bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uptake, translocation and bioavailability of imidacloprid in several hop varieties
Authors: Weichel Lars , Nauen Ralf 
Published: April 2004

AbstractThe neonicotinoid insecticide imidacloprid is the most important insecticide in hop cultivation in Germany. A laboratory study was undertaken to investigate its systemic properties and translaminar bioavailability in hop leaves. Radiolabelled [methylene‐14C]imidacloprid was applied either alone or in combination with different additives onto leaves of several hop varieties. Uptake and translocation were evaluated 1 and 7 days after foliar application under greenhouse conditions. The uptake of imidacloprid into hop leaves was most pronounced in the first 24 h after application and only negligible amounts were taken up after this period. Significant differences in the quantitative uptake occurred when imidacloprid was combined with additives, such as Amulsol, Genapol C‐100, Hasten and LI 700. The uptake of imidacloprid applied without additives was less than 10% 7 days after application, whereas the combination with LI 700 provided 70–80% uptake. Genapol C‐100 and Amulsol induced considerable phytotoxicity at the application site. Comparing hop varieties revealed differences up to twofold in foliar penetration of imidacloprid. The translaminar and acropetal bioavailability of imidacloprid foliarly applied to hop leaves was determined by a laboratory bioassay using the damson hop aphid, Phorodon humuli (Schrank). Significantly higher mortality was observed with laboratory formulations containing imidacloprid and the additive LI700. In contrast to these results from systemic tests, contact mortality at the application site was constantly high over the testing period of 7 days, highlighting the importance of this mode of entry for aphid intoxication. Copyright © 2003 Society of Chemical Industry
Molluscicidal activity of vulgarone B against ram's horn snail (Planorbella trivolvis)
Authors: Meepagala Kumudini M , Sturtz George , Mischke Charles C , Wise David , Duke Stephen O 
Published: April 2004

AbstractThe ram's horn snail (Planorbella trivolvis (Say)) is an intermediate host for a digenetic trematode (Bolbophorus confusus (Krause) Dubois) that has recently been discovered to be a significant problem in commercial channel catfish (Ictalurus punctatus Raf) production ponds in the Mississippi Delta region in the USA. In these catfish ponds, the digenetic life cycle of this parasitic trematode involves two intermediate hosts, the ram's horn snail and the channel catfish, and the final host, the American white pelican (Pelecanus erythrorhynchos Gmelin). One approach to eradicate this problem is to disrupt the life cycle of the parasitic trematodes by eliminating the snails. During our search for natural‐product‐based molluscicides to control the snails in the catfish ponds, vulgarone B, isolated from the steam distillate of the aerial parts of the plant Artemisia douglasiana Besser (Asteraceae), was found to be active towards the snails with a LC50 of ca 24 µM. Channel catfish toxicity studies indicated a LC50 of ca 207 µM. Vulgarone B may be an environmentally acceptable alternative for snail control in aquaculture. Copyright © 2004 Society of Chemical Industry
Genes similar to naphthalene dioxygenase genes in trifluralin‐degrading bacteria
Authors: Bellinaso Maria De L , Henriques João AP , Gaylarde Christine C , Greer Charles W 
Published: April 2004

AbstractTrifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) is a dinitroaniline compound which was first produced in the 1960s and has been used extensively as an agricultural herbicide. There are a few publications on the biodegradation of this xenobiotic compound, but to our knowledge nothing has been documented on the genetic aspects of its catabolism. In this article, we report the analysis of DNA isolated from bacteria previously shown to degrade trifluralin, using as probes the catabolic genes ndoB, todC, xyIX, catA and xyIE which encode the enzymes naphthalene 1,2‐dioxygenase, toluene dioxygenase, toluate 1,2‐dioxygenase, catechol 1,2‐dioxygenase and catechol 2,3‐dioxygenase respectively. Using PCR and hybridization analysis, the strong hybridization of the ndoB gene with DNA extracted from four trifluralin‐degrading isolates was demonstrated, although none of them was able to degrade naphthalene, as indicated by the ‘clear zone’ test. The results indicated the presence in these bacteria of a dioxygenase gene, whose product could act on trifluralin as its principal substrate, or fortuitously, by cometabolism. This is the first publication on genes in trifluralin‐degrading bacteria. Copyright © 2003 Society of Chemical Industry
Novel 3,3a,5,9b‐tetrahydro‐2H‐furo[3,2‐c][2] benzopyran derivatives: synthesis of chiral glycol benzyl ether herbicides
Authors: Kakimoto Takeshi , Koizumi Fumiaki , Hirase Kangetsu , Banba Shinichi , Tanaka Eishi , Arai Kiyoshi 
Published: April 2004

