water temperatures, while slow‐flowing water was important during night. Although spatial niche overlap was considerable both in summer and winter, salmon and trout segregated with respect to meso‐ and microhabitat selection, and relatively more at low temperatures. Both species changed their use of mesohabitats towards more slow‐flowing glide/flat habitats in winter. Irrespective of season, trout preferred in general more slow‐flowing water than salmon did, but the difference was more pronounced in winter. Salmon used a wider range of water depths and in particular water velocities, than did trout. Both species were less tolerant of high water velocities at low water temperatures. The seasonal and diurnal pattern in habitat selection reported have important implications for habitat research and habitat‐hydraulic modelling. Copyright © 2001 John Wiley & Sons, Ltd.
An O(n2) bound for the relaxation time of a Markov chain on cladograms
Authors: Schweinsberg Jason 
Published: August 2002

AbstractA cladogram is an unrooted tree with labeled leaves and unlabeled internal branchpoints of degree 3. Aldous has studied a Markov chain on the set of n‐leaf cladograms in which each transition consists of removing a random leaf and its incident edge from the tree and then reattaching the leaf to a random edge of the remaining tree. Using coupling methods, Aldous showed that the relaxation time (i.e., the inverse of the spectral gap) for this chain is O(n3). Here, we use a method based on distinguished paths to prove an O(n2) bound for the relaxation time, establishing a conjecture of Aldous. © 2002 John Wiley & Sons, Inc. Random Struct. Alg., 20, 59–70, 2002