AbstractNovel tricyclic 3,3a,5,9b‐tetrahydro‐2H‐furo[3,2‐c][2]benzopyran (TFB) derivatives were synthesized, and their herbicidal activities were elucidated. They were synthesized from D‐glucose as a natural chiral source. The formation of the TFB skeleton was achieved by a Friedel–Crafts type intramolecular cyclization of methyl 5‐deoxy‐2,3‐O‐dibenzyl‐5‐C‐methyl‐D‐xylofranosides. The intramolecular cyclization was dependent upon the electronic effects of the substituents at the C‐2 benzyloxy group of methyl xylofranosides. Some TFBs exhibited a remarkable herbicidal activity to annual paddy weeds, such as Echinochloa sp, without injury to the rice. Copyright © 2004 Society of Chemical Industry
Transport and distribution of lindane and simazine in a riverine environment: measurements in bed sediments and modelling
Authors: Allan Ian J , House William A , Parker Andrew , Carter Joy E 
Published: April 2004

AbstractAquatic sediments often remove hydrophobic contaminants from fresh waters. The subsequent distribution and concentration of contaminants in bed sediments determines their effect on benthic organisms and the risk of re‐entry into the water and/or leaching to groundwater. This study examines the transport of simazine and lindane in aquatic bed sediments with the aim of understanding the processes that determine their depth distribution. Experiments in flume channels (water flow of 10 cm s−1) determined the persistence of the compounds in the absence of sediment with (a) de‐ionised water and (b) a solution that had been in contact with river sediment. In further experiments with river bed sediments in light and dark conditions, measurements were made of the concentration of the compounds in the overlying water and the development of bacterial/algal biofilms and bioturbation activity. At the end of the experiments, concentrations in sediments and associated pore waters were determined in sections of the sediment at 1 mm resolution down to 5 mm and then at 10 mm resolution to 50 mm depth and these distributions analysed using a sorption–diffusion–degradation model. The fine resolution in the depth profile permitted the detection of a maximum in the concentration of the compounds in the pore water near the surface, whereas concentrations in the sediment increased to a maximum at the surface itself. Experimental distribution coefficients determined from the pore water and sediment concentrations indicated a gradient with depth that was partly explained by an increase in organic matter content and specific surface area of the solids near the interface. The modelling showed that degradation of lindane within the sediment was necessary to explain the concentration profiles, with the optimum agreement between the measured and theoretical profiles obtained with differential degradation in the oxic and anoxic zones. The compounds penetrated to a depth of 40–50 mm over a period of 42 days. Copyright © 2004 Society of Chemical Industry
Structure–antiviral activity relationships of cecropin A‐magainin 2 hybrid peptide and its analogues
Authors: Lee Dong Gun , Park Yoonkyung , Jin Ingnyol , Hahm Kyung‐Soo , Lee Hyang‐Hee , Moon Young‐Hee , Woo Eun‐Rhan 
Published: April 2004

AbstractIn order to elucidate the structure–antiviral activity relationship of cecropin A (1–8)‐magainin 2 (1–12) (termed CA‐MA) hybrid peptide, several analogues with amino acid substitutions were synthesized. In a previous study, it was shown that serine at position 16 in CA‐MA hybrid peptide was very important for antimicrobial activity. Analogues were designed to increase the hydrophobic property by substituting a hydrophobic amino acid residue (S→A, V, F or W, position 16) in the CA‐MA hybrid peptide. In this study, the structure–antiviral activity relationships of CA‐MA and its analogues were investigated. In particular, substitution of Ser with a hydrophobic amino acid, Val, Phe or Trp at position 16 caused a dramatic increase in the virus–cell fusion inhibitory activity. These results suggested that the hydrophobicity at position 16 in the hydrophobic region of CA‐MA is important for potent antiviral activity. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Antinematodal effect of antimicrobial peptide, PMAP‐23, isolated from porcine myeloid against Caenorhabditis elegans
Authors: Park Yoonkyung , Jang Seung‐Hwan , Lee Dong Gun , Hahm Kyung‐Soo 
Published: April 2004

AbstractThe antinematodal activity and mechanism of a 23‐mer antimicrobial peptide, PMAP‐23, derived from pig myeloid was investigated. PMAP‐23 displayed a strong antinematodal activity against the eggs and worms of Caenorhabditis elegans. To investigate the antinematodal mechanism of PMAP‐23, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed. C. elegans treated with PMAP‐23 showed higher fluorescence intensity by propidium iodide (PI) staining than normal cells. Confocal microscopy showed that the peptide was localized in the egg's shell and cell membrane. The action of the peptide against C. elegans membranes was examined by testing the membrane disrupting activity using liposome (PC/PS; 3:1, w/w). The result suggests that PMAP‐23 may exert its antinematodal activity by disrupting the structure of the cell membrane via pore formation or via direct interaction with the lipid bilayers. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Synthetic human insulin 4 does not activate the G‐protein‐coupled receptors LGR7 or LGR8
Authors: Lin Feng , Otvos Laszlo , Kumagai Jin , Tregear Geoffrey W. , Bathgate Ross A. D. , Wade John D. 
Published: April 2004

AbstractIn contrast to the cellular receptors for insulin and insulin‐like growth factors that are known to be protein tyrosine kinases, those of both insulin 3 and relaxin have recently been identified as being members of the leucine‐rich repeat‐containing G‐protein coupled receptor (LGR) family, LGR8 and LGR7, respectively. This has prompted an examination into the possibility that they might also be specific for another member of the insulin superfamily, namely, insulin 4. Towards this aim, a two‐chain peptide corresponding to the predicted primary structure of insulin 4 was prepared by solid phase synthesis. As conventional aeration and combination of the two S‐reduced chains in solution at high pH failed to produce target product, selectively S‐protected A‐ and B‐chains were prepared followed by stepwise, individual formation of each of the three disulfides, one intramolecular within the A‐chain and two intermolecular. Chemical characterization confirmed the purity and identity of the synthetic insulin 4 analogue. However, secondary structural analysis indicated that the peptide was devoid of tertiary conformation suggesting that the native peptide may well be either significantly longer in length or is similar to insulin‐like growth factor I or II in that it is a single chain product. Screening of the synthetic analogue for activation of transfected cells bearing LGR7, and LGR7 splice variant or LGR8 failed to identify a specific interaction. Thus, the in vivo structural identity of insulin 4 and its receptor (if any) as well as its potential function remains unknown. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
New analogues of laminin active fragment YIGSR: synthesis and biological activity in vitro and in vivo
Authors: Witkowska Ewa , Orłowska Alicja , Izdebski Jan , Salwa Jan , Wietrzyk Joanna , Opolski Adam 
Published: April 2004

AbstractEleven analogues of the laminin pentapeptide amide fragment Tyr‐Ile‐Gly‐Ser‐Arg‐NH2 (YIGSR‐NH2) corresponding to a B1 chain fragment of the glycoprotein laminin have been synthesized by the solid phase method, and their biological activity has been studied in vitro by a cell adhesion assay: all of them inhibited the adhesion of LLC tumor cells to laminin. The analogues were found to be more resistant to enzymatic degradation in human serum than YIGSR‐NH2 itself. Analogue DatIGSHar‐NH2 was selected for an experimental pulmonary metastasis assay in vivo: it had higher antimetastatic activity than YIGSR‐NH2. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Energy‐level diagrams of high‐spin and low‐spin molecules
Authors: De Raedt H. , Miyashita S. , Michielsen K. 
Published: April 2004

AbstractThe magnetic energy‐level diagrams for models of the Mn12 and V15 molecule are calculated using the Lanczos method with full orthogonalization and a Chebyshev‐polynomial‐based projector method. The effects of the Dzyaloshinskii‐Moriya interaction on the appearance of energy‐level repulsions and its relevance to the observation of steps in the time‐dependent magnetization data are studied. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum dynamics of atomic magnets
Authors: Barbara B. , Giraud R. , Tkachuk A. M. 
Published: April 2004

AbstractAfter the first evidence for tunneling of the total angular momentum of Ho3+ in YLiF4 (insulating), where electronic and nuclear moments tunnel simultaneously (two‐body entanglement), we show that pairs of Ho3+ ions also tunnel simultaneously (four‐body entanglement). Such co‐tunneling transitions, mediated by weak dipolar interactions, are discussed in terms of a four‐spin representation including the rare‐earth nuclear spin. This study of the entanglement of pairs of distant Ho3+ ions constitutes a first step to elucidate many‐body quantum‐spin relaxation. Finally, implications on the feasibility of two‐spin qubits are discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Normal state properties of BEDT compounds
Authors: Joo N. , Meddeb D. , Charfi‐Kaddour S. , Bennaceur R. , Héritier M. 
Published: April 2004

AbstractThe κ‐(BEDT‐TTF)2X organic superconductors are described by a two parameter 2D surface model, in which bandwidth and departure from perfect nesting can be varied. We have studied the spin fluctuation effect on the normal state properties in a Fermi liquid approach using the RPA approximation. The calculated NMR relaxation rate exhibits a peak in 1/(T1T), which strongly decreases when the departure from the perfect nesting of the Fermi surface and the bandwidth decrease. Our calculations show also that the spin fluctuations induce an unusual resistivity temperature dependence. These results are in a good agreement with experimental data done in κ‐(BEDT‐TTF)2X, at least qualitatively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of magnetic field on the cuprate high‐Tc superconductor La2–xSrxCuO4
Authors: Lake B. , Aeppli G. , Christensen N. B. , Lefmann K. , McMorrow D. F. , Clausen K. N. , Rønnow H. M. , Vordewisch P. , Smeibidl P. , Mankorntong M. , Sasagawa T. , Nohara M. , Takagi H. , Hussey N. E. 
Published: April 2004

AbstractThis article discusses neutron scattering measurements on the cuprate, high transition temperature superconductor La2–xSrxCuO4 (LSCO) in an applied magnetic field. LSCO is a type‐II superconductor and magnetic flux can penetrate the material via the formation of vorticies. Phase coherent superconductivity characterized by zero resistance is suppressed to the lower field‐dependent irreversibility temperature (Tirr(H)) and occurs when the vortices freeze into a lattice. Because superconductivity is destroyed within the vortex cores, an investigation of the vortex state provides information about the ground state that would have appeared had superconductivity not intervened. Our measurements reveal that both optimally doped LSCO (x = 0.16, Tc = 38.5 K) and underdoped LSCO (x = 0.10, Tc = 29 K) have an enhanced antiferromagnetic response in a field. Measurements of the optimally doped system for H = 7.5 T show that inelastic sub‐gap spin fluctuations first disappear with the loss of finite resistivity at Tirr, but then reappear at a lower temperature with increased lifetime and correlation length compared to the normal state. In the underdoped system elastic antiferromagnetism develops below Tc in zero field, and is significantly enhanced by application of a magnetic field; phase coherent superconductivity is then established within the antiferromagnetic phase at Tirr. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic resonant excitations in High‐Tc superconductors
Authors: Sidis Y. , Pailhès S. , Keimer B. , Bourges P. , Ulrich C. , Regnault L. P. 
Published: April 2004

AbstractThe observation of an unusual spin resonant excitation in the superconducting state of various High‐Tc copper oxides by inelastic neutron scattering measurements is reviewed. This magnetic mode is discussed in light of a few theoretical models and likely corresponds to a spin‐1 collective mode. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ba@Pr or Pr@Ba in R123 HTSC – To be or not to be SC
Authors: Akhavan M. 
Published: April 2004

AbstractIn spite of the vast amount of experimental and theoretical knowledge accumulated in HTSC, the nature of the interaction driving charge carriers to form Cooper pairs below Tc is still unknown. To elucidate the controversial insulating/SC Pr123, the substitution of Pr at Ba site (Pr@Ba) with Ba at Pr site (Ba@Pr) in R123 is compared and reviewed. This might shed some light on the microscopic origin of HTSC. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐parameter scaling of the Hall effect in manganites
Authors: Ziese M. 
Published: April 2004

AbstractThe Hall effect, magnetoresistance and magnetization of La0.7A0.3MnO3 (A = Ca, Ba) films were measured. A scaling of the Hall resistivity with the magnitude and direction of the magnetization was observed. The scaling relation was derived within the classical side‐jump model taking the double‐exchange interaction into account. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculation of excited‐state ionization potential for boron‐like sequence
Authors: Zheng Neng Wu , Wang Tao 
Published: April 2004

AbstractExcited‐state ionization potentials for boron‐like sequence with Z = 5–19 are studied systematically, using the weakest bound electron potential model theory (WBEPM theory) and iso‐spectrum‐level series conception. Nonrelativistic ionization energy is derived from the theory. Relativistic effects are included in the Breit–Pauli approximation. Comparison of the calculated excited‐state ionization potential with available experimental data is carried out for 1s22s22p 2P, 1s22s23s 2S1/2, 1 s22s23p 2P, 1s22s23d 2D5/2, 1s22s24d 2D5/2, 1s22s25d 2D5/2, and 1s22s26d 2D5/2 series. The present results depart from experimental results by no more than 0.133 eV for all 81 results for which experimental data are available. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Validated procedure for simultaneous trace level determination of the anti‐cancer agent gemcitabine and its metabolite in human urine by high‐performance liquid chromatography with tandem mass spectrometry
Authors: Sottani Cristina , Zucchetti Massimo , Zaffaroni Marco , Bettinelli Maurizio , Minoia Claudio 
Published: April 2004

AbstractA sensitive, accurate and reproducible procedure has been developed for the quantitative determination of gemcitabine (2′,2′‐difluorodeoxycytidine, dFdC) and its metabolite 2′,2′‐difluorodeoxyuridine (2dFdU) in human urine. The samples (2 mL) were extracted by solid‐phase extraction (SPE) and analyzed by reversed‐phase high‐performance liquid chromatography coupled with tandem mass spectrometry (HPLC/MS/MS), operating in multiple reaction monitoring (MRM mode). This procedure was validated using 2′‐deoxycytidine as internal standard (IS). The urine assay was linear over the range 0–50 μg/L, with a limit of quantification (LLOQ) of 0.2 μg/L for gemcitabine and 1.0 μg/L for the metabolite. The respective limits of detection (LODs) for dFdC and 2dFdU were 0.05 and 0.3 μg/L. The precision and accuracy of the assay were determined on three different days. The within‐series precision was found to be always less than 8.5 and 12.7% for gemcitabine and 2dFdU, respectively. The overall precision expressed as relative standard deviation (CVr) was always less than 7.1% for both analytes. The recovery of gemcitabine was always greater than 90% with a CVr <6.3%. The measurement uncertainty determined from the validation data assessed the possibility of determining this drug and its metabolite at trace levels in urine, considering that the combined uncertainty of the whole procedure was always less than 30%. Copyright © 2004 John Wiley & Sons, Ltd.
Use of isotopically labelled octanoic acid to assess the effect of meal size on gastric emptying
Authors: Jackson Sarah J. , Bluck Leslie J. C. , Coward W. Andrew 
Published: April 2004

AbstractIt has been proposed that the 13C‐octanoic acid breath test (OBT) provides a safe, non‐radioactive means of measuring gastric emptying. However, deuterated octanoic acid provides a better marker when compared with scintigraphy, as the kinetics are less complex than those of the 13C label. The appearance of 2H in saliva is modelled as a two‐compartment body water system, using an asymmetric triangular gastric emptying function. This study compared the 2H‐octanoic acid saliva test (OST) with the OBT in measuring altered states of gastric emptying in the nutritional context of diet manipulation. Gastric emptying was measured using the OST and OBT in a three‐way crossover study involving 12 healthy male and female subjects (mean BMI = 23.4 kg/m2, aged 24–57 years). Following an overnight fast, subjects were given an egg meal, labelled with 10 μL/kg body weight 2H‐octanoic acid and 100 μL 13C‐octanoic acid. The meal was nutritionally manipulated to provide a 1 MJ, 2 MJ or 3 MJ meal. Breath and saliva samples were collected at regular intervals for 6 h, with further saliva samples being collected over four subsequent days. 2H isotopic enrichment in saliva and 13C isotopic enrichment in breath were analysed using isotope ratio mass spectrometry and the data fitted to the respective gastric emptying models. The half excretion time (T1/2D), time to maximum emptying rate (T1D) and time when emptying is complete (T2D) were calculated from the 2H saliva test data, and the lag time (TlagC), half excretion time (T1/2C), latency phase (TlatC) and ascension time (TascC) were calculated from the 13C breath test data. Overall, the OBT correlated well with the OST, with a significant relationship between T1/2C and T1/2D, a significant relationship between TlatC and T1D and finally a significant relationship between TascC and T2D. Gastric emptying measured using the OST was significantly faster with the 1 MJ meal (ΔT1/2D = −0.77 h vs. 2 MJ, p = 0.004). Increases were also seen when the meal size was increased from 2 MJ to 3 MJ (ΔT1/2D = +0.44 h vs. 2 MJ), but these were not significant. These trends were mirrored in the OBT data, with significant differences between 1 MJ and 2 MJ (ΔT1/2C = −0.63 h vs. 2 MJ, p = 0.013) and non‐significant increases with the larger 3 MJ meal (ΔT1/2C = +0.10 h vs. 2 MJ). Total meal calorie content was shown to have an effect on gastric emptying using both the OBT and the OST. The deuterium method allows the direct calculation of the gastric emptying function and could be used as an alternative to gamma scintigraphy, allowing further validation of the 13C‐octanoic acid breath test. Copyright © 2004 John Wiley & Sons, Ltd.